HONING THE CYLINDERS

Following a recommendation from our buddies at Sunnen, we visited Gressman at Gressman Powersports in Fremont, Ohio (Gressman has built a number of 632 motors, in addition to countless big-number drag, sprint car and road-race engines). Naturally, the Ohio winter weather forced us to drive in sub-zero temperatures. Even with the block boxed and wrapped in the bed of my dually truck, it looked like a gray Popsicle when we arrived at Gressman’s (it may have been cryo treated as a result of the two-hour drive … just kidding … sort of), so we allowed the block to warm up for a while before we began messing with it.
With the block at room temperature, we measured the Dart block’s bores, noting a raw diameter of 4.590″ (Dart leaves enough material to allow the builder to obtain desired diameter). Since our Diamond pistons measured 4.59375″, we needed to remove a total of 0.01075″ in order to achieve the desired 0.007″ clearance.
After confirming that our main caps were snugged to 100 ft-lbs, Gressman mounted a pair of BHJ deck plates (tightening these to 70 ft-lbs).
Before honing, Gressman used a hand grinder to knock a bit of material from the webbing surfaces below the center three cylinder areas where the bores Siamese (small humps are featured in the casting) to prevent damage to his honing stones. This took only about 10 seconds per spot, so it was no big deal.
He then began honing with 500-grit diamond stones with a high load setting to hog out the bores to an initial 4.599″, followed by a final honing pass to remove the remaining 0.00175″. All cylinders were then treated to four passes with silicon carbide brushes at 30 percent load for a plateau finish. Because of the amount of material removed from the start, the entire honing process took about an hour and a half. Gressman noted that the high-quality Dart blocks feature a high nickel content (he mentioned that these blocks are about 30 percent harder than “common” iron blocks), which requires increased honing time as compared to most OE blocks.
By the way, Gressman recently purchased an RMC/Sunnen V40 multi-axis CNC machine, which the shop uses for a variety of operations, including block clearancing, cylinder boring, lifter bore correction, and block lightening (for race applications). I wish that we had the luxury of time to take advantage of a block lightening job (if for no other reason than to make the block look even cooler), but we were on a tight deadline, so I left without having a chance to see the CNC in action.
By the way, Gressman’s shop was a thing of beauty. We definitely plan to revisit in the future. This is a very nice operation and clean as a whistle.

Our pistons began life as high-density slugs.

Domes were cut flat and pin bores were roughed in at the beginning of the transformation.

A view of the unfinished pin boss area.

The outer body was machined to desired diameter and the rind grooves were cut. Notice the big chamfer cut on the top. As you can see, quite a bit of material will be removed during the machining process.

The skirts were shortened and the domes were cut to height, along with the valve pockets. Notice the huge hunk of aluminum that was removed at the pin bore sides, to remove unneeded weight.

Gas porting holes were drilled along the perimeter of the top.

The underside was finish-machined for additional weight savings.

Skirt diameter was verified for each piston before shipment.

That’s a bunch of pistons. Diamond has earned a solid reputation for quality.

Closeup view of a piston underside.

A view of a finished piston as we received it. While weight was shaved everywhere possible, no compromises in strength were made.

This view shows the deep weight-saving relief at the pin bore side.

The pin bores were polished with a mirror-like finish and pins were carefully fitted at Diamond’s facility. Note the deep location for the spiralock grooves.

Gas ports will aid in top ring stability and sealing.

PROJECT 632, PART 2

We hone the block and determine bottom-end clearances.

by Mike Mavrigian

photos by author

With our new pistons in hand, it was now time to hone the cylinders to size.
As you may recall from our previous article, our target is to build an all-motor 632 cubic-inch big block featuring 15:1 compression, enabling us to produce approximately 1,200 HP in the mid-7,000 RPM range.
Now that our pistons have arrived, we were able to hone the cylinders to final size. We’ve also measured critical clearances for bearings, crank-to-block, rod-to-block and rod-to-cam.
In the third installment of this multi-part series, we’ll paint the block, balance the rotating assembly and begin our test assembly for final fitting.

PISTONS

As mentioned in Part 1, we enlisted Diamond to make our custom pistons. Well, the little buggers arrived, and they’re gorgeous. Did I say little? At a measured 4.5937″, they’re ‘ huge. If these billet beauties were adult human females, I’d ask them out on dates. Yeah, they’re that pretty. If we had room in the magazine, I’d shoot two-page spread photo of these parts.
Okay, maybe that was a bit over the top, but you can’t blame a guy for getting excited. When I think about how these puppies are going to squeeze against the Dart Big Chief 2 chambers, I can’t help getting all giddy with anticipation.
The pistons began as high-density forgings (DRP76X), and were CNC machined to the finished state. The custom dome features a dish, along with valve reliefs for both intake and exhaust valves. The intake valve depth is 0.270″, while the exhaust valve depth is 0.064″. Total dome volume is -21.1cc. Combined with a compression height of 1.120″, 0.005″ deck clearance, our Victor MLS gaskets and the 56cc combustion chambers, this should give us a tidy 15:1 compression ratio.
Features of these pistons include the use of their P/N 9310 piston pins (0.990″D x 2.930″L x 0.165″ wall), gas porting along the dome perimeter (these ports will aid in ring seating and eliminate flutter), and a serious weight-savings via their internal mill “Maxi-Lite” machining.
Because of the extremely compact ring groove layout, the pin bore encroaches through the oil ring groove. In order to provide a “floor” for the oil ring package, Diamond included a pack of its oil ring support rails that features a 0.188″ wall. These will provide bottom support for the oil ring in the pin bore passage areas. The pins are full-floaters, and are designed to be secured via Spirolox retaining rings (0.990″ x 0.043″).
Diamond noted that the installed wall clearance for these pistons should be 0.0070″. It specifies that piston diameter must be measured 90 degrees to the pin bore, at a distance of 0.700″ down from the oil land.

CRANK FIT

We first verify-measured our main bearing bores, which mic’d out at 2.9375″.
We mock-installed the steel Lunati 4.750″ stroker crank (P/N BS-421 MN) using our Clevite Tri-Armor main bearings #MS-829 HXK, tightening the main cap bolts to a value of 100 ft-lbs (with moly on threads and bolt underheads). Installed main bearing diameters measured at 2.7535″. Our crank main journals mic’d at 2.7495″, providing us with main bearing clearance at 0.004″. According to Scott Gressman at Gressman Powersports, this build requires bearing clearances on the “loose” side. Crank endplay measured 0.008″.
One obvious concern, given the 4.750″ stroke of this crank, was counterweight-to-block clearance. Happily, we had gobs of clearance, with the tightest spots at about a healthy 1/4″. This required us to do nothing but grin in terms of counterweight clearance. The boys at Dart obviously gave some thought to boneheads like us using a long stroke and machined the block accordingly.

BEARING & CYLINDER DIMENSIONS

MAIN BORE BEARING DIAMETER — 2.753″
MAIN JOURNAL DIAMETER — 2.749″
MAIN BEARING CLEARANCE —0.004″
ROD BEARING DIAMETER —2.20325″
ROD JOURNAL DIAMETER —2.200″
ROD BEARING CLEARANCE — 0.00325″
(rod bolt stretch should be —0.005-0.0055″)
PISTON DIAMETER —4.59375″
FINISHED BORE DIAMETER —4.60075″
PISTON-TO-WALL CLEARANCE —0.007″
CRANKSHAFT ENDPLAY —0.008″
CONNECTING ROD SIDEPLAY —0.0020″

ROD FIT

Using our Clevite Tri-Armor rod bearings, part #CB-743 HXK, we test-assembled all of our Lunati Pro Mod steel rods (with pistons in place), tightening the ARP 200 7/16″ rod bolts to a stretch value of 0.005″ to 0.0055″ (70 ft-lbs with moly if torqued). With our installed rod bearing diameter at 2.20325″ and our rod journals at 2.200″, we obtained oil clearance at 0.00325″. Rod sideplay was measured at 0.0020″ at all rod journal locations.
While checking for rod big-end to block clearance, we noted adequate clearance with the tightest at about 0.050″, but we’ll likely kiss the block in a few spots just for safety’s sake.
When we mocked-up a piston/rod assembly onto the crank and rotated, we noticed a portion of the rod big end encroaching into the cam tunnel. The radius hump on the upper portion of the big end needs to be reduced slightly (maybe 0.020″ or so) to ensure camshaft clearance. Considering the 4.750″ stroke, this didn’t come as a big surprise. We’ll relieve this small hump (the hump opposite from the bearing tang side) and re-balance the rods. You’ll see this in the next issue.

DIAMOND CUSTOM PISTON DATA

Finished bore size —4.600″
Stroke — 4.750″
Rod length —6.700″
Block deck height —10.200″
Piston to deck —0.005″
Compression height —1.120″
Cyl. bore length —6.350″
Piston type —conical dish
Piston material — 2618
Valve depth —INT 0.270″
—EXH 0.064″
Effective dome volume —  -21.1 cc
Piston weight —542 grams
Required bore clearance —0.007″
(measured 90 degrees to the pin hole, at 0.700″ below oil land)

Engine type —BBC
Application —Drag race
Desired comp. ratio —15.00:1
Cylinder head —Dart Big Chief 2
Chamber volume —56.0 cc
Comp. gasket —0.045″
Gasket bore dia. —4.640″
Gasket volume —12.47 cc
Top land —0.285″

VALVE POCKET INFO
Int. depth —0.270″
Int. valve dia —2.470″
Exh. depth —0.064″
Exh. valve dia — 1.800″
Int. angle —11 deg.

ROD INFO
Lunati steel I-beam Pro Mod P/N LB01
Rod length —6.700″
Small end width — 1.133″
Thickness above pin —0.210″
Material steel

SKIRT SHAPE window type full roundDart CNC machined the block so all critical bore locations and sizes were already correct and to-size. Only the bores remained to be honed for proper piston clearance.

Dart CNC machined the block so all critical bore locations and sizes were already correct and to-size. Only the bores remained to be honed for proper piston clearance.

The initial bore diameters, as delivered from Dart, measured 4.590″.

Our billet pistons from Diamond were custom-made specifically for our combination of the 10.2″ deck block, 6.700″ rods, Big Chief 2 11-degree heads and 4.750″ stroker crank.

Diamond’s pistons are things of beauty, in addition to having the inherent quality that Diamond is known for. Our dome volume is -21.1cc. In combination with our block height, rod length and combustion chamber size, we should realize 15:1 compression ratio.

Our custom piston spec sheet. We carefully went through each item with Diamond’s Eric Simone, who was extremely helpful and knowledgeable.

• “Bling Bling:” So a customer has a new Denali or Escalade with some “Dubs,” (rims for the old folks), and wants the speedometer to display the correct speed. The customer also notices he or she doesn’t have the power the truck had before he or she put those 26″ dubs on!
So how about getting that speedometer corrected and getting that power back? Crane’s new Power Tuner can add up to 30 HP and 35 ft. lbs. of TQ at the rear wheels (for the gasoline engines). The Power Tuner will take care of any tire size change from 25″-44″, gear ratio change from 2.73-5.13, cam changes, adding a Supercharger, how firm a shift you would like, adjust tuning for the fuel you use, changing or eliminating the speed limiter, and even clearing trouble codes. Look on Crane’s Web site and find applications for the new Power Tuner by visiting the following link: http://cranecams.com/?show=newProduct&id=2.

• Valve Stem Diameter: A number of the aftermarket big-block Chevrolet 396-454 V-8 cylinder heads currently being sold are equipped with 11/32″ diameter valve stems instead of the stock 3/8″ stems. When ordering valve spring retainers and valve stem locks (”split keys”) for these applications, be sure to check the valve stem diameter in order to achieve proper fit the first time.

• The Harley-Davidson Twin Cam 88: The Harley-Davidson Twin Cam 88 engine has no provision for changing cam timing. Crane Cams has solved that problem with a reversible crank sprocket, Part # 7-3000. This crank sprocket will allow you to advance the engine’s cam timing by four degrees for more bottom-end torque and acceleration, reverse it to the four-degree retard position for more top-end power, or decrease cylinder pressure if a detonation problem occurs.

• Truing Lifter Bores: One of the more popular steps in preparing a big-block Chevrolet 396-454 V-8 engine for racing (or street performance) involves truing the lifter bores to ensure their proper bank angles and squareness.
Once the block has been machined, the lifter bores are often bushed back to their standard (0.842″) diameter. As it isn’t common to remove more than a few thousandths during the truing process to bring the lifter bores into spec, it is possible to save time (and money) by boring the block to use either Crane’s 0.875″ or 0.904″ diameter roller lifters and not have to bush the bores.
These Ultra-Pro series rollers are offered in both centered and offset intake pushrod seat versions and provide the latest technology available in Crane’s roller lifter program. The 0.904″ versions also feature their 0.815″ diameter wheel/axle/bearing assembly which provides significant increases in strength and durability as compared with the usual size 0.750″ assemblies.

• Special Grind Cams: Special grind cams are a great options Crane offers. The company can change durations/lift/lobe separations and centerlines, etc. This is perfect for the racer who always must have the edge on the track. Because this special grind is made for a specific customer, that combination may not work for someone else. That’s why these special grind cams are a non-returnable item. For that reason, Crane wants to make sure that what you are asking for is exactly what you want.

• Matching Coil and Ignition: If you’re building a custom Harley-Davidson make sure you match your coil with the ignition you’re using. If you’re trying to build a nostalgia bike and are using a kicker or points, that would require a 5-ohm coil. Later year Shovelhead or Evolution engines with electronic ignitions take a 3-ohm coil, and if you’re going all out with the new Twin Cam 88 engine for a custom bike, that would require a special coil which has only 5-ohm resistance.

• Let The Air Out: The Gen 4 big-block Chevy must have the front lifter oil galley plugs modified by removing them and drilling a 0.030″  hole in the center of the plug before reinstalling them. This hole will bleed off any air lock in the front of the lifter galley oil passages. This air lock can cause the front lifters on each side to get air in the lifter, starve the oil to the rocker arm and, of course, make noise because the lifter will not pump up.
GM started drilling the plugs in the late 1970s, early ’80s and produces a change bulletin to modify any older engines that were being rebuilt or that had dry lifters in the front of the engine. Also, the oil that then comes out of these holes will also lube the timing chain and gears as a bonus.

• Valve Lash: On Ford 1971-74 2000cc I4 camshafts and Ford 1974-87 2300cc I4 engines equipped with mechanical followers, the valve lash is measured between the camshaft and the follower, not the follower and the valve stem. Measuring incorrectly can result in incorrect valve timing and a probable reduction in performance and reliability.

• Chevy 60 Degree V-6 Camshafts: The Chevrolet 60 degree V-6 camshafts listed in Crane’s current catalog are for distributor equipped engines only. In 1991 and later applications, some vehicles used a version of this engine that was distributorless. In these instances, these camshafts will not install and function properly. However, Crane can regrind distributorless type camshafts to their specifications. Please contact Crane’s Tech Department at (386) 258-6174 for more information.

• GM’s Gear Marking Compound: General Motors sells a compound to aid the inspection of the gear mating. It is GM “Gear Marking Compound,” Part #1052351, and is available at GM dealerships. This compound can be used in many applications, such as inspecting a ring and pinion gear or mating the cam distributor drive gear. To use it to check a distributor, the compound must be brushed all the way around the distributor drive gear. Then, install the distributor into the engine using whatever gasket and hold-down device you plan on running. Tighten the distributor in place. Use your hand to hold the distributor rotor to provide some resistance to the rotation of the distributor (this is to simulate the load on the distributor drive gears). Now, hand turn the engine over at least two full turns of the crankshaft. (Remember, it takes two crankshaft revolutions to generate one camshaft revolution.) Then carefully remove the distributor and inspect the wear pattern marked on the compound.
You may find that the distributor location might need to be spaced up or down to move the wear pattern as close to the center of the distributor gear as possible. (Some distributors have adjustable hold-down collars to assist in this adjustment.) Next, you want to see how the teeth are mating to determine whether the gear lash is too tight or too loose. In certain cases, there are oversized distributor gears available that can be used to assist in the gear lash adjustment.

• Installing Reground Cams and Lash Caps on 4.6L-5.4L Fords: You must measure the amount of clearance between the roller rocker arm and the base circle of the cam. This will ensure that you have the correct clearance for your reground cams.
When the cams are reground, the size of the base circle is reduced, which means you will have to run lash caps to make up the difference. Since you have changed the size of the cam, you will want to make sure you have the same clearances as before. To do this, compress the lifter until it is solid and then install the rocker arm and cam. You are looking to get between 0.018″-0.032″ of clearance between the roller rocker arm and the base circle of the cam. This will ensure that the rocker will stay in place while the engine is being assembled.
If you have a clearance larger than 0.032″, you will need to put a shim under the lifter to get your clearances correct.

• Oil Restrictors: Crane doesn’t recommend running oil restrictors because they will starve the top end of a motor. This lack of oil will not prevent the components from being lubricated or cooled by the flow of oil, which is necessary to remove the heat created from pressure and friction. This, in turn, will create excessive wear and shorten the life of the springs, valves, guides, rockers, lifters, etc. On Crane’s Shaft Mount rockers, oil is necessary to the longevity and life of the bearings. So, if you do run oil restrictors, you must open up the restrictors to 0.100″ to ensure that you’re applying enough oil to the rockers.

• Mopar Ultra Pro Roller Lifters: With all of the new Ultra Pro roller lifters that Crane has recently released for Chevrolet and Ford applications, some of the Chrysler-oriented folks are wondering about availability for their engines.
The good news is that Crane actually did all of the development work on the Ultra Pro series in Chrysler applications, especially in the harsh environments of supercharged alcohol and Top Fuel drag racing. Crane first released 8620-bodied lifters for these usages more than 15 years ago and have now upgraded them all to the new Monel pin retained locking bar retention system.
To maintain the identity of these familiar items, we elected not to change their part numbers, but to stay with the current 66542, 66543, 66550, 66554, 66547, 66548, 140550, etc. numbered offerings. The 2005 Crane Master Catalog details all of the numbers by application, and explains the differences between the Standard, Pro Series and Ultra-Pro roller lifters.

• 1963 Ford SHC 427 V-8 Camshafts: As the nostalgia market expands daily, there are many folks looking for camshafts for the 1963 Ford SHC 427 V-8 engines. Original cams (either cast or billet) are tough to come by, but there is another option. Roto Faze Products in Torrance, California (310/325-8844) has produced new round lobe 8620 steel billet camshaft cores for these powerplants and offers them to those fortunate enough to have a Cammer.
Once you obtain the cores, you can forward them to Crane for rough grinding, heat treating and finish grinding to any of our dedicated profiles. As Crane was instrumental in the original aftermarket development of this engine in the racing arena, the company can reproduce any of its original grinds and also offers many new profiles for applications ranging from mild street to all-out drag racing.

• 502 Gen 6 Big-Block Chevy Marine Engine Cam Firing Order: If you’re thinking about replacing the camshaft in a 502 Gen 6 big-block Chevy marine engine and would like to try a different firing order, call Crane Cams and get the part number for your new cam designed for the 8.1L engine. The 8.1L camshaft will fit right into a Gen 6 502, but you will have the new firing order of 1, 8, 7, 2, 6, 5, 4, 3. The cams are interchangeable as long as you install your plug wires to match the firing order you have.

• Changing From Iron to Aluminum Cylinder Heads: When changing to aluminum cylinder heads from your trusty old cast iron pieces, you not only lighten up the engine, but you can also affect the ignition timing requirements.
Even though you might have the same exact static compression ratio as with your old iron heads, the aluminum heads dissipate heat much more effectively, resulting in a similar effect to lowering the compression ratio from 0.5 to 1 full point depending on your overall combination. Therefore, with aluminum heads, you can usually run a higher compression ratio and/or more ignition timing, as the tendency towards detonation will decrease. An aluminum block will also contribute to this effect, though not as significantly. We’ve discussed the valve lash/lifter preload situation with aluminum heads in recent Tech Tips, so refer back to those when setting your valves.

• Oil Drip: To ensure better oiling on your small-block Ford, drill a .030″ (1/32″) hole in the plug above the distributor gear under the timing cover. This will make a fast drip on the distributor gear, which will extend the life of both the gears. This can also help prevent a cutting edge from occurring on the cam gear if you’re running a high-volume oil pump.
• Flat Tappet Going Flat: First of all, the hydraulic or mechanical flat tappet lifters need to rotate in the lifter bore to get an even wear pattern. This will keep the cam and lifters running smoothly. So, setup will be important on a flat tappet cam. Spring pressure can be too high and not allow the lifter(s) to rotate in the bore during break-in. So if you are running dual springs, you will need to remove the inner springs to reduce the pressure on the lifters during break-in. Also, do not run a synthetic type of oil for break-in.
Before the installation of the cam and lifters, do not soak or pump up the hydraulic lifters! This will only make the lifter lock up and cause more problems when setting a pre-load into the lifters. Of course, you will need to apply the assembly lube (Part #99002-1 is 1 oz.) to the cam lobes and lifters. Using break-in lube (#99003-1 is 8 oz.) in the oil is another great precaution to take since oil formulations have changed during the past few years.
On the hydraulic lifters, you will need to set a preload into the lifter between 0.020″-0.060″. If you do not set any preload into the lifter and run it at zero lash, you have now tried to make the hydraulic into a mechanical lifter, which will pump up the hydraulic lifter, again causing a load on the lifter face.
After you have set your pre-load (hydraulic) or lash setting (mechanical), you will need to make sure you prime the engine and get oil up through every rocker arm, even if this takes a half-hour (big-block Chevy). Another precaution to help you during break-in is to take some white-out or paint and put a small stripe on the top of every pushrod. Before you start up the vehicle, use a clear or cut-away valve cover to watch the pushrods. After start up, watch all of those pushrods and make sure they are all spinning. If the pushrods are spinning, the lifters are also spinning, and there should be no problem through the break-in period. Remember to keep your RPMs between 1,500-3,000 and vary the RPM. Do not leave the engine at a set RPM! Varying the RPM will change the oil splash to the lifters. Also make sure your break-in period is no shorter than 20 minutes (and up to 30 minutes).

Crane Cams Tech Support

By Crane Cams Tech & Customer Service Dept.

We managed to glean a host of informative technical tips from the boys at Crane Cams.These tips cover a range of subjects from distributor gear wear to V-Twin motorcycle cams, and we think you’ll find them helpful.
• Distributor Gear Wear: It has come to the attention of Crane’s Tech and Customer Service departments that premature cam distributor gear wear and breakage can occur. The two practices that can cause gear wear are running a high-volume or high-pressure oil pump or reusing an already worn or damaged distributor gear with a new cam (or vice versa). In this case the distributor gear or cam gear has worn into a pattern and may not mesh with the new part. This can cause breakage and/or continue to prematurely wear out the gear.

• “Good” vs. “Rough” Idle: What does “good idle” and “rough idle” actually mean? Compared with what? Smooth and good idle represents a stock or near-stock idle, 600-800 RPM with a high vacuum signal. Rougher idles are higher idle speed, 850-1200 RPM, lower vacuum signal. The engine actually seems to shake (rough) with a rough idle camshaft.

• Pushrod Length and Rocker Geometry: What’s the best way to check whether this is too long or too short? Here are some do’s and don’ts. Do use Crane’s adjustable checking pushrods. Don’t use other dummy rocker arm fixtures (on the head stud checker). Do set the lash by hand at zero. Do blue the end of the valve stem. Do run the engine through two intake and exhaust cycles while observing the tracking of the roller wheel. Do adjust the checking pushrod in or out until you achieve the exact equal tracking across the top of the valve stem. If you are checking a hydraulic engine, use a solid lifter during this procedure.

• V-Twin Motorcycle Cams: Single overhead cam, roller follower, air cooled, 1000cc V-Twin? Sounds like one of the latest state-of-the-art Metric cruiser offerings? No, Crane is currently producing an exclusive batch of camshafts for the 1914 Cyclone Track Racer motorcycle engines. For a short time, these engines dominated board racing in the shorter duration events, with Indian and Harley-Davidson as their closest competition. The leading restorer of these unique bikes (of which only a handful exist in the world), Stephen Wright, depends on Crane Cams to ensure that only the highest quality camshafts are used in his masterpieces.

• Power-Tuner: For vehicles with daytime running lights, you will need to set the parking brake before turning the key to the “ON” position. This will turn the DRL off. If this is not done, it may interfere with the programming.
• “Kickback:” When, and if, it happens to a Harley, it can be very expensive to deal with and usually can be prevented easily. A Harley bike has an inductive-type ignition system that will fire when the current in the primary of the coil is switched off. If your battery is low during cranking, the current in the coil can go low enough to enable it to fire the spark plug. If this occurs with the piston in the wrong position, kickback can occur. This usually results in broken gears and a “hurt wallet.” Make sure your battery is maintained and that your starter can turn your motor over without starving the ignition system. To help eliminate a kickback condition, the Crane Cams ignition modules allow the motor to turn over for two revs before the ignition turns on. Another engineering perk to help you.

• Regrinding Used Camshafts: In those cases where Crane doesn’t offer an outright cam core for your particular application, the company can probably regrind your good used camshaft. Cams that do not have severely worn lobes can usually be reground. However, many folks don’t check for worn distributor drive gears or fuel pump lobes before forwarding them to Crane. Also, the cam’s journals should be in good shape. Crane can’t repair worn journals, distributor gears or fuel pump lobes, so be sure to check your camshaft thoroughly before considering it for regrinding purposes. Severely bent cams (over .030″) also aren’t good candidates for regrinding.
• Mechanical Lifters Camshafts: When using mechanical lifter camshafts in Ford FE 352-428 V-8 engines, Crane recommends its 99256-16 shell-type mechanical lifters (along with their 34642-16 pushrods); however these lifters are now no longer available. The 99257-16 standard-style mechanical lifters are now advised, along with Crane’s 34645-16 pushrods. These can be used with either Crane’s 34772-16 ductile iron adjustable rocker arms or the company’s new 34790-16 adjustable aluminum rocker arm kit.

• Springs for Aftermarket Heads: If you’re purchasing aftermarket heads complete, decide which cam you’re planning to use so you use the correct spring pressures. Most consumers look at the maximum lift that the springs can handle and don’t pay as much attention to the seat and open pressures. If you’re planning to use a flat tappet cam, Crane suggests you purchase the heads bare, then outfit the heads with the required springs so prevent wiping out the cam due to too much spring pressure for the flat tappet cams.

• V.O.E.S. (Vacuum Operated Electric Switch) for Harley Davidson: The V.O.E.S. is a vacuum advance, not a retard unit. It’s designed to advance the ignition timing when the engine isn’t under load. All dressers should advance at 5.5″ to 6.0″ of manifold vacuum; Softails and Dyna Glides around 3.5″ to 4.5″. Sportsters should advance at 3.0″. On all motors that have increased compression ratio or a performance cam is installed, set V.O.E.S. at 5.5″.

• American Motors/Jeep and Chrysler/Dodge/Plymouth Mechanical Lifters: The 99260-12 and 99260-16 mechanical lifters for the American Motors/Jeep 199-258 I6 and 290-401 V-8 engines, along with the Chrysler-Dodge-Plymouth 273-360 V-8’s are now available. These had been in short supply for a couple of years, but are now in stock. These are .904″ diameter, capable of carrying oil up the pushrods, and can also be used in non-pushrod oiling applications. Current suggested resale prices are $125.76 for the 99260-16 and $94.32 for the 99260-12. Standard discounts apply.

• What Goes In Must Get Out!: One of the biggest performance mistakes many street performance enthusiasts make is to not provide enough exhaust capacity for the horsepower level they are trying to achieve. Installing a bigger cam, aftermarket cylinder heads and a high-flow intake system is of little use if you can’t get the air out of the engine as well.
For maximum power and driving pleasure, tubular exhaust headers are recommended for any camshafts with durations at .050, lifter rise of 210 degrees or greater. Failure to provide adequate exhaust with large camshafts results in poor idle quality, hesitation on acceleration, part throttle surging, poor power brake performance, etc. Due to design considerations, some body styles (such as the 1982-1991 GM F-bodies) have extremely limited space for enlarging the exhaust. You should consider this limitation when selecting a camshaft for a vehicle. Less power is lost by slightly undercamming rather than overcamming.

• Hydraulic Roller Tappets: If you’re going to install a performance camshaft with higher valve lift in your 8.1L Chevy big-block engine, make sure that you check your hydraulic roller tappets. If you go too low in the lifter bore, they could bind or fall out of the original hold-down plate, causing severe damage to the engine and valve train. To solve this problem, Crane Cams has developed a taller lifter, which is made for higher valve lift and will work with the factory hold-down assembly. Use Crane Cams hydraulic roller tappet Part #26535-16 for that application.

• New Spring Application: For anyone putting Chevy Vortex heads on early 350 V-8s, Crane has a new spring and retainer for these heads. This is a dual spring that will fit the stock spring pockets with no machining. (Note: the valve guides must be trimmed to .531″ diameter and the appropriate valve guide seal used).

Part Numbers:
Springs #144832-16
Retainers #99975-16
(new multi-fit)
5/16″ Locks #99093-1
11/32″ Locks #99094-1

The valve stem locks are our multi-fit style and are available in +/- .50 heights. You will need a spring shim on the bottom of the spring when installing. This can be used with hydraulic flat tappet or roller cams. Also, remember to use our Gold Rockers (#11750-16 1.5 ratio, #11759-16 1.6 ratio) to complete the change.

• Generation IV, V, and VI Big Block Chevy: The Gen IV engines all come from the factory with flat tappet cams (1967-1995). Gen V engines still use a flat tappet cam and started using a 360′ crank seal, single row timing chain and gear set and non-adjustable rockers (‘95). Some Gen V engines were made with hydraulic rollers for marine applications only.
There is no core for these hydraulic roller cams, so a Gen IV Retrofit hydraulic roller cam must be used as a replacement, along with a double roller, timing chain and gear set with an Imco (909-592-6162) timing cover to match. The Gen VI engine comes as a hydraulic roller (1996-2000). This engine also uses a single-row timing chain and gear set, 360′ crank seal and non-adjustable rocker arms.

CAMSHAFT NEEDLE BEARINGS

Roller bearings for camshaft tunnels offer increased timing precision, reduced operating friction and the ability to handle higher loads.

by Mike Mavrigian

An alternative to traditional cam bearings is the needle roller bearing, which provides increased stability and durability for extended high-RPM racing applications.

Because of the expense of block machining and the resulting dedication of that block to the use of roller bearings, the move to roller type camshaft bearings isn’t for every build. If the mill is used in short-run drag applications, the modification likely won’t justify itself. If the engine is intended for street use only, switching to roller bearings is just plain stupid and a total waste of money. If however, the engine is being built as a dedicated screamer at its upper end for long periods of time, the move to roller cam bearings makes all the sense in the world. Due to the nature of fitting roller-type camshaft bearings, the block (and camshaft) must be dedicated to the use of these bearings.

DOES THE BLOCK CAM TUNNEL NEED TO BE OVERBORED?

There are a few aftermarket blocks that are already machined for a particular size roller bearing. If you do not have this type of block, then the cam tunnel must be bored to accommodate the specific size of roller bearing that you plan to use. Several O.D. roller bearings are available, including 1.875″, 1.968″ (50mm), 2.125″, 2.165″ (55mm) and 2.362″ (60mm).
If the block needs to be bored to accept roller bearings, it should be obvious that this requires an extremely precise machining operation, both for finished bore diameter and for bore-to-bore alignment. In general terms, the maximum acceptable runout between individual camshaft bore locations is about 0.0005″.
Bear in mind that in addition to machining the cam bores to accept the roller bearings, the cam tunnel run may require clearancing to allow pass-through of the bearings during installation. This may require tedious grinder work or machine-cutting with a carbide bit.
If circumferential cam bore oil grooves are lost during the over-boring (typically at the number one cam bore location), these grooves must be restored.
Note: since the use of roller cam bearings require all cam bores to be machined to the same diameter, this provides the added installation advantage of being able to install rear cam bearings from the rear of the block.

IF YOU INSTALL ROLLER CAM BEARINGS,

WHAT CAM DO YOU NEED?

If you plan to take advantage of roller cam bearings, you’ll need to order a camshaft that features journals specific to the size of roller bearings that you plan to use.
When installing a roller bearing in an iron block, the bearing cage should have between 0.0005″ to 0.001″ press fit to the cam bore. If you’re installing the roller bearing in an aluminum block, the bearing cage should have between 0.001″ to 0.0015″ press fit to the cam bore.
For proper installation, Comp Cams recommends using a thermal technique as opposed to pressing the bearings into place under ambient temperature. Comp recommends freezing the bearing and heating the block for safe installation to avoid bearing cage damage.

WHAT ABOUT OIL FEED HOLES?

When installing roller type cam bearings, there is usually no need to block or restrict oil feed holes to the cam bearings. Roller type cam bearings usually require only splash lubrication. However, oil feed holes can be blocked off to reduce oil aeration and windage losses, depending on the application. Also, depending on the application (especially when dealing with a production block), oil transfer grooves (such as found in the number one cam bore in a smallblock Chevy) must be restored following the boring operation in order to maintain proper oil flow to the mains.
Since the use of roller-type camshaft bearings reduce camshaft rotating friction, oil-operating temperature should reduce as well. A slight reduction in oil temperature helps to insure greater oil longevity. This issue of friction as it relates to temperature becomes more pronounced in applications that feature aggressive cam profiles and high valve spring rates. Reducing oil-related heat transfer is always a good thing. Since the oil holes in the cam bores are blocked by the roller bearing cages (and by tapping and plugging the holes if desired), more oil is subsequently routed to the crank main bearings and rod bearings, where it’s needed the most.

TOP FUEL RINGS & BEARINGS

It’s simply amazing that any components are able to withstand this nightmarish environment.

by Mike Mavrigian

A Dykes top ring from a Top Fuel engine.

(photo by author)

Note the missing plasma moly that was blown off of this top ring. This ring (and its companion set) saw a mere 24 seconds of running time, from startup to the end of the dragstrip. This particular engine powered the car to a 4.509-second run at 330 MPH.
It’s certainly no secret that Top Fuel drag engines produce horrific levels of power, to the tune of 7,000 to 8,000 HP and torque in the range of 6,000 lb-ft, currently shooting these cars to speeds in excess of 300 MPH. We thought that it would be interesting to dig into the particulars of the piston rings and bearings used in these over-the-top applications to gain an understanding of what these components are exposed to during a gut-wrenching 4.5-second blast down a quarter-mile stretch.

(photo by author)

BRIEF ENGINE OVERVIEW

These engines, limited to 500 CID, basically operate in the 8,400 to 8,500 RPM range during the entire run, utilizing a slipper clutch system that allows engine tuning within this very narrow RPM band. Engine configuration is loosely based on the Chrysler 426 Hemi format with a 90-degree cylinder angle, two valves per cylinder and hemispherical combustion chambers. Bore is at 4.19″ and stroke is at 4.500″ (combos may vary). Blocks are machined alloy forgings with ductile iron cylinder liners. These engines run “dry” with no liquid coolant. The absence of water passages result in increased block strength with the need to add a block “filler” for added rigidity. Cylinder heads are also CNC machined from alloy stock, fitted with two spark plug ports per cylinder, titanium intake valves and solid Nimonic 80A exhaust valves. Intake valves are approximately 2.45″ in diameter, with exhaust valves at around 1.925″. The valvetrain includes a billet steel camshaft, solid roller lifters and full-roller rockers, titanium valve springs and retainers. Crankshafts are billet steel, fitted with five bearing shells. Connecting rods are forged alloy. Pistons are forge alloy, with a three-ring package. Piston grooves are hard-anodized to prevent microwelding. Piston pins are secured with alloy pin buttons to aid in quick piston changeovers.
The supercharger is a 14-71 type roots unit, driven by a cogged belt. About 45.5 PSI boost occurs at wide-open-throttle. The engine oiling system is a wet sump setup with a capacity of about 16 quarts. Oil pressure is about 200 lbs. cold and about 160 lbs. during a run. The fuel mixture is primarily nitromethane, with about 15% methanol. Nitromethane features a high oxygen content, which means less air is required for combustion. Very rich mixtures are tuned. Coupled with nitromethane’s ability to absorb heat as it vaporizes, this helps to promote engine cooling. In other words, these engines run on tons of fuel and little air (instead of “conventional” 14.7:1 air/fuel, mixtures can be as great as 2:1). Fuel consumption is about 1 gallon per second. Whoof.

Here’s another view of a top ring’s plasma facing damage from the same engine.

Cylinder pressures are incredibly high, as much as 12,000 to 13,000 PSI (when detonation takes place, cylinder pressure is in the 16,000 PSI range). To put that into perspective, a Pro Stock engine may generate around 4,000 PSI of cylinder pressure. This is a major factor when considering the abuse experienced by the rings and bearings.

(photo by author)

PISTON RINGS

To find out what’s happening in the Top Fuel ring arena, we spoke with Clevite’s Don Sitter and Federal-Mogul’s Scott Gabrielson, each of whom work hand-in-hand with teams in developing packages that perform.
According to Sitter, Clevite offers a hardened ductile iron top ring (their PC479 material, tradenamed Firepower). This ring is also available with a moly face, but Sitter noted that some builders prefer not to use the moly since firing pressures in detonation instances can sometimes cause the moly to chip off, potentially contaminating the oil filter.

The second ring from the same engine features an inner chamfer.
“There are two schools of thought with regard to top ring size,” noted Sitter. “We introduced a 0.078″ axial height ring with a 0.017″ Dykes step. Prior to that the most common top ring was a 1/16″ Dykes-style ring with a 0.017″ step. In working with various teams, we found that distortional effects caused the 1/16″ ring to reduce twist, essentially turning the ring into a beveled washer. It was obvious that substantial compression was getting past the top ring. To fight that, we went to the thicker ring, which worked out very well. A favorite saying of one of the Top Fuel builders we work with is ‘mass saves your ass,’ which was certainly true in this case. We also changed the second ring to a 0.078″ moly-faced version with a barrel (radius) face.
“Considering the other variables involved, however, you can’t look at the rings as a stand-alone of the overall equation,” Sitter said. “You must also consider cylinder finish, as some builders run a 280 finish followed by a plateau finish, while others go with an as-cut 280 or 400 wall finish. There are substantial differences in the tuning of these engines, including blower overspeed, static compression, amount of fuel delivery, timing, clutch management, etc. One team may have problems with pan pressure and sealing, and by switching to dual Dykes (the Dykes ring has a dam cut about a third of the way across the radial wall, which allows pressure to get behind the ring and push it against the cylinder wall), but the same deal might not work for another team.
“Top ring gap will range, depending on the builder’s experience, from as tight as 0.028″ to as much as 0.044″. The enormous heat generated during combustion necessitates these larger gaps.

Heads and piston/rod sets are removed after every run. Rings and rod bearings are always replaced after every run. To save time, some teams replace the entire piston/rod/ring/bearing set. After examination, pistons and rods may be reusable.
(photo courtesy Clevite)

Oil is also replaced after every engine shut-down, due to the excessive nitromethane fuel wash.
(photo courtesy Clevite)

“Some crew chiefs have told me that when we went to the thicker rings, pistons ran cooler due to the decreased thermal resistance in a dry block,” Sitter said
Sitter noted that taper-faced second rings, regardless of material, tend not to be effective because any compression that leaks past the top ring will load the face of the taper ring, causing the ring to be pushed away from the cylinder wall, increasing blowby and pan pressure. A barrel-faced ring fights this because the tangent point is closer to the top of the ring. Sitter also noted that Clevite is introducing a new second ring in 2007, a reduced radial wall 0.078″ barrel-faced ring positive twist ring. This prevents the second groove from undercutting the top groove, allowing the No. 2 land to better withstand the primary firing pressure at the top ring. The reduced radial wall will also help to bring the mass back to close that of the original 1/16″ barrel ring.
“The laws of physics are routinely being broken in Top Fuel,” jokingly noted Federal-Mogul’s Gabrielson. “What these teams are accomplishing is nothing short of incredible.”
“Dykes rings seem to work very well in supercharged applications,” Gabrielson said. In the beginning, top ring materials were generally chrome plated stainless steel, but about 15 years ago this progressed to the use of ductile iron with a plasma moly face. Stainless tends not to be very compatible, with the chrome plate tearing up cylinder walls quicker. Granted, the cylinder liners are replaceable, but since the teams have only about 75 minutes to service the engine between rounds, if a wall goes away, the team will usually just swap out the entire block to save time.
“The most common top and second ring sizes have been 1/16″. Our experience has been that some crew chiefs have used Dykes second rings in place of rectangular rings, but with mixed results,” Gabrielson said. Some experimentation with wider Dykes rings (5/64″ face) has taken place, with results showing superior resistance to twisting. We’ve seen mixed reviews with regard to the wider rings, with some teams claiming improvements and others saying that they saw no change. Top rings simply don’t last, and are usually destroyed during the run, so ductile iron plasma-faced second rings are the norm, since you need a durable backup ring. Ring fracture isn’t a big issue, since the incredible cylinder pressure seats the ring on the bottom of the groove, eliminating flutter. The top ring simply fails due to pressure and heat, leaving the second ring to serve as the essential backup compression ring.”
Oil rings, because of the pressure formed around the expander, can actually be smashed. Regardless of the brand, style or type of material, rings don’t make it through more than one run, so they’re replaced as a matter of course between rounds.

Detonation events will damage main bearings as well. These mains were exposed to a single run. Note the severe scoring, the result of enormous forces created by the astronomical cylinder pressures.
(photo courtesy Clevite)

Here are three upper rod bearings that experienced a single run. Note the extrusion of material, which is especially evident in the center shell seen here.
(photo courtesy Clevite)

Wet sump oil systems are a must due to the need to change contaminated oil quickly.
(photo courtesy Clevite)

BEARINGS

“While rod bearings haven’t changed much in the last eight years,” noted Clevite’s Sitter, “there was a series of changes in 2004 involving NHRA-mandated reduction of nitro, blower overspeed, etc., in an effort to regulate speed (since speeds were approaching 330 MPH). It’s taken two seasons to get back to performance levels of 90% nitro. Now, we see more detonation and more damage to upper rod bearings. Again, because of the incredible cylinder pressures, upper rod bearings actually begin to extrude (about 0.080″ at the ends), making them appear as flanged bearings. If materials change, moving to a mild grade steel, for instance, this would still present a liability to the crankshaft, since the harder extrusion would get into the journal fillet, possibly creating a stress area. At the present time, Top Fuel crankshafts are generally changed out anywhere from three to five runs (some teams stretch this to as many as 12 runs). Since these crankshafts cost around $3,500 each, and since the team may make about 200 passes each year, the difference between buying 20 cranks versus 60 cranks per year would present a real financial problem.
“A number of detonation management issues need to be addressed before we blindly change rod bearing design,” Sitter said. “The problem isn’t the bearing … rather, it’s how the bearing is being treated. One analogy is that rod bearings can be viewed as the circuit breakers in the system.”
“Rod bearing clearances have decreased,” Sitter said. “Years ago, it was not uncommon to see rod bearing clearances in the 0.005-0.006″ range, with main bearings in the double digits. Today, rod bearing clearances range from 0.0035-0.0045″, and main bearing clearances are in the area of 0.0045-0.006″.”
“Typically, Top Fuel bearings are not coated with a special anti-friction treatment.,” Sitter said. We’ve tried Tri-armor, but there does not seem to be any big advantage. They work as expected, but don’t offer the kind of benefits you need in a Top Fuel application. The issue focuses more on how to prevent the engine from shedding parts when detonation occurs. Our V bearing works great.

This is constructed of lead indium plated overlay on a cast tri-metal lining with a conventional steel backing. This does a good job of managing the detonation environment. While the moly coatings, such as our Tri-armor treatment, survive very well, this offers no particular margin with regard to detonation events.
“Top Fuel applications experienced thrust bearing problems a few years ago, which prompted us to make several improvements to the flanges, including the use of lead indium on the thrust faces, and to work with teams and crank manufacturers with regard to thrust face surface finish,” Sitter said. “We did note that those teams having thrust bearing problems were all using a particular oil, which convinced me that some oil brands do perform better than others.”
By the way, most teams run 70-90 W synthetic oil. It’s interesting to note that because of the excessive nitro fuel wash that runs through the engine, fuel dilution of the oil is so great that the engine oil must be changed every time the engine is shut off (even following a warm-up). As noted earlier, since these are dry engines with no liquid cooling system, this excessive fuel wash helps to manage temperatures, basically preventing the pistons, heads and valves from melting.
The incredible cylinder pressures are so great that it’s not at all uncommon for hefty wrist pins to bend. In addition, rod small ends are elongated and rod big end saddles can be pulled out. When you consider their environment, it seems a miracle that any rings or bearings can function and allow these engines to perform their jobs, yet they do, weekend after weekend, all year long.
By the way: ever notice that the exhaust tubes are always turned up, with exhaust pulses exiting upwards? This isn’t just for appearance. This is due to the enormous cylinder pressures. By directing the exhaust upwards, this helps to generate greater chassis downforce for better tire bite and stability. If the tubes aimed downward, the business-end of the car might very well be lifted off of the track surface.

Typical burnout to transform the tire surface to a low-durometer, sticky state for increased traction.
(photo courtesy Clevite)

These engines are typically not fully assembled or dyno’d in the shop. Rather, they’re assembled in the car. Each run include fresh rings, rod bearings, and oil.
(photo courtesy Clevite)

Gone in about 4.5 seconds, currently reaching a trap speed of around 330 MPH.
(photo courtesy Clevite)

DRY SUMP

OIL SYSTEMS

Efficient lubrication plus reduction of parasitic power loss.

By Mike Mavrigian

photos by author

ENGINE OILING

A street engine, and many race engines, utilize a “wet sump” system to deliver pressurized oil to the engine’s internal rotating and reciprocating assemblies. Engine oil is stored in the oil pan sump (the big reservoir section of the pan). The oil is picked up by a mechanically driven oil pump, which obtains the sump’s oil via a submerged oil pickup. As the pump rotates (the pump runs whenever the engine runs, since it’s driven by the crank or indirectly via the distributor drive), oil is pressurized and distributed from this main source throughout the engine as oil is distributed through the oil passages in the block, crank journals, main bearings, rod bearings, and, eventually, to the valvetrain. Although this system does deliver oil to all required areas, the oil must be pushed through all of these passages to eventually route to the upper end of the engine. The delivered oil is then free to drain back to the sump, with delivery and drain-back serving as an ongoing cycle during engine operation.
A “dry sump” system takes a different, and much more direct approach. This uses an externally-mounted oil pump, which takes advantage of external plumbing to directly deliver oil to the engine. The oil pan does not feature a sump reservoir. Instead, the dry sump pan serves only as a containment cover and as a location from which oil can be returned to the reservoir. The oil reservoir (oil supply) is a remote container (usually mounted in the cockpit or other convenient location in the race vehicle). In very basic terms, the external pump pulls oil from the remote reservoir, and then pushes the oil (under pressure) to wherever the plumbing directs it. In this manner, oil can be directly sent to the main bearings through a block port, oil can be delivered directly to the valvetrain with one or two plumbed hoses (depending on the application) and oil can be directly delivered to a turbocharger, etc.
Dry sump pumps are offered in stages depending on how many direct-delivery and return (scavenge) routes are required. The advantages include immediate oil delivery to specific areas and elimination of oil starvation caused by angle and centrifugal forces (when the race car accelerates, brakes or turns), which may momentarily expose an in-the-pan oil pump pickup, allowing air (not oil) to travel throughout the block. In other words, the potential for oil aeration is eliminated. Since the scavenge section(s) of the dry sump pump pull oil from the dry sump pan, this creates a vacuum, pulling excess oil from the surfaces of the crank and rods, reducing parasitic drag (which means more efficient use of engine power).
When plumbing a dry sump system, size requirements may vary somewhat, but a general rule of thumb is to use -10, -12 and -16 hose, fittings and hose end sizes (for some turbo applications, a -6 hose size is recommended). Generally, a larger size is required for the return hose that runs out from the pump to the remote oil reservoir (for instance, if -12 hoses are used for all feeds, a -16 hose would be used for oil return to the reservoir).
Although a dry sump oil pan will feature threaded bungs to accept suction line fittings (where drainback oil is pulled by the pump), plumbing to the block or other areas may require drilling and tapping or the purchase of special adapters. Typically, if an adapter is needed to feed oil to the block’s main galley (at the stock oil filter location, for example), aftermarket adapters are readily available for all popular blocks. By the way, if you’re using the OE filter location for oil feed, you’ll need to remotely locate an oil filter.
An externally mounted dry sump oil pump is most commonly driven by a notched belt (toothed belt often referred to as a Gilmer belt), directly from the crankshaft snout (a pulley is installed on the crank, with the belt connecting the crank pulley to the pump pulley). Dry sump pumps, via the proper pulley diameters, are generally driven at about half of crankshaft speed.
Dry sump pumps driven by the nose of the camshaft are also available, with the pump mounted on the face of a special timing cover.

DRY SUMP SYSTEM ADVANTAGES

• Superior consistency of oil pressure
• Oil isn’t pushed away from the oil pickup during severe turns, acceleration or braking, as may occur with a wet sump system
• Adjustable oil pressure
• Increased oil system capacity
• Shorter profile pan, allowing engine to be mounted lower in chassis for lower center of gravity.
• Increase in engine power
• Positive oil delivery to critical areas of the engine
• Cooler oil supply (since the oil is quickly returned to the remote reservoir instead of being stored in the hot oil pan)

A dry sump pump features a pressure section and a scavenge section. The pressure section delivers oil to the engine, while the scavenge section pulls “leftover” oil from the dry sump pan and sends it back to the remote oil reservoir.
Dry sump pumps are built in “stages, with one pressure section and one or more scavenge sections. The additional scavenge sections (as few as one, as many as 6) allow oil to be scavenged more quickly and efficiently from specific areas of the engine, instead of waiting for the oil to be drawn down into the pan for scavenge pickup.
A typical 2-stage dry sump pump features 1 pressure section and 1 scavenge section.
A typical 3-stage dry sump pump features 1 pressure section and 2 scavenge sections.
A typical 4-stage dry sump pump features 1 pressure section and 3 scavenge sections.
A typical 5-stage dry sump pump features 2 pressure sections and 3 scavenge sections.
A typical 6-stage dry sump pump features 2 pressure sections and 4 scavenge sections.

A typical dry sump oil system features a host of components including:

• Dry sump pump
• Dry sump pump pulley
• Toothed pump drive belt
• Pump fittings (male -AN 37-degree flare to accept -AN hose ends)
• Pump mounting bracket
• In-line screened oil filter(s)
• Remote in-line oil filter and filter mount
• Remote-mounted oil tank
• Breather (separate or on-tank)
• Oil filter block-off plate for engine block
• Required -AN hose assemblies

OIL TANKS

The dry sump system oil tank simply serves as the primary oil reservoir. The tank receives the oil scavenged from the outlet ports of the dry sump pump. Once the oil enters the tank’s inlet fitting, the oil hits an internal “splitter” that directs the oil in a specific stream. After hitting the rolled inner tank wall (this softens the impact of the oil) it rolls onto an upper baffle, allowing the oil to flow out in a thin sheet, which promotes the release of air that might be trapped in the oil. The oil then falls into the reservoir, waiting to be pulled out and recycled through the engine.
A large portion of the tank volume is air, which exceeds the volume of oil being pulled from the pump. To allow air to escape, the tank must be vented, which also benefits the system by lowering atmospheric pressure in the crankcase.
Dry sump tanks are available in capacities ranging from 1 gallon to 5.5 gallons.

Here’s a 2-stage dry sump pump fitted to a Honda race engine (the engine block was rotated on the stand to better show the pump and pan). A pair of -12 AN hoses connect the dry sump pan to the pump.

This overhead view shows the pump side-mounted to the block. The toothed Gilmer belt connects the small diameter toothed crank pulley to the pump pulley. The dry sump pump runs at approximately half of the crank speed. Notice the two hose ends on the top of the pump. The larger -16 will be plumbed to the upper port of the reservoir, serving to return oil from the pump’s scavenge back to the tank. The -12 will be plumbed to the block’s main oil port to feed the engine.

The -16 hose shown here plumbs scavenged oil from the pump to the remote reservoir. A fitting/hose connection at the bottom of the reservoir is the feed line from the reservoir to the pump. Note the oil delivery -12 hose to the oil filter adapter on the block. The reservoir shown here was mounted on our shop’s engine stand for display purposes. The reservoir will be mounted in the race car cockpit area (obviously with longer hoses).

A dry sump “kit” including reservoir, pan, pump, belt, crank pulley and pump mounting bracket. The angled fitting at the top of the reservoir will accept a breather.

This Aviaid dry sump pump mounting bracket features multiple threaded holes, providing plenty of latitude when mounting the pump for optimum location (for pulley alignment).

Here, our pump is mounted to the bracket using four 5/16″ bolts.

The toothed pump drive belt slips onto the pump pulley by engaging the teeth. The pulley is also adjustable fore/aft to fine-tune belt alignment.

Here, you can see the feed hose at the bottom of the reservoir tank, where the pump draws oil from the tank to the pump.

A 5-stage dry sump pump. Note the four scavenge hose connections at the pan.

An in-line oil filter plumbed from the dry sump pump to the filter, then into the block.

This race engine features scavenge/vent plumbing from the valve cover to aid in reducing parasitic drag and to vent the engine within a contained system.

Quick-connect couplers allow quick connection/disconnection of oil hose assemblies without loss of oil. The Jiffy-Tite coupler shown here features valving that shuts off when the connection is uncoupled. Use of these quick-connect couplers allow for faster engine removal with no oily mess.

When routing your plumbing hoses, make sure they don’t interfere or rub on any moving parts. Here the two hose ends are installed at a sufficient angle to prevent the hoses from touching the timing belt, and the hoses are secured together with an aluminum hose separator.

This oil reservoir features a breather fitting at the top, two scavenge fittings near the top, and one feed-out fitting at the bottom. (Photo courtesy of Peterson Fluid Systems.)

Instead of attaching a breather directly to the top of the reservoir, a remote breather can like the one shown here can be mounted remotely. (Photo courtesy of Peterson)

A dry sump system allows multiple oil feeds. Here a direct oil feed hose is plumbed to a turbocharger using a -6 AN hose.

Dry sump pumps are built in stages. The ports marked “IN” are for scavenge hoses and oil feed from the reservoir. The ports marked “OUT” are for pressure output from the pump and for return to the reservoir. Pulleys are keyed and provide a positive retention onto the pump drive shaft. (Photo courtesy of Barnes.)

In this plumbing hookup, we installed -12 male AN flare adapters to the pan to accept -12 hose ends. For the scavenge hose being installed in this photo, we chose a straight hose end for the pan connection and a 45-degree hose end at the pump. The capped fitting seen on the scavenge side of this pump will be used to connect to the reservoir’s bottom port to pull oil from the tank to the pump. Due to the range of hose end shapes available, it’s easy to create direct and tidy plumbing regardless of the engine configuration.

Always use aluminum -AN wrenches to service the hose end connections.

Soft aluminum wrenches prevent gouging the hose end couplers, and prevent damaging the hex corners.

CAUTION: If an engine fails (by that we refer to any problem that allows metal debris to enter the oiling system), don’t neglect the dry sump system during the rebuild process. The external oil pump must be disassembled, cleaned and inspected for damage (in-line filters can be plumbed in-line in the oil return lines during system installation, which is always a good idea, But even if a filter is present, the pump should still be inspected). Naturally, the remote oil reservoir should also be cleaned. However, many people tend to overlook the hoses (and a remote oil cooler, if present).
If you suspect metal contamination, although you may try to flush and clean all of the hoses, if you’re dealing with hoses that you can’t also visually inspect (long hose or hose fitted with angled hose ends), the safest route may be to replace the hoses. That’s a call you’ll need to make on your own, but be aware that random debris might be lodged in the hose inner wall. If you’re certain that the hose is clean, by all means feel free to re-use it. If you have any doubts, though, spend the money to replace it.
As far as external oil coolers are concerned (and this holds true for any remote cooler, whether it’s for the engine, transmission or axle drive), if you suspect that metal debris has entered the cooler, replace the cooler. Unless you have access to an X-ray machine, you’ll never be certain that the cooler tubes are clean. If you reuse a contaminated cooler, you’re asking for trouble because the debris can dislodge and run into the engine. Considering the cost of a cooler (even the most expensive type) versus the cost of the engine, it’s good insurance to toss the suspect cooler and buy another.

Machined billet aluminum oil filter block on a Honda. This engine was fitted with a dry sump oil system. Note the finger pointing to a round plug. This was the OE location for a crankcase breather. Since the dry sump system pulls vacuum in the oil system, the block breather wasn’t needed, so we made a press-in aluminum plug on the lathe.

All photos by author unless otherwise noted.

2-stage dry sump system

2-stage cam-drive dry sump system.

3-stage dry sump system.

3-stage cam-drive dry sump system.

4-stage belt-drive dry sump system.

4-stage cam-drive dry sump system.

5-stage dry sump system.

(All example plumbing illustrations courtesy Aviaid)Sources

Sources

DRY SUMP COMPONENTS/SYSTEMS

ARE DRY SUMP SYSTEMS
(dry sump pans)
For more information, dial 1-800-652-0406, ext. 13401
Online, visit www.precisionenginemag.com/info/13401

AUTO VERDI RACING OIL PUMPS
(dry sump pumps)
For more information, dial 1-800-652-0406, ext. 13402
Online, visit www.precisionenginemag.com/info/13402

AVIAID OIL SYSTEMS
(dry sump oil systems)
For more information, dial 1-800-652-0406, ext. 13403
Online, visit www.precisionenginemag.com/info/13403

BARNES DRY SUMP OIL SYSTEMS
For more information, dial 1-800-652-0406, ext. 13404
Online, visit www.precisionenginemag.com/info/13404

BILLET FABRICATION
(wet and dry sump pans)
For more information, dial 1-800-652-0406, ext. 13405
Online, visit www.precisionenginemag.com/info/13405

CANTON RACING PRODUCTS
(pans, accusumps, filters)
For more information, dial 1-800-652-0406, ext. 13406
Online, visit www.precisionenginemag.com/info/13406

CHAMP PANS/JR MFG.
For more information, dial 1-800-652-0406, ext. 13407
Online, visit www.precisionenginemag.com/info/13407

DAN OLSON RACING PRODUCTS
(aluminum dry sump pans)
For more information, dial 1-800-652-0406, ext. 13408
Online, visit www.precisionenginemag.com/info/13408

JOHNSON’S HIGH TECH PERFORMANCE
(dry sump oil pumps)
For more information, dial 1-800-652-0406, ext. 13409
Online, visit www.precisionenginemag.com/info/13409
MILODON INC.
(pumps, pans)
For more information, dial 1-800-652-0406, ext. 13410
Online, visit www.precisionenginemag.com/info/13410

MOROSO PERFORMANCE
PRODUCTS
(pumps, steel and aluminum pans)
For more information, dial 1-800-652-0406, ext. 13411
Online, visit www.precisionenginemag.com/info/13411
PATTERSON ENTERPRISES
(dry sump oil tanks)
For more information, dial 1-800-652-0406, ext. 13412
Online, visit www.precisionenginemag.com/info/13412

PETERSON FLUID SYSTEMS
(dry sump pump systems)
For more information, dial 1-800-652-0406, ext. 13413
Online, visit www.precisionenginemag.com/info/13413

STEF’S PERFORMANCE
PRODUCTS
(B&B pans)
For more information, dial 1-800-652-0406, ext. 13414
Online, visit www.precisionenginemag.com/info/13414

Porsche Speed Record Run At Talladega

We work and play with the big boys.

by Mike Mavrigian

photos by author

Our three cars in the Talladega garage during testing week.

As Forrest Gump often noted, you never know what you’re gonna get. In August and September of 2005, Precision Engine editor Mike Mavrigian was contracted by Porsche Cars North America for technical involvement in a “speed record run” involving their high-dollar Carrera GT cars at the Talladega Superspeedway. The official event took place September 1, 2005 at the Talladega, Alabama track, located about 50 miles east of Birmingham.
The Carrera GT is a $440,000 exotic street car featuring an all-carbon-fiber monocoque and body, equipped with an alloy-block 605 HP 5.7L V-10 engine. The motor features titanium connecting rods, a “lightweight alloy” crankshaft, titanium valves and springs, etc. The engine’s light rotating and reciprocating mass allows it to quickly zip to 8,000 RPM in the blink of an eye (sounds like a Formula One motor). The stock Carrera GT used for the record at Talladega was produced at the Porsche factory in Leipzig, Germany and was upgraded with safety equipment only, including a six-point harness and Michelin Pilot race tires designed to handle the forces generated by the car when at speed on the severe 33-degree Talladega banking.
The goal of the event was to set a number of specific speed records with the GT, which serves as a repeat of history for Porsche fans (30 years ago, Mark Donohue set a track record at Talladega with a 1,000-HP Porsche 917/30 race car at 221 MPH). In this 2005 event, David Donohue (Mark’s son) was enlisted as the pro driver, with celebrity Jay Leno as the second driver. David clicked off a 196.301 MPH lap (a record for the production street car), while Jay handled the standing 1-mile and 5-mile runs.
Donohue also set records for the measured mile at 198.971 MPH; and the measured kilometer at 195.755 MPH. Leno set three standing-start speed records in the same car, the fastest being 156.603 MPH. Flying records are recorded from a rolling start, while standing speed records are recorded from a complete stop.
All of the record runs established during the September 1, 2005 event were recorded and verified by the Grand American Rolex Sports Car Series sanctioning body.
“It amazes me that we were able to go nearly as fast in a 2005 street car as David’s father did in a 1,000 HP race car,” said Leno, who is an avid automotive historian and collector. “This Carrera GT has air conditioning, a stereo, a navigation system and a cockpit full of leather and still goes almost 200 MPH around this course. It’s outrageous.”
Leno, by the way, did an outstanding job as a driver. We were impressed with his focus and his consistency. He started off in practice running 1.16 minute laps, dropping his lap times with each successive lap, down to a 54-second lap time (only 3 seconds off of the pro driver’s times). Jay also provided, as you’d expect, comedic relief during the event. He’s a down-to-earth car guy and a true gentleman.
Our involvement was relatively minor, helping to prepare the cars (setup, seat harnesses, radio systems, etc.) and to procure, deliver and set up all of the garage and pit equipment (platen chassis setup stand, race jacks, hand and pneumatic tools, compressed nitrogen, pit awnings, radio systems, refueling equipment, pyrometers, etc., etc.). The Porsche training instructors at Porsche’s Atlanta training center performed the tedious job of chassis adjustment, which was critical.
As part of his preparation duties, Mavrigian enlisted a handful of product sponsors to participate in this historic program. Chrysler loaned a new Dodge Ram quad cab truck equipped with the turbo diesel engine as the equipment-trailer tow vehicle. Trailex loaned us a new all-aluminum enclosed trailer (normally intended to haul precious race or collector cars, although we loaded it with tools and equipment). Sunoco graciously supplied the 100-octane GT fuel (a whopping 100 gallons), delivered direct to the track. Goodson Shop Supplies provided a range of materials including shop aprons, spill absorbent, shop towels, etc. Polaris loaned a kick-ass ATV, their Ranger model (in Porsche Guards Red color, no less. we fell in love with this thing…no matter how hard we tried, we could not get this thing stuck in the boonies behind our tech shop). Ringers also supplied a healthy package of their work gloves and radio belts. Our thanks to all of these participants.

We prepped three Porsche Carrera GTs prior to the week-long testing session at Talladega. Prep took place at Porsche’s training center in Atlanta.

The engine is a V-10 5.7L high-buzzer that yanks 605 HP at around 8200 RPM.

Underneath all of the carbon-fiber covers lurks the all-motor V-10. The Y-shaped section of carbon fiber you see here is actually part of the car’s frame. Note the horizontally-mounted coilovers.

This training cutaway section of the right front reveals the high-mounted rack, the huge 15″ ceramic brake rotor and adjustable horizontal coilover. All of the radius rods are titanium.

We spent three solid days at the Porsche Service Training Center during car prep.

A rear view of the Carrera GT. The speed-activated rear wing rises up via solenoids and can be locked in the raised position.

This cockpit view shows the 2-way radio installation that we performed on all of the cars while at the training center. Since we were forbidden to drill any holes, we improvised by taking advantage of existing under-console-holes (and used plenty of nylon wire ties).

We set up a Longacre platen in the Talladega garage, which allowed us to check and adjust suspension corner loading and wheel alignment at the track.

Would you buy a car from these jokers? Jay Leno hams it up with Precision Engine editor Mike Mavrigian during a break in the pits.

We had the Talladega track all to ourselves, which is sort of eerie considering the vast size of this track. This shot was taken during initial setup of our pit area.

Chrysler was kind enough to loan us a Dodge Ram crew cab equipped with the turbo diesel as our tow vehicle. We cruised in comfort with torque to spare (the truck didn’t even know the trailer was back there).

Trailex provided one of their gorgeous all-aluminum enclosed trailers, which we used to haul all of our tools, ATVs, supplies and pit equipment.

The official crew pass for Porsche’s Carrera GT Speed Record Run.

Jay Leno (in helmet) and pro driver David Donohue. Leno did an impressive job on the track, and kept us in stitches during the breaks.

At speed on the front straight at Talladega.

Leno and Donohue in Victory Lane following the record runs. Porsche has decided to auction the silver car and to donate all proceeds to the Katrina Hurricane Fund.

Editor’s Note: While this program and this article doesn’t deal with the builds of the Porsche engines directly, we thought our readers would nonetheless enjoy a peek at what took place. After all, it’s not every day that you get a chance to melt under the Alabama sun at a legendary track, prep ultra-exotic performance toys or hang with the likes of Mr. Leno.

STREET PERFORMANCE & RACING PISTON TECH

Insight into the world of go-fast slugs.

by Mike Mavrigian

photos by author

It should come as no surprise that piston technology has evolved over recent years, largely due to superior material availability and the advent of precision CNC-machining capabilities. While a custom piston order may have once required four to six weeks or longer, computer modeling and CNC processes have cut the waiting time in some cases to a mere few days (naturally, depending on the piston maker’s schedule. Bear in mind that top piston makers are besieged by orders from pro race engine builders prior to the start of each season, so factor this into your expectations). For popular movers such as smallblock Chevy applications, many designs once viewed as “custom” in nature may now be available as in-stock items, ready to ship.
Here, we’ll focus on forged racing pistons. While hypereutectic pistons (high-silicon content castings that are much more dimensionally stable under thermal stresses than a common type aluminum casting) are perfectly adequate for high performance street motors, as well as many race applications, they’re nonetheless castings, which are less ductile than forgings. In other words, if it’s gonna break, a casting will tend to shatter as opposed to a forging, which will go “plastic” before it breaks through.
The two most common alloy materials used in today’s forged pistons are 2618 and 4032 aluminum. The 2618 material is a nearly pure aluminum with very little silicon content.
According to Probe’s Chris Huff, this material provides increased fatigue resistance, with a tendency to bend rather than crack.

4032 alloy, on the other hand, possesses a high silicon content (usually about 12-14%), making it harder, which means that it won’t plasticize as readily as 2618. As a result, pistons made from 4032 need to be thicker and heavier to provide the needed strength. However, the higher silicon content provides a harder wear surface, and subsequently longer piston life. According to Chris, 4032 is a good choice for naturally aspirated street applications (and for relatively lower turbo boost pressures), while 2618 is a better choice for higher boost pressures (16 lbs or more). Top Fuel applications, where extremely high cylinder pressures are a constant, 2618 is the common material of choice. While 2618 alloy provides outstanding high-temperature characteristics, greater wall clearance is usually required due to this material’s tendency to expand and contract.
Dave Calvert at CP Pistons notes that although 4032 aluminum can be an acceptable choice for street and some supercharged applications, the majority of their pistons are manufactured from 2618 forgings, since this grade of very pure and strong aluminum allows precise thermal growth calculations, allowing engineers to accurately predict piston dimensional changes during anticipated cycling operation in any given engine and its track application.
The many technology changes in pistons over the previous five years or so involve increasing piston strength and resistance to fatigue. An example, according to CP’s Dave Calvert, is use of the “box style” (also called strutted) pin boss design to increase rigidity. These reinforcing struts stabilize the pin bosses and the ring grooves, adding dramatically superior strength around the piston periphery.

CNC machining offers precise and repeatable dome configurations.

Top ring grooves are typically hard-anodized to prevent microwelding.

We spoke with Barry Rabotnick, the chief tech honcho at Federal Mogul regarding that firm’s current developments. Barry noted that they’ve recently introduced a new line of high-performance/race entry-level forged pistons that offer big-time benefits at a street-level price. The new line features lighter weight and shorter skirts, with a webbed reinforcement underside. The pin boss area has been shortened up, and cut-throughs are machined into the webbing for quick oil drainback. A notable feature involves a “figure eight” skirt configuration that is slightly larger on the thrust side (a very sophisticated skirt design, made possible via 3-D computer modeling and CNC processing). Further taking advantage of CNC processing, all domes are CNC cut as well.
Ring placement has moved higher, with an accumulator groove featured between the top and second ring locations, which increases the volume of the area between the rings. As Barry explained, when a tight ring package is used, this accumulator groove prevents inter-ring pressure buildup, allowing both top and second rings to function properly. All ring lands are CNC-machined, and a 0.010″ radius is featured at the root of the top and second grooves (instead of a square cut), which increases material strength.
All of these new pistons also feature a silk-screen-applied Duroshield coating (moly graphite with polymer mix, which serves as an anti-friction/scuff coating), as well as lightweight tapered pins.
According to Probe’s Chris Huff, moving the rings higher produces several results, including a reduction in emissions (naturally a concern for the OE side). In racing applications, the top ring seals better when it’s closer to the top. This is good for drag or circle track applications, but if nitrous or a blower is involved, the downside is greater concern for blowing the top ring lands off. In turbo applications, for example, the rings need to move further away from the top to get away from the excess combustion heat and pressure.
Hard anodizing on the top ring groove is a solid move for high combustion temperature situations (turbo, etc.) and in some endurance NASCAR applications to prevent microwelding. However, notes Huff, “ring groove hard anodizing isn’t something we see much in the sportsman realm.”
In terms of piston compression height, according to Huff, “we’re increasingly seeing this in stroker builds where longer rods are being used, with compression heights moving well beyond the once-considered limits of 1.5 – 1.75″, to compression heights in some applications reaching the 1.2 – 1.3″ range.”
Huff also noted that in some cases, pins are moving up far enough that they intersect the oil ring groove. Huff’s advice is to stay away from this on a street engine. Instead, a slightly shorter rod coupled with an offset pin bore in the piston is a better route to take to reduce rod angle, rattle and load on the cylinder wall.
Gas porting (strategically-located holes drilled from the dome perimeter into the top ring groove) applies pressure directly to the rear ring face, basically eliminating side clearance, which prevents ring flutter during high-RPM operation. This works best with thin, narrow top rings (i.e. 0.043″ thick) and short piston compression height. However, since the positive pressure effects of gas porting tends to greatly reduce top ring life, this feature is applicable only to routinely-serviced race-only engines, and is never a good idea for a street motor.

COMPRESSION RATIO FORMULAS

FORMULA ABBREVIATIONS

GV………..gasket volume
DV………..below deck volume
HV………..head chamber volume
VV………..dish, valve pocket, dome volume
(minus for dish or pockets; plus for dome)
PV…………volume displaced by piston
GV = Bore (in) x Bore (in) x 12.87 x head gasket thickness
DV = Bore (in) x Bore (in) x 12.87 x inches below deck
HV = CCs
VV = CCs
PV = Bore (in) x Bore (in) x Stroke (in) x 12.87
Compression ratio = GV + DV + HV – VV + PV
Divided by GV + DV + HV – VV

Cubic inches = Bore x Bore x Stroke x no. of cyls x 0.7854

To convert cubic inches to CCs……..Cubic inches x 16.386
To convert cubic inches to liters…….Cubic inches x 0.016386

To convert CCs to cubic inches……..CCs divided by 16.386
To convert Liters to cubic inches……Liters divided by 0.016386

Engine in Liters = Bore (mm) x Bore (mm) x stroke (mm) x no.
of cyls x 12.87,
Divided by 16386 x 1000

Engine in CCs = Bore (mm) x Bore (mm) x Stroke (mm) x no.
of cyls x 12.87,
Divided by 16386

Mahle Motorsports’ Trey McFarland noted that among the many features in their forged performance and racing piston designs are shorter pins, which enables opening up the sides of the pistons to obtain both lighter weight as well as reducing overall drag. Pin bosses are moved further inboard to work with the shorter pins. This removes flex from the pins, placing the stresses back into the piston, which allows designers to build-in the degree of strength and rigidity that’s needed to best control piston growth.
Trey also noted that all Mahle forged pistons are dip-coated with a dry film phosphate coating. The intent of this coating (a proprietary material Mahle calls Grafal) is multi-faceted. This coating maintains consistency of tolerances in the ring grooves and provides added anti-galling protection in the pin bores. Since this coating is applied to the entire piston, it prevents any potential for microwelding inside the grooves. Another very notable benefit is provided by the coating’s compressible membrane, which “cushions” the piston skirt areas. This extends piston life, generates less noise (important for fuel-injected engines that use knock sensors) and reduces piston inertia as the piston rocks, which in turn reduces shock loads and harmonics that would otherwise be transmitted to the rods and bearings.
In terms of weight reduction and increased strength, Mahle’s “box in box” underside webbing structure works in conjunction with the narrower pin bosses to increase rigidity. Trey noted that this design is sometimes not feasible in applications that use aluminum rods, as these thicker rods may not provide adequate room for this design.
Another feature involves back-cutting the ring lands between the second and third ring grooves, which allows scraped oil to more quickly and efficiently be brought down to the oil ring package for superior oil control.

PISTON COATINGS

Once considered a “snake oil” treatment (in reality, nothing could be further from the truth), skirt coatings have now become accepted and commonplace. This generally involves an application of moly graphite (or similar material) to the skirt surfaces. This slick coating, especially when exposed to engine oil, offers a super-slick contact area for those occasions when the skirt touches the cylinder wall (cold starts, transitional rocking at top and bottom centers). This virtually eliminates skirt scuffing, saving both the skirts and the bore surfaces. The film buildup involved in this coating is so minimal that no honing compensation is required in terms of finished bore diameter.

Dome coatings consist of thermal-barrier ceramic applications. Shown here is a ceramic coating by Swain.

Moly graphite skirt coatings offer anti-scuff protection, providing insurance against potential damage during cold starts and piton rock. Thermal dome and moly skirt coatings shown here are from Polydyne.

Thermal barrier coatings (applied to the piston dome) are generally ceramic-based materials, which serves two purposes: since the coating reflects heat (acting as a heat barrier), a much greater percentage of combustion heat is maintained in the chamber for a more efficient burn. This coating also minimizes piston thermal expansion, since less heat is transferred into the piston body. This allows greater control of, or more even, thermal expansion, theoretically permitting the use of tighter piston-to-wall clearance. These coatings, available in a variety of “grades,” are especially suited to turbocharged applications, since some of these ceramic coatings can withstand approximately 2,100 degrees F exposure.
It’s important to note that by their nature, these hard ceramic coatings MUST be applied properly. If surface prep and curing is not executed properly, this material can flake off, which will result in severe cylinder wall and bearing damage. This is why it’s critical to have these coatings applied only by an experienced and skilled coating application shop that specializes in these treatments. In other words, don’t try this at home.
While not a coating, a hard-anodizing treatment inside the top ring groove has also gained acceptance in applications where ring micro-welding is a concern.

Sources

Dial 1-800-652-0406 and then the Quik-Link
number after a company to reach them directly!
www.precisionenginemag.com

PISTON MANUFACTURERS

Arias Pistons
13420 S. Normandie Ave.
Gardena, CA 90249-2212
Quik-Link #11054

CP Pistons
1902 McGraw
Irvine, CA 92614
Quik-Link #11055

Diamond Racing Products
23003 Diamond Dr.
Clinton Twp., MI 48035
Quik-Link #11056

Federal-Mogul Performance
26555 Northwestern Hwy
Southfield, MI 48034
Quik-Link #11057

JE Pistons, Inc.
15312 Connector Lane
Huntington Beach, CA 92649
Quik-Link #11058

KB Performance Pistons
4909 Goni Rd.
Carson City, NV 89706-0351
Quik-Link #11059

Mahle Motorsports
270 Rutledge Rd. Unit B
Fletcher, NC 28732
Quik-Link #11060

Probe Racing Components
2555 West 237th St.
Torrance, CA 90505
Quik-Link #11061

Ross Racing Pistons
625 S. Douglas St.
El Segundo, CA 90245-4812
Quik-Link #11062

Wiseco Piston Co.
7201 Industrial Park Blvd.
Mentor, OH 44060
Quik-Link #11063

Dart 11-Degree Big Chief Cylinder Head Specs
P/N………………………18500000
Material…………………355T6 aluminum alloy
Comb. Chambers……….56cc (70cc also available)
Intake valve dia…………2.470″
Intake port dim. …………1.815″ x 2.725″ w/3/4″ radius
Intake port volume………FP CNC – 497cc
Intake port location……..Raised 1.500″ spread ports
Exhaust valve dia………1.800″
Exhaust port volume……185cc
Exhaust port dim………..2.020″w x 1.780″h
Exhaust port location……angled & raised 0.900″ extended flange w/BBC bolt pattern
Intake flow………………520cfm @ 0.900″ lift/28″
SuperFlow 1020/+20cfm on SuperFlow 600
Exhaust flow…………….355cfm @ 0.900″ lift/28″
Lifter……………………..Use 0.180″ offset lifter
Manifold…………………Dart Big Chief Oval 1×4 bbl = 8″ tall
Milling…………………..56cc = 0.145″ (70cc = 0.080″)
Pistons…………………..Must use pistons for Big Chief head
Retainers………………..Titanium 10-deg
Spark plug………………0.750″ reach, gasketed Autolite AR3932
Spring cups……………..1.625″ – 0.060″ cup
Spring pockets………….1.740″ OD for 1.625″ cup (0.030″ deeper max)
Springs………………….Dart 1.625T = 330# @ 2.100″ / 0.910″ max Comp 948
Valve angles…………….Intake 11 deg x 6 deg Exhaust 7 deg x 4 deg
Valve length…………….Intake 6.600″ Exhaust 6.450″ (for 2.150″ installed height)
Valve stem dia…………..0.3415″ (11/32″) (5/16″ optional)
Valve train………………Jesel or T&D 11-deg rocker system
Valve guides…………….1/2″ OD Mag-bronze Cut for 0.500″ PC seals (0.002″ press)
Valve guide length………3.000″
Valve guide clearance……0.0014″ – 0.0021″ (with 0.3415″ dia. valve stem)
Valve guide spacing………widened for use on min. 4.600″ bore
Valve seats……………….Copper-Berylium, 0.008″ press
Valve seat dim. ………….Int 2.520″ x 2.00″ x 0.375″ Exh 2.000″ x 1.560″ x 0.375″
Valve seat angles……….. 55 deg
Head studs……………….ARP # 235-4312 (or Dart kit # 66120015)
Titanium valves………….Must use lash caps
Torque w/oil……………..Head bolts = 70 ft-lb
(Dart’s inner head studs 3/8″-7/16″ = 50 ft-lb
Manifold = 35 ft-lb
Block application………..Dart Big M, Mark IV, Gen V, Gen VI with proper head gasket
Cyl. Head weight………..42 lbs

The 0.5201 intake cam lift, when mated to our Jesel 1.85:1 rockers, will achieve an effective valve lift of about 0.962″. Lobe ramp angles are very shallow (to the eye, they look straight), so this pup should provide quite a rumpety-rump attitude.

Our roller lifters and valve springs were specially selected by Crane to suit our specific build.

This closeup shows the 0.180″ offset pushrod cup for the intake lifters, necessary for the Big Chief II 11-degree heads.

Our rocker system is a shaft roller setup from Jesel, featuring a hefty 1.85:1 ratio. Along with our custom Crane cam, this will provide nearly an inch of effective valve lift. Woof.

Our head gasket choice are MLS units from Victor.

Tri-Armor main and rod bearings from Clevite will create the necessary oil film to support our crank and rods. This is Clevite’s new line of coated bearings. The coating applied by Clevite is a proprietary polymer-based compound.

The Moroso billet gerotor style oil pump is a kick-ass unit with a built-in pickup screen, so there’s no worry about vibrating or cracking a pickup tube.

Here’s a closeup of the oil pump’s built-in pickup screen.

We opted for a Jesel belt drive for precision cam rotation.

We selected an 8″ ATI Super Damper to jive with our MSD flying magnet ignition system.

The Moroso wet sump aluminum oil pan is a recent addition to their line. The pan rail configuration requires extra tapped holes in the block’s rails.

Threaded plugs in the pan allow driver access to the center rail fasteners.

Moroso sheet metal aluminum valve covers will adorn the Dart Big Chief II heads.

The MSD Pro Billet distributor features a length that will accommodate the Dart tall-deck block.

The MSD flying magnet crank trigger will provide accurate ignition timing (this requires the use of an 8″ damper).

MSD Super Conductor plug wires are 8.5mm thick for carrying ample juice to this radical pup.

In order to take advantage of maximum coolant flow, and to eliminate the need for a water pump belt, we chose an electric pump from Meziere. This unit features a chrome finish, but black (and other colors) is also available.

Our giant-gulp carb is Holley’s 1150 cfm Dominator. This will be used if we opt for a single-carb intake manifold.

Depending on our intake manifold choice, we may run a pair of 1050s.

ARP threaded fasteners will be used throughout to anchor everything together. We opted for head studs instead of bolts.

Product Support
Thanks to the following for their involvement in this project…

Dial 1-800-652-0406 and then the Quik-Link number after a company to reach them directly!
www.precisionenginemag.com

ARP INC.
1863 Eastman Ave.
Ventura, CA 93003
Quik-Link #11064

ATI PERFORMANCE
PRODUCTS
6747 Whitestone Rd.
Baltimore, MD 21207
Quik-Link #11065

CLEVITE ENGINE PARTS
1350 Eisenhower Place
Ann Arbor, MI 48108-3282
Quik-Link #11066

CRANE CAMS, INC.
530 Fentress Blvd.
Daytona Beach,FL
32114-1200
Quik-Link #11067

DART MACHINERY
353 Oliver St.
Troy, MI 48084
Quik-Link #11068

DIAMOND RACING
PRODUCTS
23003 Diamond Dr.
Clinton Twp, MI 48035
Quik-Link #11056
HOLLEY PERFORMANCE PRODUCTS
1801 Russellville Rd.
Bowling Green, KY 42101
Quik-Link #11069

JESEL VALVETRAIN INC.
1985 Cedarbridge Ave.
Lakewood, NJ 08701
Quik-Link #11070

LUNATI
(see Holley Performance Products)
Quik-Link #11071

MAHLE MOTORSPORTS
270 Rutledge Rd., Unit B
Fletcher, NC 28732
Quik-Link #11060

MOROSO PERFORMANCE PRODUCTS
80 Carter Dr.
Guilford, CT 06437
Quik-Link #11072

MSD IGNITION
1490 Henry Brennan Dr.
El Paso, TX 79936-6805
Quik-Link #11073