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The next carb-type setup involves the same intake manifold and carburetor, but with a twist-get rid of the eight individual coilpacks and mount a distributor at the front of the engine. GM Performance offers a distributor adapter kit (P/N 88958679) that includes a cast aluminum LS front distributor drive cover (this replaces the OE front cover) designed to accept a Ford (yes, Ford) smallblock distributor. The kit includes a stubby camshaft front extension that bolts to the existing cam and provides a drive gear for the distributor.
Performance Distributors offers a way-cool Ford smallblock distributor, already fitted with an HEI coil. Remove the OE front cover, install the GM cam adapter and cover, drop the distributor in, set your timing and go. No computer, no timing module, just a carb and an electronic distributor. Performance Distributors even offers a ready-to-install set of spark plug wires for this setup. By the way, the distributor housing also provides a mounting location for a mechanical fuel pump to the engine-right of the distributor.
Since the distributor housing is, well, large, it’s obvious that the OE design water pump won’t fit anymore. Wegner Motorsports, in cooperation with Stewart, makes a unique LS water pump that is designed to work with this setup. The GM distributor housing kit runs approximately $350-400+ and the special water pump will run around $400 or so. In outward appearance, in essence, it kinda resembles an OE-style pump with longer legs to clear the distributor housing. In addition, because the water pump pulley now sticks out further from the block, you’ll also need a special pulley system that is also available from Wegner.
The only problem I encountered was actually obtaining one of the GM front distributor drive cover kits. I ordered one about three months prior to writing this article, and I’m still waiting. I ordered it through SDPC, but it’s not the company’s fault. Apparently, GM doesn’t stock many of these on the shelf, so (at least going by my experience) if you order one through GM, be prepared to wait. It’s unfortunate, since I had planned to show the engine equipped with this carb and distributor combination in this issue. But as we all know, sometimes things just don’t go as planned. The GM adapter kit is listed on P. 275 in the 2008 GM Performance Parts catalog.
By the way, while I was finishing this article I learned that the distributor adapter kit is actually made by Wegner for GM, so apparently you can buy one direct from Wegner. Had I only known. Because of the added cost in executing a carb/distributor conversion, you’ve really gotta want this setup to justify the expense.
INJECTION SETUP
Professional Products Power+Plus Typhoon intake manifold kit (P/N 52063) includes a satin-finish cast aluminum manifold; a pair of red-anodized aluminum fuel rails; a -6 fuel transfer hose assembly already assembled and ready to connect the two fuel rails at the front; intake gaskets; 6mm x 1.0 x 90mm intake manifold cap screws and washers; extension hose assembly; fuel inlet fitting; 90-degree fittings and a reducer fitting, along with a variety of additional fasteners. Basically, the kit includes everything you’ll need to install and plumb this manifold.
By the way, this intake manifold also features blank bosses that can be drilled and tapped to 1/8″ NPT in order to accept nitrous injection nozzles.
This intake manifold will accept a 96mm LS2-type throttle body (stock or aftermarket).
When tightening the intake manifold bolts, Professional Products recommends that you make two passes. The first pass involves tightening the bolts to a value of 44 lbs./in. The second pass is at 89 lbs./in. Once the engine has been run, has reached operating temperature and has cooled, re-torque to 89 lbs./in. The torque sequence must be followed during each tightening pass. The supplied 6mm manifold bolts are cap screw style, so you’ll need a 5mm hex wrench bit for your torque wrench.
Follow the manifold’s instruction sheet for remaining connections for sensors, fuel, vacuum and coolant lines. Since this manifold may be installed on either an LS1 or LS2, some differences exist in terms of OE connections. For instance, for an LS1-equipped vehicle, the MAP sensor installs to the front of the manifold. On an LS2-equipped vehicle, the MAP sensor is located on the rear of the manifold. Our manifold features a MAP sensor installation port on the front right side, just behind the throttle body location. The sensor is secured with a single 4mm x 0.5 x 5mm long screw supplied in the manifold kit. The MAP sensor location is easily changed if needed. If the vehicle harness requires the sensor at the rear of the manifold, simply drill a 0.440″ hole in the blank boss on the manifold’s rear wall, and drill and tap a 4mm x 0.5 thread pitch screw hole. The front MAP sensor hole can easily be plugged.
Note: When installing the fuel rails, the manifold kit features L-brackets that secure the fuel rails to the manifold. Pay attention to these. The longer bracket leg features a long slot hole. This long-slot leg must be positioned onto the manifold (the short leg installs to the fuel rail). If these brackets are installed incorrectly, you will place an off-angle load at the injectors, which may result in a fuel leak.
INJECTION MANIFOLD TIGHTENING SEQUENCE
1. Center on left side
2. Center on right side
3. Second from front, left side
4. Second from rear, right side
5. Second from rear, left side
6. Second from front, right side
7. Front, left side
8. Rear, right side
9. Rear, left side
10. Front, right side
If you’re building an LS2 engine from scratch and you don’t have a donor assembly to start with, be aware that fuel injector sizes differ between the LS1 and LS2 in terms of physical dimensions. For example, the injector bores in the intake manifold are 13.9mm in diameter on an LS1 manifold, but 14.7mm on an LS2 manifold. Also, injector body overall length differs. The LS1 takes a long injector (about 77.35mm overall length) and the LS2 takes a short injector (about 65.90mm overall length). You can swap between the two since various companies offer conversion kits that include O-rings, fuel rail bracket spacers and/or shorter brackets and harness connector adapters.
Stock injectors for an LS1 will work, but will require a Katech adapter kit (P/N KAT-A4096), which includes longer fuel rail mounting bolts, bolt spacers and larger LS2-type lower O-rings. This kit sells for about $40 and is available from a number of outlets, including Katech and Scoggin Dickey. Or, you can use injectors part numbered for a 2005-2006 LS2 Corvette (Bosch P/N 0280-156-049 or AC Delco P/N 217-1627). Either provides about 30 lbs. pressure at the injector. For higher horsepower demands, you’d then likely want to step up to larger injectors during the tuning process, maybe 39 lbs. or higher, which can always be tuned by adjusting injector duration via computer adjustment. For example, 0280 156 117 injectors are the short LS2 style, capable of 60 lbs., which can be “dialed down” by injector duration adjustment.
The injectors we installed are Bosch (P/N 0280 156 127, rated at 39 lbs. at 39 lbs. pressure) which is the EV6 style (a tick over 3″ long). The LS2 injectors (such as the 30-lb.-rated 0280 156 049) are about 2.5″ long with a fatter lower O-ring. If you have an LS2 manifold, either injector will work. LS2 injectors will drop right in, while LS1 injectors require the LS1-to-LS2 adapter kit, which is made by Katech and available through several suppliers, including Scoggin Dickey.
The kit (P/N KATA4096) sells for about $25. The adapter kit includes four .500″ tall fuel rail bracket spacers, four 6mm x 1.0 x 30mm bolts and a full set of larger-diameter LS2-style lower O-rings, which measure about 0.586″ in O.D. (remove the injectors’ original lower O-rings and install the kit’s larger O-rings). O-ring sizes are as follows: Original O-rings on the LS1 style injectors feature an outer diameter of about 0.563″ and a thickness of about 0.137″; the large LS2 O-rings that fit the LS2 manifold feature an O.D. of about 0.586″ and a thickness of about 0.155″.
Just for the sake of length comparison, the Bosch 0280 156 049 (originally a GM LS2 injector), measures 2.575″ in overall length. The Bosch 0280 156 127 injector measures 2.917″ in overall length.
The issue of injector selection can get pretty hairy if you’re not an injection tuner specialist, but this at least gives you a starting point. Since we anticipate making around 500 horsepower, we felt that LS2 OE 30-lb. injectors were a bit on the light side, so we opted for the 39-lb.-rated injectors. Of course, if you’re a tuner and know what you’re doing, you can always manipulate injectors via programming to achieve various output pressure rates.
The Professional Products EFI manifold will not accept stock OE fuel rails. The performance aluminum fuel rails supplied in the kit must be used. When installing the injectors, be sure to first lubricate the upper and lower O-rings with oil or silicone spray. Once seated in the manifold and fuel rails, gently rotate each injector to verify smooth rotation.
The subject of fuel injector selection can be quite daunting to engine builders who are not seasoned “tuners” of electronically controlled, fuel-injected engines.
Note: While physically interchangeable, LS1 and LS2 intake manifolds differ in terms of fuel injector bore size (the hole into which the injector seats). LS1-style intake manifolds feature an injector bore diameter of 13.9mm, while the LS2 manifold features a larger 14.7mm bore size.
One thing to remember: Just because the injector physically fits the application that doesn’t mean that it will perform properly. Injectors must be selected based not only on the injector’s own pressure rating, but in conjunction with the system flow pressure, which takes into account the fuel pump, the intake manifold volume, etc.
CRANK DAMPER
Our ATI damper hub features an interference fit. Using a small convection oven, I heated the hub to 200 degrees F (I monitored temperature of the hub with an infrared pyrometer). With a light coat of anti-seize on the hub I.D., I was able to slip the hub onto the crank snout, aligning the key pin I installed on the snout earlier.
Using ARP’s damper bolt, and with ARP moly applied to the bolt threads and both sides of the washer, I tightened the bolt to a value of 235 lbs./ft. I did this in three equal steps. Note that the OE instructions advise tightening the OE bolt to 110 lbs./ft., backing off one turn, then re-tightening to 35 lbs./ft., plus an additional 110 degrees. I spoke with ARP and they advised me to simply use the 235 lbs./ft. value (with their moly lube), when installing their damper bolt.
The ATI Super Damper (featuring an integral crank pulley) was then installed onto the hub using six flat-top 5/16″ x 18 x 1″ screws, each treated to a dab of thread locking compound. Using a T40 torx bit, these six screws were snugged to 16 lbs./ft. Note: If you expect to run an a/c compressor on the engine, you must first slip the ATI a/c pulley onto the hub before pressing the hub onto the crank. Once the damper is installed, the a/c pulley is then secured behind the crank pulley with three 3/8″ bolts and washers.
SOURCES
AC Delco
(800) 652-0406, ext. 16420
ARP
(800) 652-0406, ext. 16421
ATI
(800) 652-0406, ext. 16422
Edelbrock
(800) 652-0406, ext. 16423
Fel Pro
(800) 652-0406, ext. 16424
Katech
(800) 652-0406, ext. 16425
Moroso
(800) 652-0406, ext. 16439
MSD
(800) 652-0406, ext. 16426
Performance Distributors
(800) 652-0406, ext. 16427
Permatex
(800) 652-0406, ext. 16428
Professional Products
(800) 652-0406, ext. 16429
Scoggin Dickey
(800) 652-0406, ext. 16430
Wegner Automotive
(800) 652-0406, ext. 16431
Tags: ARP, ATI, BOSCH, DAMPER, EFI, FUEL INJECTION, FUEL INJECTOR, INTAKE MANIFOLD, KATECH, LS, LS2, MOROSO, MSD, PROFESSIONAL PRODUCTS, PROJECT ENGINE
