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The valve reliefs were cut with precision. The intake pockets are 0.270″ and exhaust pockets are 0.064″.
Notice that the pin bore location encroaches into the oil ring groove. Diamond supplied a set of support rails that are installed prior to the oil ring package. These provide footprint support for the oil ring package.
Scott Gressman torques the honing plates to our block, tightening to 70 ft-lbs.
Before honing, Gressman grinds clearance on the center main webs to prevent stone damage.
A view through this bore shows the slight material removal necessary for honing stone clearance (see the area below the cylinder wall).
This closeup provides a better view of the small casting “hump” on the main web, after Gressman removed about 0.030″ of material.
Each cylinder was honed to 4.599″during the first honing stage. Final honing opened the bores up to 4.60075″.
Piston diameter is made 90-degrees to the pin bore, at 0.700″ below the ring land.
Gressman verifies honed size prior to plateau finishing.
In order to finish the bores, Gressman used silicon carbide brushes. This will provide good seating for our plasma moly top rings.
Our finished cylinder walls.
This closeup shows the brush-finished hatch pattern.
While at Gressman’s shop, we mocked up one rod to check for rod-to-block clearance.
Dart thoughtfully clearanced the block for stroker crank use. In our case, our Lunati counterweights cleared the block by a mile (actually, the tightest area was about ?”), so we’re fine with regard to crank fit.
Our Lunati 4.7500″ stroker crank was extremely well finished, with mains all the same diameter and rods all the same. Every journal was ground straight, with absolutely no taper to be found. Nice job, right out of the box.
While test fitting our crank, we used the bearings that we’ll install during final assembly. All of our Clevite bearings have been treated to a special anti-friction coating, which Clevite tells us is even better than conventional moly graphite.
This view through the cam tunnel shows a potential clearance issue between the rod big end and the camshaft. Just to be safe, we’ll remove a bit of material from the rods. This is not uncommon when dealing with a long stroke.
Here Gressman points to the area of the rod that should be clearanced (at his fingertip).
This view clearly shows the area (the small radius hump) adjacent to the bolt hole exit that we’ll relieve. We’ll probably only remove about 0.020″ or so, at a slight angle that leans towards the rod beam.
In each case, only one hump needs to be relieved on each rod. This is the hump that is opposite the rod big end’s bearing tang area.
After we grind a small bit of material from each rod big end, we’ll rebalance our rods.
Each of our main journals measured exactly the same, at 2.7495″.
Our installed main bearings measured 2.7535″.
All rod journals measured 2.200″.
Each rod bearing (installed, with caps fully tightened to 70 ft-lbs w/moly), measured 2.2035″. We’ll monitor bolt stretch during final assembly.
Sources
Our special thanks to Gressman Powersports
for honing our block’s cylinders to size.
Gressman Powersports
For more information, dial 1-800-652-0406, ext. 13415
Online, visit www.precisionenginemag.com/info/13415
PRODUCT SUPPORT
Thanks to the following for their involvement in this project …
ARP INC.
For more information, dial 1-800-652-0406, ext. 13416
Online, visit www.precisionenginemag.com/info/13416
ATI PERFORMANCE PRODUCTS
For more information, dial 1-800-652-0406, ext. 13417
Online, visit www.precisionenginemag.com/info/13417
CLEVITE ENGINE PARTS
For more information, dial 1-800-652-0406, ext. 13418
Online, visit www.precisionenginemag.com/info/13418
CRANE CAMS, INC.
For more information, dial 1-800-652-0406, ext. 13419
Online, visit www.precisionenginemag.com/info/13419
DART MACHINERY
For more information, dial 1-800-652-0406, ext. 13420
Online, visit www.precisionenginemag.com/info/13420
DIAMOND RACING PRODUCTS
For more information, dial 1-800-652-0406, ext. 13421
Online, visit www.precisionenginemag.com/info/13421
GEAR HEAD TOOLS
For more information, dial 1-800-652-0406, ext. 13422
Online, visit www.precisionenginemag.com/info/13422
GOODSON TOOLS & SUPPLIES
For more information, dial 1-800-652-0406, ext. 13423
Online, visit www.precisionenginemag.com/info/13243
HOLLEY PERFORMANCE PRODUCTS
For more information, dial 1-800-652-0406, ext. 13424
Online, visit www.precisionenginemag.com/info/13424
JESEL VALVETRAIN INC.
For more information, dial 1-800-652-0406, ext. 13425
Online, visit www.precisionenginemag.com/info/13425
LUNATI
(see Holley Performance Products)
MEZIERE ENTERPRISES INC.
For more information, dial 1-800-652-0406, ext. 13426
Online, visit www.precisionenginemag.com/info/13426
MOROSO PERFORMANCE PRODUCTS
For more information, dial 1-800-652-0406, ext. 13427
Online, visit www.precisionenginemag.com/info/13427
MSD IGNITION
For more information, dial 1-800-652-0406, ext. 13428
Online, visit www.precisionenginemag.com/info/13428
SUNNEN PRODUCTS CO.
For more information, dial 1-800-652-0406, ext. 13429
Online, visit www.precisionenginemag.com/info/13429지
Tags: BEARINGS, CYLINDER BORE HONING, DIAMOND PISTONS, GRESSMAN POWERSPORTS, LUNATI, MAHLE CLEVITE, MANUFACTURER LIST, ROD CLEARANCE, STROKER CRANK, TORQUE PLATES
