Once the camshaft is carefully inserted into place and checked for binding and alignment, DiSomma reinstalls the crankshaft. Once the crankshaft and mains are in place, the inner fasteners are torqued to 65 lb-ft and the outers to 35 lb-ft as specified by Dart.
Beyond torquing the mains, the crankshaft endplay must be checked (the movement of the crankshaft from front to back). DiSomma usually likes to see movement kept between 0.004-0.007-inch-ours checked in at 0.007-inch, which is within specification. It is now time to install the Comp Cams beltdrive (PN 6500) onto our little hell-raiser. This unit is bolted into place as easily as a stock timing would be.
After the main body is installed, the camshaft's endplay/thrust must be checked. Comp specifies that it should be between 0.002-0.007-inch. The thrust can easily be adjusted using the beveled retention plate shown. Adjustments can be made in 0.0025 of an inch. Once the thrust is set, the adjustable camshaft sprocket and belt can be installed. With the belt and unique idler, the Comp Cams beltdrive will help stabilize valvetrain harmonics and keep our timing in check.
DiSomma will now assemble the Wiseco pistons to the fully machined 5.7-inch Lunati connecting rods via the wristpin. In order to secure the wristpin in place, Spiro Lox are used. Spiro Lox are similar to a tightly wound Slinky and are carefully inserted into the groove machined in the piston. Beyond the assembly of all eight pistons and rods, the piston rings are filed to the builder's specification. In this case, the top ring is gapped to 0.030-inch and the second to 0.034-inch. While most engines require a tighter gap, blower engines generate more cylinder pressure, thus increasing heat. Therefore, a larger gap is used to deter against ring butting (closing of the gap). All rings should be checked using a feeler gauge in its future respective cylinder.
Next, the piston and rod assemblies are installed into the block utilizing a tapered ring compressor and the butt of a rubber hammer. Take note that the connecting rods are beveled on one side. This beveled edge should point toward the end of the crankshaft journal (putting the non-beveled edges of the rods together). The connecting rod end caps are then torqued.
With a myriad of tough components and a compression ratio of approximately 8.9:1, our blowerspecific bottom end is now complete and ready to receive additional components from Moroso, Air Flow Research, ATI Racing, Edelbrock, The Carb Shop, Holley, Fel-Pro, and more. So stay tuned for Part 2, as we try to get this baby completed and fired up on the engine dyno. Early speculation has us checking in at around 1,300 hp with highoctane race gas, but we'll see.
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M2 Race Systems
5140 W. Hurley Pond Rd.
Steve Morris Racing Engines