LS2/L92 Engine Package - Blue Collar Workhorse- Tech

...The pin-to-piston clearance is also checked on the Mahle pistons, and are within spec.

Bobweights are created to simulate the measured reciprocating mass by 50 and 100 percent of the rotating mass; the weight of the pistons, wrist pins, and rods naturally make up this mass. Drilling the Callies crank accordingly (in the purpose of balancing it) preserves the integrity of the bearings and the rest of the supporting structure, including the block, which would otherwise be subject to harmful vibrations. General balancing guideline is 12 grams on a 1-inch radius for a street crank, 6 grams on a race car. This crank has a 3.5-inch radius and starts at 19 to 20 gram-inches out of balance, until Rinaldi achieves around 1.0 gram per inch of balance. Few machinists and shops are capable of producing...

...such a precise level of balancing, but Rinaldi has more than 24 years of experience, mostly on circle track racing engines. This is exactly why Chad Golen recruited him to join the team, and his immense pride in his work is evident as he deburrs all of the holes in the crank counterweights before jet-washing. Please note that the crank shown and used in this build is the lighter-weight Dragonslayer model, whereas Golen's base package will use the more economical Compstar model.

The rods are pulled apart prior to assembly so that the machined parts can be jet-washed. Thankfully, Compstar (Callies) numbers the rods and caps to avoid confusion after they are disassembled. The caps on these sturdy H-beam 4340 forged rods are also interlocking (or gusseted), making them especially difficult to come apart-hence the vice. Good for the future owner, bad for the builder. After the rods and bolts are washed, the clearance is checked again to determine additional bolt stretch. Fortunately, resizing was not necessary.

The Compstar rods and Mahle coated pistons are mated via the wrist pin and locks, with ample lube placed on the wrist pin for assembly. These two high-quality components are not the cheapest on the market, but provide nearly unlimited potential, due to their durable design and relatively light weight.

Mahle's low drag rings are one of the many high-performance features of these quality pistons, which work in concert with the ultra-flat ring grooves to produce more power, according to Mahle. The first ring to be inserted is actually the oil support rail (opening goes above the pin). The three-piece oil ring goes next,...

...then the second ring and top ring. For street/strip applications such as this, Mahle recommends boring a .0045-inch gap for the top ring, .0055 inch for the second ring, and a minimum of .0015 inch for the oil ring. There are different endgap specs for varying levels of nitrous and blown applications; the top ring needs to be filed at least .018 inch, and the second .022 inch. Incorrect endgaps will cause the rings to butt and peel off (if too small)...

...causing cylinder and piston damage, or excessive blow-by (if too large). Each ring is sized in the bore in which it will be placed. After each ring is filed down, Rinaldi chamfers the ends smooth. The ring endgaps must be oriented on the piston according to a diagram that Mahle devised for optimum performance.

After the virgin block has been thoroughly washed, the Golen spec hydraulic roller from COMP Cams is gently lubed and inserted. The cam plate secures it by being torqued with 18 lb-ft of force.