94mm Big Bore Piston Kit Instructions

Application: Pro Forged Piston Sets

Boring and honing the cylinder is critical for the long life and maximum performance for your new forged piston kit. Follow these instruction.

For best results, we recommend using a Sunnen-CK10 power hone with a torque plate. Torque to 60 ft. lbs. to prepare cylinder walls. Bore and hone cylinder block to provide clearance as follows:
Street Applications: 0030 to .0035
Racing, Turbo & Nitrous Applications: .0035 to .0040
Measure piston skirt at 90? degrees from the piston pin center line and .500 above the bottom of the piston skirt.
When using plasma/molly rings, hone cylinder walls with 625 grit stone. Always wash cylinder walls thoroughly, clean first with solvent and then clean a second time with hot soap and water. Scrub cylinder walls with a non-metallic scrub brush (scotchbrite pad) to loosen and remove honing grit. After washing thoroughly, dry cylinder walls and block using compressed air. Next apply a light coat of WD-40 rust inhibitor.

For other ring manufacutrers, follow the specifications for cylinderwall honing and preparation of that manufacturer.

Before assembly, wipe cylinder bores with a lint free cloth, and apply a light coat of 30wt. motor oil. Break in period is approx. 100 miles. Do Not break in using synthetic oils. We recommend using a 20/50 mineral based oil for the first 5000 miles prior to switching to a synthetic motor oil.

Check Valve to Piston Clearance when engine is assembled. You must have .100? minimum piston to valve clearance. Follow procedure below:

Lash #1 intake valve to zero then screw intake valve in .100? (Valves not closing completely). Turn engine over carefully by hand with spark plugs removed. Check intakes first, if OK then Check exhaust. If engine cycles without binding, you are sure that you have minimum clearance. (If binding occurs piston clearance is required).

Warning: Do Not mix wrist pins from balanced piston sets!!

Back to Tech Engine Page