Fox Body Mustang Project: Engine Damage From Minor Parts

Sep 14, 2023

Since our project car's 350 cubic-inch engine uses a hydraulic-roller camshaft, the valvetrain does not require the feeler-gauge adjustment of an engine with a solid cam. We follow COMP Cams' directions for "zero-lash" valve adjustment. Ultimately, the adjustment is made to achieve preload on the lifters. Here are COMP's operations for intake and exhaust:

Intake: Turn the engine over by hand (or by bumping the starter) until the exhaust valve just begins to open on the No. 1 cylinder. Loosen the intake-valve adjusting nut slightly until lash (resistance) can be felt in the rocker arm. While spinning the pushrod with your fingers, tighten the adjusting nut, and when a slight resistance is felt, the valve is at zero lash. Turn the adjusting nut an additional 1/4 to 3/4 of a turn past this point (depending on the cam manufacturer's specs) to achieve optimal preload on the lifter. Follow this procedure to adjust each intake valve according to the firing order (1, 3, 7, 2, 6, 5, 4, 8).

Exhaust: Turn the engine over until the intake pushrod moves all the way up, and then just past maximum lift, where the intake valve starts to close. The lifter is now at the base circle, and the exhaust valve can be adjusted by following the same steps of spinning the pushrods and tightening the adjustment nuts. Pro tip: Do not go too far (more than halfway) past the point of maximum lift.