Adjusting Big Block Lifters

[Mark A.]

When I reassembled my 69 390 hp engine, I adjusted my lifters by turning the pushrod with my fingers until it would not move, then went about 1/8 turn more. The engine ran fine. I looked in the shop manual, and it says to go 1 turn past 0 preload. I reset the lifters to this spec, and the motor would not run due to the valves being held open. I reset them back to where I initially had it, and the engine runs great. Why does the shop manual state to adjust the lifters this way? Thanks for the help. Mark

[Wayne W.]

Re: Adjusting Big Block Lifters

That is exactly the way stock lifters are adjusted. One turn down. You have to give them time to bleed down though.

[Don W.]

Re: Adjusting Big Block Lifters

Here's a good reference article....Don

http://www.corvette-restoration.com/resources/technical_papers/Valve_Lash.pdf

[Duke W.]

Re: Adjusting Big Block Lifters

I prefer to jiggle the pushrod up and down until you can't feel any play, then go 1/2 to 3/4 turn. If the pushrods are well lubricated, you usually can't feel an increase in turning torque until the lifter already has some preload.

The other issue is crankshaft indexing. AFAIK all Chevrolet hydraulic lifter cams are on the base circle when the piston is at TDC of the compression/firing stroke.

Duke