Valve Lash, Solid Lifters, Iron Block, Aluminum Heads
 

Hi Gents,

I'm readjusting the valves on my stock L89 engine. I'm doing this cold. I read on another forum that with aluminum heads and with a cold adjustment, you will subtract .006 to .007 from the factory spec. My overhaul manual has the exhaust valves set a .028 and intake valves at .024.. that is the warm adjustment.

Can anyone give me a definitive on the cold adjustment with aluminum heads?

Thanks.

Phil W.

Bueller, anyone, anyone???

This is from an engine builder and his thoughts on this matter...

It is impossible to know the exact cold adjustment UNLESS you have set them hot and then check them cold for future reference. As an aside, the reason hot is used is that different parts expand differently which would require a chart for each valve when cold. Not worth it in my opinion. Always check hot...

Dave
67 Nova Boy

X2^^^^^

Thanks for the reply. Darrell found a sheet with tech tips from Crane Cams that says the correction is to subtract .006 from the stock warm adjustment. But, these should still be checked hot for absolute correctness.

Here's the tech tip for cold engine rocker adjustment:

Iron Block Iron Heads Add .002"
Iron Block Aluminum Heads Subtract .006"
Aluminum Block Aluminum Heads Subtract .012"

I started with .006 on my last small block and found later than .004 was the perfect cold adjustment to dial it in for the correct lash. Checked them all hot and found they we're spot on. Other engine combo's can be .005 to .007 and it all varies by components. Important thing is make sure you always check them hot and adjust as necessary before hitting the road.

Thanks for the replies. I will certainly do a hot check afterwards.

I wonder how the factory did it. Did they just set them cold and send them down the line, or did they run them and readjust??

Whatever the assembly plant did is unknown but I spoke to a dealer mechanic from the '60s and he told me it was standard procedure to readjust the valves (on solid lifter engines) hot after the car was delivered.

Verne

Take a guess how they warmed the engines up!