ZL1 Cam Cold Lash
 

From what I could find, the 9181 ZL1 has a hot lash of I=.024, E=.026 ? Anyone care to give a cold lash setting? I’m guessing subtract .002 off the above specs? Any help appreciated. Thanks sYc.

With iron heads you want to ADD 0.002"

What if engine has factory aluminum heads? Still add .002?

I set mine as per specs w/alum heads and had no issue. Larry

Head material?

Block material?

Iron&iron. Basic L72 w zl1cam

Iron heads & block add .002. With aluminum heads set cold lash tighter about .005-.006 on a rat motor. If it’s aluminum block & heads about .010 tighter cold. The thermal expansion of aluminum causes the lash to increase hot.

Like you said, I would go .002” LESS than the hot lash spec. ‪for break-in.‬ Then
‪with the engine at running temp, shut it off, and set the valves on one cylinder to the Hot lash on the cam card.‬
‪Let the engine fully cool down. ‬
‪Measure the lash on that cylinder that you set hot.‬
‪That will be the cold lash setting to use on all the cylinders.‬

If it is a aluminum block and heads set .012 tighter when cold. .012 .014 You will be very close to your .024 .026 when hot.

Trusting my own experience, and your reassurance, I set them .002 tighter or I.022-E.024. Great idea on the reverse calculating lash method.