ProComp/Speedmaster aluminum heads
I dont get what ur saying. I have alumn. heads, cast iron block , and set mine at .011-.012 cold , they are always right at .018 when hot . I round it off instead of worrying about a .001 or two on a .600 lift cam .
Like I said , more than one have advised that way w/ alum. heads.
I am getting ready to adjust them for the 5-6 time in 9-10 yrs, altho it doesnt have a heck of a bunch of miles on it -----------------
Ok, so your stuff grows .006-.007 from cold to hot. And that makes sense. So what I’m saying is that if you had iron heads and an iron block you would probably need to only set the cold lash .002-.004 tight to get your hot lash.
OTOH, if you took your heads and bolted them to an aluminum block, you’d probably have to lash them at .002 cold to get your .018 hot lash. That’s because the aluminum block grows so much more than an iron head.
That’s what I’m saying. Somehow, Harvey Crane OE someone else have published that when setting cold lash with an iron block and heads you set the lash at .002-.004 LOOSE cold and when the engine gets hot the lash will close up.
I can tell you that is 100% wrong. I’ve not seen any cast iron head, cast iron block ever LOSE lash from cold to hot. Ever. So for starting out on cold lash I always say:
Cast iron heads and block set the cold lash .002-.004 tighter and then check what your hot lash is and adjust accordingly.
Aluminum heads and cast iron block cold set the lash .004-.006 tight cold and check your hot lash and adjust accordingly.
Aluminum block and heads is a bit more tricky because of the mass of the block. I say start at .010-.012 tight on cold lash and check the hot lash and adjust accordingly.
Ive seen aluminum heads and blocks grow .020 or more. The all aluminum hemi seemed to grow more than the all aluminum wedge stuff.
I hope that makes sense.