Comp Cams SOLID flat tappet CAM in a 350/383 with AFR 195 Alloy heads.

Cam card says 0.016 hot adjust.

i have a disability and find it hard to get the engine to 180f
pull the rocker covers HOT.
get burnt a few times and start adjusting rockers at EOIC comp cams method.

By the time i get a few cylinders done the engine is no longer HOT.

Done my best and by the time i got 1 side done at 0.016 car runs good,, sounds great,,
but rattles at 5500 to 6200rpm and you can feel it through the car.

whats the cold setting,,,,,, if alloy heads on a sbc
when they say hot 0.016 thou.

worried i will flog the cam out if i keep pushing it.
CAM is comp cams 12-678-4
CS XS 282S-10
solid flat tappet and i love it.

Sent Comp Cams an Email 5 weeks ago and 2 weeks ago ZERO REPLY

i am in Australia.

 

Best you can do, is to kinda guess, based off of the coefficient of thermal expansion of aluminum & cast iron vs steel; and the relative temperatures of the parts (valves get MUCH hotter than anything else, and therefore grow more, but it's hard to know by how much). And since you have no way of predicting EXACTLY what materials and temperatures you're working with, the best you can do is to get close, then check one when it's hot, and see how far off you were, and alter your setting accordingly.

Rule of thumb for SBC is that you'll gain about .003 - .004" or so of lash from cold to hot. So, set them to, say, .013" cold, and see how close to .016" one of them is when hot. Expect the int to gain more lash than the exh, so check one of each, in case they're different enough to warrant adjusting differently.

You can speed up the process CONSIDERABLY by realizing that the valves of a type all operate at exactly 90° of crank rotation from each other, in the firing order. So you could set, say, #1 intake using EOIC, then rip through 8436572 at 90° crank intervals. Then do the same for exhausts. Doesn't matter of course which cyl you start on as long as you do em in the order.

Also realize that the exact "IC" point for adjusting the exhausts is just after the intake opens, and the "EO" for adjusting the intakes, is just before the exhaust opens. Careful consideration of valve motion vs piston motion makes it clear. The correct adjustment point is when the lifter is perfectly on the heel of the lobe, i.e. exactly opposite the lobe tip, i.e. exactly 180° of cam rotation (360° of crank rotation) away from the tip of the lobe. Think of what the exh valve is doing as the engine rotates, and you'll see that it's at its max open (on the tip of its lobe) at the middle of the exh stroke. Therefore, since you want to adjust it when it's on its heel, that will be at halfway through the compression stroke. The int closes just after the beginning of that stroke, therefore the exh max closed point is a few degrees after the int opens. Since the int closes not long after beginning of the compression stroke, and the exh is on its heel at halfway through that stroke, then that's in the neighborhood of 45 or 50° of crank rotation after the intake closes; ¼ to ⅓ of the piston stroke, which is how far the engine rotates from the intake fully closing somewhere after BDC and the exh adj point at halfway between BDC and TDC. Therefore, find IC, then rotate the engine that extra little bit, then adjust the exh. Similarly, the intake is fully open right about the middle of the intake stroke, halfway down from TDC to BDC, so you want to adjust it when it's exactly 180° away from that, which would be halfway through the power stroke. The exh begins to open near the end of the power stroke, therefore the point you want to adjust it at is just before the exh begins to open. So, find the initial cyl's EO point, then rotate the engine 60° or so back, then 15° or so forward to take up all the chain slack and whatnot, and adjust that int. Precision in always landing perfectly exactly on those points will help consistency in adjustment because you won't be even the tiniest bit up on the ramp due to not being exactly on the heel of every lobe.

 

Mine said .020 hot, i set it them all to .014ish cold. Aluminum heads and iron block. Everything I read was same metals same hot and cold, aluminum heads and iron block -.006 cold.