I just finished breaking in the new cam, and had a chance to dump the oil and filter and go through the valves. Every one was exactly where I adjusted it prior to the breakin, is this common, I thought they would loosen up. If it matters the rockers and heads were previously run in with a different cam. I set them at .021 cold (aluminum heads). Should I check them when its hot? I hate working on a hot engine, besides I would think by the time you get through all the valves the temperature of the parts would be on the way down. Your thoughts, Thanks Rich

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Originally posted by 67ragtp:
I just finished breaking in the new cam, and had a chance to dump the oil and filter and go through the valves. Every one was exactly where I adjusted it prior to the breakin, is this common, I thought they would loosen up. If it matters the rockers and heads were previously run in with a different cam. I set them at .021 cold (aluminum heads). Should I check them when its hot? I hate working on a hot engine, besides I would think by the time you get through all the valves the temperature of the parts would be on the way down. Your thoughts, Thanks Rich

Http://community.webshots.com/user/67ragtp =
Rich,
With aluminum heads I adjust the valves .004 tight cold & they come out real close hot. You definitly need to check them hot with your heads.
If they were the same after run in it just means you did a good job of adjusting them the first time graemlins/thumbsup.gif
Be sure to use the EO/IC method for the final adjustment.

Mike i always set my valves going through firing order at tdc on both intake and exhaust !! Car always ran fine and wonder if i could be inaccurate this way and how much off? UD 276/284F6 IN 327 SBC. THANKS for any info, AL

Al,
I do it this way (TDC)when I assemble an engine & then redo them after breakin. Depending on cam you will probably find some loose.
Not by much but next time you check them try it both ways & see if you don't find a little difference ;)

Sounds like your pretty good at setting lash graemlins/thumbsup.gif Ive done them on imca circle cars cold checked them after a heat race and been about perfect. I guess 20 years of exp just gives you a feel for it.

67, just go ahead and check a few hot to see exactly what the hot/cold differential is for your motor. then do 'em cold. Mike, that's what I've been, there shouldn't be any changes among the valves hot, should there?

Love lashing them hot, running using the old "feelie" method!

Then I know I got them the way I want them!

pdq67

The lash needs to be checked once the motor is up to operating temperature. This is the only real way of knowing if your lash measures the cam manufactures recommendation. By checking the lash once it's cooled down again will not tell you what you need to know.

Tino

The valves always checked at the same hot or cold ( -4).

I always set them cold....I will recheck them hot to see if they are where they are suspose to be...IE my my iron block / iron head SBC's liked .002 more set cold to bring them to where they should be hot.

My iron block / iron head BBC likes .003 more when cold to bring to where they should be hot.

I have long ago given up actually lashing them hot.

Originally posted by 427L88:
67, just go ahead and check a few hot to see exactly what the hot/cold differential is for your motor. then do 'em cold. Mike, that's what I've been, there shouldn't be any changes among the valves hot, should there? =
Gene,
Yes, once you know the difference on your engine setting them cold works fine.
On small blocks I set them .004 tight on aluminum & on iron heads I set them .002 loose & recheck them hot.
On rats it's closer to -..005-006 aluminum & +.003 iron as Al said.
Also, if I have to readjust much I like to recheck them cold so I can tell my customer what to set them to either way but have found it doesn't vary much from the above numbers.
When you get down to a thou it depends on who is adjusting them anyway :D
But,,, it's a lot easier checking them on the dyno. :D

I think I will pop a cover off the next time I get it up to operating temp. The engine is an iron block aluminum head 540. The cam is one of harolds grinds and the lash is .026. I figured if I went to .021 cold I would be assured of getting the full lift of the cam at operating temp with a .004 t0 .006 expansion in mind.

Rich