I have always set mine cold.Same every time unless I wanted to make a change for some reason. I never worried about exact number hot.If set same cold they will be same when hot. I also never worried about exact recommendation on card. I start out in that area and make changes to see if engine is happier.If it picks up at say .010 instead of .014 cold then it is .010.
It is not a must have number like rod clearance. No magic number for every engine combo with that one cam.
On bracket car I would set close to mid range if unknown recommendation. Run it, make minor change the next week and see how it likes it. Doubtful that change will effect consistency for the weekend. I would do that for cpl 3 weeks to see where car wanted to be. then set on what ever you maintenance schedule is.For me it is every week before leaving shop,but then I like the working on as much or more than the run.
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I have an all aluminum SBC, I set my lash at .006 cold and end ends up right at .020 hot. I used to run an all aluminum BB Mopar it would gain more clearance than the SBC. I think it makes a difference on the castings you are dealing with as to how much clearance you gain when hot. I also run tighter main clearance with my aluminum blocks.
Originally posted by DRB Motorsports: since im making the switch this winter, how about aluminum on aluminum ? i normally set em cold and let her eat.
I have a 632 BBC, all AL. Cold I normally use .008 for .024 hot, but temp matters so it can range from .006 to .009 depending on the outside temps. I check a few valves first to get a good feel of the temp effects then go from there. During the summer months it's pretty consistent but if does move around during the spring and fall!
I would stay away from a tight lash cam with this combo or you could have open valves when the lifter is on the base lobe in some conditions which could require block heaters.
My all aluminum BBC picks up .010 cold to hot. I set .012 cold using go no go and is .022 hot. If I have time I will pull valve covers every pass and check lash, just looking for something abnormal, rarely adjusting anything. Takes like 10 minutes to run thru them all. On more than one occasion I have found a intake or exhaust valve on a end cylinder that gained .010 lash caused by a stand bolt coming loose and stand lifting up, disaster in the making if I didnt check after a pass
Posts: 2569 | Location: Moving back to the door side | Registered: April 30, 2010
Originally posted by 1320racer: Al, my cam’s lash spec is .018 hot, definitely very close to or at zero lash cold.
.006 won’t go when cold.
I lash my valves between 155-165
That aligns to what we see, my cam's hot lash allows me to do it cold, but in the spring and fall, using a .006" feeler gauge is pretty thin, couldn't see using anything thinner for sure! One my friends 9 degree deal, he has a tight lash cam (.014 hot) so he has to warm it up. Two block heaters for each side of the block work well.
