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Information Junky
Join Date: Mar 2001
Location: an island, upper left coast, USA
Posts: 73,167
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tolerances cold are wildly off from when it's at operating temp
Really?
let's see; valve stem spec. clearance (cold) is .030 to .057mm (thats new. ..plus w/ a .15mm wear limit !)
is that too tight when cold?
What if we look at Coef's of thermal expansion?
Alum ~CLTE=13.5 in/( in °F)x10-6
steel ~CLTE = 6.5 in/( in °F)x10-6
difference ~7 in/( in °F)x10-6 . . or, .000007 mm/mm/°F
valve stem ~9mm, and pick an outragously high "warm-up" Temp rise; say 500°F (above ambient)
.000007x500x9 = .032 mm
.032 mm is "wildly off"? . . .really?
__________________
Everyone you meet knows something you don't. - - - and a whole bunch of crap that is wrong.
Disclaimer: the above was 2¢ worth.
More information is available as my professional opinion, which is provided for an exorbitant fee. 
Last edited by island911; 04-29-2005 at 10:41 AM..
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