Quote:
Originally Posted by psalt
The expansion of the stem under operating conditions is 0.0005" (ferritic) or 0.00075" (austenitic).
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This is .0005" per inch right?
Its normal to see timing cards with an additional .002" on the exhaust side vs. the intake because the valves can grow.
On all aluminum sprint car engine, the .012" number is a good rule of thumb. I like to give these guys a hot lash setting, and tell them to start it up .012" tighter and check it when its hot.