[I]“It seems logical that an aluminum head, if that is what you have, has a faster coefficient of expansion than steel valves so lash will decrease as the head expands faster than the steel on heating. The exhaust valve will run hotter than the intake valve so you have more initial lash specified. That will be needed for times when the engine is run at full power.” [/I]
Yes, this is an aluminum head and steel valves. But this is an overhead cam. I think you need to consider the geometry and relationship of the cam, rocker, and valve. I am not qualified to fogure all that out to know if the end result will be less, more, or basically the same valve clearance when hot or cold. Since the manual stated to adjust hot, I assume there may be some change with temperature changes.
"If you can’t idle the engine while checking clearance then it would be reasonable to heat the engine, shut it off, pull the valve cover and check clearances soon. The difference in the cold and hot lash numbers that you provide indicate that the degree of hotness is not critical."
On this engine, it’s not possible to check clearance when it’s running.
I don’t think I can make an assessment of how much the lash will change from a cold to hot engine. I was hoping someone might have actual experience on a 22RE to know since I saw a number of online references to adjust to .007 and .011 when cold, and the book says to adjust to .008 and .012 when hot. That just seemed backwards to me.