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Old Oct 28, 2012, 01:38 PM
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I convince things to work
The Netherlands
Joined Nov 2009
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I never measured it, I just do know from experience that there is usually a little bit "spare" in the valve clearance, before they really do not close anymore. That "spare" is a few tenths of a mm, and typically the cold clearance for valves that size is 0.9 to 1 mm.
Those engines are made of steel, not aluminium, so mechanical valve clearance does not change as much due different expansion from aluminium and steel

The 3 mm over 0.5 metre @ 400 degrees sounds pretty normal, but exhaust valves usually do not expand that much, or you would not get away with a valve clearance of 1 mm on a valve of approximately that length and an operating temperature of between 300 and 400 degrees.

Engines built of all steel do not open up their valve clearance when they heat up, like aluminium engines with steel pushrods do.

Brgds, Bert
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