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Valve Clearance[ALL/1998] posted by Joseph Kmiec on
Thursday, 25 September 1997, at 10:06 a.m.
Here is an example from the the manual on valve clearance:
Correct clearance mm (in) 0.40 (0.016)
Measured clearance mm (in) 0.24 (0.010)
My question:
Why would the "measured clearance" be smaller than the "correct clearance"?
I thought that the shims are wearing out over time and the measured clearinace should be more not less.
Joseph Kmiec
Re: Valve Clearance[ALL/1998] posted by Ed Lipe on
Thursday, 25 September 1997, at 10:26 a.m.
The shims don't wear enough to notice. What is wearing is the valves and valve seats. Normally, the exhaust clearances will close faster than the intakes. Tight clearances mean less room for the material in the valve train to expand with heat. Eventually, if there's no clearance, you'll get burned valves, and seats. That is not a good thing. If you do see scoring on the shims, replace them. This will tend to wear on the camshaft. Shims should be smooth and slick.
Re: Valve Clearance[ALL/1998] posted by Joseph Kmiec on
Thursday, 25 September 1997, at 10:46 a.m.
Thanks Ed for the explanation, it make sense.
What makes tapping noise when the engine is cold?
Clearnace for example on my 740 seems to be withing the spcification (0.33mm [0.013"] when cold) but I can hear lound tapping noise when the engine is cold and the noise goes away as the engie warms up. Why?
Thanks,
Joseph Kmiec