BMW E30 valve clearance and engine noises
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What valve clearance is the E30 M20 adjusted to?
The factory value is 0.25 mm for both the intake and exhaust valves. The adjustment is done on a completely cold engine, not after a few kilometres of driving. At the same time it is worth looking at wear in the valve gear, because it affects the clearances.
In what order are the M20 valves adjusted?
The valves are adjusted one at a time: turn the first valve open and adjust its pair from the other end. On the 6-cylinder the pairs are 1-6, 2-5 and 3-4, on the 4-cylinder 1-4 and 2-3. The adjustment is made at the rocker arm eccentric on the valve side.
What can cause rattling or strange noises from the E30 engine?
Most commonly a worn camshaft or rocker arms, and regular oil changes extend their life. On the M42, a rattling noise after about 200,000 km often comes from worn timing gear and chain parts and the tensioner.
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