Troubleshooting with Steve Rothwell

BMW 2002

NOISY TAPPETS

Q I have a 1971 BMW 2002 with the

2-litre M10 B20 engine fitted. I have been given the valve clearance settings to be 0.15-0.20mm for both inlet and exhaust, and told that they should be set cold. I am sure that when this engine was produced, the settings would have been in thou and I am wondering if I have an incorrect conversion of the original setting, because after running through the clearances twice with my metric feeler gauges, the tappets still sound noisy. I use a 10W-40 semi-synthetic oil and wonder if this has a bearing on the problem.

John Greensmith

A I would not suspect that the oil has a bearing on the tappet noise you hear, and the 10W-40 semi-synthetic Is one of the recommended oils for your BMW. I would also confirm that the settings you have of 0.15mm-0.20mm for both the inlet and exhaust valve clearances are correct.

I would suspect that the problem may be wear in the rocker shaft or contact areas between the rocker and contact face, and that this may be creating a false surface when the feeler gauge is applied. With pressure off the rocker, you should also feel for any sideways movement which may suggest the bush on the shaft is worn as this will also give you a false setting when using the feeler gauge.

I would recommend that the shaft be stripped down and examined to check for wear. What I would also add is