Noisy Tappets John Deere D

53BillNAA · Sep 5, 2018

Just purchased 37 model D. Noticed a racket in the front that I first thought was a bad fan shaft bearing. Later discovered it was the tappets clacking. I adjusted
them as the repair manual stipulates. "Set left exhaust valve open position so that all tappets will move. Tighten until no motion and then back off 1/2 turn". They
may not be quite as loud but still making noise. Is normal for this particular engine?

Lee B · Sep 6, 2018

Try it with a change in the procedure?

The part where you tighten until no motion is more accurately done by spinning the push rod while tightening and upon lock up of the push rod - THEN back off 1/2 turn.

No motion being subjective in judgement where the push rod that won't turn anymore is a bit more exact. It will also result in marginally tighter clearance which is the source of the noise. Older engines can have grooved rocker arms at the valve contact area and this makes using a feeler gauge troublesome with extra clearance as a result too. 1/2 turn back business resolves the worn parts issue quite nicely.

Adjusted by the book, my 44 A is quite loud in the rocker arm area and I have discovered that the base circle of the cam takes a dip well away from TDC combustion stroke which is where the generic book method tells us to adjust valves. But at the minimum base circle found, there is no noise and my valves are not burning. So I'll do mine this way.

Noisy Tappets John Deere D

53BillNAA

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Lee B

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