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MG MGB Technical - What is noisy when it comes to valve rockers ?

Having recently adjusted my rocker clearances to 15 thou as part of a 12K service, I noticed that the rockers seem to clatter more than before. I set them up cold and so that the feeler guage was just able to move under the arm. I know that wear in the rocker can cause a variation in gap, but to me they seem fairly good. I know that by adjusting the clearance to a smaller gap, that will reduce the clatter, but at the risk of burning the valve seats.

I understand that the B series engine is supposed to have some rocker chatter, but how much is too much ? Does the use of an alloy rocker cover reduce the noise significantly. Any recommendations on a UK source?

Phil.
Phil B

Phil,
A tip on adjusting valve gaps:
Tap the rocker lightly with the handle of a screwdriver to ensure metal to metal contact at the other end where the tappet sits on the cam.
Sometimes oil can flow between the two and give a false reading and as a result the gap is set too wide.
By the way where was the gap prior to your re setting it?
Are you able to make cotact with someone who can "lend an ear" so to speak and give a second opinion?
Cheers, Pete.
Peter Thomas

It's possible to get the valvegear to be quiet without setting them tighter than 15 thou, but you have to do it with the engine hot. Everything moves around as the engine heats up and can make your clearances grow.

However, if your tappets are in bad shape, you'll never get the clearances right. Does the rattling come and go? If so you have bad tappets and they are closing and opening the clearance as they turn in the block. The tappets I just removed were completely trashed and had done about 10000 miles with regular oil changes.

ttfn,
--
Olly S
Oliver Stephenson

Phil, it is not unusual for us ( me, anyway)to have to set them up, run, let cool and recheck/reset before we get these old engines right.It is a sensible thing to do, this rechecking, anyway. Have you checked and reset a couple of times with no improvement? Maybe think of the old B engine as an old Singer foot treadle sewing machine,( if you are as old as I, you will remember these!) and a contemporary 4 as an electronic DC motor driven sewing machine, in terms of noise.It's a relatively noisy old engine, but an endearing one. However, ALL the tappets should be producing about the same noise, not say #1 and #3. If you don't have a stethescope, get a big screwdriver, and put the end of the handle to your ear, and the blade on each part of the valve gear, and you will hear if there are irregularities. Try for a regular noise level you can live with without being embarrassed. You can get the engine to run very quietly, but you will do more than just burn a valve, you will bend pushrods, at least. Loose is happy.
ken R.
Ken Rich

Thanks for the responses, I will try re-setting them again having run the engine and see what happens.

Phil.
Phil B

This thread was discussed between 10/05/2002 and 13/05/2002

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