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MG MGB Technical - oil leak rear tappet cover

i have a leak somewhere at or near thw rear tappet cover it drops on the exhaust and you would think i have a smoke screen. i have replaced the gaskets, then replaced the cover to no avail any help woul be greatly appreciated;. thanks les
l.f. frank

I have success with the cork gaskets from NAPA, but I have it coated with silicone gasket material also and no leaks.

Others have not had great results with some of the cork gaskets.

What I've heard but have tried is the silicon (red) gasket material from Roadster or something like that.

However, re-reading your post has me wondering if you are referring to the valve cover on top of engine or side engine covers - I've heard both referred to as tappet covers. I'm thinking you are at the side cover, and I've had terrible results with some of the after market gaskets, not actually fitting properly.

in the end I did use the red silicone gaskets from Roadster something. They fit fine.

It is a poor design for the side cover plates and how much over lap there is for the gasket to set against, without slipping into the opening in the block.

I've had no leaks since putting in the red silicone gaskets. I was cussing at the other seals, as they wouldn't fit the cover plates.
R.W Anderson

It may be something as simple as using the wrong gasket. When I ordered a new pair from MGOC I received 1 cork & 1 rubber/silicon. Unfortunately I installed them on the wrong covers & lost an engine's worth of oil before noticing. When I installed them correctly (cork to the front from what I remember) they worked perfectly. There are a lot of threads on this, so may be worth searching for other results.
Pat Gregory

The tappet cover is below the manifold so leaks from there would normally just drip off the block and sump, do you mean the rocker box cover/gasket? That could well run down onto the manifold. As well as the large cork gasket there are two rubber doughnuts under domed washers on the fixing bolts and it is the compressibility of these that applies pressure to the cork gasket to seal it. These compress and harden over time and should be a service item but they are not mentioned anywhere. It is also easy to overtighten the cover nuts which distorts the cover, which reduces the effect of the doughnuts as well as possibly warping the edge of the cover at the cork gasket.
PaulH Solihull

Often replacement gaskets do not fit exactly, especially if the original rocker cover has been replaceed with an alloy version. Buy some good quality cork gasket material and cut a new one using the tappet cover as a pattern. Perfect fit and no leaks.
J H Crighton

This thread was discussed between 07/10/2011 and 09/10/2011

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