The 100 Forum

My car came with a lot of oil leaks but all are gone except for the valve cover gasket leak. My gut tells me to go with an original type cork gasket BUT if silicone will do a better job I’m all for it.
I believe that my valve cover has fallen victim to a guy who thought over tightening the valve cover fasteners was as good as replacing the valve cover gasket. As a result the cover is slightly strained. The contact area is flat so I believe it’s still okay to use.

Hey Thomas,
I switched to a silicone some years ago and highly recommend it. Like you said, previous owner may have over tightened the valve cover but if it is still straight believe the silicone gasket will solve your problem.
Regards
Mike

Tom,

Not being familiar with the BN1's I'm sticking' my neck out here but
you don't mention if the Valve Cover is pressed steel or aluminum.

The OEM cover always leaked on my BT7 and I knew it would never seat throughly plus
there was no way to resurface the pressed steel covers so you could never get a perfectly flat mating surface.

I just bought a thick cork gasket and hoped it sealed all the way around...but it NEVER did,
so the obvious improvement was an aluminum valve cover.
They are heavier with more mass, they offer a perfectly flat surface for the gasket and they're more efficient.
The cork gasket may be better in this application.

Wether you go with the polished style or the wrinkle finish it will still be a
worthwhile upgrade and a solid investment.

And to answer your gasket question: After seeing both cork and silicone gaskets I would have to go with the cork.
They are much more substantial then the silicone and probably easier to apply to the cover.

Good luck,
Peter



Edited 3 time(s). Last edit at 2018-05-21 03:27 PM by petnatcar.

I have used cork gaskets on my BN 1 valve cover for 40 years and haven't had a problem. The thing is you have to make sure your valve cover is dead true on the Sealing surface . Take the valve cover off and put it on a surface that you know is true and the level and it should touch all the way around . Also only glue the gasket to the valve cover surface and leave the block surface clean, and when you install the valve cover make sure there is no oil on the block surface. This way you will be able to remove the valve cover more than once. Of course all surfaces have to be clean and smooth , if installed correctly this gasket will last for years. Regards Trevor

Lotus engines 902 , were inclined when fitted in the various cars that used it there was always a problem with sealing the rocker covers as oil lay against the gasket .
RTV silicone was developed to help stop this tendency to leak , try using it , I have and it worked very well .
The cork gasket will work but it needs careful assembly and must be totally dry when fitting and very gentle tightening , add some RTV and it will do a good job .
Another way is to make your own gasket from 3/4 mm rubber sheet using a sharp craft knife , again it requires careful , clean dry assembly

Thanks for all of the info. I ended up using cork. I cleaned all surfaces and used blue rtv to stick the gasket to the pressed metal valve cover. This insured proper alignment. (The gasket long sides were bending toward the center). Once the gasket was firmly stuck to the valve cover i carefully positioned it and tightened the nuts. Ive been driving the car and it has not leaked. Ill post if anything changes.

Good news that you got it work with the cork gasket. Some BN1 and BN2 owners look to the valve covers as the source for their leaks when it is the actual design of the head attachment to the block. If there was one more stud on the right side about in the middle that annoying minor leak could be avoided. I know modern sealants have addressed that since that engine was designed and next time I have the head off I will address mine but trying to practice " if it ain't broke don't fix it " rule as my 100M is running perfectly right now and if I pull the head know I'll mess some adjustment up when I put the ole gal back together !

Some years back my BJ8 came back from a Brit car shop with a valve cover damaged due to over tightening. I tried my best to correct the OE steel cover. I gave up and purchased an aluminum alloy valve cover from Ray Juncal. That plus a carefully installed silicon gasket remedied leaks/seepage.
Marks III.