What tappet chest gasket do I need?

[miker519]

Hi all
I could do with a little help to work out what gasket I need for my 1965 1098 engine as the 2 sets that I have bought were both cork.
The covers are leaking badly and the gaskets that were fitted were cork (fitted badly) the new cork gaskets seem to big by a couple of mm both in length and width.
Do I have the right gaskets ? are there more than one size of cork gasket, Or am I missing a trick in fitting them as I cannot get them to seal.
I thought this would be a straight forward job but it is getting very frustrating after 4 attempts. the covers are pressed steel and the front one has a breather pipe attached.
Any help or ideas would be most appreciated.
Best regards MikeR

[philthehill]

The 1098cc engine has neoprene gaskets and the steel covers have a raised outer edge. The bolts also have rubber seals and cup washers fitted over the seal.
The front cover is Pt No: 12A1212
The rear cover is Pt No: 12H941.
The gasket for both covers is Pt No: GUG5505 GM
The rubber bolt seal is Pt No: 12A1176.
The cup washer is Pt No: 12A1177.
The above part numbers are from the MOSS web site.

[svenedin]

This:

https://www.morrisminorspares.com/engin ... ll-p830243

and for the bolt:

https://www.morrisminorspares.com/engin ... 58-p830400

Do not' over tighten the bolts.

According to the diagram on Moss, the simple fibre washer 2K4958 is an alternative to the cup washer and neoprene seal. However, if you have the cup washer you may as well continue to use that and fit new seals 12A1176

https://www.moss-europe.co.uk/shop-by-m ... 51-71.html

Clean the mating faces of the block and the cover. This job, though seemingly very simple is a bit fiddly with the carburettor and manifold in the way above because it is hard to see what you are doing. If by any chance, you need to change the manifold gasket, do the tappet chest gaskets at the same time as it is so much easier with the manifold out of the way!

One other thing, as you have the type of tappet chest cover with the bent breather pipe, this is a perfect opportunity to unblock the pipe. Have a look at this thread and the video linked in the first post. From around minute 23. viewtopic.php?p=697834&hilit=breather#p697834


Stephen

[philthehill]

The fibre washer is not a direct replacement for the neoprene seal no matter what the MOSS site indicates.
The bolts are a different length dependent upon the washer/seal used. The bolt can bottom out before clamping the seal if the wrong washer/seal is used. The parts have to be replaced as a set. The neoprene seal/gasket is a better option but requires the correct covers to be effective.

[svenedin]

The fibre washer is not a direct replacement for the neoprene seal no matter what the MOSS site indicates.
The bolts are a different length dependent upon the washer/seal used. The bolt can bottom out before clamping the seal if the wrong washer/seal is used. The parts have to be replaced as a set. The neoprene seal/gasket is a better option but requires the correct covers to be effective.

Yes absolutely. I found that out some time ago actually. I ordered 2x new bolts and they were clearly intended to be used with the fibre washer because they were too short to use with the cup washer and neoprene seal. I reused the old bolts and fitted new cup washers and seals.

Stephen

[miker519]

Hi all and thanks for all the help.
Correct gaskets and rubber washers acquired and fitted after getting the specialist out to look at the car as he insisted that they should be cork?
The flow had reduced dramatically but still weeping so have given the bolts another half a turn will let you know if that stops it.
Thanks again as a newby the advice was really useful as the Haynes manual is a bit vague.

[philthehill]

There are specialists and specialists!!

[svenedin]

No they should not be cork. There are two designs of tappet chest cover, a concave and a convex. The earlier type on the 948cc does use a cork gasket but the 1098 type uses a neoprene gasket. If the breather pipe on the front tappet chest cover is blocked it will significantly increase the likelihood of leaks. That is because pressure can develop that should be completely relieved by the breather pipe. Do check it!

Stephen

[miker519]

Hi Phil And Stephen
I have checked the pipe as recommended all clear and I totally agree their are specialists and some that just think their Special
Best regard MikeR