AJS & Matchless Owners Club

Hi all,

Quick question: Does anybody have experience with leaving away the oil filter gasket between the crankcase halfs ?

I have just finisched my rebuild and I thoght I would try going without the gasket. I believe, a gasket at the Oil tunnel will for sure seal the tunnel, but it will also generate a gap outside the tunnel, causing leakage in the low pressure erea around the tunnel.

I have used loctite sealant, which is quite rubber like.

Thanks for your opinion.

Yves

Hi Yves, a common modification is to fit an o-ring, you need to machine a suitable groove in one of the casings for this, so it would require disassembly of the engine.

Here are the sizes I used:
O-ring I used measures ID 30 x 1.5 dia . The correct groove size for this will be ID 29.6 OD 33.4 , depth 1.2 (giving you a 0.3 squash).

Rob C

Thanks Rob.

Yes I have seen that Solutions else where and I liked it a lot. But I am to chicken to start milling my crankcase

For now I decided to try to go without a gasket. The crankcase is already sealed. So unless somebody shares bad expinces I would try without...

Has anybody tryed it ?

my G11CS had no oil pressure relief valve and no gasket between the crankcase halves when I got it. Oil flooded from around the oil filter tunnel. Rebuilt with a gasket and a friend machine the cases to take the later pressure relief valve. No problem. If your cases have no pressure relief valve, and they seemed to come and go year by year, I think you will get an oil leak without the gasket but you may be lucky and loctite may hold it.

I have two 600 twins without oil pressure relief valve fitted, they are both assembled without the gasket around the filtertunnel, I have never had problems with oil leaking around the tunnel, but in some other places, the crankcase is sealed with Würth RTV silicone .
Best regards
Poul

I'm sure I've read somewhere that the thickness of the filter gasket is important? I would imagine if it's too thin the end of the filter body will be bottoming out in the housing and stress the crankcase as it's tightened up so fitting no gasket wouldn't be a good idea given it was designed to be fitted with a gasket?

No, the 60-on one piece filter isn't that close to the end of the tunnel (the relief valve is between it and the end) see the cross section view in the 57-64 workshop manual. The earlier felt type filter is pushed to the end by a spring. Years ago the way you knew someone hadn't put the paper gasket in the filter tunnel was a big oil patch under the front. Obviously with 'O' rings solutions and Yamabond etc things have improved in this area.
Dave.

Thanks for that Dave, I'm learning all the time. My bike is a 1960 DL and it has a one piece filter assembly with the combined relief valve but with felt over what I assume is a steel strainer. Basically I removed it, cleaned it and replaced it.

Thanks to all for your replies. So chances are good that I will get away with having no gasket.

I have one of those rebuild oil pumps, that someone was making a while ago, which has, if I understand right, a pressure releave valve. I believe its that little brass colored thing sticking up from the pump baseplate.

I will post the result for those to come, once I have everything put together and running.

Thanks again guys


Gesendet von iPhone mit Tapatalk

For anyone stumbling over this thread. I would like to come to an conclusion.
I did run the bike after the rebuild without the gasket. Everything seamed fine. When oil temperatures where rising on a very hot day, I did have the feeling that I was loosing some more oil pressure (I have installed a gauge). Since I was Insecure about possible effects of leaving away the gasket, I decided to take the engine apart again and added the gasket. Since my initial hope, that general oil leaking could be minimized through leaving away the gasket was not confirmed I thought I would play it safe. I also realized, that my pressure release valve had been blocked by one of the former owners, for what so ever reason. So i did initially have a lot of pressure until I realized what was going on.

When I opened the halfs I could not see any damage to the sealing around the Oil filter tunnel. So I guess I would have been fine. But I now feel safe not taking any risk.

Thanks to all for the comments