Crank case oil seal

Information relating to the Matchless G12 or AJS Model 31 650cc twin
Posts: 32
Joined: Tue Jul 11, 2017 8:00 pm
Location: YORKSHIRE UK

Crank case oil seal

Postby Peteg » Sat Oct 07, 2017 5:04 pm

Hi
I'm renovating a 1963 g12 csr and while the engine is worked on I would like to do the modification to fit an oil seal to drive side crankcase does anyone know where I can find the info on this mod
Cheers Peteg

Member
User avatar
Posts: 1774
Joined: Mon Jan 01, 1990 12:00 am
Location: LANCASHIRE UK

Re: Crank case oil seal

Postby dave16mct » Sat Oct 07, 2017 9:07 pm

If you mean a seal on the mainshaft to prevent oil entering the chaincase, from memory....ahem....I think there was no mod to the crankcase. The scrolled spacer was softened, then turned down to suit an oilseal. Or a new spacer could be turned up and hardened. I don't know the details but you would have to find an oilseal to fit the crankcase, then turn the space to fit the oilseal. Have you tried a search?
Dave.

Member
Posts: 372
Joined: Wed Oct 12, 2005 9:45 pm
Location: FRANCE

Re: Crank case oil seal

Postby JEAN-NOEL » Sat Oct 07, 2017 9:48 pm

Hello Peter,
I agree with Dave. Many topics on this subject.
But the scrolled spacer usually does perfectly its job. If there is a problem, it will be not solved by an oïl seal ! In case of wet sumping, oïl will seep through the breather. So the problem to solve is the wet sumping.

Member
User avatar
Posts: 2133
Joined: Mon Oct 05, 2009 12:00 am
Location: ESSEX UK

Re: Crank case oil seal

Postby 1608 » Sun Oct 08, 2017 6:42 am

Agreed, theres no real need for a crankcase seal on these models. Wet sumping is a common problem and as said excess oil in the sump will find its way into the primary side via the breather.

Posts: 32
Joined: Tue Jul 11, 2017 8:00 pm
Location: YORKSHIRE UK

Re: Crank case oil seal

Postby Peteg » Sun Oct 08, 2017 9:00 am

Thanks for your thoughts on this
This is my first matchless my other bikes are a 52 speed twin and a 58 dominator
The triumph never wet sumps the Norton does but as it only gets into the crankcase it's not
A big job to drain if it's not been run for awhile
With the matchless I've not had it running since I bought it but while it stood in garage it emptied the oil tank int sump and chain case.dont really fancy putting a tap on.and while engine is striped thought I would fit the seal info I can find on the site says seal should be 40x52xx7mm but the hole in crankcase is a lot larger than 52mm so does it need some sort of adapter making to fit seal in.
One other question it's a 1963 650 csr on stripping the engine I cannot find a pressure relife valve is there one one this year or has last owner left it off

Member
User avatar
Posts: 1774
Joined: Mon Jan 01, 1990 12:00 am
Location: LANCASHIRE UK

Re: Crank case oil seal

Postby dave16mct » Sun Oct 08, 2017 9:58 am

The pressure releif valve was moved to the pump plate in '64 but yours might be a late '63 with this feature.
Dave.

Committee
Online
User avatar
Posts: 1967
Joined: Mon Jan 01, 1990 12:00 am
Location: HAMPSHIRE UK

Re: Crank case oil seal

Postby ajscomboman » Sun Oct 08, 2017 11:17 am

For 63 the pressure relief is at the end of the engine oil filter tunnel. On the timing side crankcase there should be a little sprung loaded plunger. Also if it's a genuine 63 CSR the timing side crankcase would be of the dynamo type with the hole blanked off with a piece of turned Ali and glued and pressed in. The dynamo clamp strap boss is still there but should not have been drilled or tapped. It was the only year that I've seen this mis-match of case halves and I've seen it on so many genuine 63 CSR's including my own that it can't be a previous owners bodge and must be a factory method of using up obsolete cases as for 64 on all models used alternator timing cases.

Posts: 32
Joined: Tue Jul 11, 2017 8:00 pm
Location: YORKSHIRE UK

Re: Crank case oil seal

Postby Peteg » Sun Oct 08, 2017 4:22 pm

There is a hole that's drilled and tapped on timing side that lines up with oil filter tunnel put does not go right through to filter and no plunger or Spring
As for cover there is what looks like a plug fitted I thought it was some kind of repair

Committee
Online
User avatar
Posts: 1967
Joined: Mon Jan 01, 1990 12:00 am
Location: HAMPSHIRE UK

Re: Crank case oil seal

Postby ajscomboman » Sun Oct 08, 2017 4:40 pm

Peteg wrote:There is a hole that's drilled and tapped on timing side that lines up with oil filter tunnel put does not go right through to filter and no plunger or Spring
As for cover there is what looks like a plug fitted I thought it was some kind of repair


Post some piccies if you can it's easier to understand what you have if we can see it.

Posts: 32
Joined: Tue Jul 11, 2017 8:00 pm
Location: YORKSHIRE UK

Re: Crank case oil seal

Postby Peteg » Sun Oct 08, 2017 5:03 pm

Will be tomorrow now taking wife out for her birthday

Next

Return to G12 / AJS Model 31

Who is online

Users browsing this forum: No registered users and 7 guests