Gasket/Sealant for Chain Case, Villiers 32A.

[565545]

I'm getting a leak at the top of the chain case when cruising. Clearly I need to look at the sealing between the two metal surfaces. Could anyone suggest the best method of making it oiltight? Gasket or sealant or a combination? Thanks Stephen

[John Wakefield]

Looks like there could be distortion between the inner & outer chaincases. Best to remove the outer case, clean up faces & check that there are good mating surfaces. If there is just a few thou gap you can lap in each mating face with valve grinding paste on a sheet of glass. If its more distorted you will need to have the cases machined true. There is just a paper gasket which should only need a bit of sealant to hold it in place. You could also use a silicone sealer.

[Peter Rotherham]

Clutch casing leaks.

Hi, you say that it's a 32A engine, and that you are 'cruising', (I assume it's a road bike - 24D or such). These cases have ALWAYS given trouble, even back in the '60s they rivalled AMC's casings for leaks. John's advice about lapping in jointing surfaces is fine, BUT........ the real problem is that they are not properly secured against the rest of the engine and, like all such parts, are prone to distortion through heat and/or damage. The inner is held in place by a stud and nut on a buttress piece on the gearbox, just above the final drive sprocket. The case then SHOULD sit flush onto cast-in lines along the outside of the gearbox housing which continue onto the crankcases. (Watch out for excess gasket material between the Crankcase/Gearbox joint). The front of the inner sits flush against a fairly thick gasket which fits over the bearing housing of the LH crankcase. The outer fits on with an absorbent gasket between. A small pin at the rear locates the two correctly. The central stud, with its recessed nut should pull all this lot together. However, as you can see, almost 40% of the assembly is unsupported and just where it will get hit if the bike hits the ground.
So, how to 'cure' the leak. 1. Check that both halves of the casings fit flush to each other and the engine block. 2. Is the small circular gasket on the bearing housing there? 3.Using golden/blue or even (gulp) RED Hermatite smear both jointing faces and fit the correct gasket between them. 4. Is the small pin in place? 5. Does tightening up the stud onto the gearbox lift the inner case away at the front? 6. Check seating before fitting outer case and tightening up the centre nut. DO NOT over tighten this nut as that will splay out the cases too.

Finally. Please be aware that there are, as with all Villiers output, several variations on a theme. DOT required a different primary drive ratio so had larger cases and engine sprockets made, also several light car and industrial applications had parts that looked correct, but were'nt. In the early days of the GRA when spares came from Autojumbles this was a real problem.

Hope this helps.

Peter R.

[Brian Thompson]

Chaincase oil leaks etc.

Excellent post Peter, and many thanks indeed for sharing 'the knowledge'!

It's something I need to attend to on my own bike, and from the sound of it quite a few other members will benefit from your info too...!

Thanks again.

Brian.

[riflegreen]

On the works engines , Villiers or Greeves , I used two gaskets , one Evosticked to the outer chaincase & one glued to the inner .

Made them pretty oil tight and didn't damage the gaskets when work was needed on the clutch .

Chris

[Brian Thompson]

Thanks RG, great tip!

I was wondering, did you use any additional sealant between the two gaskets or just fit them 'dry'? I guess they would have been pretty well 'oiled' in any event, after they'd been on and off a few times.

I was also once advised that for similar reasons on his comp bike, an owner didn't bother with gaskets at all, just using a smear of HT Silicon sealant on the chaincase instead. I guess whatever the method used, the thing is to ensure that any gloop used is applied sparingly to avoid it squidging out and getting where it's not wanted.

Brian.

[mickmetcalfe]

Thanks RG, great tip!


I was also once advised that for similar reasons on his comp bike, an owner didn't bother with gaskets at all, just using a smear of HT Silicon sealant on the chaincase instead. I guess whatever the method used, the thing is to ensure that any gloop used is applied sparingly to avoid it squidging out and getting where it's not wanted.

Brian.

I've gone without the gasket in the past and its o.k but it just doesnt feel right. As already stated, the thickness of the gasket is often used in ensuring clearance to the clutch etc.

These days I always use a gasket and have had great success with normal B+Q clear silicone sealant so I guess the temperatures involved dont warrant the expense of the HT stuff.

Many years ago, I made a gasket by smearing string with red hermatite and then laying it in place on the joint face. It 'kind of' worked...