Oil pump gaskets G80S 1956

[56G80S]

Making some progress towards getting the Matchless back in one piece. As an aside, spent a short morning session getting SAE140 into the swinging arm using the body of a hypodermic syringe, lowering the spring clip for the centre stand trying to drill out the broken stub of the bottom screw that holds the centre panel between the oil tank and battery casing.

This afternoon, fitted the oil pump pluger, and guide pin (after double checking the pin), gently flattened off the oil pump rear plate and front rocker feed plate, cleaned up the plates, re-cleaned the crankcase mating surfaces and fitted the rear plate. I had to adjust the gasket as I've fitted a slightly oversize stud in place of the top screw, next the crankcase. I even more now wish I'd put studs in the other three standard holes. The carpal tunnel means I do't have proper feeling in right thumb, forefinger and middle finger. Fear of snapping, stripping was overwhelming!

The paper gasket for the front just isn't right.

No matter which way your turn it, there would be no feed to the rockers and recutting is difficult on such a small scale. Apologies for the poor pic quality, my phone is only showing thumbnails for some reason.

Just have to try my best!

Johnny B

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[ajscomboman]

They do line up you just have to flip it and rotate. I've not had one that doesn't line up yet from a gasket set. I have used a scalpel to make the odd one a nicer fit though.

[56G80S]

Rob, I tried flipping it, that's why there are two photos, although they are poor. Perhaps my spatial awareness is rubbish, so now you've made that comment, I'll try again tomorrow.

I'd be very happy to be wrong and prove you right. My fine motor skills are not up to standard at the moment and don't want to cut.

Johnny B

[ajscomboman]

It could well be that they manufacturers have altered something since I last had a gasket set. I've got to do the same thing on a motor here on the bench I'll report back my findings as well. If things have changed I'll be contacting them as they were fine.

[56G80S]

Edited first post with better pics. I can't recall who the supplier was, the cancer interrupted everything.

Johnny B

[Duncan]

From memory, which may be wrong, you only need to line up the one that feeds the rockers. If you look at the end plate there is only one take-off, the other hole is against the blank of the plate so cant feed anything.

[boris]

Sorry to hijack this but I have a weep from the real plate. Can the plate simply be removed without bits flying everywhere and the gasket replaced or do I have to drain the oil tank to avoid a huge mess?

On the gasket front I'll make something from some Flexoid I have. Is is it simply a square with four bolt holes or is there also a central cut out for bore of the pump?

[ajscomboman]

Sorry to hijack this but I have a weep from the real plate. Can the plate simply be removed without bits flying everywhere and the gasket replaced or do I have to drain the oil tank to avoid a huge mess?

On the gasket front I'll make something from some Flexoid I have. Is is it simply a square with four bolt holes or is there also a central cut out for bore of the pump?

Nothing fly away so you'll be safe to remove and replace the gasket.

[clive]

When i have tried to do it oil does tend to weep out but its manageable.

[56G80S]

Front plate fitted. Clive, it was the feed to the rockers that concerned me, not the top hole, as there's no matching hole in the front plate. There was no way round that the gasket didn't almost entirely blank of the little elliptical hole in the front plate and the round exit from the crankcase itself.

I'd not heard of Flexoid but looked it up and oil pump is quoted as one of the uses! Max temperature 120 C.

Johnny B