The BSA A7-A10 Forum
Technical (Descriptive Topic Titles - Stay on Topic) => A7 & A10 Engine => Topic started by: beezermacc on 24.10. 2016 23:45
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I've had a problem with my trusty A10 wet sumping for quite while so, about a year ago, I fitted an anti wet sump valve which cured the problem. The oil return has always looked a bit feeble so I decided to take a sledge hammer to the problem! I know the original anti wet sump valve is in the crankcase half and I couldn't be bothered to strip the whole engine down to fix that. Even if you do a complete strip you don't know if you've fixed it until you've built it up again! So, I've fitted an SRM pump, on the assumption that the new pump, with tight tolerances, should prevent oil leaking into the sump, and I've removed the auxiliary anti wet sump valve. So far, so good! However, because I wasn't sure whether this would cure the wet sumping, I thought I'd fit an alloy sump plate with drain plug so I could drain the sump easily and measure sump contents after a week or so. The problem with the alloy sumps is they require you to retain them with allen screws. The problem is that the threads in the crankcase are short and every time you tighten an allen screw the threads are weakened. I've got loads of crankcases with knackered threads in that area. So, I've drilled the new sump plate with a 9.00 mm drill, but not all the way through, and used tappet cover nuts and 5/16 spring washers to secure the new sump plate. I skimmed the tappet cover nuts down to accommodate the washers and the resultant job is great! (Even though I say so myself!). So, I keep the original studs in situ, and the tappet cover nuts provide a greater thread-to-thread contact than the originals... nice, tidy job. I've given the bike a short run and no leaks, and over the past four nights, no wet sumping! Just getting a beer from the fridge!
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I hope the beer doesn't leak out, Andrew. *beer*
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You will find your new set up woks a lot better if you turn it 90 deg and put the drain on the left side so on the side stand you can easily get to the drain plug and the plug will always be at the lowest point.
Even more important, should you forget to replace it or nip it up tight the oily crankcase fume will blow out to the left, find the hot exhaust and alert you to the mistake before the rear tyre is covered with oil.
Why every idiot who makes these sumps puts the outlet where it is very hard to access and blows directly onto the rear tyre God only knows but it is an idiot stupid piece of design.
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I've fitted it facing forwards which looks OK to me.
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Why every idiot who makes these sumps puts the outlet where it is very hard to access
I have one on both bikes, both have the gauze being separate so allows you to fit it anyway you want
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I think all the alloy sumps assume using a separate gauze so you can fit them any way you want.
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HI All,
I fit the plates with the magnetic plug farthest away from the pickup pipe
I had trouble on a BSA single where the magnet held the ball in the pickup closed
On a few bikes I made longer studs to use instead of the allen screws
On my own SR the allen screws have worked fine for the last 15 years
On the A10 engines I build I convert the anti drain valve to the A50/65 position with the ball against the back of the pump
John
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Alloy sump, I have the drain plug facing forward which is easy to get to and it keeps the magnetic plug farthest away from the pickup tube. *smile* *smile*
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HI All,
I fit the plates with the magnetic plug farthest away from the pickup pipe
I had trouble on a BSA single where the magnet held the ball in the pickup closed
On a few bikes I made longer studs to use instead of the allen screws
On my own SR the allen screws have worked fine for the last 15 years
On the A10 engines I build I convert the anti drain valve to the A50/65 position with the ball against the back of the pump
John
John,
I am able to do this modification, but I had a question. Do you lap some type of seat into the back of the pump body, or have you had good luck just using the pump as-is?
I think I would feel better if there was a very thin seat lapped in but if its not necessary than why bother?
Lee
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HI Lee,
Hmmm !!! ?? the €64M question
In my opinion lapping steel into alloy is a bad move, the hard carborundum will embed in the alloy
If you want to give the ball a little tap against the pump body, Remember the pumps are SOFT!!
The wider the seat the less pressure per sq mm
HTH
John
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Here's what I did on the A65 sump as she wet sumps a bit.
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In my opinion lapping steel into alloy is a bad move, the hard carborundum will embed in the alloy
If you want to give the ball a little tap against the pump body, Remember the pumps are SOFT!!
The wider the seat the less pressure per sq mm.
John,
Maybe you bit your lip when I've mentioned in the past that I lapped-in my oil retaining ball (in the case, not against the pump). Between the SRM pump, lapping the seat, and a new ball and spring, wet sumping has reduced to hard-to-detect, at least over two week periods. Not arguing with your point about embedded particles, but I don't seem to have any trouble form them. Of course, it's possible I should use a better measurement method than a quick peek past the tank cap.
Richard L.
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Hi Richard,
If it works then don't complain LOL *smile*
An issue that can arise when the ball valve housing is modified so the ball seats on the rear face of the pump
(as on A65's) is that the gasket (from the gasket sets or A65) is not a good accurate fit and even a few fibres can prevent the ball from seating properly *problem*
I make my own gaskets very carefully, to avoid this problem
SRM are now selling a new improved gasket for the pump
Regards
John
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Sorry to ressurect an old thread but,
John
What size ball and spring do you use for this mod? The same ball I assume but how about the spring?
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I think the spring may be slightly longer *????* bought one from SRM a while ago with later intent... have a look on their site
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Will do Dutch thanks now why didn't I think of that?
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*dunno*