On my 1965 B40F, when I remove the sump filter I see two tubes. The larger diameter one, about 5/16" (8mm) o/d, I assume is the scavenge (return) tube? I prodded a wire in there, hoping to feel a ball bearing, but didn't feel anything, and can't see inside it because of oil. When I push the wire in, it goes up inside the tube about an 1 and 1/2" and then is stopped by something. A bend in the tube, perhaps? Just checking that is normal.
Also, what is the smaller dia tube I can see nearby? Is it a pressure relief tube? Again, I don't feel a ball in there.
Thanks in advance. Phil.
For your age of B40, it should have a scavenge pipe that is integral with the oil pump and this should poke down through the filter in the sump cover. The scavenge tube on the pump should have a ball bearing non-return valve in it but this may have stuck in the open (upper) position. As long as it isn't stuck in the closed position preventing oil from returning to the oil tank, I wouldn't worry about it since, in practice, it doesn't do very much (it simply stops oil draining back into the sump from the return pipe to the tank). The oil pump scavenge pipe should be the only one you can see from below the engine. Have you got a picture you can show of the other pipe?
Thanks for this AWJDThumper. I was a bit worried that pushing a wire up the pipe and feeling it hit solid resistance after about 1 1/2" I might have pushed the ball up and got it stuck somehow. Anyway, I hope not. What will the wire be hitting?
Regarding the other pipe, please see photo attached.
Thanks again.
Phil.
The short pipe is not part of the original lubrication system and, without further dismantling, only the individual who fitted it could explain its purpose.
I think you need to investigate, a loose bit could cause a lot of damage to your engine.
Does it move if gently pulled or pushed?
No.
From photo looks like it could be wedged between pump and crankcase?
I'm not sure whether your sump plate is rectangular, or square and just looks off from the angle of the photo. The later engines had a second pipe into the sump which came from the pressure relief valve. These were the ones with the square sump plate.
I believe the transition was around '65, but BSA were infamous for introducing changes based on what parts they had, rather than precise timing. I've no idea whether there was any crossover, though.
I'm guessing somebody on here will have more knowledge than me and be able to identify which yours is.
I have my (early type) oil pump on the bench at the moment and can't really feel the ball bearing at all when I shove a small drill bit up it. I can see it and I can hear a tiny "plop" as it unseats, but I probably wouldn't if it were in the engine.
Thanks very much for your help so far. If it helps, my plate is rectangular. Phil.
That sounds fine, with the cases split you can the line of the oilway from the relief valve to the sump.
Thanks for the photo has increased my knowledge.
If I'm understanding Dabbist correctly, the engines with the square sump plate had the second pipe. Mine is rectangular, but has a second pipe which looks very like the one on Dabbist's picture. So I guess there was some overlap, ie some rectangular ones had the second pipe, as Dabbist suggests, and the second pipe I can see is indeed a pressure relief valve pipe.
Where is the pressure relieved to?
Phil.
Ok, the confusion is my fault. Which is what we get when I try to work from memory. Sorry about that. :-[
The second pipe was always there (mine's a '62) but they changed the square sump plate part way through, putting a second hole in the filter for the smaller pipe to pass through.
That pipe is where the pressure is relieved to, the "feed" to the pressure relief valve being the big end feed . I confess that I'm not sure why they bothered with the pipe, without it, it would have just vented into the same space anyway.
Many thanks Dabbist and everyone. I'm not doing anything with the information at this stage, but at least I now know what both pipes are. Much appreciated. Phil.
Phil
De ja vous. I posted on the same matters...with photo...from my B40F. No ball bearing found either on oil pump scavenge. I also have the pressure relief valve tube.
I guess if you're concerned about it you could always disconnect the oil return line from the tank and squirt oil down it. If it doesn't come out at the bottom (and you get oil back into the tank when it's running) then your ball must be in place and doing it's thing.
Yes, thanks. I guess the main thing is that the oil is getting back to the tank when the engine is running. I suppose I'll be able to see that happening simply by shining a torch into the tank and looking for oil squirting out of the return pipe? How soon after starting the engine should the oil be arriving back at the tank? Phil.
I think this might be the old thread referred to in the "Sump Gauze Mystery" discussion? Phil
Thanks Phil