Britbike forum Forums British Motorcycle specific Brands Bsa bulletin board A65 oil pump

I did the test of my oil system by installing all the oil lines, oil pump, filling it with some oil and turning an oil pump with a drill. I spotted oil leaking from my pump even before using a drill so my question is:
- what's your opinion about gluing both parts of oil pump together just to keep oil inside?

Correct way is to lap all the surfaces flat and true then use a smear of welseal or similar.
Takes a while but works well.

+1 to what NickL says, i believe the factory used Shellac between the pump faces, i use a thin smear of Welseal.

Hylomar works good too.

But be very cautious lapping the feed side surfaces. If they end up too tight, the drive gear will bind and it is difficult to make it thinner.

The other gears all have at least one flat side that can be surfaced down a hair to relieve a bind but the drive gear doesn't.

My routine is to lap the feed side faces to where I an satisfied with the drive gear fit then fit the driven feed gear along with the drive gear and check for binding.

Those two are your most critical fit regarding oil pressure and wet sumping leakage. The scavenge side is left for last and done using the same system.

AKA Indian Head gasket cement.

Be sure to mark all of the gears carefully so you can reinstall them in the same positions. I didn't and could never get the pump to turn after reassembly and I didn't grind any of the plates or gears.

I don't think I'll be lapping this pump now, did all the lapping yeas ago when I prepared a pump to be installed in my former BSA.
So glue only this time and I see I must be super careful not to use to much of it - areas to use it are very small.

And,……. Be very careful the pump does not shift on the gasket as you firm up the stud/nuts. It only takes an RCH to foul the ball on the gasket. I usually increase that ball gasket hole a bit.

And , another thing, quoting from the good book
"Examine the mating faces of the crankcase
and oil pump, making sure they are clean"

I remove the studs and check the pump to case fit with engineers blue, you will likely find that the alloy around the studs has pulled up, easy fix with a light countersink,.

And ... one more thing, using optical aids , jewellers loupe or magnifying glass, examine the seat for the feed side non return valve ball bearing in the pump body, mine looked like a ploughed field, use a spare ball glued to a dowel and grinding paste to lap the seat , this greatly reduces wet sumping.

+1

These are all great tips on theses pumps. My pump builds always begins with marking the gears and their position.

This thread points out or at least reinforces the history of these old bikes. While the BSA designs were somewhat outdated even in the sixties, there was nothing that was inherently wrong with their designs. The problem was attention to detail on fit and assembly. If you take great care in rebuilding these old motors and gearboxes you will end up with a good running and quite reliable machine. BSA was in their death throes in the late sixties and early seventies and was slapping these bikes together using a disgruntled workforce trying to ward off the inevitable.

Today we are the beneficiaries of BSA's demise and can pick up a basket case for a song and make it a nice rider.

Mr Mike

Long time no see, Mr Mike. I had my pump already lapped 15 years ago, but was lucky enough to buy original DD iron body pump which found a place in my former BSA engine and works there even today in the hands of a new owner. So with this one I carefully added some sealant between mating surfaces and assembled it back together. My oil pump gasket is very well done, with one hole for a valve distinctly bigger, so I hope everything will work properly. Now I'm waiting on an oil tank which got somehow blocked in a return tube inside and when this is done I can try my oil system again.
Mr Mike if I remember correctly you developed something to improve bike's oil pressure could you remind me a thread with a write up about it?

Adam,
it is interesting you should ask. Just recently I got a call from the second new owner of my 66 A56L that i sold some years ago. The new owner wanted to understand about the oil pressure system. I explained it to him and he told me the bike still had great oil pressure. When I installed the modification the bike ran at about 55 psi at speed and idled at about 20 psi. The system is real easy to install and eliminates the existing OPRV. I made a new bushing to replace the OPRV but could have modified one of the earlier OPRV's and accomplished the same thing. I have a writeup some where and some pics. I learned that the problem wasn't the pumps. The pump flows plenty of oil but a leaky OPRV and hysteresis results in low oil pressure, I may have mentioned the modification years ago on this site but there was little interest. I probably still have a couple of the little relief valves I used to control pressure. I am down to a single motorcycle these days, a B50. If you have any interest send me a private e-mail and I'll see what i can dig up.

Mr Mike

With a pleasure, private email sent.
I remember years ago you sent me a write up about additional Norton type oil filter, which I installed in my BSA and was very happy with it. Such a filter is installed in this new bike as well.

Edit - I used your email address from this forum but it didn't work, what is your email address now?

Having the OPRV bypass hole only three threads from the end of the valve and no seal on the threads provides a big leakage path. A while back I suggested a new OPRV that routed the excess oil externally to eliminate that problem and change the piston to a ball sitting on a Dowtey seal to eliminate the leakage there. This might be similar to what you did.
Also, dumping the excess oil into sump or return pickup drilling can be changed to route the oil into the feed side of the pump rather than back to the tank, much they way Porsche changed their 911 oiling.

I think leakage thru the threads of the OPRV and leakage by the piston (or ball depending on the year), and hysteresis all contribute to low oil pressure in the A50/65.. The system I came up with eliminates the OPRV and closes the bypass passageway. I made a bushing to close the OPRV cavity and tapped a hole to hook up the return and a gauge. A small pressure relief (60psi) is positioned in the return line to the tank.' It opens at 60psi and controls the pressure very well. Hysteresis is prevalent but has very minor effect.. The return line to the tank at this point is the feed side of the pump and at atmospheric pressure. During my testing of the system i installed a needle valve in the return line. The system would overpressure itself with the needle valve closed but only a small cracking open of the needle valve dropped the pressure to a level needed by engine lubrication systems. That is when I selected a 60 psi OPRV.

Adam, my email is [email protected] if you want the writeup and some pics It is very simple and provides dramatic increases in oil pressure.

Mr Mike

Mr Mike, did you got my email?
If not check your spam folder.

Adam,
I did find your e-mail in my junk mail, however, I inadvertently deleted it before i could send you the writeup and pics of the A65 oil pressure modifications. Send it to me again. If you have low oil pressure on your A50/65 this will fix it. I might even still have a couple of the OPRV's I tested in coming up with the modification that I will give you.


Mr Mike

Adam,
Send me your email one more time.

Mike

I can just write it here, it's not confidential:
[email protected]

10-4 Adam,
I'll put the stuff I have on the oil pressure system together for you and send it in the next few days.

Mr Mike

Thank you Mr Mike.

Adam,
I sent you a rather lengthy e-mail with embedded photos. Not sure of exact size, but your server rejected it. Not sure what to do next.

Mr Mike