A10 oil pump test

[Else]

Hello all. I would like to test my oil pump to make sure it's pumping the correct amount of oil and can maintain decent pressure. I get return to tank but not much, just intermittent spits of oil. Doesn't look enough to me. I have stripped it and checked for wear, looks very good so I suspect it has been replaced recently. It has an SRM pressure release valve fitted which I have also stripped and cleaned and inspected.
Does anyone know who could test it for me?
Thanks Andy

[berger]

if it's not chucking oil out of the breather all over the floor when the bike is running it is working ok, they all spit oil with air it means they are doing their job.

[Swarfcut]

 Plenty on the forum about the oil pump.  Whenever I build a pump a quick test for freedom of movement as each gear is added is to drive the input gear with a rod with a cut out at the end to engage the driven tab. That way each gear can be added and if things tighten up repositioning the gear teeth makes it move smoothly again. Reckon this is why it was recommended to keep the original gears in exactly the same relationship to keep the wear patterns matched on the gear teeth. Not so building a pump from the best of the bits.
  Once the pump body with gears is assembled, nose and base plate added and tightened down and everything is turning smoothly with no tight spots, use the rod in a cordless drill to drive the pump with the inlet and scavenge ports immersed in oil.

  A good pump will  give a jet of oil from each outlet port. I used a ball point pen as a drive rod, nothing special. Once satisfied with the gears and pump performance, add the drive spindle and test that the pump can be turned by hand. These spindles can also go tight, if so reposition by half a turn. If there is no improvement try another if you have one...or relieve one side of the slot to give a little leeway on the driven tab. Add the retaining ring only when the pump is the best it can be.....the old Mazak groove for the ring is easily damaged. .
  As Berg's says, they  will gulp and spurt oil when the sump is getting empty. That's the scavenge function working. More oil in the sump gives a constant stream.

Swarfy.

[Colsbeeza]

Else, The scavenge/return side of the pump has larger gears, and pumps about 30% higher flow rate. So intermittent air bubbles is quite normal.
Col

[CheeserBeezer]

Apologies for my previous post where I got completely muddled with tech terms. Here's what I should have said.....
Interesting...... A mate of mine had poor return to the tank. To cut a long story short, we ended up removing the SRM anti wet sump valve, problem solved! It seemed that the SRM anti wet sump valve was preventing some of the oil getting into the gallery prior to hitting the timing side bush. I suspect the spring was getting coil bound before the ball had cleared the oil gallery. The bike had seized on three occasions prior. Having removed the anti wet sump valve, we ran the bike with no ball and spring (AWS) for a while and the oil flow back to the tank was excellent. We then fitted an outboard Anti wet sump valve (I know, not everybody likes or approves of them) and this prevented wet sumping and did not affect the oil return to the tank. More recently, a different mate had poor oil return to the tank. This turned out be a damaged pump. The circlip had come off the end, bits of mazak had dropped into the timing case and the crankshaft worm wasn't engaging properly with the oil pump gear. We fitted a second hand pump - all good. If your bike has an SRM anti wet sump valve, that's the first thing I'd remove.

[Catz]

Apologies for my previous post where I got completely muddled with tech terms.

Phew. When i read your original post i thought i'd put some dodgy SRM gear on my bike.
I was going to say that i'd had no problems with my SRM PRV and i also have their own oil pump fitted. Works a treat like a river of oil back into the tank.

[Else]

Apologies for my previous post where I got completely muddled with tech terms. Here's what I should have said.....
Interesting...... A mate of mine had poor return to the tank. To cut a long story short, we ended up removing the SRM anti wet sump valve, problem solved! It seemed that the SRM anti wet sump valve was preventing some of the oil getting into the gallery prior to hitting the timing side bush. I suspect the spring was getting coil bound before the ball had cleared the oil gallery. The bike had seized on three occasions prior. Having removed the anti wet sump valve, we ran the bike with no ball and spring (AWS) for a while and the oil flow back to the tank was excellent. We then fitted an outboard Anti wet sump valve (I know, not everybody likes or approves of them) and this prevented wet sumping and did not affect the oil return to the tank. More recently, a different mate had poor oil return to the tank. This turned out be a damaged pump. The circlip had come off the end, bits of mazak had dropped into the timing case and the crankshaft worm wasn't engaging properly with the oil pump gear. We fitted a second hand pump - all good. If your bike has an SRM anti wet sump valve, that's the first thing I'd remove.

Thanks Mate. the previous owner/restorer has fitted an SRM anti wet sump valve in-between the oil feed hose and the crankcase. I removed it and stripped it down, cleaned it but didn't make any difference to the return flow. I'll try taking the spring and ball out.
I've got a table lift coming this weekend so will get back to it once thats assembled.
Forgive my ignorance, I'm new to these old twins, what is a Mazak? Tried googling it but no luck. When you stated gallery do you mean the top of the engine, valves, rockers and pushrods?
Thanks so much for helping with this, I'm learning fast and thoroughly enjoying it.
Else

[Catz]

Forgive my ignorance, I'm new to these old twins, what is a Mazak? Tried googling it but no luck.

Indeed. I take it to mean bits of swarf and detritus and stuff.

[berger]

Mazak more commonly known as Zamak is a zink based alloy that is said to be a good precision casting material . google Zamak instead .

[Else]

Mazak more commonly known as Zamak is a zink based alloy that is said to be a good precision casting material . google Zamak instead .

Aha, that makes sense, thanks.

[Else]

Apologies for my previous post where I got completely muddled with tech terms.

Phew. When i read your original post i thought i'd put some dodgy SRM gear on my bike.
I was going to say that i'd had no problems with my SRM PRV and i also have their own oil pump fitted. Works a treat like a river of oil back into the tank.

That was what I was expecting to see but maybe that won't happen with a standard pump. I believe I've read somewhere that the SRM pump is higher capacity.

[Catz]

That was what I was expecting to see but maybe that won't happen with a standard pump. I believe I've read somewhere that the SRM pump is higher capacity.

I was quite surprised when i saw the oil return with the SRM pump fitted.

[chaterlea25]

Hi everyone,
Around 1970 BSA upgraded the A50/65 oil pumps using larger gears, they also introduced iron body pumps late in the day.

Apparently when BSA closed there were a thousands and thousands of the larger pump gears leftover. These gears wound their way to SRM who took on the manufacture of new pumps incorporating the original gears...

I must have been one of the first customers of the blue pumps and have fitted several more over the years to other peoples A10's all without  issues.

A couple of years ago I did an engine rebuild on an Ariel Huntmaster, at the time SRM pumps were out of stock , the owner ordered a "hepolite" pump. The first one sent  i rejected due to incorrect drillngs where the body bolts broke into the oilways, the pump was replaced without issues, and I was told to bin the reject.
The Ariel showed great oil return and has run great, however it has taken to wet sumping if left for too long.

In spite of CB's issue with the A65 nrv mod all the engines I have been involved with that have the mod have not had problems.

Fitting the mod requires very careful assemply as it is easy for the gasket to impinge on the ball seating even the improved gasket  available. I cut my own gaskets that are snug around the studs to keep them in place while fitting.

John

[Rex]

I've always known the material that BSA used on their oil pumps as "Mazak" and is the same zinc pot-metal that BMC and Ford etc used for door handles years ago.
There's no problems with it other than it "grows" dimensionally and becomes stiff to turn (or even seizes) when left immersed in dirty oil, and becomes very crumbly.
Makes me cringe when someone posts that he's found some old BSA that's stood in a barn for fifty years and when he asks would he ought to do, some knob will always suggest he puts clean petrol in it and kicks it over. That's the quick way to destroy the pump, it's driving gears and the engine (if it does start) if the pump has nipped up, as they usually do.

[berger]

yes rex but the name is possibly a blighty thing and known as mazak  , it is german zink - aluminium magnesium and kupfer - copper - zamak is what comes up in all the searches i have done. so maybe blighty re named it magnesium - zink first as blighty would do.