SRM oil pumps?

[JulianS]

When the body distorts the oil chambers can distort causing the tight spots and spots with greater than designed clearance. Tight is some places and worn or worn out in others.

[Rex]

Don't know enough about A range pumps, but on BSA singles the advice is to always remove and strip the oil pump when the bike hasn't been run for a while, as it becomes stiff to rotate, and if it's stiff enough it'll strip the pump drive PDQ consequently leading to a seized engine.

[chaterlea25]

Hi Steverat,

if I can put it on straight, and it returns oil to the tank, likelyhood is that it is supplying it to the engine too

As the song said "It ain't necessarily so"
 

If the pump is leaking either through the end plate/ gasket/ or porus body there will be little oil pressure to the big end's
The leaked oil will drain to the sump, as there is very little restriction on the return side it may appear that the oil circulation is "OK"

John

[Steverat]

Yes I take your point. We decided on an SRM pump today, already ordered. After all the arguing back and forth I had lost confidence in. the obviously worn BSA pump and I just don’t have the time to play with it since Josef is coming for the finished bike in March.

[Steverat]

SRM were quick, pump came this morning! Lovely looking item, very pleasingly packed with all the bits I might need. But I'm confused by the instruction sheet, it seems to be telling me to leave out the spring loaded ball. What do you think? I can't phone them for guidance since its the weekend but it would be nice not to have to wait for Monday. I've highlighted the relevant sentence in pink.

[berger]

steverat if your bike engine has the spring and ball in the timing side crank case and the bronze main bearing ignore that bit because that is for converted A7s/10s

[Swarfcut]

  Steve, before you fit that lovely new pump, prime it with oil and make sure it works. Also use a pressure oilcan on the oilway to the timing bush.  This will force oil to the big ends. You can also remove the PRV and make sure oil is flowing from the bush to the PRV.  Also worth removing the rear tappet cover and filling the pushrod tunnel with oil. This will drain down into the camshaft trough and overflow into the sump, ready for the scavenge side to start working immediately rather than running the return side of the pump dry until oil works its way down there. This way all the essential bearings and the camshaft and followers are well lubricated for the  first start up.



 Not long now.......

 Swarfy.

[Steverat]

That’s sage advice many thanks

[metalflake11]

  Steve, before you fit that lovely new pump, prime it with oil and make sure it works. Also use a pressure oilcan on the oilway to the timing bush.  This will force oil to the big ends. You can also remove the PRV and make sure oil is flowing from the bush to the PRV.  Also worth removing the rear tappet cover and filling the pushrod tunnel with oil. This will drain down into the camshaft trough and overflow into the sump, ready for the scavenge side to start working immediately rather than running the return side of the pump dry until oil works its way down there. This way all the essential bearings and the camshaft and followers are well lubricated for the  first start up.



 Not long now.......

 Swarfy.

They are all tested on the bench before they leave S.R.M. You can take that to the bank, I've seen Gary Hearl doing it with my own eyes.

Every pump and P.R.V. every time!

[Steverat]

steverat if your bike engine has the spring and ball in the timing side crank case and the bronze main bearing ignore that bit because that is for converted A7s/10s

Still confused I'm afraid, there's no way for me to fit spring and ball between the pump and the timing chest, I just tried with a 3/16" ball (diasappears into the pump) and a 1/4" ball ( won't go into the timing chest, prevents pump from bolting down onto the joint face). I have the standard bronze bush A10 engine, not converted. Do you (and SRM) mean that I don't need to fit spring and ball? The supply side hole into the engine has the same diameter (just over 3/16") as its mating bore in the pump, so there's no way that a ball on a spring in the timing chest could seat on the pump - if it goes into the timing chest, it goes into the pump too.

So do I leave out the spring and ball, or what am I missing?

[Swarfcut]

Steve.... The standard set up for your crankcase is a non return ball valve at the bottom of the oilway from the pump output to the timing bush. This valve is supposed to prevent oil from the tank draining into the sump when the machine is not in use. If you gently push a matchstick or similar into the oilway you should feel the ball.....it will move in as you push and out again under the influence of the small return spring underneath as you let go.

   Because this valve is only accessed from inside the cases, the later similar A65 engine had a design change to enable the ball valve  to be easily serviced by simply removing the oil pump. The confusion you have is partly due to the poorly worded instruction leaflet from SRM and probable inclusion of  spurious parts to the oilpump pack, namely an extra ball and spring, to cover modified engines.

  If you still have the standard valve in situ you just need the pump and the gasket, making sure the gasket holes do not obstruct the oilways.  LEAVE THE EXTRA BALL AND SPRING OUT!

  If there is no ball valve already in place, then we may have to think again, but its an easy fix.

  Swarfy.

[RDfella]

Steve, the standard, unmodified system has the spring and ball tucked away inside the crankcase. Can only get to it with a full engine strip. You may just feel the ball with a piece of wire if you poke it into the oil feed hole.

[Steverat]

Thanks guys you are brilliant.
Straight back into the garage with matchstick in hand - yessss! Felt the internal ball valve.
Pump now on.