Baffled, confused and covered in oil!!!!!!

[bikerboy]

bikerboy the oil return to the tank should blow a bit of air with the flow once it has scavenged any surplus from the sump on start up
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I am aware that the scavenge is higher geared than the feed so at low revs the return does splatter a bit but over about 1000 revs its pretty consistent and has been on every A10 I have ever had. This flows as I have always known an A10 to return

[chaterlea25]

Hi BB,

I will check it but it was ground until it was round and then a new bush line bored as is the norm nowadays. It seems to fit fine, definitely no play for sure

A lot of off the shelf bushes will not be a good fit in the alloy case and leakage occurs between bush and case
(is what I was trying to say)

John

[Colsbeeza]

Hi Bikerboy, A well-established member suggested for my stripdown a few years ago that I leak-test the T/S bush. It had been installed by a well-known engineering company and line-bored. I put a large rubber sleeve through the bush for sealing and immersed the crankcase half under water, and blew compressed air down the oil feed hole. Bubbles did come out from one particular spot between the bush and crankcase on one side only. Since the bush was new and had done only 80 miles I was very reluctant to replace it at huge expense. So I cleaned it with carb cleaner, dripped some Loctite 641 down the crack and ground back the surface and put some 2-pack epoxy over the offending spot. I rechecked and no bubbles. It does sound like butchery, but oil pressure was great before and after. 1000 miles later still no problem. When I told him what I had done I did not get a reply and haven't heard from him since. Seems he may not have approved. OK if you have unlimited finance!
I think if it had been leaking more severely, I would have replaced it.
Col

[Gavin]

Sorry I have not read all 11 pages, however, I did have a similar problem, not identical symptoms, but eventually took the bike to old mate Orabanda who pretty soon removed the oil pump, and the gasket behind it which revealed (as the photo shows if you blow it up a tad) a small score from the top left hand oil way to a gap leading back to the sump.

At idle sufficient oil was being returned to the tank to show oil returning, while the remainder was returning to the sump. Once over 40mph the oil built up in the sump and went everywhere. Just a thought from my encounter... check the base where your oil pump sits and ensure it seals. Once that offending score line was sealed... another wonderful A10 !!!   

[KiwiGF]

bikerboy the oil return to the tank should blow a bit of air with the flow once it has scavenged any surplus from the sump on start up
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I am aware that the scavenge is higher geared than the feed so at low revs the return does splatter a bit but over about 1000 revs its pretty consistent and has been on every A10 I have ever had. This flows as I have always known an A10 to return

The scavenge gears are wider so pump more oil, but they turn the same speed as the pressure side.

The A65 pumps have different gears to A10, I guess longer teeth? and pump around 35% more than an A10 pump, the SRM pumps use the A65 design gears (I think….).

I have an A65 pump body and gears on my A10, with A10 drive end, so 35% extra volume at any given rpm.

I wonder if its possible to mix up A10 and A65 gears and the result is a pump that does not have the much larger scavenge capacity than the pressure side?

Another point worth emphasising is that the (gears) pretty much pump constant volume at any given rpm eg volume pumped is the same regardless of the pressure/oil viscosity etc, same goes for scavenge side so it would take a major blockage to prevent flow back to the tank, and there is no PRV in the scavenge side to limit the pressure build up if such a blockage occurred.

[JulianS]

The A10 and A65 gears were the same part from 1956 until 1969 according to the parts books, and had 14 teeth. There were improvements to the A65 pump by dowelling then body to nose and adding an O ring seal to the nose where the drive goes through. The last A65 pumps were iron bodied.

The photo shows the later A65 high delivery gears, much wider and with 11 teeth. The SRM pump uses the same gears.

[Swarfcut]

  Just a few random thoughts...I'm baffled as well by now!!

    Breather bush....Reckon the configuration and orientation of the holes is the same for all types, but Longstroke engine has the drive peg in a different place, and timing mark is different, tho'  the cam gear blank is the same for all. All on the Forum, but unlikely you have the wrong gear set. Breather intake profile changed over time, later models have a shield over the bush, and so use a different part for the outer cover.

 Over supply has been mentioned often enough, and we know the cases are suspect, as detailed in earlier posts. Poor seal of bush to crankcase is a real possible, see Col's experience.

 Oil Pumps, plenty on the Forum. Early bikes have a "Straight Cut" to the gears, this profile changed to a more "Petal Profile" and although  having the same number of teeth, do not mix. Later pumps have bigger Petals but fewer teeth,  carried over to the A65 etc which shares the same basic pump body.  Building up an A65 pump with  A10 nose is possible but frowned upon by purists, but if you can find one with a cast iron body you get the best of both worlds at a far more economic cost....Julian got there first with a little more detail.

  Oilways, don't forget the one that leads from PRV blow off to cam trough. This is not found on early engines, which vent into the oil pump cavity. 

 Swarfy.

[muskrat]

G'day BB.
Again without going back to page 1.
The steel end plate of the pump can/does over time become worn from the gears trying to mill their way through. This reduces the scavenge sides capacity to pump.
Whenever I have a pump apart I lap the end plate and extension housing on a piece of glass to remove the marks.
Cheers

[berger]

regarding everything that has been said about this engine chucking oil out of the breather i know these engines run with flat cam lobes, convex followers , 2 inch of piston slap , well maybe super pocketed valve seats . snapped cranks!!!!!! as in mine in 1980 did ,  mine present day with 10thou difference in piston heights after getting the big end eye round again after some pillock had shaved a cap years ago and she still hits 7000rpm when i'm on one!  in worty's case an eighth of an inch play in the timing side bush --- not quite but might as well have been , a loose oil pump and for gods sake a million more horrors that i found and worty's didn't chuck oil out when it got hot, in fact it's a wonder it didn't blow itself up!!!! if you read worty's engine strip on this forum you will wonder what the hell is going on with this engine that makes it chuck oil out when it gets hot and worty's horror didn't !!!. send it to me i NEED to know why?

[berger]

worty's horror engine, ball bearing in cam oil hole , how the hell did that get there?? my snapped crank , worty's idler bush loosened because of the crank dancing about like a northern soul geeza on powder. i wish i could find or not deleted more photos of the loose oil pump and as i say it didn't chuck oil out it relied on the big ends being splash fed because of a lack of pressure and the shells took the strain and luckily not the journals. so what is going on with that engine chucking oil out when worty's should have been the engine throwing oil out -- regarding feed and return flows ???????  and look how much worty's crank had danced about! i am baffled by your problem but i need to know WHY!?

[bikerboy]

A lot of off the shelf bushes will not be a good fit in the alloy case and leakage occurs between bush and case
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Oh my bad I misinterpreted what you meant that is definitely worth a check

[bikerboy]

I put a large rubber sleeve through the bush for sealing and immersed the crankcase half under water, and blew compressed air down the oil feed hole. Bubbles did come out from one particular spot between the bush and crankcase on one side only
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Highlighting what chaterlea said and well worth a check

[bikerboy]

Hi Gavin

I can see what you said and thought the last time I had stripped it that I had found a crack in the crack case behind the pump and not on the sealing surface. Unfortunately when stripped it was not cracked (my mistake) it was just a bit of a score that was no problem the sealing surfaces are fine although I am going to check them for flat before it goes together again.

[bikerboy]

Oilways, don't forget the one that leads from PRV blow off to cam trough
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Mine does go to just above the oil pump a tiny hole in the crankcase. I have blown it out and it appears fine but I did wonder if maybe my PRV spring was weak therefore oil going straight thru into that oilway in turn filling up the timing case. I have already swapped the PRV with one of my other A10's so think its unlikely but I am going to change the ball and spring in the PRV anyway.

[bikerboy]

Again without going back to page 1.
The steel end plate of the pump can/does over time become worn from the gears trying to mill their way through. This reduces the scavenge sides capacity to pump.
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Hi muskrat there was nothing apparent wrong with the pump thats why I have sent it to be tested as their test rig is bound to give better results than me inspecting it by eye.

Thanks to all of you for your suggestions I do take them all seriously