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

[chaterlea25]

Hi BB,
The oilway as you said his up to the timing gears, But also continues to the rear of the engine then right angles along parallel to the camshaft.. there is a drilling from the cam trough into this passage, which has an alloy plug pressed in at the crankcase half joint.. it is this passageway that takes the bulk of the oil that is bypassed by the PRV.

John

[KiwiGF]

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.

As per my prior post the pump will pretty much pump the same volume regardless of resistance (and consequent pressure) so a weak PRV will make little difference to volume pumped.

99% the issue is on the scavenge side, where pressure is minimal.

I do realise given the circumstances everything has to be checked…..

[bikerboy]

The oilway as you said his up to the timing gears, But also continues to the rear of the engine then right angles along parallel to the camshaft
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Many thanks after all these years I did not know that the oilway continued on to the cam trough. Now I do and I checked and it is all clear 

[bikerboy]

As per my prior post the pump will pretty much pump the same volume regardless of resistance (and consequent pressure) so a weak PRV will make little difference to volume pumped.
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I tend to agree no matter how much is pumped into the sump then the scavenge if working properly should be able to deal with it. I would have stuck with that thought until this damned engine and now I am beginning to wonder.

Having so many bikes does not help I thought this still had old pistons in it but when I stripped it the ones in there are new.

Still confused and still waiting on a verdict regarding the oil pump

[bikerboy]

Right I resume the saga of the plunger A10 

Oil pumps back from testing (I sent two off) apparently they were both working absolutely fine.

Scavenge feed removed and checked out, blow one way and it seals blow the other and it is as clear as a bell. All oilways blown out and where possible something poked thru to check they are all clear. I did think of taking the sludge trap back out for a look but cant see the point. IMO the problem must be on the scavenge side so if any feed pipes were blocked then the sump would not fill up anyway.

Poked a bit of 14/030 cable up the scavenge pipes to see if there was any obstruction all seems clear.

I have extended the breather pipe from the crankcase so that at least I can get a tube on it and save myself coating the back end of the bike in oil again. I was thinking of putting a tube on the breather and taking it to a clear bottle of some type so that I can keep my eye on it while I try it.

Any other suggestions before I bolt it together AGAIN?

If it still pumps out oil I will put it back in the garage for a year or two as I have enough other projects that are not driving me insane to get on with. Meanwhile I will keep my eyes open at the jumbles for a set of plunger crankcases purely because I cannot think of anything else that it might be.

[Swarfcut]

 Somewhere in the previous posts mention was made of the pistons and bores. Poor sealing of the rings is a recipe for blow by and crankcase compression,(though whether this would cause a continuous flow of oil from the breather) and could be a contributing factor. My earlier thoughts on the pick up pipe hold true, it gave me the same symptoms. If the motor is built up again and still plays up, try it without the tappet covers. With no crankcase pressure (and normal oil return) that would point to the problem being related to the pistons rather than the lubrication system.

 Pass me another straw to clutch......

 Swarfy.

[bikerboy]

Poor sealing of the rings is a recipe for blow by and crankcase compression
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I agree and I am going to take the pistons and the bore in to be measured up but if the bores or rings were faulty I would expect the cylinder head to show signs of burning any oil that got past the rings. The inlet valves are the perfect straw colour with the exhaust valves being a fair bit darker which is exactly what a lovely cylinder head and valves should look like. I will add it does not smoke AT ALL even when oil is pumping out of the breather. Compression test is fine, new pistons and a relined bore. I do have a leakdown tester which I will put on it but I will be honest I find it hard to believe its the bore.

Thanks for your suggestion tho because sooner or later this fault will be exposed I am just gutted it has taken so damned long 

[berger]

i went to the pub  breather timing or cork not working , these engines running with one ring wouldn't chuck oil out of the breather as you describe it. send it to me down the river on a biscuit and hope it floats  now there's a thing a re lined bore with sleeves - maybe the problem , gaps and spacers hit and miss liners?  ok i am going to bed

[bikerboy]

Well I had quite a detailed chat to Andrew of Priory Magnetos to get some spares. We came to the conclusion that either the gauze plate in the sump is not letting enough oil back from the crankcases or too much oil is going up to the rocker box which slowly filles the sump up. Its about all that is left. I aim to punch a couple of big holes in the sump gauze before I put it back on and if it cures it then I can just replace the gauze with a new one. If that fails I aim to block the rocker feed and see what happens, I have a blanked of breather in the rocker cover so I can squirt a bit of oil in there ever mile of so to make sure its lubed up ok.

If that fails I will change the crankcases next.

Fingers crossed 

[KiwiGF]

Well I had quite a detailed chat to Andrew of Priory Magnetos to get some spares. We came to the conclusion that either the gauze plate in the sump is not letting enough oil back from the crankcases or too much oil is going up to the rocker box which slowly filles the sump up. Its about all that is left. I aim to punch a couple of big holes in the sump gauze before I put it back on and if it cures it then I can just replace the gauze with a new one. If that fails I aim to block the rocker feed and see what happens, I have a blanked of breather in the rocker cover so I can squirt a bit of oil in there ever mile of so to make sure its lubed up ok.

If that fails I will change the crankcases next.

Fingers crossed 

Sorry if this has been mentioned but there are 12 pages of comments 🤔 and I’ve not read them all….but I was doing an oil change today and whilst waiting for the tank to drain it occurred to me that the oil tank breather/tower could cause mayhem if blocked or restricted as the return flow would pressurise it, and maybe force more oil up to the rockers, possibly also cause the flow side to increase in volume….maybe via the non return ball/spring 

Simple check would be to go for a ride with filler cap removed.

[bikerboy]

Well, well, well I appear to have cured the damned problem and the answer was just ridiculous.

I wont take all the credit mind. I phoned Andrew at Priory for some bits and pieces to rebuild the engine YET AGAIN and we had a somewhat detailed chat about things. We decided two things, it was either pumping too much oil to the rockers OR it was not getting the oil out of the sump quickly enough and therefore the sump was filling up bit by bit as I rode until it pumped out of the breather.

I said to Andrew that I had checked the sump gauze and was not happy that oil could get through it quickly enough. Basically I held the gauze over a container and pumped some oil on to it from my oil can. I could actually count to 6 quite slowly before the oil actually starting dripping through the gauze. As a test I decided to leave the gauze off for test purposes.

Well I left it off and rigged up a container to catch any oil that did come out of the breather as I am sick to death of being covered in oil. After doing 20 miles, with my eye one the container all the way, there was no oil whatsoever coming out of the breather or any sign of any oil in the tube coming from the breather. 

The bike run perfectly and as it used to start pumping out after about 7 or 8 miles I am actually confident that I have cured the damned problem.

Yes the gauze was brand new, yes it looked ok, so its yet another big sign that some pattern parts are pure crap.

Thank you so much for everybody who showed an interest and attempted to help with some great suggestions but I am actually confident this time that the problem has been found.

5 years trying to track down a stupid problem caused by a stupid bit of wire bloody gauze.

Before anybody thinks I spent 5 years non stop on this I never I do have quite a few bikes so kept pushing this one to the back of the garage with pure frustration

[berger]

bikerboy sometimes problems are so difficult but yet so easy, rate pleased for you

[Triton Thrasher]

Can you post a picture of the gauze?

It would be interesting to know what is actually wrong with it.

[bikerboy]

The offending item

[limeyrob]

That's really interesting.  At first sight the gauze looks OK but I suspect the wire size is too big to while the pitch looks right the gaps are too small.  Almost impossible to notice.