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#710942 - 10/09/17 1:05 am Intermittent oil return flow from 1968 Lightning..  
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Gordon Smith Offline
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Hi all, scoured as many past threads as I could find and haven't come across a thread that answers my particular problem.

Did a fairly extensive rebuild, new primary side roller bearing, new timing side-bush and realign, rebore +060 pistons and rings, gearbox bearings , replaced all Oil seals, replaced oil pump with SRM piston type and SRM ORPV as well. Oil tank cleaned out and flushed with a cleaning agent, blown dry all good, seemingly. Oil sludge trap had been removed by previous owner( so didnt remove again).Replaced both oil hoses between oil tank and engine pipes( Correct way around too!!)

Did the oil pump test with hose and cordless driver attached and worm drive removed, got good flow through pump and but return flow back though into tank was very flaky and intermittent, yet through plastic hose into separate oil receptegal looked ok..

Boxed everything back up. got the bike running. Just got steady drips back into oil tank via the usual return pipe. Stopped and checked a few times, still no steady flow. drained sump in between and found approx. 1-2 litres still in the bottom of the engine each time and oil tank was empty . Last time same thing, revved the bike up a few times, to see if any better flow back into oil tank and suddenly engine oil pours out from under the bike near the rear chain case area, with oil tank empty once again. Gearbox oil still in tact and correct quantity.. I use 10-40 multi semi synthetic

Any thoughts from anyone please? could a broken timed breather or incorrectly installed breather be at fault ? Any other suggestions?

Thanks in anticipation

Gordon

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#710962 - 10/09/17 7:29 am Re: Intermittent oil return flow from 1968 Lightning.. [Re: Gordon Smith]  
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kommando Online content
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The return side has double the capacity of the feedside so it's a mixture of air and oil. A check for you is to pour some oil into the rocker box and wait until it's drained into the sump. Then repeat your test and with the surplus oil in the sump the return flow will be all oil, then as the sump clears it will revert to a mixture of oil and air and be spurty.

As you have a buildup in the sump you need to check the non return ball is not sticking in the sump pick up, you don't have a magnet in the sump plate do you?

Ps save the semi synthetic oil for after the engine is run in, your rings will never seat with that oil. Use a high ZDDP Dino oil for first 1500 miles changed often.

Last edited by kommando; 10/09/17 7:35 am. Reason: Oil
#710965 - 10/09/17 8:03 am Re: Intermittent oil return flow from 1968 Lightning.. [Re: Gordon Smith]  
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If you were getting a good oil return to a separate receptacle but poor return to the tank, I would check for blockages in the return pipe or the return fitting and pipe inside the oil tank.
Have you fitted a return line oil filter? The oil should flow into the outer ring of holes and out of the centre threaded hole


1955 BSA B31 400cc "Stargazer"
1962 Greeves 200cc "Blue Meanie"
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#710967 - 10/09/17 9:19 am Re: Intermittent oil return flow from 1968 Lightning.. [Re: kommando]  
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Gordon Smith Offline
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Thanks Kommando, will try that suggestion on the weekend.

Yes I have a magnetic sump bolt fitted, I should eliminate that possibility I'm assuming. The ball valve is free to move and not stuck in the down position with plate removed

Good point about the oil, will hunt around for some mineral multi grade 10-40 or 20-50 ?

Andy

Have blown out and poked some wire through both sets of pipes in the oil tank, when I cleaned it out, pretty confident those lines are clear of blockages... I have blown some air back up the return pipe from the bottom of the sump plate area, might try that again to be sure.

No extra filters added any where on the bike

Thanks to both of you for your replies so far.

Gordon

#710972 - 10/09/17 11:40 am Re: Intermittent oil return flow from 1968 Lightning.. [Re: Gordon Smith]  
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kommando Online content
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Quote
Yes I have a magnetic sump bolt fitted, I should eliminate that possibility I'm assuming.


It is a remote possibility but best eliminated for a test as it has been an issue before.

20/50 would be my preference, the tolerances and clearances on these engines are as they were in the 50's and 60's so thicker oil is preferable especially in hotter climates.

#710973 - 10/09/17 11:42 am Re: Intermittent oil return flow from 1968 Lightning.. [Re: Gordon Smith]  
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And when ever the oil pump comes out, replace the ball & spring that sits behind it.
The spring is quite weak and is supposed to be replaced every 30,000 when ( i the day ) you pulled the bike down for a decoke & bottom end.


Bike Beesa
Trevor
#711039 - 10/09/17 9:02 pm Re: Intermittent oil return flow from 1968 Lightning.. [Re: kommando]  
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Gordon Smith Offline
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Thanks Trevor, I did purchase one of each, so will install both those items..

Kommando, thanks for your tips

G

#711409 - 10/13/17 11:51 am Re: Intermittent oil return flow from 1968 Lightning.. [Re: kommando]  
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Gordon Smith Offline
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Kommando, no joy with adding the oil through the pushrod tunnel , still no flow back to oil tank nor changing the magnetic plug for standard vareity sump plug.

Any other thoughts at all please ?

#711414 - 10/13/17 1:19 pm Re: Intermittent oil return flow from 1968 Lightning.. [Re: Gordon Smith]  
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Replace the oil return line, another possibility is debris between the suction line and the pump inlet, or an air leak in the same section where the sump pickup meets the cases. its either part blocked on the inlet or the delivery from the return half of the pump.
Coincidentally there is another thread here with almost exactly the same ingredients and symptoms
http://www.britbike.com/forums/ubbthreads.php?ubb=showflat&Number=710058#Post710058

At work this kind of thing would happen a lot, Fitter A strips component and plugs drippy oil ways to prevent mess. Sometime later , weeks , days whatever, fitter B reassembles component, fails on test run, strip to find J cloth blocking oil ways, jamming valve/ blocking pump, blocking c/w flow.

Some holes attract insects, there is a chance that some creature is stuck in the oil return ways. My Cagiva fuel tank lid drain pipe gets blocked by flies which crawl into it. see Bee Gap, i cut and pasted this bit from a beekeepers site, applies to other flying insects as well.
We all "KNOW" that bee space is between 4.5 mm and 8 mm and it is also widely reported as being between 6 mm and 9 mm. However it is not a "variable" quantity, it is either 5.3 mm + or - 0.5 mm or it is 9.0 mm + 0.0 mm - 1.0 mm. In other words there are two distinct bands of possible bee space and these occur because in some situations the bees will work individually, but in other situations they need to be able to work back to back.

A gap of:- less than 4 mm... is too small for any but deformed worker bees to pass through. Any spaces, cracks or crevices of this or smaller dimension will be filled with propolis or sometimes a mixture of wax and propolis and on yet other occasions pollen may be mixed in with the filling (I suspect that this is for reasons of porosity or possibly the transmission of light, but I am not certain).

A gap of:- 4.3 mm is a standard European spacing for wires in a Queen Excluder.

A gap of:- 5 mm if used between the wires of a square mesh will make an excellent pollen stripper as the workers can get through, but a significant portion of pollen will be stripped from their legs.

A gap of:- 5.2 - 5.4 mm is a spacing that can be used to exclude or differentiate Drones, as Workers and Queens will freely pass, but Drones cannot.

A gap of:- 6 mm Is the smallest gap that bees will leave between adjacent comb surfaces (outside of the usual clustering area) the bees can defend this more easily and they can work individually within this dimension. The smaller gap around the periphery of the nest, also renders the nest less susceptible to draughts, and may help in maintaining humidity.

A gap of:- 7 mm not used by the bees themselves, but some people regard it as a valid bee space to use in some parts of beekeeping equipment. If this spacing occurs between the side faces of frame top bars they are the least likely to suffer from accretions of wax. Frames spaced at 35 mm pitch (normal Hoffman spacing) that have top bars 28 mm in width give rise to this 7 mm gap.

A gap of:- 8 mm is a popular bee space among those that design their own equipment as it falls midway between the 1/4" and 3/8" figures so often quoted in old books. I used to be keen on this dimension myself, but I have come to regard it as 'neither one thing or the other' and now I favour 9 mm or in some circumstances 6 mm.

A gap of:- 9 mm is the usual space the bees will leave between adjacent areas of capped brood. This allows two layers of bees to work back to back, usually in an oval pattern roughly in the centre of a frame.

Last edited by gavin eisler; 10/13/17 1:33 pm.

71 Devimead A65 750
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#711425 - 10/13/17 3:04 pm Re: Intermittent oil return flow from 1968 Lightning.. [Re: Gordon Smith]  
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kommando Online content
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All what Gavin said plus

You can get hose where the inner lining has come loose and the flap created blocks the flow when the oil is pressurised but not if you blow through the same pipe using your lungs. Normally happens with old pipe but worth a check.

Also did you fit a filter in the return line, these sometimes have a non return valve and if fitted the wrong way will block the return. Others have bypass valves and the pressure is set too high.

#711453 - 10/13/17 8:35 pm Re: Intermittent oil return flow from 1968 Lightning.. [Re: Gordon Smith]  
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gunner Online content
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Quote
Did the oil pump test with hose and cordless driver attached and worm drive removed, got good flow through pump and but return flow back though into tank was very flaky and intermittent, yet through plastic hose into separate oil receptegal looked ok..


This statement is very revealing and sounds like there may be a blockage in the return side to the tank.

I would check several areas as follows:-:
- ensure the twin pipe oil manifold is fitted correctly and that the return side manifold is not obscured by misalignment or misplaced a O ring.
- you might want to disassemble the oil pump and check for broken gears, debris etc. Be careful and ensure each gear goes back exactly the same way.
- Repeat the cordless drill test procedure, there should be no leaks from the pump body or gasket interface with the crankcases. Use Loctite 518 anerobic gasket sealant in the pump bottom and top plates, this will stop leaks and maintain pressure.
- Check the OPRV, hopefully you are using the later BSA piston type (or SRM version). I guess its possible that the OPRV is not releasing pressure and not dumping excess oil back to the crankcases/return oil line

Last edited by gunner; 10/13/17 8:44 pm.

1968 A65 Firebird
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#711686 - 10/16/17 12:31 am Re: Intermittent oil return flow from 1968 Lightning.. [Re: gunner]  
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Thanks Gunner

I will check the joint on the manifold to crankcase, the o ring may have moved, it is a very tight fit when the engine is in the frame

- The oil pump and OPRV are brand new items installed upon rebuilding after engine reconditioning.

Gordon

#711689 - 10/16/17 12:57 am Re: Intermittent oil return flow from 1968 Lightning.. [Re: gavin eisler]  
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Gordon Smith Offline
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Kommando

I replaced hoses with new items, can check again.

No extra oil filters installed, just original in tank item

Regards Gordon


Gavin, thanks for your input, will take on board your thoughts and investigate further. I had seen that other thread and thought it very similar to my issue too!!!

Gordon

#711705 - 10/16/17 11:09 am Re: Intermittent oil return flow from 1968 Lightning.. [Re: Gordon Smith]  
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Insects in brit motors, see this Vid https://www.youtube.com/watch?v=iBPB96Yfs18&t=1949s FFWD to 21:30 ( wasp ), 23:10 (ladybird)

Last edited by gavin eisler; 10/16/17 11:14 am.

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#711758 - 10/17/17 1:09 am Re: Intermittent oil return flow from 1968 Lightning.. [Re: Gordon Smith]  
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Better check that hi dollar oil pump too.

#711769 - 10/17/17 3:02 am Re: Intermittent oil return flow from 1968 Lightning.. [Re: sloppyoil]  
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Gordon Smith Offline
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Sloppyoil

Being a new item and pumping in one direction the correct way, I just assumed the scavenging should be the same too.

And your right it was expensive !!! When I get it off again, will check that as well...

Thanks for your thoughts

Gordon

#717045 - 11/29/17 12:05 am Re: Intermittent oil return flow from 1968 Lightning.. [Re: Gordon Smith]  
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Hi all, have dismantled again, back down to removal of oil pump, OPRV, oil tank, oil lines etc.

Dismantled oil pump, nothing amiss that I could see there. OPRV seems to work correctly as well. Oil flow test using attachment to hand held portable drill gives steady flow but not great pressure or high quantity of oil flowing back to tank. If you continue test , oil tank needs to to be topped up to keep level up to pump and return flow doesnt keep up with feed flow from tank to the pump.

during the test, at high revs from the attached drill, oil leeches out from around the timing side bush and flows back down to sump, I'm assuming this is normal?

One other item I thought a bit odd, the level in the oil reservoir attached to bottom pick up when using the portable drill doesn't drop that much when in use. When it is first started, oil is sucked up very quickly to the pipe in the sump, but after that the level doesn't drop that much when drill is rotating at fairly high revs ?

Possible damaged pick up pipe in sump area?


Running out of options/ideas?


Gordon

#717049 - 11/29/17 12:50 am Re: Intermittent oil return flow from 1968 Lightning.. [Re: Gordon Smith]  
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Check all oil ways with pipe cleaners and compressed air, Blow through and poke through all return passages from pump pick up to pipe union in tank, ( pump will need to come off to blow through all ports)check the oil manifold isnt dented, seems like something is restricting the return flow it should clear the sump and maintain tank level. If that doesnt fix it , then send the pump back.

Have you checked the pump / casing joint is truly flat, a light rub with studs removed and face cleaned and some engineers blue will tell all. Its very common to find the stud holes have a protruding lip, easy to fix with a light countersink, be sure the gasket isnt masking any of the ports , trim to suit .

Yes oil will ooze out of the TS bearing, most should go to the bigends but the bearing is not sealed.


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The poster formerly known as Pod
#717197 - 11/30/17 10:16 am Re: Intermittent oil return flow from 1968 Lightning.. [Re: gavin eisler]  
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Gordon Smith Offline
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Thanks Gavin, have air blown all the passages and they seem to be clear.Haven't checked the oil manifold for dents, I know its not loose though. I didnt check the stud holes for any protruding lips as yet. Gasket has been trimmed to suit all ports

if I have a sticking or galling OPRV ,could this affect return oil flow?

Gordon

#717198 - 11/30/17 10:48 am Re: Intermittent oil return flow from 1968 Lightning.. [Re: Gordon Smith]  
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HI Gordon,
[quote=
if I have a sticking or galling OPRV ,could this affect return oil flow?
Gordon[/quote]

No it should not affect return as the PRV is on the pressure side

Have you tried putting a length of clear plastic tubing on instead of the oil return rubber pipe and lead this up and into the filler neck
That would bypass anything that might be restricting the return lines
The only other thing that has not been really checked is the possibility of an air leak on the suction side of the pump
You would need to rig up a pressure (or vacuum) test, blocking the return pipe from the engine and apply air pressure to the pickup pipe in the sump ??

John

#717199 - 11/30/17 10:51 am Re: Intermittent oil return flow from 1968 Lightning.. [Re: Gordon Smith]  
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Quote
One other item I thought a bit odd, the level in the oil reservoir attached to bottom pick up when using the portable drill doesn't drop that much when in use. When it is first started, oil is sucked up very quickly to the pipe in the sump, but after that the level doesn't drop that much when drill is rotating at fairly high revs ?

Possible damaged pick up pipe in sump area?


There have been cases where the oil pipe has leaked in air where it is pressed into the crankcase on the OD. What you are describing would be explained by the leak being covered by oil initially so the return side pumps 100% oil and the level drops, then once the gap is exposed by the dropping oil level air is pulled in instead of oil and the effective capacity of the return side is reduced.

#717230 - 11/30/17 4:33 pm Re: Intermittent oil return flow from 1968 Lightning.. [Re: Gordon Smith]  
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Really quite a frustrating situation for you I'm sure Gordon.
Just a thought, would it be possible to fit up the original oil pump if you still have it and do the drill test with that pump on the bike as a comparison in performance to the SRM pump?
I recently lapped the bottom of a pump on a surface plate to make sure it was flat & guess what ....it jammed up solid when installed on the bike ! ('70 T Bolt) .
I then installed another pump of unknown pedigree and spun it with the drill which resulted in an indicated (on my gauge) 45psi, and yes oil oozed from around the timing side bearing as well.
Wish I could remember what the return side looked like but I don't recall noticing that the return seemed on the weak side as you have been experiencing.
Hang in there.....if you remain PERSISTANT you will PREVAIL !

Phil

#717248 - 11/30/17 6:16 pm Re: Intermittent oil return flow from 1968 Lightning.. [Re: Gordon Smith]  
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I have no BSA specific experience, however that in your original post you say that after brief running you then drain 1-2 litres from the sump beggars belief. I would expect an engine running with that in it not only to be pumping it out the breather, but putting up a smokescreen like the Bismark, and hardly able to run at all without busting its cases.
I imagine the feed side pump capability to be somewhere in the region of a pint/minute at say 3000 rpm, of course with a gear pump this is not as positive as some might like to suggest, and will be reduced by back pressure, viscosity reduction of oil as temperature rises, and precision of fit of gears in bores and side plates.
Your observations suggest that there is hardly any scavenging at all.
The feed side, assuming the new bigends and timingside bush to be as good as new, should be easily reaching a high pressure when cold so opening the OPRV, when the oil is hot, I would still expect say 50 psi at 3500 rpm.
Can you put a known good pressure gauge on it? I would want to be assured of this before running the engine further.
Doubt about the quality of the scavenge side would make me double check the much more important feed side.

#717436 - 12/01/17 11:35 pm Re: Intermittent oil return flow from 1968 Lightning.. [Re: gavin eisler]  
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Originally Posted by gavin eisler
Insects in brit motors, see this Vid https://www.youtube.com/watch?v=iBPB96Yfs18&t=1949s FFWD to 21:30 ( wasp ), 23:10 (ladybird)


Yes,
Had the tank off the M20 and left it uncovered overnight - bad move.
Following day reassembled and off we went,
All was fine for about 300 km then the bike would not rev past 1/4 throttle so it was a trailer entry to the All British for me ( first time ).
A quick check found the remains of a wasp firmly embedded in the banjo filter under the Concentric carb.


Bike Beesa
Trevor
#717451 - 12/02/17 11:03 am Re: Intermittent oil return flow from 1968 Lightning.. [Re: chaterlea25]  
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Thanks John, no I havent tried that one as yet, at least that would eliminate or highlight an issue. I haven't got a pressure gauge fitted on this bike unfortunately. I would have to work out how to do the second option with a vacuum gauge

Kommando, I'm leaning toward something like that as well, but would need a complete strip down to get to the area concerned to check it out. Last resort case I'm thinking.

Phil, Havent got the old one in a working state unfortunately, as I damaged the original spindle trying to refit it. Worth consideration however if I run out of other options !!


Thanks for everyone's ideas, will work through as many of them as I can in the short term..

Gordon

#717452 - 12/02/17 11:13 am Re: Intermittent oil return flow from 1968 Lightning.. [Re: koan58]  
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Thanks Koan 58, I haven't been game to run it more than a few minutes with no return oil flow showing up in the tank.

Bike hasnt got a pressure gauge and unlike later models,no off take on engine cases doesn't allow space to fit one down near timing case area.

#717462 - 12/02/17 3:28 pm Re: Intermittent oil return flow from 1968 Lightning.. [Re: Gordon Smith]  
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You can just remove the oil pressure release valve and jam it shut temporarily, then do a short engine run and see if the problem is cured, if it is then the OPRV is opening too soon and dumping all the oil to the sump and little if any is getting where its needed.

#717472 - 12/02/17 5:31 pm Re: Intermittent oil return flow from 1968 Lightning.. [Re: Gordon Smith]  
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If you disconnect the pipes from the oil tank and hang them high, even better with longer/higher ones, filled with oil, sump open with tub under, leave overnight. Then see if either of them drop significantly. This could provide clear directions to go in.

Irrespective of what the OPRV is doing, the much higher capacity of the return pump should easily cope with any delivery rate.
With crankcase flooding happening so quickly, the scavenge seems to be hardly working at all.
If you're sure the passage from pump to tank is clear, the problem has to be from the return gears themselves back down to the sump pickup.

A65 experts:
-Does this year of engine have the OPRV bypass back to the return line, or not? It could make a difference in fault finding.
-If so, where does this OPRV intercept the return line? Presumably just before the pump?

I can't avoid feeling that the return pump (assuming it is healthy itself) is drawing air from somewhere and losing its prime.
If a leak in the scavenge pipe, it would have to be at a high level, to allow the sump to fill so much. Maybe where Kom suggests, where the pipe is pressed into the case. A check for this might be to use a pump with a "football adapter" in the scavenge pipe and see how well it holds pressure, and you may hear a leak inside the case, or even passing the gears of the pump.

Then go from there. Good luck!

#717481 - 12/02/17 7:23 pm Re: Intermittent oil return flow from 1968 Lightning.. [Re: Gordon Smith]  
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Hi Gordon,
Quote
Thanks John, no I havent tried that one as yet, at least that would eliminate or highlight an issue. I haven't got a pressure gauge fitted on this bike unfortunately. I would have to work out how to do the second option with a vacuum gauge


No need for a pressure gauge and you could rig up a U tube with some clear tubing for vacuum testing if you decided to try that

A simple method of pressurising the return oil system can be done with a bicycle or foot pump as Koan has suggested
You should be able to hear any air/oil bubbling out any leaking spot

To the best of my knowledge, the bypassed oil does not go to the return side of the system
It simply loops around to the inlet side of the feed pump

Kommando. as Koan has mentioned the return side of the pump has a greater capacity then the feed so no matter how much the feed side delivers then the return should be able to clear it

On a side note (but relevant thought) Opel / Vauxhall "Insignia" diesel models have a rubber seal on the oil pick up pipe from the sump
These can harden and leak in air, result blown engine !!
Oil pumps would much rather suck air than oil

John

#717490 - 12/02/17 8:17 pm Re: Intermittent oil return flow from 1968 Lightning.. [Re: Gordon Smith]  
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I am fully aware that the return has double the capacity of the feed but stranger things have happened and an inverted timing side crank feed seal on a Triumph allowing the oil to dump straight to dump will flood the return. As the obvious faults are not then it's going to be an odd solution that solves this issue. It's been nearly 2 months and no solution.

#717502 - 12/02/17 9:14 pm Re: Intermittent oil return flow from 1968 Lightning.. [Re: Gordon Smith]  
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I do agree with you that I suspect the answer to this will be unusually illuminating, quite a challenge.
However, why would you think that any feed situation could trouble a return side pump that is working properly? Particularly in your quoted example of a Triumph pump, which is far more positive and self-priming than a gear pump.
Even if the feed pump has unrestricted flow, it can't get anywhere near the capacity of the return. I've had the feed seal fail on mine (once only in 35 years) and it did nothing other than show as a much reduced pressure on the oil gauge, no wet-sumping at all, and allowed me to get 40 miles home with no problem.
Logically, I can't see how this can be anything other than a problem with the efficiency of the return pump suction.

#717511 - 12/02/17 10:34 pm Re: Intermittent oil return flow from 1968 Lightning.. [Re: Gordon Smith]  
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kommando Online content
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I mentioned it as it's a simple test that cannot cause harm, it has been reported that in a Triumph an inverted seal will allow a flow of oil that exceeds the ability of the scavenge to clear the sump. It is not logical but observation beats theory and yes positive displacement pumps should continue to flow even if the output is restricted, but on a C15 I saw a non return after the pump block and reverse the flow of oil on the feedside.

#717548 - 12/03/17 9:48 am Re: Intermittent oil return flow from 1968 Lightning.. [Re: Gordon Smith]  
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One thing I haven’t seen mentioned yet (although after reading the full thread i did start to skim near the end)

The oil return pipe from the bottom of the engine also feeds the rockers,

Question 1) is the split pin installed in the cylinder head? The split pin gives a level of back pressure, which will allow enough oil to the rockers but ensure most of it goes back to the tank. If it isn’t then you’ll have more than enough oil to the rockers and it will... eventually wet sump.

2) As already stated, the oil flow will glug away, it takes a LOT of revs to get a steady stream, add more pipe work, filter and/or cooler and this effect will seem worse still. A drill acting on the pump will not spin it anywhere near fast enough to give a steady return flow.

Oprv won’t effect it, but if it’s a stainless unit they will eventually gaul and stick... stripped 2 and both have this problem, fitted a lyfords ball type to the OIF (the light goes off better than it did with the SRM unit) and an NOS (new Bsa) piston type to mine, although I have also used lyfords ball type with no problems.


beerchug
#717551 - 12/03/17 11:06 am Re: Intermittent oil return flow from 1968 Lightning.. [Re: Allan Gill]  
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Alan

The split pin is still in position and wasn't touched during disassembly. On advice from a friend of mine outside of this forum, I disconnected the feed line to the rockers, started the bike and it had no flow from the manifold/pump area to speak of. There is heaps of oil in and around the rocker area however, so this oil must be coming from the push rod tunnel / sump plate areas I'm assuming.

I have re fitted the original OPRV, and this give's a seemingly better "intermittent flow of oil " back to the tank with the portable drill attachment fitted than the new SRM OPRV unit

Thanks to everyone for their thoughts, I have a few things to try when I have it all back together yet again to try out.

Gordon

#717555 - 12/03/17 1:17 pm Re: Intermittent oil return flow from 1968 Lightning.. [Re: Gordon Smith]  
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I struggle to see how the OPRV will effect the return flow, either you have enough oil going into the engine... or you dont. the oprv (not that you don't know this) either directs oil directly to the sump... or shuts off and you'll get oil coming past the bush and journal shells. either way it will make its trip to the sump.

Have you removed the OPRV and cranked the engine over to see how much is coming on the inlet side? a couple of kicks with the plugs out and you should see a welp of oil coming through, if its not much more than a dribble then the motor isn't getting primed or there is a restriction on the feed side (kink in the pipe or blockage)

Is the stand pipe in the sump loose? this will reduce oil to the return and cause wet sumping.


beerchug
#717568 - 12/03/17 3:34 pm Re: Intermittent oil return flow from 1968 Lightning.. [Re: Gordon Smith]  
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Have you seen what a proper running A65 return flow looks like? Try pouring a pint of oil into the sump and run the pump with the drill. You should see a continuous flow of oil back to the tank. If not then you have a problem.

#717574 - 12/03/17 4:56 pm Re: Intermittent oil return flow from 1968 Lightning.. [Re: Gordon Smith]  
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Always worth double (quadruple+) checking, but from the 1st posts it seems it doesn't remotely do this with even 1-2 litres in the sump. That's almost at a level where it should return to the tank by gravity, joking!

#717582 - 12/03/17 6:03 pm Re: Intermittent oil return flow from 1968 Lightning.. [Re: Gordon Smith]  
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Then put oil in the sump, block off the return line (without rocker feed) with a pressure gauge and run the pump with a drill motor. If you cannot generate 50 PSI the pump is bad. The return side is larger volume but should generate as much pressure as the feed side.

#717592 - 12/03/17 8:11 pm Re: Intermittent oil return flow from 1968 Lightning.. [Re: Gordon Smith]  
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I can't see that blocking the return pipe with a gauge will tell much beyond what we know, which is that even with a sumpful of oil the return is still largely air. Even the best oil pump is unlikely to produce any meaningful pressure on air.
If the return pump has a depth of oil at the bottom end of its scavenge pipe, the flow should be of continuous oil, until the pipe is able to draw in air.
So the question surely has to be where is this air coming from?
It can only come from the return gears downwards to the sump pickup.
As far as I know, on your engine, this is a simple, direct route. So the test of using a tyre pump to pressurise the pickup pipe and looking/listening for air leaking would be informative.
I have already asked if any A65 experts know if this year would have had a bypass from the OPRV overpressure vents to the return line, rather than simply dumping it into the motor in the old-fashioned way. I've seen this mentioned, but I can't find any information about it, so it may be a myth?
If there were such a bypass, it would be valuable to know where it joined the return line ie before or after the return pump. If before the pump, then it would be a potential source of air needing eliminating in the fault-finding process.
I also repeat my earlier suggestion to establish whether there is any draining into the sump through feed and return lines, by hanging high oil-filled pipes on both lines overnight, with sump removed. This could give useful info about pump quality and non-return valve sealing efficiency.
Being a Triumph guy for my sins, I'm not used to all these non-return valves, but what I do note is that BSA considered it important to put one in the scavenge pipe.
The NR valve in the feed line is obvious enough, otherwise the whole oiltank could drain into the crankcase.
The return line could never do such a thing, the worst would be a drain back of the pipes to the tank and rockers, a few 10's of ml at most.
So that they went to the trouble of putting that NRV in suggests that it was important to prevent the oil draining back through the return gears and leaving them high and dry, ie not primed with oil.
Gear pumps are not great at self priming, especially when they have to pump air to draw oil from a distance below, so I suspect the NRV was intended to give it the best start.
Just ideas! Dave

#717605 - 12/03/17 9:52 pm Re: Intermittent oil return flow from 1968 Lightning.. [Re: Gordon Smith]  
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"I will check the joint on the manifold to crankcase, the o ring may have moved, it is a very tight fit when the engine is in the frame"

Sometimes excess weld on the lower frame rail lug prevents the manifold bolt from completely unscrewing, its ok to dress some material off this area to allow the bolt to clear, pretty sure I took a file to mine years ago.

I had a huge post typed up but lost it.
In summary, early model A65s bypassed to the sump, later to the return line.
Its either sucking air somewhere, or something is blocked , or the pump is faulty ( lets hope not seeing its new, even old clapped out pumps will clear the sump if the rest is OK).
Back flush all return lines with a small nozzle air line, starting at the discharge to the tank , finishing at the sump to pump gasket face, got to be sure nothing is in the holes, put a net on the end to catch any possible debris.
With the pump removed to check joint flattness, run the pump backwards with a cordless drill and a bit of 1/4 bore rubber hose to drive, do this in a clean tub of kero, see if anything comes out. run it correctly and check pump action crudely by part blocking delivery holes while submerged, this will at least prove the pump sort of works/ or not. Blow out kero and refill with real oil if happy.
With the pump off, poke the NRV and see if oil drops out ( it should if the NRV is doing its job)put some kero in the pump/ case suction gasket face port,to fill the line to the sump NRV, clean all around the area where the suction leg meets the cases, look for weeps, if all is well the ball will hold this line full. The air pressure test will be better but at least you will have flushed the line of oil first.

The other chap having this bother , Trevor, found the oil pump gasket had moved and one of the return ports was not 100 %.
Have a good hard look at the return pipe run where it leaves the manifold and crosses the lower frame horizontal, if the manifold pipes get tweaked this can point the pipe to a nasty turn and squeeze which could restrict flow.I remember once "straightening" the manifold pipes in an idle moment during a rebuild then finding they were bent for a good reason when I attempted to refit them.


71 Devimead A65 750
56 Norbsa 68 Longstroke A65
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The poster formerly known as Pod
#717632 - 12/04/17 4:47 am Re: Intermittent oil return flow from 1968 Lightning.. [Re: Gordon Smith]  
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You can tell where the OPRV dumps the excess oil by looking at the pickup tube. If it has a ball check valve at the sump plate the connection is into the return drilling between the pickup and pump and makes the excess go to the pump and not into the sump. That is the reason for the check valve at the sump pickup, not to prevent the oil from draining away from the pump. Once primed the pump is never "high and dry" due to the oil's surface tension.
There were pictures of this but they were Photopuked.
I fail to see why people continue to use gaskets for parts such as this which seem to cause more problems than they are worth.
Triumphs have check valves at the pump. I believe T140s have a dual check valve on each pump chamber.

#717673 - 12/04/17 3:08 pm Re: Intermittent oil return flow from 1968 Lightning.. [Re: Gordon Smith]  
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That's very helpful Dave. So it would seem this engine has the OPRV bypass back to the return line, as the sump pickup checkvalve was mentioned early on.
It opens another possible avenue for air to leak into the return line before the pump?

#717731 - 12/04/17 10:27 pm Re: Intermittent oil return flow from 1968 Lightning.. [Re: Gordon Smith]  
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Not unless you have a crack in the casting?

As an experiment, you could setup the oprv so it is permernantly closed and start the bike. That way the sump drain bypass is eliminated from the problem.

Last edited by Allan Gill; 12/04/17 10:28 pm.

beerchug
#717735 - 12/04/17 10:59 pm Re: Intermittent oil return flow from 1968 Lightning.. [Re: Gordon Smith]  
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What does the NRV in the sump pickup look like? I guess it's a ball, what stops it blocking the tube when it goes to the top of its travel? Is the bottom seat removable for cleaning/ reseating?
Not much to think about till some results of pressure/drain down tests come in.

#717901 - 12/06/17 11:18 am Re: Intermittent oil return flow from 1968 Lightning.. [Re: Allan Gill]  
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Alan

yes, did try it with th OPRV off and kicked over, with plenty of oil oozing out.

I couldnt move the return pick up by hand at all.


Koan 58, yes it has a ball in a partially "closed in" end pipe. It seems to be working correctly, no flow from the oil tank when engine not running. Ball is free to move with a piece of wire poked up when at rest.


Gordon

#717902 - 12/06/17 11:24 am Re: Intermittent oil return flow from 1968 Lightning.. [Re: kommando]  
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Kommando and Koan 58, they are two options I can try once I have it back together and running again if I'm still having issues

Regards Gordon

#717954 - 12/06/17 8:08 pm Re: Intermittent oil return flow from 1968 Lightning.. [Re: Gordon Smith]  
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koan58 Online content
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Hi Gordon,
We seem to have established that yours is the later bypass system? I must go with the only convincing information provider, Dave Mad, and I think he knows his stuff.
Going on that tack, I would think that the valve at the sump end should be given more than a "it seems ok" sort of check. There is only one way to check valves, subject them to pressure.
If your problem is genuine, it has to be due to a fault in valve/pressure/suction, or pump.
Any of the simple suggested tests would give us something to go on.
Best of mate

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