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#717452 - 12/02/17 11:13 am Re: Intermittent oil return flow from 1968 Lightning.. [Re: koan58]  
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Gordon Smith Offline
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Victoria, Australia
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.

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#717462 - 12/02/17 3:28 pm Re: Intermittent oil return flow from 1968 Lightning.. [Re: Gordon Smith]  
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kommando Online content
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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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koan58 Online content
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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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chaterlea25 Online content
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Cork Ireland
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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kommando Online content
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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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koan58 Online content
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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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Allan Gill Online sleepy
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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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Gordon Smith Offline
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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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Allan Gill Online sleepy
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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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koan58 Online content
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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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koan58 Online content
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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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gavin eisler Online content
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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.


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#717632 - 12/04/17 4:47 am Re: Intermittent oil return flow from 1968 Lightning.. [Re: Gordon Smith]  
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DMadigan Offline
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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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koan58 Online content
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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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Allan Gill Online sleepy
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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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koan58 Online content
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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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Gordon Smith Offline
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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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Gordon Smith Offline
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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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