The BSA A7-A10 Forum

Technical (Descriptive Topic Titles - Stay on Topic) => A7 & A10 Engine => Topic started by: brackenfel on 24.02. 2011 19:54

Title: Oil Return..
Post by: brackenfel on 24.02. 2011 19:54
I'm probably being over -cautious but knowing this bike it probably pays to..
1961 A10 GF.. had quite a few bits off including timing cover, oil tank which has been thoroughly cleaned (took ages to get the last of the thick dark slime out of the bottom!) and oil pipes.
Now it's reassembly time.. Oil tank half full of Silkolene straight 40. Feed pipe (lower union) removed to allow oil through the pipe, oil only a very fine slow trickle, presume this is ok & due to cold thick oil.. Reconnected again. Return pipe disconnected.

Now the question.. How can I be sure the pump is primed & working??  I know, these things wet sump  (this one did) so it shouldn't be a problem..
Well, now it doesn't seem to wet sump so much, although I have no idea what oil PO used..
Working on the assumption that I should be able to turn the bike over (plugs out) via the kickstart I should see oil come out of the return union.. How long does this take? so far nothing has emerged & my arm is tired.... I would have thought I'd see something fairly quickly..
Don't want to take everything off again but neither do I want to convert the motor to scrap..

Any thoughts apreciated..
Thanks
Adrian
Title: Re: Oil Return..
Post by: RoadRunner on 24.02. 2011 21:58
Hi Adrian,
You're one step ahead of me (maybe several) but from memories of previous threads it takes a while for the oil to return. But I may be talking a load of old tosh though - still I'd be interested to know for sure since I'll be going through the same parnoid prance in the next couple of months!

Looking forward to the other replies.

RoadRunner
Title: Re: Oil Return..
Post by: bob flashman on 24.02. 2011 23:28
Hi, away i've found to get the oil round a rebuilt engine is simple,take the plugs out put the bike in a high gear and take for a walk ie just  push it along the road this usally only takes a short distance and if you look down whilst pushing you can see the oil comeing out the oil pipe in the top of the oil tank.
Title: Re: Oil Return..
Post by: brackenfel on 25.02. 2011 07:14
Hi Bob,
Nice idea but you haven't seen my driveway - steep and slopes the wrong way!!  Take the point though, maybe I should organise a push... *smile*

Adrian
Title: Re: Oil Return..
Post by: Goldy on 25.02. 2011 10:31
Because the oil pump has such a small delivery I think it,s impractical to get oil through to the return pipe. If you remove the relief valve you will get oil through to there using the kick start. If you then start it up and stop it again a number of times this will get the oil through until you can see it at the return. The timing side bush and big ends get oiled first and if you keep stopping  it,s not going to get too hot. I would also look back at the topic on banjo bolts if you have repro ones.
Title: Re: Oil Return..
Post by: alanp on 25.02. 2011 14:23
A while ago I looked at the trickle of oil flow coming out of the feed pipe at the bottom of the pipe and was a bit nervous about starting it up. However, once I'd taken the pipe off completely and confirmed it wasn't blocked, I started it up. In a short time oil came squirting out of the return tube in the oil tank. Clearly for so much oil to return it must have got down through the pipe to the pump in the first place. I guess there must be some level of suction created by the pump, which is likely to be the way anti sumping valves work by pulling the ball off its seat once the engine/pump is turning.
As Goldie says, especially if the engine has been rebuilt, remove the PR valve and kick it without the plugs in until oil arrives at the PR valve, refit the valve and start the engine.
It's fine to be cautious, these things are precious.
Alan
Title: Re: Oil Return..
Post by: brackenfel on 26.02. 2011 08:50
Thanks Alan & Goldy,
I'll remove the PR valve & check that way. I took it off & cleaned it a while back so I'll be able to see if there's fresh oil there & check for flow using the kickstart..

Thanks again to all for your guidance, appreciated...

Adrian
Title: Re: Oil Return..
Post by: A10Boy on 02.03. 2011 12:39
It's quite normal for a rebuilt engine to take a full minute or two before oil returns to the tank. This wont be a problem if you use plenty of oil on the big ends and prime the sludge trap during assembly. I usually start the engine, count to 60 and if no oil has returned, I switch off and let it cool for a few minutes then try again. Remember if you are starting it in winter, use a thinner oil as this primes more easily.

HTH