The BSA A7-A10 Forum

Technical => A7 & A10 Engine => Topic started by: Cider1 on 13.03. 2010 14:05

Title: Help I have an Oil Leak!!!!!
Post by: Cider1 on 13.03. 2010 14:05
Gentlemen
I wonder if one of you knowledgeable people can give me some guidance before I start stripping the engine.
I have a 1959 Golden Flash which I've run for two years with no real problems.  I use it regularly come rain or shine, summer and winter. When I first got it, wet sumping was problem.  After fitting a plug into the sump plate it was was easily drained before a run.  As far as oil leaks go, there weren't any, just the odd weap from variuos places.
Now to the problem:  I haven't used the bike for over six weeks till today.  I drained the sump, checked the oil was returning with the engine running and then set off for a gentle cruise.  After 10 miles or so I stopped to check over things and found there was a trickle of oil coming from what appeared to be the area of the breather between the engine and gearbox.  I thought this may have been some residual oil after the wet sump so carried on, thinkinking it may stop.  The trouble is it didn't, and whenever I stopped there was a trickle of oil onto the ground.  It seemed that there was a lot of oil leaking but when I got home after 60 miles, the oil in the tank had only gone down by about 1".

My question is what do you think has happened to the bike during the six weeks I haven't ridden it?

Thank
Frank
Title: Re: Help I have an Oil Leak!!!!!
Post by: Richard on 13.03. 2010 17:35
Take it out for another ride tomorrow and check it again, it may be you filled the oil tank to much, anyway its an A10 they all do that sir, joking apart it may be ok although after 60 miles one may have thought any surplus oil would have cleared
Title: Re: Help I have an Oil Leak!!!!!
Post by: RichardL on 29.05. 2010 01:10
Gents,

There are a few topics named "Oil Leak", so I figure this one is as good as any for posing my questions.

I am leaking oil, from where I am not sure. The biggest accumulation is in the form of a coating of the top of the gearbox, but it works its way down to the front portion of the silencers as spots. Nothing seems to be coming from the timing cover, nor from the head or rocker box on the timing side. I think there is some minor seepage around the oil-line fittings at the tank, but I am hard-pressed to understand why a small leak there would schmear the top of the gearbox. Maybe it's air turbulence? Maybe the most likely place for this leak would be at the gearbox cover gasket or the clutch-lever hole. The only thing is, I don't know if there is so much agressive splashing inside the outer cover as to push oil out the top.


If anyone knows right off the bat what this is, that would be a big help. Otherwise, I will try to pinpoint the origin by taking a short ride and investigating before the oil is all over the place.  Any other thoughts?

Richard L.



Title: Re: Help I have an Oil Leak!!!!!
Post by: madsens on 29.05. 2010 11:42
Hi Frank

I've got exactly the same scenario with my 1962 GF - after a couple of years with the usual small amount of oil weeps it is now weeping on a "larger" scale, and it also seems to come out of the  breather hole - I've fixed a smal hose on the breather, and thats were it drips from - and as mentioned on my earlier tread about idling problems my bike will only fire on the timing side cylinder when idling...  so I'm wondering if these two things could be related ?
I have not been able to do a compression test yet, but could it be possible that with worn pistonrings on the primary side oil could get underneath the piston and out via the breather hole ?


regards
Joergen
Title: Re: Help I have an Oil Leak!!!!!
Post by: MG on 29.05. 2010 12:06
Joergen,

You have oil in the crankcase and at the lower portion of the píston and cylinder anyway (along the skirt, up to the scraper ring, that's why it is fitted to the piston). When the valve guides are worn otoh, oil will get into the combustion chamber from the rockerbox and will be burnt there, resulting in blue smoke from the exhaust, the same will happen with worn rings, with oil going past the skirt up to the combustion chamber.
The other effect is lack of compression and excessive so-called blow-by, meaning that a large amount of the combustion pressure will escape past the rings into the crankcase, building up pressure there and causing excessive oil leaks from the breather.
So yes, worn rings COULD be the problem. But if the engine doesn't smoke and lack power, I don't think this is likely to be the case.
Anyway, a compression test will tell you.

Cheers, Markus
Title: Re: Help I have an Oil Leak!!!!!
Post by: wilko on 30.05. 2010 01:42
To answer the original question, take off the sump plate and with a piece of wire or something give the non return ball a few prods to make sure it's free to move, spray some petrol or something to give the tube a wash.My mates A10 started gushing oil out of the breather and nearly emptied his tank because the ball was stuck closed and not returning the crankcase contents.
Title: Re: Help I have an Oil Leak!!!!!
Post by: RichardL on 30.05. 2010 02:50
Wilko,

Thanks for the thought. That is probabaly not a bad idea in any case, but it might not apply to oil on the cover of the gearbox, which is on the opposite side from the breather port on the swingarm.

I taped a piece of cardboard above the gearbox cover to track the direction of the oil spray. The oil droplets accumulated near the front of the top of the gearbox, as if it is coming from the timing cover just under the rear tri-point. The problem is, while it is a bit wet under there, there is not an obvious sprayer. Also, with the cardbord in place the top of the gearbox cover was dry, so I know it wasn't coming from those gaskets.

Yes gents, I am a bit embarrassed that I am unable to easily find the leaky culprit. I think there is something going on here in airflow that distributes the droplets, but i'd be happy to cure it without knowing the whyfor. I suppose it means new gaskets and sealer at the inner and outer timing covers. I'll keep you posted (even if bores you to tears).

Richard L.


Title: Re: Help I have an Oil Leak!!!!!
Post by: MG on 30.05. 2010 10:19
Richard,

Have you checked the oil pipe connections to the crankcase?
Just a thought before you start taking the covers off.

If you, like myself, are using EP gear oil in your g'box, you can clearly identify where leaking oil is coming from by it's distinctive smell (or the taste in case you caught a cold  *smile*), compared to the normal engine oil.

Cheers, Markus
Title: Re: Help I have an Oil Leak!!!!!
Post by: RichardL on 06.06. 2010 00:38
Gents,

Now that I know my oil leak is under the inside timing cover, I want to postpone fixing it. Do I dare ask if anyone has any ideas about applying/slathering something on from the outside that would stem the tide until I fix it as winter work? JB-Wld expoxy, for example? Bad idea? Can't work?
Won't help?

Richard L.
Title: Re: Help I have an Oil Leak!!!!!
Post by: A10Boy on 07.06. 2010 16:36
I would just live with it until i could fix it and just wipe it off after a run.
Title: Re: Help I have an Oil Leak!!!!!
Post by: RichardL on 07.06. 2010 17:23
Andy,

Too late for that. I applied (and smeared-in) a light bead of RTV silicon sealant on the the underside of the tri-point. I will be test riding tonight to see if it did any good. I will let the gathered throng know the results. Don't get me wrong, there is no way I would consider this a legitimate fix, but summers are for bodging and riding, while winters are for more complicated and careful repairs. In the worst case, I will just have to scrape off the silicon when I get around to the repair.

Richard L.
Title: Re: Help I have an Oil Leak!!!!!
Post by: RichardL on 10.06. 2010 04:49
Gents,

As update to my last post, I just got around to my first test ride since applying an external application of RTV clear silicon to stop an oil leak. This temporary application of a smeared bead of silicon along the parting line of the inner timing cover appears to have stemmed the tide, for now, at least. The top of my gearbox was thoroughly dry. If this lasts through the riding season, I promise to do a proper repair while the heater in my garage is required to keep my fingers from freezing.

As an aside, Chicago will be in quite a frenzy tomorrow, as my office is not that far from where the Chicago Blackhawks play hockey, and they just now won the  Stanley Cup.

Richard L.
Title: Re: Help I have an Oil Leak!!!!!
Post by: RichardL on 10.06. 2010 04:57
Tracking back, the point of my original post was:

1. Can't identify location of oil leak.

2. Tape absorbent cloth or paper towels or bandaging all around the vacinity of the leak that you are trying to track.

3. After a test ride, remove the absorbent material to observe where leak(s) occur(s).

4. Disassemble covers (etc.) and repair oil leak with new gasket and gasket sealer, or, as in my case, apply external sealant as temporary fix until time is right to make repair.

Richard L.
Title: Re: Help I have an Oil Leak!!!!!
Post by: Rocket Racer on 20.06. 2010 00:53
I always understood that some EP oils can contain sulphur, which can be corrosive to the bushes in your gearbox (or engine) and therefore may not be a good thing to run in a BSA
I could be wrong, but I dont use them just in case... *whistle*

Richard,

Have you checked the oil pipe connections to the crankcase?
Just a thought before you start taking the covers off.

If you, like myself, are using EP gear oil in your g'box, you can clearly identify where leaking oil is coming from by it's distinctive smell (or the taste in case you caught a cold  *smile*), compared to the normal engine oil.

Cheers, Markus
Title: Re: Help I have an Oil Leak!!!!!
Post by: MG on 20.06. 2010 08:54
RR,
Generally, API-GL4 spec oils are no problem in this respect. The more modern API-GL5 oils (for rear axle gears mainly) are more problematic.
However, there is a standardized test for the corrosive effect (DIN 51759). A piece of copper is exposed to the hot oil and the effect on it is described with a special code. These values usually can be found in the oil's data sheet. It looks something like this: 1 - 100 A 3, where 100 is the oil temp (100°C), A 3 is the time the test specimen are exposed to the oil (3 hours here) and the first digit describes the corrosive effect (1...no effect, 2...tarnishing, 3...visible, initiating corrosion).

Imho the time of using engine oil in gear boxes is over. Like with modern engine oils, the development of gear oils has not stagnated since the 50's. The requirements for engine and gear oil are not really comparable, and during the years each oil has been adapted to fulfill it's specific task.
So if the risk of copper corrosion has been ruled out, I think modern EP oil is the way to go.

Just my 2p worth, as per usual.  *smile*

Cheers, Markus
Title: Re: Help I have an Oil Leak!!!!!
Post by: Brian on 20.06. 2010 09:18
I have aways used EP 80-90 gear oil in my gearboxes and have never had a problem. These oils are designed for automotive gearboxes that have contained Bronze synchro rings since they were invented.
Title: Re: Help I have an Oil Leak!!!!!
Post by: MG on 20.06. 2010 09:31
Yep, but not the GL5 spec oils that were designed for the rear axle gears. These can cause problems, so be careful!
Title: Re: Help I have an Oil Leak!!!!!
Post by: Rocket Racer on 21.06. 2010 06:47
That's really interesting, I had a look at the several empty gearbox oil containers I had and both were marked as GL5.
I also have a container of motul gearbox oil (for a guzzi I used to own) that contained molybenum for the load in the diff and that had both the notations GL4 and GL5.

In my plunger B series that runs straight 50 in the engine, I've always just run 30/40 over the last 25 years.
Apologies for hi jacking this thread that was about oil leaks!


Yep, but not the GL5 spec oils that were designed for the rear axle gears. These can cause problems, so be careful!
Title: Re: Help I have an Oil Leak!!!!!
Post by: BSA_54A10 on 21.06. 2010 12:21
When the only boxes with syncro were on Rolls Royces & Caddies then  corrosion ( also errosion ) was a problem.
However syncro is now standard on just about everything and the bulk of syncro cones are brass.
So just about any modern box oil will be safe in out boxes