Author Topic: A10 oil filtering  (Read 8140 times)

Offline Dynamo Regulators Mike

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A10 oil filtering
« on: 22.05. 2008 09:11 »
Hello chaps. I am seeking insights into the high oil consumption of my A10.
She has been using about a pint per 200 miles for the last 1000 miles. Full engine rebuild including rebore  to +80 about 1500 miles ago. At the same time the head was done up, with new guides where necessary and valves. After a few hundred miles of topping up the oil and occasional white smoke from the exhausts (more from RHC), I stripped off the top end again, but found nothing at all amiss, except witness of a possible oil path from pushrod tunnel to cylinder on the head gasket. I have checked compression which is good at around 130 psi. (8:1 nominal pistons), and she starts and runs well, pulling like the proverbial train, despite the oil burning. Plugs are black, but Boyer ignition must help here, with the much higher available HT voltage. No significant oil leaks anywhere by the way.
Now, I have an oil filter fitted in the toolbox, the 2CV type. Oil is decent quality 20W50.  I suspect that the filter has a considerable bearing on the oil usage, but I cannot understand why. My suspicion is that the engine is running with excess oil in the cases, i.e. wet sumping. Suspicion is that crankcase oil level is high, so excessive oil on the bores inevitably getting past rings into cylinders. No oil from breather though. Return to tank looks reasonably strong but perhaps not as much included air as I would expect. Focussing in on the oil system, I first checked the oil pressure feed. Maximum cold pressure about 60 psi (SRM regulator valve, with two washers removed, else about 75 psi), with typical hot running pressure 40 psi, which I consider pretty good. Then move gauge to return line, monitoring at rear engine connection. Cold pressure around 20 psi, falling to just off the zero stop, perhaps 2-4 psi after just a few miles. With the filter temporarily replaced with a plain ¼ BSP male-male adaptor, working pressure fell by perhaps 1 psi, just perceptible on the 100 psi guage. But smoke in the exhaust on static revving was definitely less, and oil return to tank appears slightly greater.
Last evening took her on a 50 mile run with filter out of line. No sign of the occasional white smoke. Plugs looking cleaner, and oil level not dropped (but may be too soon to tell). So it looks like a partial result. But why should a pound or two of back pressure make such a difference? A gear type pump is considered to be positive displacement, more or less constant flow at a given speed, so that pressure is a function of flow. I guess I will have to check the pump again, but I did have it apart at the rebuild and it seemed to be in fine fettle then.
Problem is that I really want to have a filter in-line. Perhaps I will try a Vokes WDB40 filter I have on the shelf (picked up a new element for it at Netley Marsh last week for £2). Placed above the gearbox with much shorter total length of line hopefully this will cope better with any small back pressure. No idea of how efficient a filter this small element is compared with the paper canister one, but better than none).
Sorry this is so long, but it really is headache for me. Any suggestions and insights very welcome please. Any other measurements to take? There are other case reported anecdotally where filter in return line has caused problems, including on this forum, but no real explanation as to why, as far as I am aware. On the other hand there are many machines with filters fitted who are getting the benefits of cleaner oil, without apparent hassle.
Please HELP.

Mike
Mike Hutchings
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Director, DRL www.dynamoregulators.com

Offline fido

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Re: A10 oil filtering
« Reply #1 on: 22.05. 2008 09:29 »
Welcome to the site, Mike. They tend to recommend cheap oil, changed frequently when running in, to allow the rings to bed in without glazing the bores.  You don't mention your running in regime, sometimes you can cause problems by treating the engine too gently or not varying revs enough. I tend to let the revs go higher on downhill stretches so you can get some variation without stressing the engine too much.

Offline Dynamo Regulators Mike

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Re: A10 oil filtering
« Reply #2 on: 22.05. 2008 13:48 »
Thanks for the welcome Fido. It hadn't occurred that this was my first post here, as I registered a while ago now and have been reading the messages for some time. I placed this post here as this forum seems to provide more considered answers than others. More debate than dictate.

As for running in, I employed supermarket 'Wilko' 20W50 for the first 500 miles or so, before changing oil and filter. Used the engine progressively harder and more revs as mileage progressed. This has always worked for me before. If anything I used it harder earlier this time. My unplanned inspection opportunity after a few hundred miles showed the bores to be running in nicely, with the honing patterns still visible but fading.
Mike Hutchings
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Director, DRL www.dynamoregulators.com

Online RichardL

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Re: A10 oil filtering
« Reply #3 on: 22.05. 2008 15:52 »
I don't know how often you are riding to accumulate the 200 miles. If it is infrequent. and we assume wetsumping is actually the cause of oil loss, could it be that said wetsumping has occured from the bike sitting, as opposed to failure to scavange the crankcase? It sounds like you are a frequent rider, as I wish I was. However, my bike seems to be in a constant state of building, rebuilding or repair (my fault, not that of the A10 pictured at http://www.a7a10.net/forum/index.php?topic=166 ).

Richard
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Offline a10gf

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Re: A10 oil filtering
« Reply #4 on: 22.05. 2008 15:59 »
manormike wrote
Quote
More debate than dictate
That's a good comment, and welcome to the forum. Detailed posts (and good pictures) are welcome and valuable, it gives lot's of practical information to evaluate and learn from.

Good topic this one, I have been thinking about oil filtering (like everybody, I suppose) for my plunger, and hope this thread will provide good info (Am looking for some small filtersystem that works good enough and is safe to use).

Erling

A10 GF '53 My A10 website
"Success only gets you a ticket to a much more difficult task"

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Re: A10 oil filtering
« Reply #5 on: 22.05. 2008 16:01 »
If there was a lot of oil in the cases, I'd expect, like you, for there to be a fair bit coming out of the breather. It's hard to believe that a return filter could make the difference, but I suppose the extra pressure and plumbing could affect the scavenging a tad as you suggest. And maybe the contents of the filter can trickle back down the return line when the engine is stationary? Is there a ball valve in there to prevent that, I wonder, which the return pump has to keep off its seat? If the return flow is visibly less, it has to be saying something . . .  SRM say - or said to me anyway - that they don't recommend return line filters. Man said 'they could make wet-sumping worse' and then went on to say that any proper filter needs to be on the feed side like a car, and there's no way of doing that. I reckon anything's better than nothing in principle, but his first point may perhaps be valid. Your best bet has to be to run another couple of hundred miles without the filter and see what happens but excess oil in the cases (to some modest degree) does seem the most likely cause, I agree. Good luck!
Bill

Offline Dynamo Regulators Mike

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Re: A10 oil filtering
« Reply #6 on: 22.05. 2008 18:08 »
In response to a couple of points raised. The bike has now covered just on 1,700 miles in the five months since its rebuild, just before Christmas. 850 of these were in a trip across Belgium over five days. (Top up oil was really expensive there.) There is little or no drain down on standing but it has rarely stood for more than a week.

Agreed that the ideal place for a filter would be after the feed from the pump but that would mean major surgery. At least fed from a tank of filtered oil the pump should never supplied with debris contaminated oil, which would be otherwise be the case. Sounds like the SRM man has direct experience of filters adding to oil system ills. The Vokes filter  was fitted to the 1954 Daytona winning bikes http://www.restorenik.com/daytona/vokes.htm so there can?t be any fundamental problem with a return line installation. There is a non-return ball valve in the sump pickup pipe so the filter should not drain back, at least not too rapidly. That ball and seat are not accessible even after a full strip down, unlike the anti drain ball valve behind the pump, between the crankcases.

I have now replaced the long pipes to the toolbox with an standard length return pipe. Latter is about 18? long vs. 54?. So three times the pressure loss in the pipe alone. No wonder the filter?s contributing to pressure drop was smaller in comparison. Cold pressure drop read less than 10 psi, falling very rapidly.

Clearly a larger flow of oil in the engine will occur at higher engine speeds. At steady speed the scavenge side should also have proportionately larger capacity so all is well. But there will be a lag on slowing down as the oil flows down to the sump. Under this condition it has occurred to me that the scavenge side has most work to do. Its additional capacity compared with the feed side may well be exceeded transiently. If this is made significantly worse by the return line flow resistance then crankcase level will rise and more oil would likely be burnt until the pump catches up. I have noticed that occasionally an increase of smoke occurs on slowing after a relatively fast run. But it comes back to why scavenge flow may be affected by working against a small pressure head. Perhaps the entrained air in the system complicates matters further in some way.

I will continue to run without the filter for at least long enough to see if oil consumption has indeed fallen. And will also think about how I might install the WDB40 filter. It should fit under the ?ski-slope? which would add minimal oil line length so perhaps tolerable pressure drop for the best of all worlds. But there are other jobs to do on the bike (as always Manorsound), not to say on house and garden. Will let you know how it goes.   
Mike Hutchings
A10, B50, T800; 1,2,3 (& DVR2)
Director, DRL www.dynamoregulators.com

Offline fido

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Re: A10 oil filtering
« Reply #7 on: 23.05. 2008 07:35 »
Could you have a leak at the oil pump gasket?

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Re: A10 oil filtering
« Reply #8 on: 23.05. 2008 07:36 »
Reckon your thinking is hard to beat. But it's very surprising to me that the scavenge pump is that sensitive to volume and a smidgeon of pressure, be it from the filter or the line length, as I have always assumed scavenge pumps can cope with almost anything. Appears that things are more delicately balanced than one might think . . . be fascinated to hear more in due course. Maybe a change of filter type, as you propose, will sort it. Other people here have been running return side filters, so perhaps they'll chime in with comments based on experience . . . I'm quite glad I've held back on that front!
Bill

Offline LJ.

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Re: A10 oil filtering
« Reply #9 on: 23.05. 2008 09:35 »
Yep! I also had given the oil filter a try on my A10s system, I have to admit it does make sense in theory to use 20/50 and filter but I found my bike just did not like it. I cant remember if the bike used any more oil than normal but it did chuck out a lot of fine oily mist out of the breather. That is one of the main reasons for reverting back to standard, (turbulance was messing up clothing) no filter and use of straight 40 oil, no problem since. What is it that we are afraid of here to want to use a filter and 20/50 I have to ask? There have been many bikes covering thousands of miles without filters, ok sludge traps may get filled but then... A strip down is deserved after such long and loyal reliablitily. I can well do without the fuss and hassle that some seem to have, and indeed like I had during my experiments.

I sometimes wonder just what the expected mileage BSA hoped for in designing and building these machines. They have obviously done very well, hence so many are still around and running.

If it wasn't for other factors I think the best answer must be to use a cheap 20/50 with no filter and change the oil at no more than 500 miles, but this being a thinner oil would raise the risk of giving leaks. My own preference is to use Castrol XXL40 being thicker I dont get any leaks at all and with the engine being baked in the oil it does smell very classy and gives a highly pleasing aroma! (you can tell I'm not an engineer)  *eek*  *lol*
Ride Safely Lads! LJ.
**********************
1940 BSA M20 500cc Girder/Rigid- (SOLD)
1947 BSA M21 600cc Girder/Rigid-Green
1949 BSA A7   500cc Girder/Plunger Star Twin-(SOLD)
1953 BSA B33  500cc Teles/Plunger-Maroon
1961 BSA A10  650cc Golden Flash-Blue
1961 BSA A10  650cc Golden Flash-Red

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Re: A10 oil filtering
« Reply #10 on: 23.05. 2008 10:40 »
Just to put an opposing view, I have a filter ( return side ) - non return valve and use 20/50 without problems at all.
I don't get to ride as often as I would like though.
Only thing I get (along with quite a few others ) is a bit of smoke on one side after starting, it clears in a very short time.
It is not always the same side that smokes - leads me to believe it's valve guides, something which has not been mentioned in this thread so far?

All the best - Bill
All the best - Bill
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1959 Rocket Gold Flash - blinged and tarted up  would have seizure if taken to  Tesco

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Re: A10 oil filtering
« Reply #11 on: 23.05. 2008 12:53 »
well, it starts to sound, per LJ, as if the installation of some sorts of filter can in certain cases cause an increase in crankcase oil level when the motor's running. In principle having a filter, even on the return, has to be better than not but I am sure there are loads of engines out there that have done a gazillion on the same crank without one.
I use modern 20/50 in all engines with plain big ends as long as I know the cranks are clean inside; and straight grade for roller b/ends. Some engines seem to last for ever or near enough, others less. Probably a lot to do with the quality of regrinds, assembly etc. I change oil every 1000 miles out of habit.
Bill

Offline Dynamo Regulators Mike

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Re: A10 oil filtering
« Reply #12 on: 24.05. 2008 14:52 »
Have put in another 60 miles with no filter. Still too early to be sure of oil consumption but no smoke at all seen, despite bursts of hard riding. But I do feel slightly uncomfortable running without the protection potential of a filter. Trouble is that I am an engineer, and specialise in Condition Monitoring via wear debris monitoring of oil. Oil filters have been fitted in the car world for many decades and have been common in production motorcycle engines since the ?60?s. It is very well established that it is especially valuable to filter out debris in engines with plain bearings, and our BSA?s have more than their share; timing side main and big ends. If an engine lasts say 10,000 miles without filtering then it is reasonable to expect 20 k miles to wear to the same degree kitted out with a filter that removes most particulate of a size comparable to bearing oil film thickness. And it means I can safely use quality multigrade oil, which are more available and less expensive than the straight stuff longterm. But this is not another oil thread.  *eek*

An engineer?s curiosity driven nature and attraction to problem solving leads people like me to spend arguably too much time and effort in ?improvement?. But it is more fun and rewarding than another expensive routine rebuild. A key aspect of the Classic Bike pastime as far as I am concerned. Perhaps it has the same perverse attraction to me, that maintaining and fettling original style voltage regulator box has to you LJ, when a modern fit and forget alternative is readily available. ;)

Hoping to buy a lower range pressure gauge soon in readiness to closely monitor pressure heads whilst experimenting with the WDB40 filter. Will also take a close look at the oil pump when I get the chance to see if that is at all suspect. Now I recall speaking to an ex Small Heath apprentice who recounted experimental work with the gear pumps. There were apparently some counterintuitive findings regarding efficiency. Another interesting area to explore.  *smile*
Mike Hutchings
A10, B50, T800; 1,2,3 (& DVR2)
Director, DRL www.dynamoregulators.com

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Re: A10 oil filtering
« Reply #13 on: 24.05. 2008 17:39 »
While I was knocking off my usual Saturday miles on the A10 this am I was wondering about the oil level in your tank Mike. (Makes a change from worrying about mine.) With the filter, was the level lower than you'd have expected after a run, which would indicate that the level of oil in the cases was too high, I wonder? If you have a drain plug, I wonder did you ever drain the thing to see what came out just after a run, when the filter was fitted? And is the level more constant, higher, whatever, now you're filter-less again? Just idle ponderings, I seem to think about oil levels far too often! At least I don't have to think about dodgy voltage regulators any more! Wet day for it too . . . lights on all the time
Bill

Offline LJ.

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Re: A10 oil filtering
« Reply #14 on: 24.05. 2008 19:45 »
It's a very fair comment you make Mike about the engineers interests in oil on an A10 and I do look forward to hearing of a successful remedy from someone soon especially if its from discussions held here on the A7 & A10 forum. The way oil prices are going, and I wonder how long we will all be moaning about the price of engine oil like the price of Petrol here in the UK, I too would certainly move over from the rather expensive straight 40 Castrol oil to a multi and filter.

The discussion is puzzling, we are aware of back pressure because of filters and maybe longer oil pipe lines etc. I wonder how the pump manages with Straight 50 oil which is even thicker than 40 or multigrades. Surely the 50 grade is causing back pressure also, particularly when cold.

By the way... I am begining to wonder if your also known as 'Blue Flash' on another forum? If so, great to have you here! The 8" front wheel hub from you has just been 'spoked and rimmed' and has been running again the last couple of days (Many thanks again for that)... What a difference from the 7" front brake.

Back to Oil filtering  :!
Ride Safely Lads! LJ.
**********************
1940 BSA M20 500cc Girder/Rigid- (SOLD)
1947 BSA M21 600cc Girder/Rigid-Green
1949 BSA A7   500cc Girder/Plunger Star Twin-(SOLD)
1953 BSA B33  500cc Teles/Plunger-Maroon
1961 BSA A10  650cc Golden Flash-Blue
1961 BSA A10  650cc Golden Flash-Red