The BSA A7-A10 Forum

Technical => A7 & A10 Engine => Topic started by: blackbikemike on 18.11. 2009 17:08

Title: More wetsumping
Post by: blackbikemike on 18.11. 2009 17:08
I have avidly digested all the previous stuff on the forum about wet sumping, but here's my experience, open to suggestions please: Recently bought 1952 A10 plunger, which has been fairly thoroughly gone through: Reground crank, new standard bore, new pistons and rings, new valves, guides, springs. It was rebuilt over the past few years but hasn't been ridden for probably 20. I bought it knowing it had an ongoing problem, so when I first ran it I took out the drain plug (SRM), out came just under a pint of oil. Replaced drain plug, checked everything, it fired second kick, sounds lovely, oil returning strong into oiltank, after about 30-45 seconds starts smoking from both pipes  (quite a LOT of smoke) until engines splutters to a halt with oiled plugs. Undo drain plug, out comes another pint of oil. Remove sump plate, observe that oil is dribbling from scavenge pipe, poke up scavenge pipe....dribble stops. Left it for two days and the fresh tray had caught at the most a couple of tablespoons full. Replace sump, prime, kick, starts and runs clean for a minute or two then starts smoking again. Stop engine, remove drain plug, out comes another pint! So I haven't fixed it, but could it still be the scavenge pipe? Or the other non return valve? Or the pump? All suggestions gratefully received. I can't take it out for a decent run cos it's not road registered yet.
Title: Re: More wetsumping
Post by: Desburnett on 18.11. 2009 17:53
Suggestions based on oil is entering cylinders and causing plug fouling. Providing head gasket is good oil can only enter past rings or guides. If pressure is building up inside crankcase this would force oil past rings so check the cork spacer / breather in the timing side and check the crankcase breather behind the cam shaft is free / open.
Check the breather in the oil tank is free / open. Finally check the condition and mounting of the oil pump. If its worn it will allow oil back into the sump and if its mounted incorrectly (without the fibre washer on the outpost) then other gremlins will set in.
Regards,
Des
Title: Re: More wetsumping
Post by: a101960 on 18.11. 2009 21:16
Two things occur to me. Have you tried removing the sump plate and giving the ball a little tap? It may well be that the ball is not seating properly. The other thing that could be causing this problem is that the pressure relief valve setting might want checking. Again make sure the ball is seating properly and check the spring. If the pressure is to high the oil will be dumped into the sump and your crank assembly could be getting insufficient lubrication. If the sump is filling up then eventually the oil will find its way up past the pistons and be burned off. One final thought. Are the piston rings fitted upside down? that would allow oil to reach the combustion chamber. However given that your sump is filling up with the engine running I would suspect a problem with the pressure release valve. Try the anti syphon ball valve first as it is easy to get at and a little tap might just cure the problem. A10s and A7s are quite well known for the anti syphon valve  problem but this would normally be a problem when the engine is not running. In fact thinking about it if the scavenge side of the pump is being overwhelmed then I would strongly suspect the pressure relief valve, or a leaking pump.
Title: Re: More wetsumping
Post by: blackbikemike on 19.11. 2009 09:09
Thanks very much guys for your prompt and clear responses. I have poked the anti syphon ball, but I didn't tap it, so will try that again first. After that I will work through your suggestions and hopefully sort it. Thanks again, I will keep you posted. 
Title: Re: More wetsumping
Post by: Triton Thrasher on 19.11. 2009 09:54
I know little about BSA Twins but the oil pressure relief valve sounds doubtful as a cause of the cases filling with oil when running.  The scavenge pump is bigger than the feed pump, so if oil is building up during running, the scavenge system is not working.  Potential causes might be a gauze screen in the sump blocked with stray sealant; pickup pipe jammed against the bottom of the sump plate; vacuum leak between sump pickup and oil pump (test by sucking with the end blocked); scavenge side of oil pump somehow more knackered than the feed side;  flexible return hose restricted by kinking or internal collapse;   return pipe in oil tank too restricted, forcing too much oil to cylinder head; insufficient restriction of oil feed into cylinder head; no breather on oil tank.
Title: Re: More wetsumping
Post by: blackbikemike on 19.11. 2009 13:35
Thanks TT. I've eliminated some: Gauze screen is brand new SRM and clean (washed it again just in case),Pickup pipe is well clear of plate,and the breather tube to tank is clear. I took the PRV off and gave it a tap just to be sure. So I will add to my list checking the vacuum, pump and hoses. I'm also going to try changing the rocker feed balance pipe from the race style ally one back to original and checking the banjo bolt holes, but I'm beginning to think it's going to be the pump one way or another.
Title: Re: More wetsumping
Post by: rocket man on 19.11. 2009 20:00
another thing you could try put a rubber pipe on the pickup pipe put it in a container and
place it in a larger one under the sump so then you will know if its that
Title: Re: More wetsumping
Post by: Rusty nuts on 19.11. 2009 21:22
The only scenario I can think of in which the plugs would oil so rapidly is chronic crankcase pressurisation.
You say you have good return to oil tank so that pretty much rules out pump. If it's leaking badly it's not going into the sump it will be filling yor timing cases.
PRV, I doubt it it. As I understand it, it dumps oil back into gallery next to pump & the only way into the sump is is up through the timed breather!

"Anti syphon ball valve" (assuming we are talking about the same thing i.e the cause of wet sumping) is not "easy to get at" on my longstroke, maybe later engines are different, only way to get at mine is by splitting cases & I had assumed same for later engines and anyway unless it's gone completely "walkabout" I can't see it being that. You'd have no oil in your tank to start with!
Assuming that the pistons actually have oil scraper rings fitted, I would clean plugs, run it till plugs oil up & remove rocker box inspection cover, there should be no more than a small amount of oil collecting where there rocker bolts run through the head, if more, pressurised oil is being pushed up & returning into head via valves you will see a flood.
 If that is the case it must be the timed breather/cork or the the crankcase breather pipe as pointed out by Des.
Unless the rocker oil feed banjo bolts are completely wrong (big holes) then you would get excess oil possibly passing past valves.
Hmm! You mention rocker feeds *idea* & there was a post recently!!!
http://www.a7a10.net/forum/index.php/topic,2001.msg12809.html#msg12809
Title: Re: More wetsumping
Post by: Triton Thrasher on 20.11. 2009 08:00
The only scenario I can think of in which the plugs would oil so rapidly is chronic crankcase pressurisation.
You say you have good return to oil tank so that pretty much rules out pump.

But is it normal to drain a pint out of the sump after a run?  Why was that pint not pumped back to the tank?
Title: Re: More wetsumping
Post by: Rusty nuts on 20.11. 2009 08:39
A pint seems quite a lot, after a run there's about half a pint in my sump.
Only get a pint after standing for several  weeks.
Suppose a blocked oil tank breather could prevent proper return, the tank pressurises as more oil is returned, to the point where the resistant pressure is greater than that applied by the pump. Maybe there is just too much oil, nowhere to go but up!
Title: Re: More wetsumping
Post by: Triton Thrasher on 20.11. 2009 09:58
A pint seems quite a lot, after a run there's about half a pint in my sump.

If 1/2 a pint is normal, could the original poster be overestimating his 1/2 pint as "just under a pint?"
Title: Re: More wetsumping
Post by: blackbikemike on 20.11. 2009 10:14
Could be overestimating, will repeat experiment and measure accurately, using the tube idea (nice one) to ascertain EXACTLY where it's coming from. Haven't got any time at the moment, but I'm certainly encouraged to have a list of "possibles" to mull over. I didn't know half a pint in thesump after a run was normal, so maybe I've haven't got a wetsumping problem, just a plug oiling problem.Thanks again for all your input. 
Title: Re: More wetsumping
Post by: groily on 20.11. 2009 11:28
The only time I ever had a motor which actually choked on oil pumped up to the piston crowns in those sorts of substantial quantities (beyond what can be burned off) was when someone had assembled it with the wrong rings.
The compression rings were too narrow for their grooves and were acting as mini-pumps as they moved in said grooves. The engine would start readily when clean, oil return would be normal as it wasn't a lube prob, then it would start to smoke, then die as the oil snuffed everything out. Small lakes of oil in there. With the head off, I could see it happen in front of my eyes by turning the motor on the kickstart. I was amazed. The reason obviously was the rings were not for the type of pistons actually installed. Changing them solved it immediately.
No idea if there's any chance of that as a possibility with this 'rebuilt' job, but if you decide the oil is returning properly and the levels are normal in tank, rockerbox and crankcase after all, and the breathing is OK . . . it has to be something fairly fundamental.
There are literally no limits to the horrors one can encounter in newly-acquired machines. Often, the horrors mount in a pretty direct relationship to shininess. I have yet to acquire a machine who's engine didn't need some degree of dismantling to make it proper. I live in hope, but not expectation.
Title: Re: More wetsumping
Post by: chaterlea25 on 20.11. 2009 14:39
Hi All,
I would think even a half pint of oil is too much to drain off after a run
In normal operation the scavenge pump has twice the capacity of the pressure side so it should clear the excess in the sump, this is why when you start the engine after sitting for a while the return flow is constant until the sump clears!

I agree with groily's suggestions and observations,
""There are literally no limits to the horrors one can encounter in newly-acquired machines. Often, the horrors mount in a pretty direct relationship to shininess. I have yet to acquire a machine who's engine didn't need some degree of dismantling to make it proper. I live in hope, but not expectation.""

Another thing that can happen when an engine has sat for a long time is that the rings can seize to the pistons, this will give enough compression to start the engine but oil will soon travel up past the rings when running
HTH
John O R
Title: Re: More wetsumping
Post by: groily on 20.11. 2009 16:24
With you too John OR
Just one or two other such horrors . . . a running B31 (a current bike) with an Ariel piston up it (no oil control ring on that particular one) and a copper 'head gasket' thrown in for good measure because the deck height was also wrong; a VH Hunter which on starting up after a ' full rebuild' sent the big end cage straight back into the oil tank finely minced (quite pretty that); a twin of another marque with both pistons kissing the head, no oil retention device whatsoever on the drive side main shaft, and missing one camshaft end plug which had been replaced with . . . car body filler; another BSA with a similar jagged plastic metal plug in a 'repaired' crankcase after throwing a rod. Then there are mis-assembled gearboxes, the inevitable electrical spaghetti and all the rest of it. It's why, despite an optimistic nature generally, I don't live in expectation. Is also why I don't trust 'shiny'. Is also why I don't worry when getting anything 'new' to play with whether it works well or not - I assume it won't work for longer than the vendor's planned 5 minutes, so can't be disappointed. Unknown reasonably-priced quantities of these mature years simply have to be pulled substantially apart to be sure they're OK. And sometimes higher-cost better-known quantities with apparently excellent provenance have to be too . . . 
Title: Re: More wetsumping
Post by: A10Boy on 20.11. 2009 18:08
Are you sure you have a good return to the oil tank?

I cant see how you can have both a good return to the oiltank AND a pint of oil in the sump, unless the oil is breeding!

John is correct, the scavenge side of the pump has a higher output than the supply side, so the sump should never fill while the engine is running.

Maybe you have a cracked pump, or duff pump gasket, which is letting the pump cross-over the flows so that [some of] the supply oil is pumped into the return oil way and the oil which should return to the tank is just staying in the sump. - have you checked the pump and gasket?
Title: Re: More wetsumping
Post by: Rusty nuts on 20.11. 2009 20:42
this is why when you start the engine after sitting for a while the return flow is constant until the sump clears!
Err, and then the flow is not constant? That would worry me. There has to be oil in the sump for the scavenge pipe to "scavenge" it.
Title: Re: More wetsumping
Post by: bsa-bill on 20.11. 2009 21:14
NO - as Andy has said the scavenging side has greater capacity then the feed side therefore it pumps what oil is in the sump and a certain quantity of air which is also present in the sump, this results in a intermittent (spluttering) return into the oil tank.
Also means the sump should be almost empty when the engine is stopped other than oil that is clinging to surfaces inside the engine, drains down from the rockers and I suppose anything that slurps (nice word that) over the camshaft through when the bike is hauled onto the stand.
The amount that drains down from the rockers is of interest, I assume there is a limit to the amount that will pass past the cam followers in any given time, if the rockers are over fed then there could be a build up in the pushrod tunnel giving rise to symptoms similar to those described  but it's not one I've heard of before.

All the best - Bill
Title: Re: More wetsumping
Post by: dpaddock on 21.11. 2009 15:37
FWIW, I get 135 ml (~1/2 pt) two minutes after engine shutdown, and 175 ml after 24 hrs in my A10.

David
Title: Re: More wetsumping
Post by: RichardL on 21.11. 2009 19:49
In the cousre of time, some old posts are forgotten or unknown. I hope the video linked to this previous post of mine is useful in seeing the sputter versus flow nature of the oil return. Nevertheless, It gives me a chance to show the bike to peolple who know what they're looking at, a quite rare commodity in my neck of the woods. (Groily, I think I may have already apologized for shininess.)

http://www.a7a10.net/forum/index.php/topic,1129.msg8220.html#msg8220

Richard L.
Title: Re: More wetsumping
Post by: alanp on 21.11. 2009 20:43
Richard, I've just noticed the chromed hubs front and back. Haven't seen that before. Maybe I should get out more?
Title: Re: More wetsumping
Post by: chaterlea25 on 21.11. 2009 21:41
HI
dpaddock,
When I went to school there were 568ml (cc) in a pint
so 135ml is less than 1/4 pint, 175ml just over
This is the amount I would expect
HTH
John O R
Title: Re: More wetsumping
Post by: Rusty nuts on 21.11. 2009 21:57
NO - as Andy has said the scavenging side has greater capacity then the feed side therefore it pumps what oil is in the sump and a certain quantity of air which is also present in the sump, this results in a intermittent (spluttering) return into the oil tank.
Also means the sump should be almost empty when the engine is stopped other than oil that is clinging to surfaces inside the engine, drains down from the rockers and I suppose anything that slurps (nice word that) over the camshaft through when the bike is hauled onto the stand.
The amount that drains down from the rockers is of interest, I assume there is a limit to the amount that will pass past the cam followers in any given time, if the rockers are over fed then there could be a build up in the pushrod tunnel giving rise to symptoms similar to those described  but it's not one I've heard of before.

All the best - Bill

Sorry Bill I have to disagree, If the sump is almost empty except clinging oil you'd have a serious problem, more than likely a seized engine, it is not only the big ends etc that require oil, the camshaft (certainy long stroke engines as they do not have a trough) & more importantly cylinder bores rely on oil throw/pressurised mist from the crank, without it they'd seize.
Also acts as a coolant.

These engines are designed to be pressurised to a point (hence timed breathers) to enable oil to lube aforesaid & oil control rings are there to prevent that oil progressing into the head itself.
Spluttering from the return is proportional to engine/oil pump rpm. At tickover it splutters, at higher revs it'a constant flow.

Short of us all going for a ride, draining our sumps into our wives finest measuring jugs & establishing an average I would say anything from 1/4 to 1/2 a pint acceptable.

But we digress, getting back to the point, I think Groily has the most plausible explanation, rings, or as my earlier post, rocker feed bolts with dirty great holes & its flooding through the valves & into the head. I'd put money, if I wasn't so tight on Groily's theory.

Anyway enough of this I'm off to wet sump with a few a few pints of Fullers finest.
For those not familiar, think heavy monograde, lubricates well, relieves stress from vital components, but can cause difficulty starting of a morning *beer*
Title: Re: More wetsumping
Post by: bsa-bill on 21.11. 2009 22:02
Hi John, are you remembering Davids US pint is a tad smaller than ours  *smile*

All the best - Bill
Title: Re: More wetsumping
Post by: bsa-bill on 21.11. 2009 22:23
Ah now Rusty Nuts, I'm not at all sure about this, now matter how many revs you have, the scavenging side MUST always have more capacity than the feed side.
So if at any point in time the feed is delivering more oil than the return side can take away something is wrong with the pump or it's plumbing.
If the return side did not always pump more than the feed side then there would come a point when the sump would fill to a level that would stall the engine or worse the sump would contain all the oil and starve the feed side, however before this happened you would notice the smoke screen in your mirror!!!.
I would suggest that at higher revs it will LOOK like there is a constant flow but in fact there never can be, it would simply be to dangerous to have a situation where both sides of the pump produced equal flow.
I agree that the sump will contain oil after the engine has stopped, this will be the oil that is splashed about and then runs down the case and so on as you say, but at the moment you touch the kill switch the sump should be next to empty.

All the best - Bill
Title: Re: More wetsumping
Post by: Rusty nuts on 22.11. 2009 10:16
Bill, I think we are arguing over semantics here.
Bsa service sheet 116 I believe re PRV  begins "in order to maintain a contant flow to the white metal big end bearings........."
I didn't (don't) dispute the fact the "system" has a greater scavenge capacity, ergo, if the feed is "constant" then the return must also be.
On that point I believe we are singing from the same hymn sheet, just to a slightly different arrangement!

The only point of contention is how much oil collects or should I say is present in the sump between delivery & collection.

I am happy with my residual half pint, it may be a wee bit less, I don't measure it, just use a big 1pt yogurt pot & judge by eye.
I'm sure a 1/4 pint is fine too.
I would not buy a bike that had a "next to empty" sump.

I've started mine after standing for several weeks having forgotten to drain & based on what comes out when I do remember after such a time period
there must have been close to a pint, but engine coped without throwing oil out of timed breather, creating smoke screen etc.

Sure hope Blackbikemike resolves his problem shortly as this thread is heading off at quite a tangent.

Cheers

Rusty
Title: Re: More wetsumping
Post by: bsa-bill on 22.11. 2009 10:40
Hi Rusty - I prefer the word discussion than argument  *smiley4*

My Flash smokes when fired up and not always the same side but clears after a couple of hundred yards,  this I put down to the amount that drains down after stopping, must have a look and see how much there is.
Could be a bit of wetsumping too as I don't get to ride it as often as I would like, despite retirement.
However when I think of wetsumping I think back to my very first Flash that once but only once dumped a half pint or so onto the ground via the breather exit, it had been standing idle for weeks though.
I don't think a bit of smoke at start up is a worry if it is the result of oil collected in the sump getting burnt off after startup, I can remember when advice was given to the effect that good practise was to take your foot off the accelerator going down hill in order that oil would be sucked up into the cylinders for extra lube.
There again I can remember when garages always had a Redex dispenser by the pumps - I'm off now ( beginning to sound like an old F*** ) 

All the best - Bill
Title: Re: More wetsumping
Post by: Rusty nuts on 22.11. 2009 11:08
"arguing over semantics" is just a turn of phrase Bill
There are no arguments here, just healthy discussion
that's what sets this forum apart from some others.
Now then, smoking at startup is I believe caused by........................................ *smile* *smile* *smile*
Title: Re: More wetsumping
Post by: Triton Thrasher on 22.11. 2009 17:37


These engines are designed to be pressurised to a point (hence timed breathers)

I think timed breathers are an attempt to stop the crankcase pressurising.
Title: Re: More wetsumping
Post by: Rusty nuts on 22.11. 2009 17:52
If that's the case why run at half crankshaft speed not full?
Title: Re: More wetsumping
Post by: bsa-bill on 22.11. 2009 18:19
it might go around at half crankshaft speed but how many holes does it have in it ????
enquiring minds need to know ;)

All the best - Bill
Title: Re: More wetsumping
Post by: Triton Thrasher on 22.11. 2009 20:30
If that's the case why run at half crankshaft speed not full?

Because it's easier to fit somewhere around the camshaft.  Do the holes line up once every crank rev, as the pistons come down?
Title: Re: More wetsumping
Post by: chaterlea25 on 22.11. 2009 20:43
HI Bill And rustynuts
Bill, I dont think less than 20 ml will make much differ between US ans us over here in a 1/4 pint!! LOL

Rusty,
The breather objective is to have a negative crankcase pressure overall, so "timed" are open as pistons are decending
closed on the upstroke (assending)
on a lot of other engines they use a simple flap valve to do the same thing!!!!
Cheers
John O R
Title: Re: More wetsumping
Post by: Rusty nuts on 22.11. 2009 20:52
Bill there's one hole & I think John O R answers TT's?
Title: Re: More wetsumping
Post by: bsa-bill on 22.11. 2009 21:18
Well it's been a while since I built my timing side up ( this project has taken 5 years so far - hangs head in shame ) but I rather thought there where two holes in it so that one of them lined up every crank revolution with the breather exit gallery,  could be wrong though I know I'm often wrong SWMBO tells me so.
Now here's a thought, I remember when fitting up the breather that if the thickest cork gasket was used the dowel on the camshaft pinion has not a lot of contact with the breather, has it ever been known for the cam pinion to lose contact with the breather ????.
This would put the timing of the breather out with what consequences ??

All the best - Bill
Title: Re: More wetsumping
Post by: blackbikemike on 23.11. 2009 11:05
Once again thanks for all your input. I haven't done any more since my last post (no time *sad2*), but two more points: The very first time I started it, got lots of smoke from crankcase breather, so obviously clear, but since then minor smoke but good chuffing pressure. My compression tester says 150 psi after a couple of strokes (on both cylinders) so could it still be sticking/incorrect/incorrectly fitted rings? Re amounts of oil, my initial "pint" theory may have been an inadvertent fishermans tale, looking at whats in the tray after three attempts is more like a pint. Also, on removing the exhaust pipe quite a lot of oil is visible in the head, in the pipe, in fact all the way down to the silencer. Any way, I don't think I'm going to get anywhere without stripping down further, so I'll post again once I have *smile*
Title: Re: More wetsumping
Post by: olev on 23.11. 2009 12:10
Bill,
I don't think you are right when you reckon you could be wrong.
and I think its just not right for SWMBO to say you are always wrong when some of the time you're right. Its just ... wrong.

The breather is 4" in circumference and has 2 off 3/8" holes opposite each other.
so a point on the breather circumference travels 2" in a full revolution and 1" on the down stroke.
This means breathing occurs for only 3/8 of the down stroke, ranging from a crack to a fully open 3/8" hole.
I also remember reading somewhere (could be on this forum) that there are camshaft pinions with the pins in different locations wrt the timing dots. So some machines may have their crankcase breathing timed different to others.
I still strongly suspect some top end oil leaks are caused by a pressurised crankcase preventing oil returning to the sump so causing it to collect in the rocker covers.
but ... I'm probably wrong.
Title: Re: More wetsumping
Post by: bsa-bill on 23.11. 2009 15:06
Thank you so much olev, I thought I was right but had no intention of removing a timing cover to prove it.
As for TheyWMBO I recall a mail I once had from one of you countrymen when I was bemoaning how my wife came down to the shed and took my mind off what I was doing resulting in a cracked rocker box ( left the comb in and tightened it down - DOH )
His remark was "If your wife can get in your shed her chains to long" not very PC but I do love Ausie humour.

Yes I also recall the mail re the pin on the breather

All the best - Bill
Title: Re: More wetsumping
Post by: chaterlea25 on 23.11. 2009 18:55
Olev,
What about the breather sleeve going from fully open to the closed position??
3/8 + 3/8 = 3/4 in.
One inch travel for half  revolution of the crank,
since the volume changes most at mid stroke it makes sence for the holes to be lined up at this position
Or am I losing the plot???
Cheers
John
Title: Re: More wetsumping
Post by: Rusty nuts on 23.11. 2009 20:45
Bill there's one hole

I looked at the breather I intend(ed) to use in the new project, it has one hole, it also, I have discovered today doesn't exactly fit the inner timer cover it's mean't to unless you're willing to the use a soft drift! Came in several boxes of bits with the plunger & I assumed! Oh look, a breather may come in handy one day!
God knows what it's from, can't remember what went in the plunger but that did at least did fit & it runs fine so I'm in no hurry to go look.
Until my memory improves I shall stick to less technical posts.
Still think 1/2 a pint is acceptable though!!!
Title: Re: More wetsumping
Post by: blackbikemike on 24.11. 2009 14:36
Ok, got the pump off today, a little too easily I think! I took off the stud nuts, and one came happily out with the stud attached. attempting to undo the locknut (LH thread) I could feel the pump moving, not just in and out, but very fractionally up and down. Further inspection showed that the studs were only finger tight, (though the locknuts WERE tight) so I'm wondering if this could be part of the problem? Gave the non return valve ball bearing a bit of a poke while I was in there, and that seems to be free and moving on it's spring. The pump looks OK (I think) I have included a photo. Another slight puzzle, I rotated the drive easily with my finger, then took off the end cover to inpect the cogs (fine), I didn't remove the screws, left them in the cover, so they'd go back in same holes, but once I'd tightened it up again, I couldn't spin the drive with my finger! I'm assuming once the drive is being driven by the crank it will turn easily, but maybe if the pump WAS loose, it will surely have worn the pump drive and crank drive.If the pump was loose, could this be causing the problem, but if so, how? Also removed union bolts from rocker boxes, apertures look the same size to me (see photo). Leaving it apart for the time being whilst back at drawing board! PS, should I loctite the pump studs?
Title: Re: More wetsumping
Post by: bsa-bill on 24.11. 2009 18:01
Rocker feed bolts are different lengths? I think they should be the same and although the holes look about right size ( I think they should be 3/64 ") because they are different one or both may be wrong.

Pump being loose could be causing problems, if you could move your timing case cover up and down a bit you would expect it to leak, however as your engine did not seize that suggests that the feed side was at least getting enough oil to all the important bits, the return side leaking is a different matter though, for all it has more capacity than the feed side any oil escaping is defeating this and this escaped oil might well slowly build up in quantity.

Other members might like to comment on the rocker feed bolt holes as I'm not certain about the size.

All the best - Bill
Title: Re: More wetsumping
Post by: Rusty nuts on 24.11. 2009 20:25
Rocker feed bolts are different lengths?
Doubt that makes any difference as oil is fed through those holes into the centre of bolts & into rocker spindles
Is there oil pooling inside the rocker boxes if not it must be rings.
Title: Re: More wetsumping
Post by: A10Boy on 24.11. 2009 20:29
Quote
Sorry Bill I have to disagree, If the sump is almost empty except clinging oil you'd have a serious problem, more than likely a seized engine, it is not only the big ends etc that require oil, the camshaft (certainy long stroke engines as they do not have a trough) & more importantly cylinder bores rely on oil throw/pressurised mist from the crank, without it they'd seize.
Also acts as a coolant.

Rusty, sorry but the premise of your "theory" is wrong. You seem to think that an [almost] empty sump will cause bad oil flow and result in a seized engine - incorrect. Oil to lubricate the engine is fed via the pump from the oil tank, - not the sump.

Cars store their oil in the sump, a "Wetsump System", and if this was empty, seizure would be certain. Our BSAs have a seperate oiltank, this is known as a "Drysump System", called that as no oil is stored in the sump, - in fact that is why when it goes wrong and oil fills the sump its known as "Wetsumping"

The oil system is designed intentionally so that the scavenge side of the pump has a higher output than the supply side to ensure that the minimum amount of oil is retained in the sump,- its pumped back to the oiltank where it belongs, this is the reason why the end of the scavenge pipe is so low in the sump plate. If "used" oil wasn't cleared, it would be blown out of the breather etc.

Bill is entirely correct when he says that the only oil [which should remain] in the sump is that which drains down from the wet engine when its stopped.
Title: Re: More wetsumping
Post by: Rusty nuts on 24.11. 2009 20:47
Thank you, I understand all principles involved.
I never said anything about" bad oil flow"
 I did not imply that oil should be stored merely that there is inevitably some residual oil to be found in the sump at any given time & that 1 pint is abnormal  
half to a quarter is acceptable & a dribble is IMHO not.
If you've go a bike that doesn't blow oil out of the breather ever, that is one exceptional bike.
Title: Re: More wetsumping
Post by: MikeN on 25.11. 2009 12:21
. Another slight puzzle, I rotated the drive easily with my finger, then took off the end cover to inpect the cogs (fine), I didn't remove the screws, left them in the cover, so they'd go back in same holes, but once I'd tightened it up again, I couldn't spin the drive with my finger! I'm assuming once the drive is being driven by the crank it will turn easily,

I think that if the pump spindle revolved freely before you took it apart  and it doesnt now that you have re-assembled it then you need to investigate why. You are correct that the crank will turn it easily but thats not really solving it.
  Also,when you inspected the gears in the pump did you check them for excessive end float caused by wear in the body and end covers? this can allow oil to drain past the gears and into the engine.
 Mike
Title: Re: More wetsumping
Post by: bsa-bill on 25.11. 2009 16:55
Hi again Rusty - Quite agree the length of the bolts wont be an issue ( provided they screw all the way in ) but the fact that they are different lengths would indicate that at least one of them was not fitted at Small Heath and therefore it might be wrong and therefore the size of the hole in it might be wrong - however comparing them to the bolts out of my project the size of the holes looks about right.

The pump going tight is something I have noted, it's a case of if you've no reason to think it's got problems it's best left well alone unless you mark everything before you dismantle, my road going Flash pump went stiff a bit when re-assembled ( you can't resist having a look in can you ) but has done a good thousand miles since build up without problems.

Anyway here's to a successful conclusion.

All the best - Bill

Title: Re: More wetsumping
Post by: rocket man on 25.11. 2009 19:29
heres an oil pump gasket srm do them it does away with the washer
which i think is a great idea
Title: Re: More wetsumping
Post by: blackbikemike on 26.11. 2009 09:35
Everything back together now, watched the pump to make sure it was turning ok, seems fine, that gasket looks like a good idea. Can't test it yet cos it's stuck in the conservatory, and if I start it and the house fills with smoke (or even hopefully just exhaust fumes) there could be trouble  *eek*. I'm not overconfident I've fixed anything, but we'll see. It's easy to see how it can look like the pump is in there tight against the case, because the worm makes it feel like that even when it's still a mill or so from home, so maybe ;)
Title: Re: More wetsumping
Post by: muskrat on 26.11. 2009 11:51
G'day Mike. the pumps nearly always tighten up when reassembled. I don't like putting them back like this. you have to spin them whilst tightening the screws evenly a bit at a time. Some times a gentle tap with a hide mallet will help. If it's still stiff undo and start again. The last one took me nearly 1 hour but was as free as a bird. Putting back tight will wear the worm. Loctite the studs. The banjo bolts look OK.
Just gave my 100 mile old A10 cafe it's first oil change with only 4 oz coming from the sump.
Cheers