Baffled, confused and covered in oil!!!!!!

[duTch]

 The mesh size is definitely worth checking....fwiw, I discovered the brass mesh strainer around the pickup in my Gutzzi fell apart about four years ago so I replaced it with some 100 wire stainless mesh because I figured the 40 wire was too coarse and listed replacement ones looked too dodgy.... I had to pull the sump soon after to replace a seal and found the mesh had sucked a big tear hole .....so sourced some new brass not so fine and did it again- still monitoring it (nb, the strainer is~70mm dia. x 50mm high)..
 In addition, as far as I can tell from the online images, the SRM type gauze is only a flat disc whereas the original item is cylindrical and allow much more flow.....

[RDfella]

Just another thought, though I’m clutching at straws here – when I rebuilt my A10 I couldn’t get a proper oil flow (return to tank was a light dribble). The pump mating face was flat and I’d stripped and checked the pump. Everything was in order and I was really without a clue.
Then someone (forget who) on this site suggested a pump gasket with bigger holes. Couldn’t see why that’d make a difference, as the gasket mated with both c’case and pump holes OK, but tried it anyway. Success – a positively gushing return flow.
So, does your gasket have oversize holes – and after all the stripping and checking is the lone gasket at pump drive end still in place? Obviously the latter doesn’t apply if using the one piece gasket.

[JulianS]

There are some very nasty pump to crankcase gaskets offered.

Photo top right is the very nasty one, note the small holes, smaller than those in pump and case thus masking the oilway and reducing flow, also the mounting holes are too large and allow the gasket to be displaced.

Top left is a genuine BSA new old stock, see the larger oil holes and smaller mounting holes.

Bottom is SRM gasket extended to deal with the spacing of the pump on the front mounting stud. The large hole is for the modified anti syphon ball used on the end feed conversion.

[RDfella]

Another thought – if the rocker feed is excessive, the oil pump will draw from the tank, but not all will be returned. Some will start accumulating in the crankcase, causing wet sumping. I can think of two reason this may happen: the rocker banjo holes are too big, or the tank breather is blocked.

[bikerboy]

Firstly thanks to all for your ideas and I will answer as I can

Musky

I did exactly that with a hose but I doubt that I went up to 20 psi so good call a recheck on that one

Gauze too tight, now thats not a bad call I have checked that the sump pipe has not been bent down to hit the pump and that has a load of clearance but that gauze is tight maybe I should check that out

Yes the crankcases are untested but I obviously checked all the oilways and blew them thru but the one from the PRV valve still worries me its tiny and maybe some crap has got in ther to block that.

The breather slipping as well is doubtful but well worth a check

When it comes to the oil pump, yes it has the spacing washer behind the drive and yes it has the fibre washer under the front bold. As for the gasket I always specifically check the holes line up perfectly knowing what gaskets are like nowadays.

The oil pump was not changed as such, it was on my other A10 and running fine but I put a rev counter drive on that and used the pump on the plunger engine when I rebuilt it so in my eyes it should be good.

Oil lines round the wrong way? Thats not really possible on the plunger as its totally different to the swinging arm model

End float I managed to get down to 2 thou which is pretty good in itself, I did use shims instead of making a one piece shim but there is no sign of anything in the sump that would indicate them breaking up, plus its done it from the start and I have only done 100 miles on it now

I will say I have dropped the sump 3 times now and on two occasions I have considered it had too much oil in it so my next move is firstly to degrease the damned thing its coated in oil yet again but at least I know it wont rust

Next I am going to take the PRV out of one of my running A10's just in case and put it in this one as a test

If that fails I am going to strip the timing case side down, check the breather location and send the oil pump away for a recon unit, a guy on the south coast  has said he will do a recon exchange pump for about £85 which is not unreasonable.

While the pump is off I am going to (yet again) whack an air line on all the oilways particularly the one down to the sump to see if that has some form of a leak or something in it.

If all that fails I might seriously consider setting fire to it

[edboy]

i think we have all been there bikerboy.
i rebuilt a plunger engine and hadnt noticed that the plug for the prv to camshaft gallery was missing.oil ***** out everywhere and i thought i had cracked cases.
you learn so much more on the second engine rebuild.

[RDfella]

bikerboy - know how you feel - I was on the brink of smashing up my GF when it suddenly started refusing to pump oil soon after a rebuild. Spent hours on it, getting nowhere. Never did find the cause, but it's OK now.
Before you start stripping things and throwing money at it, try the simple ones first.
Is the tank breather clear? A bit of hose should quickly confirm that.
Are the rocker banjo bolts the right ones? If the holes are too big, that could cause your problem as the return to tank would be diminished.
Re the sump gauze - that's only really to prevent crap from getting to the pump and damaging its teeth. Most filtration is done by sedimentation in the tank so, provided your engine is clean, try running it without the gauze for a few miles.
Lastly, on SA models the sump pickup pipe has a pin welded in it just above the ball to prevent the anti-drain ball from going too high. Does the plunger have a pin as well? Because if they're missing, apparently the ball can rise too far and block the return pipe.