Oil valve solution to oil falling to crankcase

I don't know the answer here.
A couple of years ago I put a Mk3 engine together as a 920.
That started with bare cases so I had to buy the timing cover and fixings.
I bought all of that from Rabers just before they closed shop.
It was all NOS.
A week or two after getting the cases on Ebay I managed to buy the original oil pump and crankshaft for the same cases. They had sold earlier to another buyer, but that fell through.
I didn't do anything to the pump other than fit a new external rubber seal.
The 920 engine can sit for 3 months and barely show any drop in oil tank level. For all intents, wet sumping does not occur with that engine.

My Mk3 850 drains down into the sump at a steady rate. If it isn't ridden at least once every two weeks, expect a smokey startup. If it goes much more than a month, the sump needs draining.
Same system, but more miles on the parts, although I'm not sure that it was ever sealed up like the 920 is.

Glen
 
Thomasa said:
This may have been asked by now up-thread but why doesn't my MKIII anti-drain valve work?
Click to expand...

Unless it's jammed open then it probably is working to slow the rate of drainage (you could remove it to check) but may not stop it completely because the oil can leak across the pump (and then to the sump) through the pump shaft clearance, hence the AMR pump shaft O - ring modification.

MK3 timing cover

When the anti wetsumping valve on a MK3 timing cover dosent work what are the usual problems to look for? Not had it apart yet but the piston moves freely The spring and seal are new
www.accessnorton.com www.accessnorton.com

Wet Sumping, Oil Pressure Relief Valve and AMR Modification

I recently had my timing cover modified by AMR in Tucson. Basically the modification is the addition of a ball valve and spring that pushes up against the outlet of the oil pump. The timing cover is bored to accept the spring and ball valve. Also there is a special seal (1/8 inch thick O-ring)...
www.accessnorton.com www.accessnorton.com
 
Harleys have been wet sumping for years with factory check ball and spring at the pump. Some leak a lot, some leak very slowly, none are perfect.
 
Thomasa said:
This may have been asked by now up-thread but why doesn't my MKIII anti-drain valve work? Years ago I lapped it to the case and put in a new spring but it sometimes works but usually not. Does anyone have a MKIII whose valve unfailingly works? My former boss at the MC shop said it was pointless to mess with it but I did anyway. As usual he was right. What do/did we not know in 1990?
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Mine works fine . Never inspected or cleaned it or anything . Same with the oil pump itself . 30 ,000 kms . , or so . Drove it today 250 more kms .
 
marshg246 said:
AMR is probably right...

Be sure that the rubber of the seal is past the end of the oil pump bush - so the ball can seal against it. If you install the MK3 cover you will get a different seal and oil pump bush.
Click to expand...
Greg
Just pulled the timing cover and it was a Mk3 bush.
It protrudes 3.9mm whereas the o-ring is only 3.3mm so the bush will stick through the o-ring by 0.6mm.
Trouble is, the pre-Mk3 bush of my old pump protrudes 3.8mm, so will stick through the o-ring by 0.5mm.
Even checked the bush on my spare 650ss pump and the bush protrudes 3.6mm, will stick through by 0.3mm
Both o-rings supplied by AMR (one spare) have the same dimensions.
Any advice welcome - but I will go back to Mike at AMR for his view.
Cheers

Oil valve solution to oil falling to crankcaseOil valve solution to oil falling to crankcase
 
I think I have found the issue. The large flange on the Mk3 bush does not allow it to fit into the recess AMR machined.
The pre-Mk3 fits in nicely (see photos) whereas the Mk3 would not fit in the recess and would stand 1.1mm back
I think I will re-assemble and test.
Cheers

Oil valve solution to oil falling to crankcaseOil valve solution to oil falling to crankcase
 
If I understand correctly, the spigot of the brush sits inside the hole in the timing cover doesn’t it? So the fact that it protrudes past the o ring doesn’t matter?

The large flange doesn’t need to sit in the recess, that’s where the o ring sits. Isn’t it?
 
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Fast Eddie said:
If I understand correctly, the spigot of the brush sit inside the hole in the timing cover doesn’t it? So the FCR it protrudes past the o ring doesn’t matter?

The large flange doesn’t need to sit in the recess, that’s where the o ring sits. Isn’t it?
Click to expand...
Yes I think you are correct - my thinking was that the smaller flange diameter may allow the bush to extend further into the timing cover, giving the ball a better chance to seat.
...and Mike (AMR) has confirmed that to ball is intended to seat against the bush. Thinks in this case the Mk3 bush thing is a blind alley.

Starting from first principles I'm thinking of making an oil pump gasket with no holes - just to confirm there is no other (shudder) oil path.
Otherwise may have to make up a rig like peterjoe did some years ago.
Cheers
 
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I can’t recall the details now Rob, but remember some discussions about how oil can bypass the pump and leak past the PRV threads. Is this where you might look ?

Another thought… as that bush wasn’t designed to seal against a ball bearing, is it possible the face is not perfect? Maybe lap it in against another ball ??

I’m shootin’ from the hip here…
 
robs ss said:
Yes I think you are correct - my thinking was that the smaller flange diameter may allow the bush to extend further into the timing cover, giving the ball a better chance to seat.
...and Mike (AMR) has confirmed that to ball is intended to seat against the bush. Thinks in this case the Mk3 bush thing is a blind alley.

Starting from first principles I'm thinking of making an oil pump gasket with no holes - just to confirm there is no other (shudder) oil path.
Otherwise may have to make up a rig like peterjoe did some years ago.
Cheers
Click to expand...
Rob,
how deep is the machined recess in the timing cover? If its deeper than 3.35mm use of the Mk111 spigot will stop the O ring being compressed when the cover is fitted.
On Velocette’s it is standard practice to gently tap the ball bearing with a hammer onto the seat to create a nice seal. As the Norton spigot was never designed for such a seal I would definitely be looking at the outer end of it as suggested.
 
Fast Eddie said:
I can’t recall the details now Rob, but remember some discussions about how oil can bypass the pump and leak past the PRV threads. Is this where you might look ?

Another thought… as that bush wasn’t designed to seal against a ball bearing, is it possible the face is not perfect? Maybe lap it in against another ball ??

I’m shootin’ from the hip here…
Click to expand...
Thanks Nigel - yes, if I stay with the AMR system I will lap a seat (30 degrees?) into the bush to give the ball a decent chance.
That may well be why the myth of 50% chance of AMR success arose - the bush end was never designed for a ball to seal against it.
Actually, the Mk3 bush doesn't look too good for the stock Norton plunger either!
Cheers
 
robs ss said:
Actually, the Mk3 bush doesn't look too good for the stock Norton plunger either!
Click to expand...
The Mk3 plunger should seat against the (Mk3) seal not the bush.

andover-norton.co.uk

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andover-norton.co.uk
 
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Thanks Lab that has clarified its purpose and position for me
 

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Well, I did something I should have done earlier - with the timing cover off, blocked the pump outlet (cling-wrap held on by the o-ring and filled the oil tank. Result - no leaks other than from the pump-crankcase interface at about the same rate as I was sumping. Drained the tank, pulled off the pump, gasket looked fine but noticed the crankcase gasket face had imperfections (see photo) The AMR gasket, like the one I pulled off is only 0.2mm thick.

So, made a dummy oil pump gasket (no holes for oil) from 0.5mm cardboard (no gasket paper handy) and tightened the pump on.
Result (after 30 minutes) not one drop of leakage. Appears the thinner paper couldn't accommodate the rough surface of the crankcase (back of the pump looked fine).

Next, made another cardboard gasket, this time with oil holes, and ground the nose of a small dremel stone to the same diameter as AMR's ball (6.4mm).
Then lapped the end of the pump bush with the stone until a good angled face was evident.
Made a jig (copied @PeterJoe - post #170 above) - see photo below.
Assembled everything, filled the tank and let it sit for an hour.
Result - not one drop of leakage in that hour (previous was 2 drops a minute)

So - problem seems to be solved - just need to get some 0.5mm gasket paper

I will report back in a month or so to confirm the fix is good.
Cheers
Gasket face.JPGCheck valve test rig.JPG
 
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robs ss said:
Well, I did something I should have done earlier - with the timing cover off, blocked the pump outlet (cling-wrap held on by the o-ring and filled the oil tank. Result - no leaks other than from the pump-crankcase interface at about the same rate as I was sumping. Drained the tank, pulled off the pump, gasket looked fine but noticed the crankcase gasket face had imperfections (see photo) The AMR gasket, like the one I pulled off is only 0.2mm thick.

So, made a dummy oil pump gasket (no holes for oil) from 0.5mm cardboard (no gasket paper handy) and tightened the pump on.
Result (after 30 minutes) not one drop of leakage. Appears the thinner paper couldn't accommodate the rough surface of the crankcase (back of the pump looked fine).

Next, made another cardboard gasket, this time with oil holes, and ground the nose of a small dremel stone to the same diameter as AMR's ball (6.4mm).
Then lapped the end of the pump bush with the stone until a good angled face was evident.
Made a jig (copied @PeterJoe - post #170 above) - see photo below.
Assembled everything, filled the tank and let it sit for an hour.
Result - not one drop of leakage in that hour (previous was 2 drops a minute)

So - problem seems to be solved - just need to get some 0.5mm gasket paper

I will report back in a month or so to confirm the fix is good.
Cheers
View attachment 106906View attachment 106907
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I’m not quite understandi’ Rob, was it the gasket or the lapping wot dunnit ?
 
Fast Eddie said:
I’m not quite understandi’ Rob, was it the gasket or the lapping wot dunnit ?
Click to expand...
The leak was the gasket, but I have lapped to bush to just to be sure, to be sure (getting sick of empty/refill oil tank!!)

There is one final test I will do after fitting new gasket - see what, if any, the leakage rate through the pump is, without the ball. Just to see how effective the o-ring mod AMR did to the oil pump is.
Cheers
 
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robs ss said:
The leak was the gasket, but I have lapped to bush to just to be sure, to be sure (getting sick of empty/refill oil tank!!)

The is one final test I will do after fitting new gasket - see what, if any, the leakage rate through the pump is, without the ball. Just to see how effective the o-ring mod AMR did to the oil pump is.
Cheers
Click to expand...
That’s very interesting and I wonder how many of us have the same leakage.
 
Fast Eddie said:
That’s very interesting and I wonder how many of us have the same leakage.
Click to expand...
I think the answer is to fit a gasket somewhere around 0.5 - 0.75mm thickness.
I will use 3-bond white for reassembly.
Cheers
 
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