Oil valve solution to oil falling to crankcase

Yep , I think it is really good , haven't left it long enough though , I keep riding , it's tough , I ride all three , , it helps keep the battery's up ! , , I need to mark the dip stick and leave it for a week .

Shelby-Right said:

Yep , I think it is really good , haven't left it long enough though , I keep riding , it's tough , I ride all three , , it helps keep the battery's up ! , , I need to mark the dip stick and leave it for a week .

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Obviously it was sumping bad prior ?

I think in about 5 days it was right down , but still over the screen , this may have increased as I noticed the heavy oil filled crank , made it a lot harder to start, I purposely left the pump , as I want to try the cover , i:e just one change . It's easy to get the cover off if I need to service the pump . Cheers.

Shelby-Right said:

I think in about 5 days it was right down , but still over the screen , this may have increased as I noticed the heavy oil filled crank , made it a lot harder to start, I purposely left the pump , as I want to try the cover , i:e just one change . It's easy to get the cover off if I need to service the pump . Cheers.

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To me wet sumping is all about the operation/tolerances of the pump...the cover alone is lipstick ...which is why AMR do the pump and cover modifications in unison

All good , but for me , like fault finding at work, one change at a time makes it easier to pin point the problem .

Shelby-Right said:

All good , but for me , like fault finding at work, one change at a time makes it easier to pin point the problem .

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Each to their own i suppose... I only engage that thought for carburetor tuning mainly...my service included new pump (fitted & tested).. seals....new timing chain ...new rotor and pick up plate (that i had on the shelf) and mk3 plunger cover..with a SRM oprv ...ive observed the norms and have had a op gauge fitted for quite some time...and from its readings was why I fully serviced the timing chest....I won't be digging back into that for a long time....meanwhile I will service/modify the original pump (fit seals) and bore mk2 cover to except spring and ball...for another rider or for myself at a much later date....Cheers

I am amazed by the shear volume of threads/posts on Norton heavyweight twins oil pump/wet sumping!

Doesn't everyone understand by now that there is only one main reason for wet sumping - Excess end float of the pump gears allowing oil to leak between the end of the gear and the pump end plate. Any other reasons have nothing to do with the pump.

If you experience wet sumping within a couple of months of non-use there is a problem and you may want fix it. Using taps and valves only hides the symptoms and does nothing to fix the underlying problem.

You don't really need to fix the oil pump though, because it still provides sufficient oil to the engine. The centrifugal forces acting on the oil in a rapidly spinning, 360 degree twin, crankshaft, do a good job of feeding the big ends, unlike in a Norton converted to a 180 or 270 degree twin in which only the first big end benefits and the second suffers. It is however, annoying.

Old pumps are likely to leak excessively because they are worn out (although that is difficult to do) and require repairing (you can easily find the correct factory procedure for servicing the pump elsewhere).
New oil pumps which leak excessively are just badly manufactured.

All my oil pumps are between 55 and 66 years old and only one caused wet sumping, with disastrous consequences. I bought an ex racing 750 motor to replace the 88ss lump in my hybridracer and didn't check the pump before racing it. In the first meeting at Castle Comb I was getting used to the extra power so not using all the revs, but still came second, 0.1 sec from the winner. All seemed good. At the next meeting at Brands Hatch it rained all day so I was short shifting and just trying to keep the leader in site without taking risks - another 2 second places and I still hadn't started thrashing it. On to Donington Park for a couple of Formula 750 and one Battle of the Twins races. It was a hot day on a high speed track. I started the first race from the back of the grid and by the first bend was up into sixth place. All seemed to be going well and Norton was really flying. Half way through the race and as I braked for the chicane the back wheel went it's own way throwing me onto the track and that surface is like sandpaper! It turned out that the pump was very worn and, at continuous high revs, couldn't return it to the tank as fast as the the feed pump, ably assisted by the spinning crank, sucked it in to the engine. The breather pipe vented the excess oil into the catch tank and onto the rear tyre! I patched up myself and the bike and, with an extra large catch tank, made the remaining 2 races. Keeping the revs down a bit I managed a fifth and a sixth. it was nice mixing it with the fancy framed big Ducatis in the Battle of the Twins and discovering that antique 750 Featherbed Nortons can be faster than 900SS Ducatis. After that I carefully built up another oil pump with no noticeable end float and all was well again.

hybridracer said:

I am amazed by the shear volume of threads/posts on Norton heavyweight twins oil pump/wet sumping!

Doesn't everyone understand by now that there is only one main reason for wet sumping - Excess end float of the pump gears allowing oil to leak between the end of the gear and the pump end plate. Any other reasons have nothing to do with the pump.

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Well, that ignores my firsthand experience (post #216 on this thread) plus the 3rd by AMR:
1. leakage through the oil pump gasket
2. leakage past the pump end plates
3. internal leakage past the oil pump shafts (HP side to LP side).
So, there is more than one reason.

In 47 years of owning my Norton it had only wet sump 2 x and only did it when sat for a few months but it was an everyday rider most of its life till 2013 when I brought a new Triumph Thruxton and then a newer Thruxton in 2018 and my Norton will sit for some time before its ridden but it takes over 4 months to drain down to the crank, the last time I had the oil pump out and it's still the original pump there was no end play or wear on the gears and my pump has never been rebuilt in the 47 years of ownership, but if I ride it regularly and not let it sit for more than 3 months it all good still, it's been well over 12 years now since I been in my timing case when I installed the Joe Hunt, maybe even longer as I run an auto timing chain adjuster, so could even be over 15 years ago when I replaced the crank cases.
It's been over 1 month now since I rode the Norton when reinstalling my old Amal carbs, the bike is running great but at the moment I am rewiring the whole bike as I been running the lights off a battery eliminator and now rewiring it up for the stock rec and zener as well a small battery, the light stopped working ages ago but found the 2 head light wires broken in the bulb mount and fitting a new horn, but so far the oil tank has dropped just a little bit, my round alloy oil tank only holds 2 ltrs of oil but I run a Lochart oil cooler without a themo switch and also run with a STP oil mixture in the oil, but before that the original Featherbed oil tank that I was using held over 4 ltr of oil, but if I ride it weekly or regularly then I have no problems with wet sumping.
But to me if it did drain down if I let it sit only takes a few minutes to drain the crank case while I check everything else before a ride, it's no big deal for me and if sat for sometime there be other things to do while the oil drains, check tyres, brakes, chain adjustment and lube, check the nut behind the handle bars lol, get my riding gear ready, the list goes on, but the oil tank is the first thing on the list.

Ashley

hybridracer said:

Doesn't everyone understand by now that there is only one main reason for wet sumping - Excess end float of the pump gears allowing oil to leak between the end of the gear and the pump end plate. Any other reasons have nothing to do with the pump.

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However, maintaining a tight fit between the gears and end plates isn't practical unless the pump is lapped every few hundred miles or so.
The factory accepted that by (eventually) fitting the anti-drain plunger to the 850 Mk3 timing cover.

Also, regardless of the fit between the feed gears and end plate, there's still the potential for leakage 'across the pump' between the crests of the teeth and housing of both feed gears and perhaps to a lesser extent between the meshed gear teeth.

L.A.B. said:

However, maintaining a tight fit between the gears and end plates isn't practical unless the pump is lapped every few hundred miles or so.
The factory accepted that by (eventually) fitting the anti-drain plunger to the 850 Mk3 timing cover.

Also, regardless of the fit between the feed gears and end plate, there's still the potential for leakage 'across the pump' between the crests of the teeth and housing of both feed gears and perhaps to a lesser extent between the meshed gear teeth.

Checking the oil pump

Low oil pressure - indicated on the oil-pressure gauge or dashboard warning light - could provide an indication of wear or damage to the pump.

www.howacarworks.com

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Agreed Les
And that path (via the teeth tips) plus the side-plate to gear gap only give slight oil flow through to the big ends, which may leak if not at TDC and a "bit loose". I strongly suspect that is a very slight proportion of most people's sumping problems.
The three I mentioned in #228 plus the potential short-circuit of pressure relief valve to the sump (pre-Mk3) probably are the major causes of wet-sumping.
Cheers

L.A.B. said:

However, maintaining a tight fit between the gears and end plates isn't practical unless the pump is lapped every few hundred miles or so.
The factory accepted that by (eventually) fitting the anti-drain plunger to the 850 Mk3 timing cover.

Also, regardless of the fit between the feed gears and end plate, there's still the potential for leakage 'across the pump' between the crests of the teeth and housing of both feed gears and perhaps to a lesser extent between the meshed gear teeth.

Checking the oil pump

Low oil pressure - indicated on the oil-pressure gauge or dashboard warning light - could provide an indication of wear or damage to the pump.

www.howacarworks.com

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Don't forget a damaged or not sealing oil pump discharge seal , or missing seal .

Shelby-Right said:

Don't forget a damaged or not sealing oil pump discharge seal , or missing seal .

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With that seal missing, wet sump quickly gives way to crankcase air ventilation sumping, just ask SwooshDave...

Most of the discussion here is essentially dancing around denials of the fundamentals. If oil is contained in a reservoir that's above the location of a gear-driven oil pump, given time (whether long or short periods) it will drain because GRAVITY ALWAYS WORKS. It isn't just Nortons either. Equally afflicted Harley-Davidson finally acknowledged the fact by moving the oil container to a level nearly even with the pump as a pseudo-sump on Big Twins. Buell did the same by using the swing arm on the XB models as the oil reservoir. Air-cooled Sportsters never got either solution and while not particularly prone...they do sump.

Accepting that, and adding the fact that I do not ride any of my ten machines as often as I should, particularly the 850 Commando, I am convinced that the reed-type, sump-located, breather is the best compromise overall. Not only for dealing with dumping effectively but for vastly improved crankcase breathing benefits.

Regarding their use on my 1973 model, I see choices and have questions. Whether JS Motorsport, NYC Norton, or the (apparently discontinued) CNW, there are slight variations in the same concept. I can sort that, but the one thing they have in common throws me. All of them have a "standpipe" which doesn't exist on the stock sump plug they replace. Not being an expert on Commando oiling, I can only guess it is there to ensure the reed will get airflow and not clog with oil in a sumped engine. This makes me curious about whether one of these would work without a standpipe. I also wonder if the NYC version, using a swivel banjo is more leak-prone in the long run. On the other hand, does the fixed outlet on the JS Motorsport version limit hose routing options?

Can someone explain (and help clarify) the design details on these reed sump breathers, please? These things are too much money to mistake.

Kip said:

Most of the discussion here is essentially dancing around denials of the fundamentals. If oil is contained in a reservoir that's above the location of a gear-driven oil pump, given time (whether long or short periods) it will drain because GRAVITY ALWAYS WORKS. It isn't just Nortons either. Equally afflicted Harley-Davidson finally acknowledged the fact by moving the oil container to a level nearly even with the pump as a pseudo-sump on Big Twins. Buell did the same by using the swing arm on the XB models as the oil reservoir. Air-cooled Sportsters never got either solution and while not particularly prone...they do sump.

Accepting that, and adding the fact that I do not ride any of my ten machines as often as I should, particularly the 850 Commando, I am convinced that the reed-type, sump-located, breather is the best compromise overall. Not only for dealing with dumping effectively but for vastly improved crankcase breathing benefits.

Regarding their use on my 1973 model, I see choices and have questions. Whether JS Motorsport, NYC Norton, or the (apparently discontinued) CNW, there are slight variations in the same concept. I can sort that, but the one thing they have in common throws me. All of them have a "standpipe" which doesn't exist on the stock sump plug they replace. Not being an expert on Commando oiling, I can only guess it is there to ensure the reed will get airflow and not clog with oil in a sumped engine. This makes me curious about whether one of these would work without a standpipe. I also wonder if the NYC version, using a swivel banjo is more leak-prone in the long run. On the other hand, does the fixed outlet on the JS Motorsport version limit hose routing options?

Can someone explain (and help clarify) the design details on these reed sump breathers, please? These things are too much money to mistake.

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Assuming your 73 is an 850 or a 750 with the big nut on the bottom of the engine...

The "standpipe" connects to the pipe in the neck of the oil tank via a hose. There is no way to eliminate it and you shouldn't want to. There are no issues with the "standpipe" for any of them on a 73 model. The cNw breather requires your crankcase to be sent to cNw empty. Unless your engine is apart, buy the NYC or JS Motorsport breather and follow the instructions - one of the best things you can do for a Norton.

marshg246 said:

Assuming your 73 is an 850 or a 750 with the big nut on the bottom of the engine...

The "standpipe" connects to the pipe in the neck of the oil tank via a hose. There is no way to eliminate it and you shouldn't want to. There are no issues with the "standpipe" for any of them on a 73 model. The cNw breather requires your crankcase to be sent to cNw empty. Unless your engine is apart, buy the NYC or JS Motorsport breather and follow the instructions - one of the best things you can do for a Norton.

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No - we aren't talking about the same thing! I'm not asking about the nipple that the hose connects to, rather it's the tube that sticks up above the screen. Also, the current cNw breather is out of the question, but I was under the impression they used to have one similar to the NYC/JS type...sorry to confuse.

Kip said:

No - we aren't talking about the same thing! I'm not asking about the nipple that the hose connects to, rather it's the tube that sticks up above the screen. Also, the current cNw breather is out of the question, but I was under the impression they used to have one similar to the NYC/JS type...sorry to confuse.

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The tube that sticks up above the screen into the crank case, is there to ensure the oil level is left in the crank case.

Without that tube ALL of the oil would be returned to the tank via the breather, leaving no oil in the cases to be whipped up be the crank and lubricate the cam, pistons, bore, main bearings, etc.

The vast majority of the internals in a Norton engine are fed by splash / mist. The oil pump only feeds the big ends and a tiny dribble to the rockers.

Without that tube, you’d effectively starve a lot of this splash / mist lubrication.

That makes sense - thank you! Is there an "ideal" level? How is the height of the standpipe in reed breathers determined?

The plain bearing big ends of the con rods are pressure feed, as they should be, with the "surplus" doing the splashing and making the mist?

Is this splash/mist lubrication primarily for the cylinder walls, camshaft, lifters, and ball main bearings?

It seems to me too much oil in the crankcases would be nearly as bad as too little if it meant "sumping" while running was putting a lot of drag on the flywheels, extra pressure in the cases, and so on. In fact, this sort of implies that the stock oiling system/pump has a feed/return ratio that I've never heard/seen discussed. Is the pump geared to scavenge as much as it feeds...more...less?

In terms of other details of design, does one of these red valve sump breathers have advantages/disadvantages over the other.

My assumption would be that the designers of these breathers have established the ideal height of this standpipe.

I run two of them (NYC Norton) and can vouch that they function perfectly.

That’s as far as my analysis goes. I learned a long time ago to stop digging once I’m happy !

Kip said:

It seems to me too much oil in the crankcases would be nearly as bad as too little if it meant "sumping" while running was putting a lot of drag on the flywheels, extra pressure in the cases, and so on. In fact, this sort of implies that the stock oiling system/pump has a feed/return ratio that I've never heard/seen discussed. Is the pump geared to scavenge as much as it feeds...more...less?

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Well known fact and well discussed. The scavenge (oil return) side of the oil pump pumps more than the feed side. Clearly, the sump would be full while running if that were not the case! This is also a fact on every "dry sump" British bike I am aware of (probably every dry sump engine ever built).