Anti-Sump Failure

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Tim

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These are pictures of my anti-sump valve during a ride today on the 73 Commando 750. Luckily, I have an oil pressure gauge. It was still running good when I shut it down. I'm a little slow, but no more anti-sump valves for me. I was lucky this time and didn't trash the engine. The trailer is a mess, though.

Anti-Sump Failure


Anti-Sump Failure


Tim
 
Is that the Ducati valve?

You would think if the Yamaha valves work a Norton wouldn't reject a Ducati valve like that either.
 
That's the second one I have seen come apart in that fashion, Is that the one with the clear in the center? Miles design?
 
I'm beginning to think all this "wet sumping" nonsense is just that-nonsense. I could see where lapping the pump and gears would make it work more efficiently, but the Domi motor, in continuous production from 1949-1975 and the factory engineers never saw a need for an inline valve. Sounds like an answer to a question that never should have been asked.
 
My '71 Roadster has a '75 Mk III motor. where is the inline anti-sumping valve? I have had this motor down to split cases and I've never seen it. In the pump body?
 
Danno said:
My '71 Roadster has a '75 Mk III motor. where is the inline anti-sumping valve? I have had this motor down to split cases and I've never seen it. In the pump body?
Click to expand...

It's normally fitted in the MkIII timing cover: http://www.nortonmotors.de/ANIL/Norton% ... &Plate=004 - items [41] & [42]. Also, the MkIII pump rubber seal, part 066190 [26] is different to earlier pump seals.
 
Danno said:
I'm beginning to think all this "wet sumping" nonsense is just that-nonsense. I could see where lapping the pump and gears would make it work more efficiently, but the Domi motor, in continuous production from 1949-1975 and the factory engineers never saw a need for an inline valve. Sounds like an answer to a question that never should have been asked.
Click to expand...

There is one theory that this didn't manifest itself until the advent of common use of multigrade oils.

As for the wetsumping being nonsense, I guess until you see a Sasquatch they seem kind of silly too. :mrgreen:
 
According to description, those are the plunger and spring for the oil non-return valve. I remember the 750 seal fitting directly into the timing cover. But I thought that outlet was where oil was pumped through the timing cover to the rocker feed line. How would it keep oil from draining down from the tank into the cases via the pump? The oil inlet is connected to the back of the timing side crankcase half behind the cover.
 
swooshdave said:
Danno said:
I'm beginning to think all this "wet sumping" nonsense is just that-nonsense. I could see where lapping the pump and gears would make it work more efficiently, but the Domi motor, in continuous production from 1949-1975 and the factory engineers never saw a need for an inline valve. Sounds like an answer to a question that never should have been asked.
Click to expand...

There is one theory that this didn't manifest itself until the advent of common use of multigrade oils.

As for the wetsumping being nonsense, I guess until you see a Sasquatch they seem kind of silly too. :mrgreen:
Click to expand...
Yup! Or it could be like the most successful product in Western Civilization: Elephant repellant. I use it all the time and it works like a charm.
 
Hortons Norton said:
That's the second one I have seen come apart in that fashion, Is that the one with the clear in the center? Miles design?
Click to expand...
Yes, that's the one. Clear in the middle. It appears to have broken on the input side. Never again!!!
Tim
 
Tim said:
Hortons Norton said:
That's the second one I have seen come apart in that fashion, Is that the one with the clear in the center? Miles design?
Click to expand...
Yes, that's the one. Clear in the middle. It appears to have broken on the input side. Never again!!!
Tim
Click to expand...

So is that the same one CNW sells? Too much stress on the line thus on the housing?
 
Danno said:
According to description, those are the plunger and spring for the oil non-return valve. I remember the 750 seal fitting directly into the timing cover. But I thought that outlet was where oil was pumped through the timing cover to the rocker feed line. How would it keep oil from draining down from the tank into the cases via the pump? The oil inlet is connected to the back of the timing side crankcase half behind the cover.
Click to expand...

the oil non return valve is the anti wet sump valve.
the oil pump outlet seals to the timing cover, that passage go's to the end of the crankshaft and also feeds the rockers. in theory it stops oil from migrating through the oil pump to the crank and rods where it seeps to the sump.

the MK3 oil pump is different where the rubber seal fits along with the seal.
 
swooshdave said:
Tim said:
Hortons Norton said:
That's the second one I have seen come apart in that fashion, Is that the one with the clear in the center? Miles design?
Click to expand...
Yes, that's the one. Clear in the middle. It appears to have broken on the input side. Never again!!!
Tim
Click to expand...

So is that the same one CNW sells? Too much stress on the line thus on the housing?
Click to expand...

It looks like the same one, but this one was purchased from another well known parts dealer. It has been on the bike for less than 500 miles. There did not seem to be any stress on the line or the valve. The hose made a gentle curve to intersect the junction box pipe. The spring style hose clamps that came with the valve were used. After removing it tomorrow, I'll take a closer look.
Tim
 
I think there are specific instructions for hose length on the cnw instruction sheet. I haven't looked at it for a long time though so I'm not 100%
 
Hi Tim,

That is the same valve that we offer, made by Al Miles, and what has happened to it is unacceptable.

I will contact Miles right away and get his take on it.

I hope you will contact the vendor you bought yours from as well as this is obviously a problem we have to look into.

I will report back and let you know what I found out from Al after talking to him.

Matt / Colorado Norton Works
 
Matt
Thanks for your concern. Attached is a picture of the valve after I removed it from the bike. As you can see, nothing is broken, it just came apart where the clear plastic part connects to the black part. I assume there was a ball which has fallen out. The bike went 3 or 4 miles after the failure. I replaced the oil line today, started and rode the bike and everything seemed normal. Oil pressure was around 40 lbs warm. The engine doesn't appear to be damaged.

Anti-Sump Failure


Tim
 
I've seen that type with the clear plastic and wondered how they were assembled. Appears that type are glued and didn't hold? Vibration & the downward tension of the left side of valve caused to separate?

Thought about getting one of those awhile ago, glad I got a complete metal one.

Lucky you Tim that you have a pressure guage and caught it.
 
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