Wet Sumping Redux

rick in seattle · Feb 21, 2010

Within the past 3 months, a few members reported oil flow rates out of the sump while the bike was stationary and unused for a few weeks. I apologize for raising this issue again, but I cannot find the relevant posts in the archives. Can someone point me to the right post? Over the winter, my rebuilt Mk3 has drained
0.25 fluid oz per day with the crank in an arbitrary position, i.e. no effort was made to store the bike at TDC.

pelican · Feb 21, 2010

I'm not sure about the other topic...

with mine at tdc it took about 2 weeks to drain the whole tank into the sump...might be different now that I've lapped the pump? We'll see

Danno · Feb 21, 2010

I have been told the Mk III has an anti-wet sumping valve built into the timing cover. There is a check valve between the pump and the rocker shaft oil supply that's not present on older models, but i can't see how it would do anything but stop the oil in the rocker line from draining back. Something's going on that keeps all but a little from draining out of the tank. More precision in later oil pumps?

bill · Feb 22, 2010

Danno said:
I have been told the Mk III has an anti-wet sumping valve built into the timing cover. There is a check valve between the pump and the rocker shaft oil supply that's not present on older models, but i can't see how it would do anything but stop the oil in the rocker line from draining back. Something's going on that keeps all but a little from draining out of the tank. More precision in later oil pumps?

danno
you need to do a little more research before you post on this. THE CHECK VALVE STOPS THE FEED TO THE CRANKSHAFT/ROCKER FEED PASSAGE!!!! with that said it is also known that that valve sticks and no longer functions as meant.

MexicoMike · Feb 22, 2010

Mine drains 1.3 oz per 24 hours after resurfacing the oil pump per the Norton shop manual with the engine left at whatever position it was in - I did not intentionally put it on compression. It drained considerably more before resurfacing but I never put a measuring cup under the drain so I don't know the actual amount. So now it would take approximately 24 days to dump one quart of oil into the sump from the tank, assuming it continued to drain at the same rate. Actually it would take longer since as the oil level in the tank drops, the rate of draining slows due to the reduced head pressure (about .45 psi/ft of height).

rvich · Feb 22, 2010

Here are some other recent threads on this topic:

does-wet-sumping-cause-any-damage-t2755.html?hilit=wet damage

oil-pump-and-wetsumping-t5566.html

steven wardlaw · Feb 22, 2010

I've got one one cnw anti sump check valves and I don't really trust it . I wish I had a manual cutoff vave that also had a ground wire switch for the ignition so that you could not crank the bike with valve in shutoff position. As much as I don't trust the anti-sump valve I also don't trust myself to turn a manual valve on and off.

Hortons Norton · Feb 22, 2010

That would be great to have it wired to the ignition! Then the worst thing that could happen is that you forget to turn it off and it wet sumps. If one could make a switch and valve in one small package that would be best, The valve in this post looks very stout and I am sure would last quite some time. You could attach the switch to it somehow and then run the wire to it. Gets me thinking, OH NO!!!!!!!

MexicoMike · Feb 22, 2010

"Then the worst thing that could happen is that you forget to turn it off and it wet sumps. I

But isn't that the worst thing that can happen if you do nothing at all?

Hortons Norton · Feb 22, 2010

MexicoMike · Feb 22, 2010

OK, well then what is the amount of oil drained from the tank to the crankcase that will cause problems? Knowing that amount and knowing your individual bike's amount of wetsumping per day, one could easily determine how long the bike can sit without an issue.

For example, if one quart of wetsumped oil is the limit before problems occur, knowing the engine's wetsump rate tells you how often the engine would have to be run to avoid any issue. Obviously if the wetsumping exceeds the "safe" amount in just a few days, it would be a PITA. But if it took several weeks or more, that probably wouldn't be an issue for many people because either they ride the bike often enough or it would be easy enough to crank it up every 3-4 weeks.

Hortons Norton · Feb 22, 2010

So then don't use one Mike.

swooshdave · Feb 22, 2010

On my Interstate when it wetsumped it would be very difficult to kick over. Drain, refill, start. TDC helped some.

Cookie · Feb 22, 2010

Personally I've seen some dumb stuff from wet sumping including an engine rebuild that was not needed.
The most common is hard starting, overfilling because it looks empty, and blowing a seal. Seems like I've heard of sombody who blew a primary seal and managed to blow his engine in the past.
When Franco and I were working on his bike the fist oil drain just kept coming and coming. I'm sure that wasn't a record for oil from a Norton but it might be close. I assumed the bike sat for a long time and the PO found an empty oil tank and just filled it.

MexicoMike · Feb 22, 2010

"So then don't use one Mike."

Sorry If I seem obtuse or troublesome; it is not my intent.

Sure, like everyone, I would prefer that the engine didn't wetsump. I would consider a manual valve but I'm pretty confident that at some point I would forget. I just think there is no manual valve sufficiently foolproof for ME. Heck, folks take off in airplanes with the gust locks on the flaps and/or rudder and the locks are bright red with streamers hanging down. How do they manage to preflight and get in, never having noticed? But they do.

A valve that had some really obvious handle, as folks have discussed that interferes with the kick starter would work fine I guess but I don't care for what that would have to look like.

Cookie · Feb 22, 2010

I've been happy with my CNW type valve. It hasn't caused a bit of trouble and keeps the oil out of the sump, saving a bit of hassle for me.
That said it would be fairly easy to use a ball valve, put a couple of contacts on it, and wire it through the kill switch.
As mentioned the problem I'd have would be forgetting. I once wired a kill into my Jeep so nobody could steal it while I was out sailing. On at least a couple of occasions I nearly flattened my battery before remebering the switch.
On the same Jeep when folks were stealing trailer hitch adapters I drilled into mine, put lock screws in, and bondoed and painted so it could not be removed. A few years later I decided to pull it off and beat on it with a sledge hammer until I recalled the lock screws.
I forsee myself kicking 400 times while wondering what is wrong.

MexicoMike · Feb 22, 2010

LOL!! You may be a long lost relative - sounds just like stuff I've done!

Nowadays I make notes of everything and type them into my "log" for whatever - car/bike/boat to avoid it. But sometimes I forgot that I made an entry on a particular subject...

ML · Feb 22, 2010

Wet sumping is good. It's a quirk of the Norton, reminds you to check the oil. I do this after every long run and top up as needed so next time its just start and go. If the bike sits for 2 weeks its maybe down a pint or so. If it gets well below the outlet, I drop the sump drain and refill, but on a well used 850 thats a month of sitting around. Don't see it as a problem and doubt it ever will be. Having a valve in the feed line would worry me more.

Mick

Danno · Feb 22, 2010

bill said:
Danno said:

I have been told the Mk III has an anti-wet sumping valve built into the timing cover. There is a check valve between the pump and the rocker shaft oil supply that's not present on older models, but i can't see how it would do anything but stop the oil in the rocker line from draining back. Something's going on that keeps all but a little from draining out of the tank. More precision in later oil pumps?

Click to expand...

danno
you need to do a little more research before you post on this. THE CHECK VALVE STOPS THE FEED TO THE CRANKSHAFT/ROCKER FEED PASSAGE!!!! with that said it is also known that that valve sticks and no longer functions as meant.

So the crank is lubed by way of the same outlet as the rockers? My research will consist of measuring how much oil there is in the sump after x amount of time since I just changed the oil.

aceaceca · Feb 22, 2010

I have owned and ridden a number of Nortons. Wet sumping has never concerned me. I never check the oil tank before firing up. As far as I am concerned it hurts nothing. Just slow idle the engine and the oil will all be back in the tank quickly. I have not heard from any of the posters here that wet sumping ruined their engine or blew seals out. I suppose, like many supposed fixes, they are perceived to be worthwhile, but may in fact be asking for trouble. If it ain't broke, leave it alone. Thats my 2 cents worth.

Wet Sumping Redux

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