Cheap & easy solution for wet sumping problem

Here's what I think is the easiest, cheapest solution for the wet sumping problem which can blow your PTO mainseal by inverting the lip when firing up with too much oil in the sump (causing too much pressure against the main oil seal).

A simple 1/16" cross section oring of 1-1/16" ID fits best (some may need a different size). With the oring installed and backed up by the engine sprocket there is no where for the lip/mainseal to go but to stay where it is. The engine sprocket will prevent the main seal from dislodging from its recess and the oring prevents the oil seal lip from inverting.



With the above setup there is about 0 clearance between the oring and the engine sprocket - not enough interference to create wear on the oil seal. There is only a few thousands of clearance between the engine sprocket flange and the oil seal housing so the oil seal isn't going anywhere. You will still have pressure in the sump but its not going to hydraulic stop your pistons unless you completely overfill the oil tank and cases. So the only other problem left is sluggish kickstarting with a flooded sump (similar to kicking a cold motor). Beats the heck out of sump shutoff valves that can blow your motor if you forget to turn them on (a valve connected to the ignition switch is the exception).

The secondary solution which everyone already knows about is a breather low in the cases allowing your sump oil to be pumped out and into the oil tank more quickly.

It this solution too simple? Personally I love simplicity and reliability. Has it been tested? No I haven't tested it yet. I'll throw in an oring next time my sprocket is off. So I'm jumping the gun here but don't let that stop anyone from giving it a try. I don't see any downside and if it works it could shut down a lot of needless worry. Just be sure to check the fit and return with some feedback.

The seal inverting is only one of the consequences of wet sumping. I have seen the seal get expelled from the crank case - I'm not sure this would prevent that (the MKIII has the solution for that). On my bike, if the sump fills up oil will leak into the primary from one of the 3 bolts that attach it to the engine, even though I've used Loctite on them. Very annoying with a theoretically dry primary.

H

maylar said:

The seal inverting is only one of the consequences of wet sumping. I have seen the seal get expelled from the crank case - I'm not sure this would prevent that (the MKIII has the solution for that). On my bike, if the sump fills up oil will leak into the primary from one of the 3 bolts that attach it to the engine, even though I've used Loctite on them. Very annoying with a theoretically dry primary.

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How can the oil seal be expelled when there is only about .020" clearance between the oil seal and the standard steel engine sprocket flange? The seal is 3/16" wide. I'm not saying its impossible but I can't see it. Maybe you're talking about a belt drive sprocket with more clearance between the sprocket and the oil seal - in that case you might have to stack up another thicker oring against the 1-1/6" cross section oring to take up more space.

jseng1 said:

H

How can the oil seal be expelled when there is only about .020" clearance between the oil seal and the engine sprocket flange?

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Maybe expelled isn't the right term. "Pushed out" enough to let oil leak past.

I'd try your idea, but my bike doesn't wet sump more than 1 hour's worth after a ride. Manual ball valve user and mad scientist I am. I definitely would not recommend a manual ball valve though.

More giggles: My spin on oil filter is on the feed side of the oil pump before the ball valve. I've got it all going on. Still waiting for the motor to blow up, and I don't baby it. Rear tire squares up in 700 street miles. Might have to send you a big order for parts after I blow the engine up. Darn thing just won't let go.

However, when I finally blow it up, burn a hole in the pistons, or whatever forum predicted calamity occurs, I'll try your o-ring idea for reals.

No disrespect meant.

i'll just start mine up now and then

This does not solve wet sumping, all it does is potentially prevent one of the side effects.

maylar said:

Maybe expelled isn't the right term. "Pushed out" enough to let oil leak past.

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It might move a little but it shouldn't move more than the side clearance to the sprocket which is about .020" and I don't think it would leak - especially if it had rubber on the OD Maney style.

I forgot to add than the seal should be viton (or silicone) so it won't crack when exposed to air like some common rubber orings will do. 1/16" cross section with 1-1/16 or 1-1/8" ID should work.

swooshdave said:

This does not solve wet sumping, all it does is potentially prevent one of the side effects.

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Only thing that prevents excessive wet sump entirely over whatever period of time is the worst thing you can do. Turn off the flow at the source.

A good breather solution helps keep the crank case pressure from pushing against the seal with a full sump. It's the excess pressure in the reduced space in the crank case with a sump full of oil that blows the seal out. Well, that's how I see it anyway. If there is nothing but oil in the crank case and no other air space, pressure is bound to push the oil out. How many times did I repeat myself in that paragraph. I lost count.

I am going to pull off my primary soon, and part of this is to inspect the main seal and three mounting bolts for leaks. After being laid up with a broken collarbone the last four months, I am sure the bike is fully wet sumped. I will try the oring. Thanks, Jim!

If you ride your Norton regularly then no problems with wet sumping , well my Norton anyway, if I let it sit for a few months then 1/2 my oil tank will be in the crank case keeping thing nice and lube, taking the drain plug out after its been sitting for a while is so easy and take less than 5 minute to drain the access oil out can do this while checking everything else that should be done before any lay up ride, to me its no big deal to do, but if your bike wet sumps after a few days then something is not right and should be looked into, after 46 years of ownership I have only needed to pull the drain plug out to get rid of access oil 3 times.

Ashley

I put one of these sump plugs in for when the ride sits too long.
I look in the oil tank, if the oil level is down too much I'll remove the smaller magnetic plug, drain some oil out, put in tank and kick away. Only takes minutes to do.

Wet sump oil leak after 3 months.

maylar said:

Wet sump oil leak after 3 months.

View attachment 81019

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What breather are you using?

Schwany said:

I'd try your idea, but my bike doesn't wet sump more than 1 hour's worth after a ride. Manual ball valve user and mad scientist I am. I definitely would not recommend a manual ball valve though.

More giggles: My spin on oil filter is on the feed side of the oil pump before the ball valve. I've got it all going on. Still waiting for the motor to blow up, and I don't baby it. Rear tire squares up in 700 street miles. Might have to send you a big order for parts after I blow the engine up. Darn thing just won't let go.

However, when I finally blow it up, burn a hole in the pistons, or whatever forum predicted calamity occurs, I'll try your o-ring idea for reals.

No disrespect meant.

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Give it to me, I'll blow it up for you !

Fast Eddie said:

What breather are you using?

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Mike's XS. There are no leaks while running. Zero (knock on wood). This was taken after 3 months in storage, just from wet sumping. I put epoxy around the seal now.

maylar said:

Mike's XS. There are no leaks while running. Zero (knock on wood). This was taken after 3 months in storage, just from wet sumping. I put epoxy around the seal now.

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Hmmm… the oil is covered in belt dust, which (to my mind) would indicate it was leaking whilst running…

Chuck_Wagon said:

I put one of these sump plugs in for when the ride sits too long.
I look in the oil tank, if the oil level is down too much I'll remove the smaller magnetic plug, drain some oil out, put in tank and kick away. Only takes minutes to do.

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I do the same with the 650ss. You do need to strain the oil if re-using. I didn't and found a tiny round bit of stone stuck in the rocker feed banjo.
It all turns into a bit of a chore just to go for a ride.
I tend to head for the MK3 instead, it holds the oil in the tank for quite awhile.

Glen

trident sam said:

Give it to me, I'll blow it up for you !

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My hero. I'm not trying to blow it up. It is supposed to blow up on its own according to expert interweb forum advice.

swooshdave said:

This does not solve wet sumping, all it does is potentially prevent one of the side effects.

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Title of the thread is indeed a bit misleading.

-Knut