occasional wet-sumping

[martyk]

After fixing an intake manifold leak, my new re-build is settling in, but I have a sump question.

The rebuilder has changed the sump on this '46 Chief. Previously, the sump had a somewhat rounded face, with an elbow near the top that connected to the return line to the cast iron pump. The screws that attached the sump to the lower-end were recessed into this face.

Now the sump face is flat. The screws that attach it to the lower end seat flush on the face, and the return elbow comes out of the bottom of the sump face.

If I let the bike idle on the sidestand, it starts wet-sumping, smoking, blowing oil out of the exhaust, and no oil comes out of the return line in the tank. If I hold the bike up vertical, off the side stand, I get a huge amount of oil from the return line and it starts pumping OK. This didn't used to be a problem. Any idea why the rebuilder would have made this change? Are there advantages to the newer setup? This bike doesn't have a center stand, and its kind of a pain to always have to hold it vertical after starting.

Thanks for any feedback,
Marty

[T. Cotten]

Marty!

The update to a late "scraper"-style pick-up is a very common one, and I intend to do the same on my '34 project.
(And a similarly updated '41 is on my bench ready for trial.)

The theory is that the flywheel' "windage", or thrown oil, will be peeled off with sufficient force to prime the return pump.

Your original "drool tube" depends upon sitting in a pool of oil to prevent it from losing prime.

Although this certainly seems like a circumstance where "If It Works, Don't Fix It" should have been applied, you might still be able to recover the original intent by massageing the vane of the scraper to where it is closer, and more parallel, to the flywheels.

It would take good luck, so I wish it for you.
(Wish me the same on this '41!)

....Cotten

[brian_groff]

Hi Marty,

The oil scraper is what you described (suction at the bottom, three fillister screws, not recessed). At some point, Indian casted this into the cases, but for '46 and '47, I KNOW this was the part you described. The scraper works fine! (If you ever pull your engine, you're free to pull it out and look at it ... it's all one piece, no biggie deal).

The wet sumping is due to too much clearance between the oil plunger and its bore. Oil leaks past the pluger into the sump. The fix is very simple, but you'll need some help from a local hard chromer.

1. Drain the oil.
2. Remove the plug on top of the oil pump, toward the front of your bike.
3. Remove the plunger (I don't remember if this is possible at this point ... you may need to pull the whole pump off for disassembly ... I'm traveling right now and don't have my references at hand either).
4. Mic the plunger bore, and have the hard chromer build up and grind down the plunger to a clearance of 0.0005" to 0.0015".

There's a guy in Oakland, CA that has done this for me before. The cost was maybe $100. You may want to take in the pump body and plunger so he gets the right fit. Send me your email address and I'll forward you the contact information later this week.

mailto: brian_groff@msn.com

[martyk]

Brian, 'T', thanks for the feedback. Judging purely from outside appearance, I believe, I did have the "sump valve oil return" before the rebuild (Group 10A of Greer's catalog). I now seem to have the scraper oil return (Group 10B).

Previously, I was able to let the bike idle on its side stand without a problem, but cannot do that now. I don't think the problem is clearance on the plunger, since that's on the feed side of the pump. It sounds like too much clearnace there might let oil seep down and fill the lower end while the bike is parked. But the bike doesn't wet sump immediately after starting. If I stand it up vertical, off of the side stand after starting it, it doesn't wet sump at all. I only have this problem if I let it idle while its leaned over on the side stand.

I've learned to deal with this, but its annoying. This winter I plan to pull the scraper. (Can I do that without pulling the engine?) Since it doesn't sound like this is a common problem with the scraper, I've got two theories. One, the clearance between the scraper and the flywheels is too great (Cotton's suggestion). -or- Two, the scraper may be bent slightly, so that the left side (away from the oil pump) pushed slightly rearward. This would take the force of the oil as it comes off of the flywheels, and drive it away from the pump. If that appears to be the issue, I should be able to pull that end of the scraper slightly forward, so a slight angle drives oil toward the pump.

BTW, I've got new scavenge gears, and the scavenge capacity of the pump has been checked out.

Thanks again for the feedback. Let me know if you have any other thoughts, and I'll post if I get this resolved.

[indianut]

I am pretty sure you will have to either raise or lower the engine to get the scraper out. You may be able to lean the bike to the left and remove the 2 drain screws and with a thin screwdriver and flashlight you may be able to move the scraper.

[exeric]

Why do you leave it idling on the sidestand ? I've never trusted an un-attended running motorcycle, The very nature of a motorcycle is to get on it and go !

[martyk]

Originally posted by exeric
Why do you leave it idling on the sidestand ? I've never trusted an un-attended running motorcycle, The very nature of a motorcycle is to get on it and go !

I'm usually astride the bike, putting on gloves, zipping my jacket, etc., while it warms up. The bike's not un-attended.

Its a darn near impossible to do those things while the bike's warming up, if I have to try to hold it vertical off the side stand with my legs. Plus, if I'm nolding it vertical with my legs, and trying to do those things with my hands, the bike's not held stationary by the side stand and can roll freely. Of course, if I could hold it vertical with only my left leg, I guess I could put my right foot on the break.

[T. Cotten]

Marty!

Testing pumps, especially the scavenge side, has generated more than one set of criteria.

My own bench-testing experience tells me that variables are very broad in scope, and some promoters are ignoreing temperature as well as other critical factors in testing diagnostics.

It would be helpfull to all to standardize our approaches, and make our readings make sense to all.

Just what units of measure, and what exactly do your mean by "capacity"?

Looking forward to your reply,.. after I get back from D-port...

....Cotten

[exeric]

Martyk, I wasn't trying to be a wise @ss and I now realize I neglected a very important factor. You ride in California and I ride in Florida. Florida is as flat as a pool table and hot as an oven. In Florida the bike is usually level so it's easy to hold it up and you can count the number of cold days on one (un-gloved) hand.

[martyk]

Eric, no problem. I figured you're riding habits, and maybe your bike's characteristics, are just different from mine.

Cotton, some additional info. on the scavenge testing. I didn't test the pump myself, so I can't address details. I sent the pump to John Bivens. He tested it on his test rig with my original scavenge gears. He said that the output exceeded the input and was adequate, but suggested new gears, since I was seeing this problem. He tested it again with the new gears and, although I don't remember the numbers, said that the scavenge volume now far exceeds the volume of the input pump. Also, the bike doesn't wet sump *except* when I leave it running while its over on the side stand. I think your initial suggestion to try to adjust the scraper, is a good one.

My original reasons for this post were to verify with the Indian community, that the swap of the drool-tube sump for the scraper was considered a good and legitimate decision by my rebuilder, and that the issue I'm seeing is an anomaly. Feedback so far has convinced me that, yes, the swap was a good decision and, yes, what I'm seeing is a bit weird.

I'll try adjusting the scraper the next time I work on the bike. In the meantime, if anyone has had a similar experience, and fixed it, I'd be interested to hear how you did it.

Thanks for all the feedback,
Marty

[brian_groff]

What kind of kick stand do you have?

Sometimes the "jiffy stand" gets loose and needs to be tightened up. This straightens the bike ... making it more vertical ... less prone to the symptoms you're experiencing.

[martyk]

Thanks Brian. I don't know what kind of stand it is. I believe its original with the bike. It looks like the appropriate '46 Chief stand in the Greer cataloge.
I notice that there are stands for 18" tires only and for both 16" and 18" tires. This bike originally had 16" tires and still does. That should set it lower and make if less "tippy," or less prone to lean over on the stand.
I adjusted how tight the stand was, when I assembled the bike, and got it to lean just enough so that it won't fall over too easily if bumped. So I don't think its leaning excessively.
I'll just have to wait till I get into the engine a bit this Winter and see if I can find why this pump doesn't pull oil when the bike's on its side stand. I suspect that its something to do with how the scraper is positioned. If I eventually get it resolved, I'll post the results.

Thanks much,
Marty