[Lefty]

While paging through some performance books the other day I thought a crank scraper may be a good idea. A web search found this site with some interesting ideas, plus some good results with a Porsche problem (SAE papers and all).
It looks like it would be easy to do with just a significant amount of time to profile it. Further though and it seems it may be a cure for the Honda plunger oil pumps getting a bad rap at high rpm's. There are stories of disappearing oil running em up there. Thoughts?

https://www.crank-scrapers.com/What is a crank-scraper.html

 

[LiamG6]

Interesting thought lefty. Trust you to dig this info out haha. I wonder if you could modify the windage tray or add a teflon scraper to it, the crankshaft is quite simple on these old bikes so it wouldn't be too difficult to profile it. I still think the issue with the plunger pumps is the high RPM cavitation, but I think that is only an issue at sustained running close to redline (or above standard redline in race bikes etc), coupled with the pressure relief mechanism in the oil filter cover periodically just diverting the oil back into the sump, but I think the crank scraper could be investigated purely as a way to reduce the losses in the engine, provided the rods, pistons and cylinders still get the lubrication they need. I think Jensen has proved that with correct maintenance and good oil and some minor modifications that the plunger pump is capable and the cams and followers can survive a lot of miles. I believe Jensen has added a pressure relief valve to his cappellini paper filter conversion and is running 20W 60 oil but other than that all standard and he has put 10s of thousands of kilometers on his bomber over the last few years with no sign of cam or follower wear.

Begs the question, which oil is more prone to becoming entrained in the windage, ie is 5W 30 thinner and therefore more likely to be caught up in the windage or would 20W 50 be more likely to remain in it because of the higher viscosity. Also I wonder how effective the standard windage tray is at stopping it. Obviously Honda was aware it was an issue if they put the tray in but was it even remotely effective and can it be improved while still getting adequate splash lubrication. I wonder if a scoop added to the windage tray to catch the oil and help return it to the sump could be a way to combat this without going all out with a profiled scraper. And back to your point about disappearing oil, could the cavitation in the pump at high rpm's be caused by lack of oil around the pickup due to excess amounts being caught in the windage. One key thing to note on that point is the cappellini gear oil pump relocates the oil pickup to the area of the sump under the gearbox, rather than the right side of cases. Interesting topic

 

[ancientdad]

Interesting thought lefty. Trust you to dig this info out haha.... ...One key thing to note on that point is the cappellini gear oil pump relocates the oil pickup to the area of the sump under the gearbox, rather than the right side of cases. Interesting topic

Definitely an interesting topic - Lefty got me thinking about it too, he's the deep reader and thinker about stuff like this. I've always found it curious that the oil pickup was in the front of the engine on all the twins because acceleration makes the oil go to the rear of the sump, and never really thought too much about the entrained oil around the spinning crank. Not too worried about it for mine though, it will be getting thrashed in short bursts on the street or drag strip, but I can certainly see the value of trying something to remedy the situation for those taking their 450s to the track for continuous hot laps

 

[LiamG6]

The worst part about the oil pickup being on the right hand side is the kick stand is on the left, that must have led to countless issues from being run on the side stand too long with barely enough oil around the pickup. It does seem an odd spot for it.

 

[ancientdad]

The worst part about the oil pickup being on the right hand side is the kick stand is on the left, that must have led to countless issues from being run on the side stand too long with barely enough oil around the pickup. It does seem an odd spot for it.

Yes, it adds to the odd decision to put the pump forward and on the right - probably a manufacturing cost aspect but since it was 50 years ago, I suppose it's possible they just didn't think of certain circumstances. It's always so much harder to properly modify something factory-designed without having the necessary equipment to accomplish it within the limits of its current design. I usually run mine a bit overfull, can't hurt to have a larger quantity to help dissipate the heat and keep enough around the pump in demanding conditions (while not being too much to affect crankcase pressure)

 

[Lefty]

Good points on the pickup location. I should look into running a pickup line to a more central location. At this point I'm thinking about cutting the front angled part of the windage tray off and fitting a piece of aluminum angle. It seems like a good location because being at a tangent would cause deflected oil to run down into the sump. Maybe some of the vortex air would deflect into the sump causing issues there? Who knows, maybe a additional baffle below the tray? The 500T had breathers on both cam covers so that sure seems like a good idea to control positive pressure from blowing oil mist out.
Here's som pics to show what I'm thinking


It's already pretty tight in there and the outside flywheels are only about 5mm from the case walls so not much you can do there. The inside flywheels counter weight would necessitate a gap in the scraper unless you knife edged it. Another option would be milling a recess in the case and fit it on the backside(I think this would be how they're retrofitting some on cars only between the block and oil pan), but I think it would isolate the lower case volume more possibly causing issues.

 

[mike in idaho]

If it's a roller/ball bearing crank there isn't enough oil volume being pumped in there for a scraper to make a difference. Sounds like a solution looking for a problem to solve.
There would be more to gain by improving the crankcase breathing to get the extra air out of there to reduce pumping losses and help the ring sealing.

 

[Lefty]

If it's a roller/ball bearing crank there isn't enough oil volume being pumped in there for a scraper to make a difference. Sounds like a solution looking for a problem to solve.
There would be more to gain by improving the crankcase breathing to get the extra air out of there to reduce pumping losses and help the ring sealing.

Good point, but there's still oil being flung around/scraped airborne off the cylinder walls. Did you read the article about the amount of oil that can be held in suspension? Don't think it's possible? There was a post recently about a guy toasting his engine on the freeway from no oil and Bill Lane says he's seen it.

 

[Lefty]

If it's a roller/ball bearing crank there isn't enough oil volume being pumped

I got to question this too, always heard the 450 produces volume not pressure

 

[LiamG6]

I did some reading on plunger pumps in the past, they actually produce high pressure and low volume, it's actually a bad pump for this kind of crank bearing because the rollers don't need pressure, just volume.

 

[Lefty]

Well, how much oil leaks out of the equivalent bearings isn't really the point. The question of oil entrained in a vortex at constant high rpm's and possible remedies is. I do know #1 running racers are knife edging cranks and running stock pumps, so there seems to be a connection. I was hoping Bill would chime in. Bill, you out there?

 

[LiamG6]

I think the crank scraper will help with efficiency and reduced losses to get more HP at the rear wheel, and more oil in sump will certainly help the oiling issues but I think there are more problems with the oiling than just excess oil entrained in the windage. From my understanding, the plunger pump at high rpm either creates too much pressure and opens the bypass too often, or the oil pump piston rpm is too high and it just starts to pump air rather than oil. If you could slow the speed of the oil pump down, that would help but as it runs off the clutch basket rotation the only way to reduce the speed is to change the size of the primary or secondary gear, not really feasible. Another way would be to reduce the inlet restriction into the oil pump, ie if you bore out the inlet check valve to a larger size to reduce restriction making it easier for the oil to be pumped at the higher rpm there would be less cavitation, you would need to install a bigger ball to act as a check valve though, and then it doesn't solve the oil pressure bypass problem but you can file the inside edge of that to effectively require more pressure to open. Also using 5w30 or 5w40 oil could help things.

I'd love to see the crank scraper if you can develop one, would be cool to see a dyno comparison too.

 

[Lefty]

Well, I'm sure it's been tried before, ive seen pics of entire 450 engines insides with special coatings to promote faster oil drainage(I think). Someone out there has a good idea what it's worth. I'll never directly dyno test one but I'd be easy enough to install one and get a idea if it helps. If you have less oil in a catch bottle that'd be a good indicator.

 

[Lefty]

Here's a good discussion to get you thinking about better oil control
https://speedtalk.com/forum/viewtopic.php?f=1&t=51996

 

[Lefty]

I filled the crankcase with three quarts of water the other day t help visualize and was kinda surprised. I always assumed the level was significantly lower than the tray. Not the case. A full sump is about 1/4" higher than the tray. If you kept your oil high, the crank is actually sumerged a bit. Racers recommend running the level on the low side because of the massive heating done to the oil while waiting for the flag to drop. Granted while running there's probably 1/2 quart in the system, but the level then is still at the plate level or barely below it. But because of the pump design and location, that's the way it has to be really. I'm still mulling over a scraper, but the case is so tight and the oil level is so high, a scraper could easily turn into a dam and make matters worse. I think a major benefit of the cappilini remote pickup in conjunction with a oil cooler to maintain capacity is allowing a lower sump level.


Now, my idea is to remove the rubber footed screen off the bottom of the pump and in its place, attach and seal a machined block that would be tapped for a copper line to run directly to the bottom of the sump. That way by using a oil coolers capacity I could lower the sump level a small but I think significant amount.
Think it would work?

Edit: I just had a thought and laid a straight edge across the top case and measured the dipstick level to compare. At the max full line the oil level is not as high as I though but still above the tray. The crank wouldn't be submerged. I think the water didn't completely fill the right case the way I poured it. And the alternator cover holds a little.

Edit: interesting to check the level while running.