Oil Starvation: No Room Left for Doubt

[Guest ratchethack]

I remain convinced a vortex in the oil is snaking its way through the hole in the top of the screen cover alongside the oil pickup tube.

 

Wouldn't the simplest fix be to make some sort of stopper to cover that gap? Something like a suction cup with a hole through the center? Push this onto the pickup tube such that the perimeter of the cup rests on the cover.

I like it, but not sure if the flow rate is high enough to create this kind of a vacuum vortex - AKA cavitation??

[twhitaker]

It is not so much the flow rate but the restriction the screen puts on the flow of oil. The path of least resistance will be the opening in the top of the strainer when it is uncovered as the oil sloshes to the back of the sump.

 

Not sure how big this gap is but maybe a thick walled o-ring just might be enough to plug it if it's concentric.

[DVH]

If as gregs says the pressure dropped on accelerating, wouldn,t you also get the same problem climbing mountain passes forcing the oil to the back of the sump, I also would have thought sump height vertical baffles were required to stop the surge of oil away from the pickup

[Guest ratchethack]

If as gregs says the pressure dropped on accelerating, wouldn,t you also get the same problem climbing mountain passes forcing the oil to the back of the sump. . .

Sherlock Road Geez here again.

 

Road grades here in the US usually max around something like 8%, I think. Not much compared to the G-forces of acceleration and particularly, deceleration - though Greg's measurements indicate that braking is not evidently a problem, the pickup being at the front of the sump.

 

I also would have thought sump height vertical baffles were required to stop the surge of oil away from the pickup

If you think about the semi-enclosed space formed in the sump by a baffle plate at the level it needs to be to fit between the sump and the block, it forms a "compartment" that's for the most part closed. If not for the holes, you could hang the motor vertically by it's crank nose and have a well full of oil trapped in there. Of course this is extreme, but under hard acceleration, this kind of well of trapped oil, even with lots of holes in the top, would surely keep the pickup buried.

 

Just thinkin' out loud. . . . .

[Wick]

When ever this gets figured out, I'll need three of them.

 

Wick

[DeBenGuzzi]

When ever this gets figured out, I'll need three of them.

 

Wick

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I don't know why I found that so funny. But I'm on the same page here, The smarty pants powers that be can figure it out, I'll be in the crowd holding my dollars waiting for the snake oil.

[pete roper]

If you think about the semi-enclosed space formed in the sump by a baffle plate at the level it needs to be to fit between the sump and the block, it forms a "compartment" that's for the most part closed.  If not for the holes, you could hang the motor vertically by it's crank nose and have a well full of oil trapped in there.  Of course this is extreme, but under hard acceleration, this kind of well of trapped oil, even with lots of holes in the top, would surely keep the pickup buried.

 

94391[/snapback]

 

My feelings too. When there is the correct amount of oil in the motor and the crank etc. isn't thrashing around then the oil level should be about at the level of the bottom of the block. When everything is whizzing around ten to the dozen there will be oil in suspension and clinging to other surfaces within the motor and draining down from the heads etc. but I would still expect that the level of the oil in the sump would be fairly close to the bottom of the block especially as some of it's *volume* will be air as it will become aerated.

 

The thing is that it isn't really so much the fact that you have to completely prevent the oil from moving rearwards, you simply have to slow it down! The times when the pick-up exposure will be occuring are almost certainly in the lower gears when you're accelerating hard. In the higher gears the forces exerted simply aren't as great, (You know that you're accelerating harder in 1sts and 2nd than you are in 5th and 5th? Yes?) so the likelyhood of exposure of the pick-up is also less. My guess is that if you simply cover the surface of the oil with a plate, even one with drain slots in, it will act as a sufficient deterent to the oil sloshing back in those vital seconds where you're accelerating HARD in the first two or three gears. In the lower gears you are not only accelerating harder but, because of the lower ratio the revs will build faster so you'll actually spend less time in the lower gears which in turn means that the time that the baffle plate has to do it's job is also les than it would be if you were accelerating at the same rate in a higher gear, geddit? It may seem a bit 'Brain-Hurty' but its not really difficult.

 

Ideally some sorts of vertical baffles and/or guides to ensure that the oil is kept by the pick-up would be best but IMHO a solution can probably be found with the installation of a simple plate, (Which in itself will help with de-aeration of the oil, another good thing.) and being a great believer in the 'KISS' principle it's what I would suggest is needed rather than a horribly complex and heavier construction involving various 'Curtains' hangng from the plate into the sump. YOMV (Shrug.)

 

Oh, and DeBen. There is no reason why you should have to sell your soul for a simple plate type solution. The plates I got cut for earlier Tonti's which are no more or less complex than a simple plate to suit a V11 are cut out of 2mm stainless steel, (Chosen because I have seen plenty of thinner plates made of aluminium fracture.) and shipped to the USA I think they ended up costing something like $95US which is scarcely NASA budget stuff and I was making a profit on that, not a huge one, but adequate to make it worth my while.

 

Pete

[Guest ratchethack]

Pete, I think I've read most of your posts on this. May I say again, many thanks on behalf of the Forum for your *vast* experience, knowledge, and "hands-on" approach - and thanks particularly for your generosity as always in sharing it so openly - not to mention y'er writing skill and superbly deviant humor! Always greatly appreciated.

 

Thinking out loud again - yeah, I know - in my case, with as little personal experience as I've got with baffle plates (none), there's 2 kinds of things that can happen, and there's zero chance that both are gonna be good. . . .

 

Now then.

 

Since the crank spins counter-clockwise, wouldn't it be best to have a fairly large hole located on the left-hand side of the baffle plate immediately opposite the crank throws, slightly wider than the cheeks of the counterweights, running from flush with the case wall to the mid-point, and NO hole at all on the right-hand side?

 

This would seem to in effect use gravity to a significant degree to strip the bulk of the whipped-up whirling mass of oil and air off the left-hand side of the crank as it deflects off the crankcase and immediately isolate it in the relative calm under the plate for de-aeration. It would seem to me that the other holes in the plate for the filter and oil pump, pickup, pressure relief valve, dipstick, and maybe a few other strategically placed small ones, etc. would then tend to relieve the resultant pressure gradient set up across the plate by allowing mostly separated air to pass up through the plate.

 

Stick with me here......Now the stream of rushing air and oil going down through the large left-hand side hole opposite the crank throws would then tend to attract and draw whatever oil is coming down off the cam, draining out of the rocker boxes, and from everywhere else that it's accumulating above the plate. It would then tend to pull all this oil and air off the plate and into the stream via the relative vacuum created by it's flow (the Bernoulli effect, as I recall?) - so you wouldn't need - or want - a slot on the right-hand side - or any holes much of anywhere else to get oil back under the plate. I'm thinking this would create a calmer, more isloated and effective de-aeration cavity in the sump, and thereby give the oil a better chance to dump heat through the finning of the sump.

 

Sounds pretty good to me - but of course it would, I stole all the main stuff from you and then just dreamed up the rest.

 

I've got an Italian involved in the physics, you see, so I figure it has to be right for a Guzzi. That's really the entire basis of my rationale, and it just sounds right when I read it back to myself , so I'm stickin' to it.

 

-- Or should I best get back to my office responsibilities that I've been trying so hard to avoid all day and leave this alone??

[guzziownr]

"...and shipped to the USA I think they ended up costing something like $95US"

 

Homeland security is going to have a field day with your luggage.

 

DW

 

[Ballacraine]

Sounds plausible, RH......

 

I don't know if the oil will agree with your theory though!

 

Nige.

[Lamedog]

At the risk of standing in front of a logic train moving as fast as this one, may I ask if we are solving a problem supported by long-term data on overall engine life?

Greg's observation identifies one of the "thousand cuts" that eventually take out the engine. But I thought this engine, with minor changes that don't include windage plates, has demonstrated a "very long life" in bikes no less subject to acceleration "abuse" than the bulks of ours. Are we striving to create a 200K mile engine that weighs a ton?

Put me on the list of windage plate wanters. A real light one please. At least it will give me a place to store my spare sump gaskets. BTW: Greg - this isn't an attempt to double gasket sales is it?

[belfastguzzi]

BTW: Greg - this isn't an attempt to double gasket sales is it? 

94452[/snapback]

yeah, but sales of burnt-out oil warning light replacements will plummet

[Guest Nogbad]

Only a small minority of bikes will do more than about 20K miles with one owner.

 

Of those bikes that do, most will be working hacks like Kwak GPZ500s and old Beemers.

 

By the time a Guzzi gets to the sort of mileage when an engine rebuild is necessary it will have gone through about 10 owners and will be semi classic.

 

There are many many engines more fragile than the V11, yet the bikes still sell and no one worries too much.

 

Conclusion: Ride it how you like, it will last long enough.

[Josh]

Anybody near Land O' Lakes Florida? Check outcrank-scrapers.com,maybe these guys can help. Are we ready to get serious?

[Guest Nogbad]

A proven solution already exists. It's called a "deep Vee" sump.

 

Personally I think these look the dogs nads, and if I was worried that's what I would fit. Plus you get an external oil filter!

 

The oil slosh problem is down to the wide and shallow standard sump. If you want to see why, take a litre jug and fill it with 500 ml of water. Move the jug smartly sideways and see how much water you lose, and whether the bottom of the jug was exposed. Now pour 500 ml of water into a small roasting tin and do the same. See!

 

The deep V is the jug, the standard Guzzi sump is the roasting tin.