Sloppage sheet prototype?

[jrt]

Hey Ratch,

Since you have it out, could you measure how far up on the dipstick is the upper oil level? 7.5cm or so????

Thanks,

J

[badmotogoozer]

Ryan! I thought you avoided my posts like the plague!

 

 

No, not your posts... just the GW thread. That is an argument fuelled by speculation on both sides. It's a waste of brain energy. I've said before that I enjoy MOST of your posts.

 

I'll trust your math, Dave might want to double check it though I figure this is one of those things that has potential upsides, fairly inexpensive, and no real downside. Greg and Pete know far more about these machines than I do and if they both are in agreement, that's all I need.

 

Rj

[Guest ratchethack]

Hey Ratch,

Since you have it out, could you measure how far up on the dipstick is the upper oil level? 7.5cm or so????

Thanks,

J

From the face of the dipstick head, the high and low marks are 157 mm and 186 mm respectively.

[jrt]

perfect- thanks!

J

[pete roper]

Just for the record I think that there have essentially been three lengths of dipstick and consequently the level of the oil in relation to the crank has changed. The early motors, up to the LeMans II/T3, prior to the fitting of the sump extension, used a *short* stick. The quantity of oil specified for the motor was the same, 3 litres give or take, but obviously without the sump extension three litres would bring the level up higher and closer to the crank than on later engines with the extension and that is indicated on the short sticks.

 

Problems first started presenting themselves when the engine capacity was increased from 750 to 850cc. Not only did the stroker crank mean that the pin, web counterballancers and rods came closer to the oil, (The 850 crank has an 8mm longer throw so it gets everything 4mm closer to the oil.) increasing the windage problem but also the increase in the diferential between the crankcase's maximum and minimum volume increased to the point where oil expul;sion through the breather began to be an irritating issue. When the bore was increased to 88mm to take the motor out to 950 the situation became critical, hence the fitting of the extension, it's main purpose is to move the oil away from the crank and increase the volume of the case.

 

With the extension fitted, (or in the case of the later Tonti's the one piece 'Deep Sump'.) the dipstick was extended and the 'Full' mark moved lower comensurate with the depth of the extension. While if ring seal is a bit dodgy the 950's will still tend to puke a bit of oil out through the breather the system usually copes OK. The 1100's, even in the Tonti frame, don't seem to pump out oil as vigorously as the earlier models but I think this may be due to the fact they are geared 14% higher at the rear wheel and probably don't get the tits reved off them like we used to back in the '80's.

 

With the advent of the 'Broad Sump' I *think* the dipstick length was increased again and the level lowered slightly, this is probably the result of two things, 1.) the need was felt to move the oil level further from the crank, (Once again a longer stroke! As well as a bigger bore.) to prevent windage picking up oil so effectively and 2.) the addoption of the *broad* design meant that less depth was needed for the same, perfectly adequate, quantity of oil. The unfortunate thing though is that due to the forward mounted pick up and the sloppage problem a lower *static* level also translates into a greater chance of pick-up exposure under hard acceleration conditions and THAT is where we find ourselves today!

 

My theory, which on earlier engines seems to have been bourne out by experience and rigorous testing both on the road and track, is that the windage issue, (oil being picked up from the sump and/or kept in suspension in the air inside the case and therefore being more prone to being pumped out and overwhelming the condensor system.) can be addressed very effectively by fitting some sort of primitive windage/baffle tray between the block and the sump spacer, (or sump on 1100 Tontis.). Once the tray is installed the oil level should be just BELOW the level of the plate. With the Broad Sump models this too will be possible with a plate in place as the plate will perform the same function of effectively separating the oil in the sump from the cyclonic forces exerted on it by the spinning crank. This may well mean that you can get a bit more oil in the sump without risk of it being breathed out which, along with the plate to hinder rearward slop, will also help prevent pick-up exposure, so double bonus there!

 

Another advantage I have found using a tray in my old Tontis are that my engine runs appreciably cooler with a tray installed, (I have both oil pressure and temperature guages on my SP.). My thoughts are that with the tray installed oil returning to the sump and in the sump is less aerated and therefore able to dump heat through the sump fins more effectively, air is a superb insulator and aerated oil won't be able to dump heat by conduction to the sump walls as effectively as de-aerated oil. As a rider to this statement though I know Greg was having heat problems with the 'Super Eldo' and fitting one of my plates didn't make an appreciable difference I don't think?

 

I firmly believe that the MAJOR problem is simply one of rearward slop exposing the pick-up. Address that by doing something to prevent the slop, (And a plate is easy to make and install.) an I reckon that the problem will simply disappear. Whether people agree or not is entirely up to them but I'll STILL wager a Barnyard full of Bunyips that I'm right.

 

Pete

[jrt]

OK, so I admit it. Dave's comments really piqued my interest, so I did took some measurements on my V11 and since I have a G5 block in my basement, I took a look at that as well.

From a back of the envelope calculation using numbers posted above, and from just looking at the V11S dispstick in the G5 block (they're really close to the same, if not the same), the oil level in the V11S, when full, is about at the upper gasket. Fine, that's been said before, and now I believe it.

The oil level on older bikes is about 20 mm higher..or the oil level on the broad sump motor is about 20 mm lower. The distance from the bottom of the crankshaft lobe and the top of the oil is about 60 mm on the V11S motor and about 40 mm on the older models. This ASSUMES that the V11S and G5 crankshafts have the same diameter lobes. This explains why I was remembering 3" (7.5 cm) and Ratchet measured 6" (16 cm).

At this point, Pete and Greg are but were're all having fun pushing our pencils around here at the Group W bench.

 

So, this brings up the next ignorant question- why not just fill the crankase up with another 20 mm of oil (a quart?)? Sure, it'd be closer to the crankshaft, but still 40 mm away.

J

 

Dammit, Pete just added that while I was typing and measuring and bears, oh my. Thanks Pete, that answers my question- too much pressure build-up.

[Skeeve]

WRT: Griso&Breva engine sump redesign vs. v11 motors:

 

Externally, apart from the filter being in a *cavity* and therefore actually easily changed it is deeper and narrower than the 'Broad Sump' design. If you look at some of the publicity guff I think they have a computer generated image of it's internals in there somewhere but needless to say all it shows is a box with a series of silly looking multi-coloured tubes in it, while you probably could work out what is going where by studying it at length most of us have more interesting things to do like watching the all North Korean tiddly-winks championships on pay TV

Pete

 

Try this:

 

It clearly shows that:

 

1) the oil pickup is an inverted hemispherical cup

2) the pickup is surrounded by cofferdams, meaning it lives in the bottom of its own semi-private sump within the sump, somewhat immune to sloshing

3) the oil filter now lives in its own little dry box within the sump, which has? has not? a manhole cover, but at least one never needs to drop the pan in order to change the oil filter, nor even has to drain the oil to change the filter! Cool... not necessarily pertinent, but cool!

 

Ride on!

 

PS: thanks for taking the time to try to clarify this topic for all us non-mechanical types, Pete! You rock!

[pete roper]

 

1) the oil pickup is an inverted hemispherical cup

2) the pickup is surrounded by cofferdams, meaning it lives in the bottom of its own semi-private sump within the sump, somewhat immune to sloshing

3) the oil filter now lives in its own little dry box within the sump, which has? has not? a manhole cover, but at least one never needs to drop the pan in order to change the oil filter, nor even has to drain the oil to change the filter! Cool... not necessarily pertinent, but cool!

 

 

Thanks for that, I hadn't seen that pic before. There is no 'Manhole' on the Breva/Griso sump. The filter just sits there in it's cavity.

 

Pete

[Guest ratchethack]

. . . . I reckon that the problem will simply disappear. Whether people agree or not is entirely up to them but I'll STILL wager a Barnyard full of Bunyips that I'm right.

 

Pete

I'll take that bet and raise you a Gaggle o' Gwerbles.

 

Thanks f'er puttin' up with all the shennanigans 'round here, Pete.

 

Would you consider autographing my sloppage plate f'er posterity?

 

And if you serialized 'em, it would be so much more convenient - and profitable! - for collectors. . . . .

[dlaing]

Once the tray is installed the oil level should be just BELOW the level of the plate. With the Broad Sump models this too will be possible with a plate in place as the plate will perform the same function of effectively separating the oil in the sump from the cyclonic forces exerted on it by the spinning crank. This may well mean that you can get a bit more oil in the sump without risk of it being breathed out which, along with the plate to hinder rearward slop, will also help prevent pick-up exposure, so double bonus there!

Excellent explanation!

You now have me more than half convinced.

[dlaing]

From the face of the dipstick head, the high and low marks are 157 mm and 186 mm respectively.

FWIW that is what I got, too.

Face of dipstick is where the o-ring is.

Subtract another 13mm if measuring from the other face of dipstick (at the bottom of the threads, where Greg recommends measuring from)

Maybe someone's math is good enough to figure out the one to root two relationship, I won't bother.

I still think the best way to figure out the manual recommended oil level is to drop the pan and look.

But it may all be irrellevant if Pete and Greg say it is OK to run the oil up to gasket between sump and crankcase, especially with a windage plate in place reducing blow-by.

So, if that is settled, possibly my last nit-pick is, how difficult is it to drop the sump?

[pete roper]

 

But it may all be irrellevant if Pete and Greg say it is OK to run the oil up to gasket between sump and crankcase, especially with a windage plate in place reducing blow-by.

So, if that is settled, possibly my last nit-pick is, how difficult is it to drop the sump?

 

 

Dave, a couple of things here and PLEASE don't take this the wrong way.

 

When I said (In I think the *other* post.) that the amount of oil required was the amount that prevented the problem of pressurisation and windage throwing oil out of the breather was the *right* amount this was of course assuming that there would be sufficient in the sump for performing it's alloted task, which is to lubricate and COOL! The latter is very important, you could probably get a way with 1/2 a litre of oil being re-circulated as long as it was changed very frequently and could return to the sump or be scavenged quickly enough for LUBRICATION purposes but as I'll endeavor to explain in my next little rant about the lubrication system one of the primary tasks of the oil is to remove heat, not from combustion, but from the frictional forces within the oil as the bearings work upon them. As I said before the corect amount of oil is *sufficient* for it to perform it's tasks of cooling and lubrication without getting expelled, if it gets expelled until there isn't enough for it to perform those tasks then, sorry, the crankcase isn't big enough. D'you understand? The capacity of the motor isn't just *Above* the pistons, it's below as well. Although the 90 degree configuration offsets the true capacity difference from Max to Min it is stil appreciable and is one of the three causes of oil expulsion.

 

Secondly 'Blow By' isn't the issue here, I'm sorry but you are using a technical term incorrectly. Can I suggest that if you don't know the correct terms you try and use alternative, non-technical descriptions of what you're trying to say otherwise you just muddy the water and will, more importantly, confuse other people. I can extrapolate what you're trying to say but it is technically incorrect. I'm NOT trying to have a go or 'Put you down' but using incorrect terminology will confuse people and eventually make things more difficult for everyone. If people want an explanation of some of the technical terms that I and others use in relation to motors or are confused PLEASE ASK! Most of it is common sense, but that is easily lost if several people are using the same, often incorrect term, for a part or phenomenon.

 

As I said, I'm NOT having a go at you, please understand that, I'm sure you think I'm some sort of crazed Nazi, I'm not actually, but it IS important that everybody understands and uses the terminology correctly.

 

Pete

[mike wilson]

When I said (In I think the *other* post.) that the amount of oil required was the amount that prevented the problem of pressurisation and windage throwing oil out of the breather was the *right* amount this was of course assuming that there would be sufficient in the sump for performing it's alloted task, which is to lubricate and COOL! The latter is very important, you could probably get a way with 1/2 a litre of oil being re-circulated as long as it was changed very frequently and could return to the sump or be scavenged quickly enough for LUBRICATION purposes....

 

Very clearly demonstrated in total loss systems (both four and two stroke) where the amount of oil used per cycle is miniscule. Many engines would manage with about a pint for 3-4 hundred miles. Once engines began making serious HP and were unable to use the fuel charge for cooling, the present system of using the oil for two purposes came to the fore.

 

I am, however, still unconvinced that a windage plate will prevent the oil slopping enough to allow air to be taken in. It will be an interesting experiment and I'm looking forward to seeing the results.

 

m

[Guest ratchethack]

. . . . . . a windage plate in place reducing blow-by.

Dave, as Pete mentioned, this is an improper use of the term "blow-by". Please, I am also not "having a go" at you here. This is basic engine operation kinda stuff, and I think most "engine guys" think of it as so elementary that everyone must know it. Please forgive the assumption.

 

No windage, baffle, or slop plate will ever have any effect whatsoever on blow-by, and no reduction of oil height in the crankcase will have any effect on it either.

 

Piston rings serve 2 basic functions: 1. to seal the combustion chamber pressures of combusted fuel/air (exhaust) that try to escape into the crankcase between piston and cylinder walls. They also allow full compression of the culinder heads in the compression stroke. The upper two rings are typically designed for this purpose. 2. to keep the oil that's being constantly flung up against the exposed cylinder walls below the piston from migrating up past the rings into the combusion chamber. The lower ring is an oil-control ring, and serves to "scrape" oil off the cylinder walls and return it to the crankcase through slots in the ring and piston. The above sealing operations are of course occuring during each stroke of the piston.

 

When an engine fails to "seat its rings" during the critical break-in period, the ability of the rings to perform both of these major functions is greatly diminished. That is, combustion gases under high pressure escape past the rings into the crankcase (blow-by), cylinders fail to reach full compression in the compression stroke, and oil from the crankcase escapes past the rings into the combustion chamber. There are many who are much more articulate than myself about describing how the critical cross-hatch honing pattern of the cylinder walls "wears in" by passage of new rings over them. See Moto-man's description at the link below. This "wearing-in" is what either happens correctly or fails to happen during break-in. As Moto-man describes, When rings fail to "seat" from too low combusion pressure, blow-by initiates the formation of a varnish or glaze on the cylinder walls and pistons and "bakes on". Once this begins, there is no possibility that the rings can wear-in -- ever. At this point the rings have for the most part been rendered permanently far less effective at doing what they were designed to do. The engine suffers loss of power due to poor compression, the fuel charge will pre-ignite (burn too fast) due to oil fouling, and it may foul plugs more frequently due to burning oil.

 

Blow-by (described here - NOTE - I do NOT endorse the product represented here - I know NOTHING about it!) http://www.misterfixit.com/blow-by.htm creates unwanted positive crankcase pressure. If you imagine the cumulative effect of a volume of combusion gas being added to the crankcase with every power stroke, it's not hard to understand that this constantly replenished high volume of gas under pressure has to go somewhere. The crankcase breather system is the only escape route. The large volume of gas coming from the combustion chambers via blow-by then quickly overwhelms the breather system, which is not designed for handing the relatively huge volume of gas now flowing through it. Of course, this flow of gas has picked up oil vapor, mist, and droplets from windage in the crankcase and carries it all into the breather system, in effect, flooding the frame oil condenser faster than it can condense out, and the airbox fills with oil as a result.

 

I believe the large probability is that this is what is happening in y'er Guzzi.

 

Again, the best likely option is a ring job and honing of the cylinders followed by proper engine break-in. Alternately, if the pistons and cylinders are too far gone (unlikely IMHO), a re-bore would be the next option.

 

I have followed the principles of engine break-in described here: http://www.mototuneusa.com/break_in_secrets.htm for about 40 years with superb results. Without exception, every new and rebuilt engine I have broken in using the break-in techniques described there has never used any perceptible amount of oil between changes. This includes probably a dozen engines, everything from a rebuilt Bultaco Pursang 250 single to a factory-new BMW 6, and just about every conceivable engine configuration in between, including a turbo rotary.

 

I believe the expectation based on long experience of those who have made and run "slop plates" in Guzzi's of the kind under discussion here is that these plates have the secondary benefit that Pete described of reducing windage significantly enough so that the "normal" volume of air/oil mixture passing through the condenser/frame and breather system is reduced to the point where a higher level of oil may be maintained in the sump without additional oil passing through the breather system. This seems perfectly reasonable to me, and this is also my expectation.

 

Hope this helps, my friend.

[dlaing]

 

Secondly 'Blow By' isn't the issue here, I'm sorry but you are using a technical term incorrectly. Can I suggest that if you don't know the correct terms you try and use alternative, non-technical descriptions of what you're trying to say otherwise you just muddy the water and will, more importantly, confuse other people. I can extrapolate what you're trying to say but it is technically incorrect. I'm NOT trying to have a go or 'Put you down' but using incorrect terminology will confuse people and eventually make things more difficult for everyone. If people want an explanation of some of the technical terms that I and others use in relation to motors or are confused PLEASE ASK! Most of it is common sense, but that is easily lost if several people are using the same, often incorrect term, for a part or phenomenon.

 

What is 'blow by'?

and what is the correct term for excessive oil being blown into my air filter box?

My concern was that raising the oil level enough for the windage plate to be effective, would blow more oil into my airbox.

Your assertion that the windage plate will actually reduce "oil breathed out" is reassuring

 

 

 

Blow-by (described here - NOTE - I do NOT endorse the product represented here - I know NOTHING about it!) http://www.misterfixit.com/blow-by.htm

Thanks!