oil filters

[Guest ratchethack]

I don't believe any of this will create paranoia among our readers.

But au contraire, John. As expected, all this 'much ado about nothing' seems to've already aroused the, um, usual unfounded, wild, false speculation shooting off in all directions, along with the usual hysteria -- and in this case, not much question about paranoia. . .

 

Exhibit A:

The difference between a 10PSI and a 30PSI bypass is lost oil pressure when you need it!!!!!!!!!

Even a 10PSI bypass valve might fail to bypass enough to prevent healthy oil pressure in cold conditions.

But a 30 PSI bypass valve will greatly increase oil pressure depravation in cold start situations.

This is exactly why I find myself repeating things ad nauseum.

 

Maybe someone else will do the honors here and explain how bypass valves in oil filters work (again)?

 

So's to avoid more tedious repetition . . . [sigh]. . . I'm gonna make another attempt at going back into "bypass mode" (again). . .

 

We'll see how long it lasts this time. . .

[Dan M]

 

This is exactly why I find myself repeating things ad nauseum. Maybe someone else will do the honors here and explain how bypass valves in oil filters work (again)?

 

 

I thought I put it plainly enough in post #40 "The filter does not limit pressure, the valve in the filter just redirects the flow." - - Whatever the reason for the valve opening , thick oil or dirty paper, the oil still flows. It is the path of the least resistance even when the valve is pushed open there is still an amount of oil going through the paper. Remember, it is an oil filter, it's made to flow oil

 

I'm gonna make another attempt at going back into "bypass mode" (again). . .

 

We'll see how long it lasts this time. . .

 

Aw, come on Ratch, You live for this stuff.

[dlaing]

 

This is exactly why I find myself repeating things ad nauseum. Maybe someone else will do the honors here and explain how bypass valves in oil filters work (again)?

 

 

I thought I put it plainly enough in post #40 "The filter does not limit pressure, the valve in the filter just redirects the flow." - - Whatever the reason for the valve opening , thick oil or dirty paper, the oil still flows. It is the path of the least resistance even when the valve is pushed open there is still an amount of oil going through the paper. Remember, it is an oil filter, it's made to flow oil

 

I'm gonna make another attempt at going back into "bypass mode" (again). . .

 

We'll see how long it lasts this time. . .

 

Aw, come on Ratch, You live for this stuff.

From the link RH posted:

http://www.mgnoc.com/_overlay/Archives/oil_filters.htm

I tried to find out why there is variance in this parameter. What value is having a 27 psi internal relief valve setting compared to 12 psi? Consider the problem from a comparison of probable situations. For example, if a vehicle is being driven with cold oil in it, the filter with the higher internal lift-off pressure will more strongly resist bypassing the filter element (a good thing), but the increased pressure drop will mean less pressure at the filter

[Ryland3210]

Ryland, this is interesting. I'd like to look into location of these components but the pump bypass is typically on the pump, so, before the filter. The pressure sending unit's location is typically after the filter so what you are reading is pressure after the filter (Don't you think?) So what is happening between the pump and filter is unknown, but obviously the filter's bypass has to do not with how much pressure the pump puts out but how much the filter's media restricts the flow. In other words, what you are reading is not altered by the filter's bypass valve and there is no way of knowing if the oil is going through the paper or the valve when it gets to the sending port. 80 psi is certianly not unheard of for a pump relief setting, and the pump relief is the only thing that will limit the pressure. The filter does not limit pressure, the valve in the filter just redirects the flow. I'll look for a diagram of the oil circuit

 

 

Oh, Dan, Oh, Dan, please, please don't stay in bypass mode! (where is the begging on bended knee emoticon?!)

 

The only technical question on this subject left unanswered as far as I know, is: on which side of the filter is the pump pressure relief.

 

Did you find an oil diagram or drawing of the manifold the relief valve is mounted on?

 

Just get me that one answer, and then maybe I'll go into bypass mode. Then my brain filter won't have to deal with so much input.

[Dan M]

Oh, Dan, Oh, Dan, please, please don't stay in bypass mode! (where is the begging on bended knee emoticon?!)

 

The only technical question on this subject left unanswered as far as I know, is: on which side of the filter is the pump pressure relief.

 

Did you find an oil diagram or drawing of the manifold the relief valve is mounted on?

 

Just get me that one answer, and then maybe I'll go into bypass mode. Then my brain filter won't have to deal with so much input.

 

I looked at the shop manual this morning and all it has is a rather poor exploded view of the oil system. There is no diagram of oil flow. Seems the only way to tell is to drop the sump, pull the filter housing, which contains both the thermostatic valve and the pressure relief valve and see which way it flows. This is however a bit of work to diagnose and prove something that really isn't a problem to begin with. Since no one has presented any evidence that there has been any accelerated engine wear or damage from filters with different spec relief valves! These oil systems are small and the pumps are of greater than needed pressure and volume. That my friends is why there is a pressure relief valve in the system. There is so much pressure and volume available - 80psi in your testing - that the difference between when a 10psi filter bypass and a 30psi bypass opens with all other conditions being equal is probably a fraction of a second. The difference will be how long it stays open. That will depend on how soon the oil can get through the paper. I see no way of determining when it happens or how long it lasts. Since there is no evidence of there ever being a problem resulting from these valves, I see no need to continue to beat this horse.

[dlaing]

One of Pete's great posts:

OK, this is going to be very simplistic but I hope it will clear up a few matters pertaining to how the oil delivery system works. While I can't be sure the subliminal message I'm getting from some posters is that they seem to think that the oil pump and delivery system is much the same a s a garden lawn sprinkler! Oil id pumped out of the sump and then just sort of casually sprayed around all over the place and hopefully some of it will get to where it's needed and make things slippery. Sorry, there is a bit more too it than that.

 

Firstly though lets look at the Guzzi motor. It is a very simple, robust and durable design and it will generally take abuse quite happily. One of the reasons for it's inherent strength is that it uses 'Plain' or 'Slipper' type bearings. These work by having a journal, (on the crank or camshaft.) that rotates in a bearing either in the crankcase itself in the case of the cam or in replaceable, bolted in inserts in the case of the crank main bearings and split shell type beaings in the rods. In between the journal and the bearing there is a gap, the bearing clearance, and this is absolutely critical because what prevents the bearing rubbing on the journal is a thin film of oil. This film of oil alone is ompletely inadequate to deal with the pressures being exerted on it by the forces of combustion but as the journal spins in the bearing, as long as there is an adequate supply of oil at an adequate pressure provided between the two parts, will form what is known as a hydro-dynamic wedge, conveniently at the point of greatest pressure on the film of oil!

 

The thing is to get a decent wedge happening you need to not only have a decent and CONTINUOUS flow of oil supplied to the bearing but the clearance has to exactly right and both the journal and the bearing need to be as near as damn-it perfectly round.

 

So how do you get the oil into the bearings? The clearance betwixt journal and bearing is about 1 to 1.5 thou per inch of journal diameter! If we were working on the 'Lawn Sprinkler' principle, especially with something whizzing around 6,000 times a minute we are scarcely going to get much oil into the bearings and it's going to be under bugger all pressure. So, what do you have to do? Well, it's pretty simple really, you feed the bearings from INSIDE the journal in the case of the big ends and through a series of drilled galleries in the case and crank to get the oil to where it needs to be.

 

So lets look at how oil gets to your bearings.

 

Well, it starts off in the sump. In the case of the V11 'Broad Sump' motor the pick-up protrudes down to close to the bottom of the sump from above, through the gauze screen designed to take out the 'Big Lumps' should any suddenly appear! The pick-up goes more or less directly to the pump, this in itself is important because, and here is one of the most important things to remember when dealing with anything that is being pumped, THERE IS NO SUCH THING AS SUCK! The oil pump doesn't *SUCK* oil out of the sump, all it does is create a low pressure area within the pump body and the gas pressure within the crankcase will PUSH the oil up the pick-up and into the pump. Once the oil is through the pump it is then under pressure and being forced along mechanically but until it gets to the pump it is only being pushed by a fairly weedy sort of pressure. For this reason it is important to have as few impediments to flow as possible, that means a short, wide, gallery with as few bends as possible. While the pick-up on the V11's is quite nice and large the oil does have to turn through 90 degrees, twice, before it reaches the pump and the gallery in the block is no bigger than the earlier motors.

 

Once the oil is through the pump and pressurised it is sent to the filter where the bits are strained out, (we hope!) the good news is that Guzzi motors are very clean and there isn't much inside them to wear or shed bits of 'emselves and load a filter up. Once filtered the oil then passes on to the oil pressure relief valve which is contained within the oil filter/thermostat housing bolted to the bottom of the block. The purpose of the relief valve is simply to prevent the oil pressure rising too high either when the oil is thick and cold and possibly at higher RPM. The oil itself has internal friction and if the pressure is too high it will both sap power and also try to spin the bearings. While the 'Ring' type main bearing inserts Guzzi uses are not prone to this and the back clearance of the shells to rods also seems to be pretty good a spun bearing is a rare thing in a Guzzi, or any other engine, nowadays but it can happen. Maintaining the correct oil pressure also means that the filter won't become over-pressurised, pop it's gasket or explode, which tends to be messy!

 

After this the oil will pass over the thermostat which, when it gets hot enough, opens and allows the oil to pass through the cooler before going off for delivery to the bearings. From there on the oil simply has to get to the bearings and it does this through a series of galleries and pipework bolted on to the bottom of the block, essentially though it's very simple. After the thermostat the oil delivery is split. Some of it is sent to the front main bearing, some of it to the back. Both front and rear mains have a groove in the centre of the bearing face that allows some oil to circumnavigate these bearings and from there go on to the front and rear cam bearings. Also, above this groove, in the journal of the crank's front and rear main there is a hole drilled at a 45 degree angle in the crank itself that goes up to the crankpin. The crankpin itself is hollow and cross-drilled so that once the oil has filled the gallery in the pin it can flow out thrugh the big end bearings and out of the side clearance of the rods.

 

The camshaft too has a gallery running down the centre of it and some, but not all, Guzzi cams have cross drillings to allow oil that is forced up the inside of the camshaft to spray out and feed various bits like cam followers with oil by splash, Some of the more aggressive aftermarket cams even have cross drillings in the cam lobes themelves.

 

Finally oil travells up one further gallery to the top of the block above the front cam bearing where there are two drillings, one to take the oil pressure sender unit and the other one that takes the feed to the rocker gear in the cylinder heads.

 

OK, that's how it gets there. Next we'll look at why the clearances are so critical and why even a momentary loss of pressure can be catastrophic.

 

Pete

This is a great thread, and probably worth somebody bumping so that Pete can enlighten us a little more.

http://www.v11lemans.com/forums/index.php?...466&hl=suck

[Ryland3210]

Thanks for finding this, Dave.

 

I'm going to store this gem from Pete in my archives.

 

I'm glad to hear that the pump relief is after the filter. It's better that way, in my opinion.

That completes my understanding of the Guzzi pressure supply circuit. I'm inclined to join Dan and move on.

[Guest ratchethack]

There's nothing like a diagram for clarity on plumbing stuff.

 

The following should pretty much nail it for anyone still in doubt.

 

It's a typical automotive setup. Unless Guzzi did something completely unexpected here, I reckon it's 100% safe to conclude it's wot we got in our V-11's.

 

Now if I'd been interested at the time, when I put my Roper plate in, I would've tracked the galleries to confirm this when I had the PRV assembly in my hands. . . Anyone up in Santa Monica at Todd's for the "Roper Big Block Strip Tease and Convert Slush Box Extravaganza" next week (see "Rebuild Exhibition" thread) can have a few pokes at this whilst quaffing brews with The Maestro. Damn it, I may just hafta make the "sacrifice" meself. . . [sigh] . . . When Duty calls. . .

 

For further clarification, I found the bulletin at the link below very informative.

 

SOURCE: Champion Laboratories Technical Service Bulletin 83-1R2 http://www.filtercouncil.org/techdata/tsbs/83-1R2.pdf

[Ryland3210]

There's nothing like a diagram for clarity on plumbing stuff.

 

The following should pretty much nail it for anyone still in doubt.

 

It's a typical automotive setup. Unless Guzzi did something completely unexpected here, I reckon it's 100% safe to conclude it's wot we got in our V-11's.

 

Now if I'd been interested at the time, when I put my Roper plate in, I would've tracked the galleries to confirm this when I had the PRV assembly in my hands. . . Anyone up in Santa Monica at Todd's for the "Roper Big Block Strip Tease and Convert Slush Box Extravaganza" next week (see "Rebuild Exhibition" thread) can have a few pokes at this whilst quaffing brews with The Maestro hisself. Damn it, I may hafta make the sacrifice meself. . . [sigh] . . . When Duty calls. . .

 

For further clarification, I found the bulletin at the link below very informative.

 

SOURCE: Champion Laboratories Technical Service Bulletin 83-1R2 http://www.filtercouncil.org/techdata/tsbs/83-1R2.pdf

 

Sorry, RH, it does not clear up my doubt, because Pete Roper is a pretty credible source of information of this type. The circuit will work either way, although differently in terms of the resulting pressure fed to the engine. The circuit you found is certainly not uncommon, but since it appears to be generic, there is no 100% certainty it is how Guzzi designed theirs.

[Guest ratchethack]

Sorry, RH, it does not clear up my doubt, because Pete Roper is a pretty credible source of information of this type. The circuit will work either way, although differently in terms of the resulting pressure fed to the engine. The circuit you found is certainly not uncommon, but since it appears to be generic, there is no 100% certainty it is how Guzzi designed theirs.

Hmmmmmmm. Pete's of course pretty high on my credibility list, and by the evidence of many years of reading his posts, seldom (if ever?) makes any mistakes on anything relative to Guzzi's. . .

 

I reckon that since bypass relief pressure is a matter of complete insignificance, as I've been saying all along, that like me, Pete's likely not paid much attention to tracking the galleries in the PRV assembly himself. . .

 

Shall we consider it proof positive as determined in Todd's garage this weekend, and verified thereby, by none other than a panel of judges consisting of the Most Honorable Mssrs. Egan, and Roper Hisself??

 

I reckon we could make this more interesting if you'd be interested in making a small wager. . . ??

 

Wot say you, John?

[Ryland3210]

Hmmmmmmm. Pete's of course pretty high on my credibility list, and by the evidence of many years of reading his posts, seldom (if ever?) makes any mistakes on anything relative to Guzzi's. . .

 

I reckon that since bypass relief pressure is a matter of complete insignificance, as I've been saying all along, that like me, Pete's likely not paid much attention to tracking the galleries in the PRV assembly himself. . .

 

Shall we consider it proof positive as determined in Todd's garage this weekend, and verified thereby by none other than a panel of judges consisting of Todd Egan and Pete Hisself?? -- well, I reckon we could make this more interesting if you'd be interested in making a small wager. . . ??

 

Wot say you, John?

 

I've already sent a message to Pete.

You are entitled to reckon what you will. Everyone is entitled to an opinion. The location of the pressure relief valve has an effect on the pressure delivered to the engine. You think it is insignificant, I don't, and you may be right. Nevertheless, I want to know the truth of the matter.

I'll pass on the wager. I wouldn't want to bet against Pete, and I don't think you would either.

Let's wait and see what we learn.

[Guest ratchethack]

I've already sent a message to Pete.

You are entitled to reckon what you will. Everyone is entitled to an opinion. The location of the pressure relief valve has an effect on the pressure delivered to the engine. You think it is insignificant, I don't, and you may be right. Nevertheless, I want to know the truth of the matter.

I'll pass on the wager. I wouldn't want to bet against Pete, and I don't think you would either.

Let's wait and see what we learn.

Hmmmmm. Such haste with an email to Pete already! And no wager a-tall?!

 

Alas and alack -- were we only able to see wot was sent?!

 

We will, of course, expect to see any reply from Pete accompanied by a verifiable acknowledgement of exactly what he's being asked to confirm or deny (preferrably accompanied by a copy of, or at least a reference to the diagram in question), since a reply such as, "You're right, John!" without any ties to context, could of course be considered -- um, shall we just say, err, less than authentic?

 

The concern here of course would be that Pete'd be less than likely to wade thru this progressively odious thread just to discover exactly wot all the fuss is about -- hopefully the man's got lots better things to do!

[dlaing]

I know, it does not show anything conclusive, but here is something to keep the speculation going.

21 is the thermostat and 12 is the pressure relief valve

gobble gobble

[Ryland3210]

Hmmmmm. Such haste with an email to Pete already! And no wager a-tall?!

 

Alas and alack -- were we only able to see wot was sent?!

 

We will, of course, expect to see any reply from Pete accompanied by a verifiable acknowledgement of exactly what he's being asked to confirm or deny (preferrably accompanied by a copy of, or at least a reference to the diagram in question), since a reply such as, "You're right, John!" without any ties to context, could of course be considered -- um, shall we just say, err, less than authentic?

 

The concern here of course would be that Pete'd be less than likely to wade thru this progressively odious thread just to discover exactly wot all the fuss is about -- hopefully the man's got lots better things to do!

 

I wanted to get to Pete in time, since his rebuild is starting this weekend, as I understand it, and yes, I did not want to leave it to him to happen to find the question herein. It's not even clear he is monitoring this thread.

To me it's not about who is "right". It's the facts, period.

 

In my message to Pete, I made no reference to personal beliefs or opinion, just asked him to either confirm the statement in his dissertation last year, or inspect his engine while apart if he had any doubts.

[dlaing]

There's nothing like a diagram for clarity on plumbing stuff.

 

The following should pretty much nail it for anyone still in doubt.

 

It's a typical automotive setup. Unless Guzzi did something completely unexpected here, I reckon it's 100% safe to conclude it's wot we got in our V-11's.

 

Now if I'd been interested at the time, when I put my Roper plate in, I would've tracked the galleries to confirm this when I had the PRV assembly in my hands. . . Anyone up in Santa Monica at Todd's for the "Roper Big Block Strip Tease and Convert Slush Box Extravaganza" next week (see "Rebuild Exhibition" thread) can have a few pokes at this whilst quaffing brews with The Maestro. Damn it, I may just hafta make the "sacrifice" meself. . . [sigh] . . . When Duty calls. . .

 

For further clarification, I found the bulletin at the link below very informative.

 

SOURCE: Champion Laboratories Technical Service Bulletin 83-1R2 http://www.filtercouncil.org/techdata/tsbs/83-1R2.pdf

Que Surprise! I disagree.

And I agree with Ryland's emailing Pete as you are with 100% certainty undermining Pete's credibility and Pete deserves a response!

It would not at all be unexpected for Guzzi to do it differently than your diagram indicates.

I found another diagram that also showed a similar arrangement except the filter was off to the side passively filtering the oil, while oil passed unfiltered between sump and bearings. I suppose that is the design needed if the filters do not incorporate a bypass valve. But still it showed that there is more than one way to do it.

The Guzzi Lubrication System is likely a result of changing strategies through the years.

This google book preview of Mick Walker's Moto Guzzi Twins Restoration gives a good break down of some of the changes.

http://books.google.com/books?id=h9XfM0Vjb...TigjU#PPA102,M1

Walker does not really answer our question, but he does say on page 101-102 that the pressure relieve valve allows the oil to bypass the filter and continue circulating if the filter becomes clogged.

In order for that to happen your diagram would not indicate the way a Guzzi is designed.

But maybe the author is wrong???

 

On a side issue, the PDF that you posted said,

"If the filter has been installed on the tight side, the

gasket may not blow out and the lockseam will unwind as the pressure continues to

rise."

Sound familiar?!? Maybe Guzzis are prone to pressure regulation issues.

Now I really want Ryland to get together an oil pressure gauge kit!