These Things Run Pretty Hot!

[Greg Field]

You do no need to get to 212 f to get water out of the oil. Water begins to simmer in the 185-degree range, depending on altitude.

 

On a side note: If you use a French press to make your coffee, try using 190-degree (when water in an open pan begin to "mutter"), and the coffee's flavor improves dramatically over that made with 212 F (rolling boil) water.

[Guest ratchethack]

In the UK summer ha hah ha , very rarely budged above 95 F even after a couple of hours on the road.

DVH, I believe you mean 95 C. At a running temp of 95 F, y'er Guzzi would be a sick pup indeed, your own body temp being nearly 4 degrees F above this.......

[Dan M]

I love Redline and their oil, but the truth is, viscosity drops rapidly, with any oil I've ever tried, including theirs, for every degree over 90 C. I know this 'cause my sorely flogged Eldo's oil-pressure gauge and temp gauge tell me so. Even with Redline. The oil may not cook at these temps, but it thins out such that the pressure is dangerously low. You have to have guages to monitor how rapidly it happens or you would never know.

 

 

90341[/snapback]

 

 

Hey Greg,

 

How much pressure do you consider "dangerously low"? Even with hot, thin oil and hot engine components that are expanded providing larger clearances, doesn't your pressure rise to "acceptable" levels off of idle? I think the engineers have taken all of this into consideration when recommending which viscosity to use.

For years I'd shudder at the thought of too thin oil and low pressure and still opt for heaver vis in an air cooled motor. But engineers in their constant quest for fuel econony and reduced emissions are calling for thinner & thinner oils. My car as an example uses 5W20 year around. I have seen some cars call for 0W50!! Surely modern engines have tighter clearances and can make adequate pressures with this watery stuff but I think our guzzi engines are completely safe with 20W50 at 120c. I'll stop rambling now.

 

BTW, I'll try your french press coffee trick. Sounds good.

[DVH]

DVH, I believe you mean 95 C.  At a running temp of 95 F, y'er Guzzi would be a sick pup indeed, your own body temp being nearly 4 degrees F above this.......

90364[/snapback]

 

 

Your right 95 C, 95F would be very sick hahahaha

[Guest Buddy]

I would be interested to know if there is any differance in oil cooling due to the air flow through the oil coooler between the faired Le Mans and the unfaired V11 Sport. Does anyone have a comparison? Also the mesh grill over the oil cooler has a fairly small mesh size which can get partially blocked. In chilly England I run mine, as per the chart in the handbook, on 15w 40, but in Italy 20w 50 is the norm. I also don't let the oil go beyond 4,000 miles maximum.

[TX REDNECK (R.I.P.)]

Greg, what type of oil temp. dipstick are you running, and do you have any pictures?

 

 

I'm not sure what kind Greg has but, MG cycle has these

 

http://www.mgcycle.com/oil.html

[Guest Nogbad]

Hey Greg,

 

I have seen some cars call for 0W50!! Surely modern engines have tighter clearances and can make adequate pressures with this watery stuff but I think our guzzi engines are completely safe with 20W50 at 120c. I'll stop rambling now.

 

BTW, I'll try your french press coffee trick.  Sounds good.

90372[/snapback]

 

My car uses 0W30 with oil change intervals up to 20000 miles depending on what some arcane internal sensor thinks of the condition of the oil. The W figure is the cold viscosity only, the upper figure is the hot viscosity, so at running temperature 0W50 should be the same viscosity as 20W50.

 

Viscosity isn't directly related to film strength or lubricity anyway. Not that I am about to put 0W30 in the Guzzi! Anyway at £15 a litre I couldn't afford it.

[al_roethlisberger]

I'm not sure what kind Greg has but, MG cycle has these

 

http://www.mgcycle.com/oil.html

90413[/snapback]

 

 

That's what I've got... had it for a couple years with no problems.

 

The only issue I've had with the temp-stick is that it is sometimes pretty hard to get out if the engine is hot... it sticks, and the darned knurled surface is darned hot

 

 

Also, I had to paint mine to really be able to read it well.

 

Al

[Guest Nogbad]

It is worth remembering that the oil pump is a positive displacement pump. In other words, oil flow is proportional to pump speed, and that the pressure will rise until the flow at that speed is forced through whatever resistance is there. This is why you need a relief valve as with tight clearances and thick oil the pressure could get high enough to burst gaskets etc.

 

Provided the oil circuit is leak free and healthy, a low observed oil pressure when hot does not mean there is a lack of flow. It is the flow of oil that carries the heat away and is the most important thing to preserve.

 

Bearings fail if the filter comes loose or if the relief valve sticks NOT because of low pressure but because of low flow.

[Greg Field]

It is worth remembering that the oil pump is a positive displacement pump. In other words, oil flow is proportional to pump speed, and that the pressure will rise until the flow at that speed is forced through whatever resistance is there. This is why you need a relief valve as with tight clearances and thick oil the pressure could get high enough to burst gaskets etc.

 

Provided the oil circuit is leak free and healthy, a low observed oil pressure when hot does not mean there is a lack of flow. It is the flow of oil that carries the heat away and is the most important thing to preserve.

 

Bearings fail if the filter comes loose or if the relief valve sticks NOT because of low pressure but because of low flow.

90710[/snapback]

 

What Nog says is true.

 

Consider, however, that the oil will take the path of least resistance. When the engine and oil are very hot, the oil system can begin leaking the oil nearly as fast as the oil supplies it, so the pressure drops, and the flow goes to where the oil is leaking the most. This path of least resistance is not necessarily through the plain bearings that need the oil the most. In other words, you can have plenty of flow elswhere in the engine but little or none at the mains.

[mike wilson]

It is worth remembering that the oil pump is a positive displacement pump. In other words, oil flow is proportional to pump speed, and that the pressure will rise until the flow at that speed is forced through whatever resistance is there. This is why you need a relief valve as with tight clearances and thick oil the pressure could get high enough to burst gaskets etc.

 

Provided the oil circuit is leak free and healthy, a low observed oil pressure when hot does not mean there is a lack of flow. It is the flow of oil that carries the heat away and is the most important thing to preserve.

 

Bearings fail if the filter comes loose or if the relief valve sticks NOT because of low pressure but because of low flow.

90710[/snapback]

 

But pressure is a function of flow. So, all other things being equal, low flow will relate to low pressure. What you say is true absolutely for a roller bearing engine but only relatively for a plain bearing engine. It is true that, at a microscopic level, it is bearing design that creates the pressure that holds components apart but without high flow (and its associated pressure) the oil will not be in the right place to do that.

 

mike

[guzzimeister]

Hi

 

RR oil thermometers for the Vw11 replacing the dipstick are available from tombrook@t-online.de. €50 note sent to Anke at this address gets you one in about 2 weeks. Nice lady, excellent service. She sometimes ebays selling Ural stuff.

 

Cheers

 

Guzz

 

PS mine runs at between 80 and 95 which it is definitely too cool. Mind, my mk1 V11 used to run so hot in traffic the ECU would shut it down for a second, so a bit better I suppose.

 

Greg, how much are the thermo dipsticks, do they ship to the UK. Had one years ago on a 2000 v11 and it was useful for keeping an eye on the temp when touring europe, In spain in heavy traffic had it upto 120 F but surprisingly dropped quickly once under way.

In the UK summer ha hah ha , very rarely budged above 95 F even after a couple of hours on the road. Never had the flickering oil light on the 2000 v11 or the lemans.

90353[/snapback]

[tripletango]

Do you mean F or C?

IMHO the 6000 mile service interval for oil is a bit long.

I suspect the last couple thousand miles of that interval, the oil is likely to run very thin at high temperatures, and I am surprised some people use 5,10,or15W40, although in cool climates it probably is fine.

The people getting milk shake on the inside of the valve covers may actually want to put a cover over their oil cooler in cooler months....and as Dan and Spectro suggest, getting the temperature over the water boiling point is a good idea....still it scares me how thin the oil is at that temperature.

But it is a Guzzi and it will be fine 

90358[/snapback]

 

I think that thin oil is fine. It only requires a few molecules of thickness to protect from friction. Thin oil circulates freely, which is good. If you are concerned about heat breakdown then a good synthetic is better than regular oil in that regard or so they say!

[pete roper]

I think that thin oil is fine.  It only requires a few molecules of thickness to protect from friction.  Thin oil circulates freely, which is good.  If you are concerned about heat breakdown then a good synthetic is better than regular oil in that regard or so they say!

91413[/snapback]

 

 

Sorry, but this isn't accurate. The oil performs two functions in a plain bearing. Firstly there has to be a through-flow of oil to remove heat, a layer only a few molecules thick can't do this. Secondly what keeps the bearing and journal separate is not the film of oil per-se. The forces acting on the oil film are much greater than the 50 or so PSI that the pumped oil protect against. Just do a simple set of sums on the pressure exerted on top of the piston and the surface area of the bearing and you'll see this is so. What actually protects the bearing and enables it to work is a rolling wave-form within the oil film itself which forms, very conveniently, at the point of greatest pressure on the film. This is what is known as the 'Hydro-dynamic Wedge' and is what allows a plain bearing to function. as the point of the wedge the oil pressure is in fact multiplied by some very large amount, (a factor of ten always springs to mind but I'm not absolutely sure?) and it is for this reason that bearing clearances are critical. Too large and the wedge can't form. Too small and the through-flow of oil is too small and the bearing will cook.

 

While it is true that at any given instant, as long as there is a layer a few mollecules thick separating the bearing and it's journal then all will be OK, the whole process is dynamic and on-going in service and therefore it can't be looked at in such conveniently simple terms.

 

Pete

[tripletango]

Sorry, but this isn't accurate. The oil performs two functions in a plain bearing. Firstly there has to be a through-flow of oil to remove heat, a layer only a few molecules thick can't do this. Secondly what keeps the bearing and journal separate is not  the film of oil per-se. The forces acting on the oil film are much greater than the 50 or so PSI that the pumped oil protect against. Just do a simple set of sums on the pressure exerted on top of the piston and the surface area of the bearing and you'll see this is so. What actually protects the bearing and enables it to work is a rolling wave-form within the oil film itself which forms, very conveniently, at the point of greatest pressure on the film. This is what is known as the 'Hydro-dynamic Wedge' and is what allows a plain bearing to function. as the point of the wedge the oil pressure is in fact multiplied by some very large amount, (a factor of ten always springs to mind but I'm not absolutely sure?) and it is for this reason that bearing clearances are critical. Too large and the wedge can't form. Too small and the  through-flow of oil is too small and the bearing will cook.

 

While it is true that at any given instant, as long as there is a layer a few mollecules thick separating the bearing and it's journal then all will be OK, the whole process is dynamic and on-going in service and therefore it can't be looked at in such conveniently simple terms.

 

Pete

91426[/snapback]

 

Good answer Pete. Sure the oil operates in the engine in many different ways. I was referring to metal to metal protection.

To me thick oil that is relativerly difficult to pump is a big problem as suggested in your response. Gotta flow otherwise it will not work correctly in the myriad of functions it performs.

5w or 50w when at operating temp both seem as thin as water! But 50w maybe too dam thick at thirty and 5w may be on the edge at 100 degrees.

Answer is simple don't cheapskate on quality of oil and change according to the work load you put on the engine.

6000 miles to me on the slab may be fine but in day to day cycles I would change at half the distance.

In the GUzzi at least there is no clutch or gearbox crap screwing up the mix.

R