measured data: Stelvio NTX oil temp vs air temp [cool weather]

[Daniel Kalal]

Each point represents at least 45 minutes of steady running under point conditions.  For continuous running with the air temperature below 50 F (certainly, under 40 F) It might make sense to shield the oil cooler.

[Bill Havins]

Very nice data.  And I don't envy you collecting those data points at below 40°F.  Brrrrrr...

[pyoungbl]

Finally!  It is good to see some real data comparing the air temp to oil temp on the Stelvio.  I'm betting that the oil temp would be at least 10F lower in rain...maybe as much as 20F.  On a recent 2500 mile trip I was surprised to find that I could rest my hand on the valve cover after a few hours of Interstate riding in 50-60F weather.  This chart verifies that.  The oil cooler is bringing the oil temp down too low.  It's time to do some serious thinking about a thermostat for the oil circuit, at least on my NTX.  Thanks Daniel.

Peter Y.

[Wayne Orwig]

The chart will only be complete with a long 35F degree ride in rain, and a long 110F ride in the dry of Death Valley.

When will you have that data?

 ~;

As expected, a pretty linear relationship. No wonder I see a lot of water in the oil in the winter. It never gets to the point that it will boil the water out of the oil.

Actually, a test with and without the oil cooler covered is needed now.

[Vasco DG]

Wayne, while the Griso oil cooler is in a different place the effects of a baffle are the same. I don't know whether you saw the 'Simply Brilliant' thread? Mark III made an easily adjustable baffle to combat the over cooling issue on his Griso. I've done extensive testing in cold and wet weather and believe me it's hard to get the oil hot enough unless tou really flog it and as soon as you return to 'Cruise' the oil temp plummets. If it's wet? Forget it, getting the oil hot enough, even if the ambient is warmish, is a not happening thing.

Pete

[old head]

So, if the oil cooler on the Griso and Stelvio is that efficent, can they be used on the ones that run in the hot and humid climates.

I only have the dreaded oil can pop up when its over 95 outside.  It only started happening within the last year, never had a problem before.  Strangely, it started happening after changing from 20w50 v-twin to Redline 20-60 motorcycle oil.  Have changed back to 20-50, but it hasn't been that hot so haven't had the issue.

Old Head

[Vasco DG]

Oil cooler on your Breva is thermostatically controlled. Also the pushrod motors are not subject to tappet and cam damage due to overcooling.

If you are getting the oil can icon appearing it might be worth checking which type of oil pump you have as there was a bad run of trochoidal pumps but they seem to have all gone in Norges. Chances are your problem is the sender switch.

[old head]

Oil cooler on your Breva is thermostatically controlled. Also the pushrod motors are not subject to tappet and cam damage due to overcooling.

If you are getting the oil can icon appearing it might be worth checking which type of oil pump you have as there was a bad run of trochoidal pumps but they seem to have all gone in Norges. Chances are your problem is the sender switch.

Thanks, I will replace it and see what happens. 

Old Head

[Ad B]

Hi Daniel,

At which point do you measure your oil temperature?
I have the pick up at the drain plug.

Following is the test in boiling water...

So it's accurate enough...

I'm running out of time now.
I'll come back tommorow.

Ad B

[Daniel Kalal]

At which point do you measure your oil temperature?

It's the sump temperature using a dipstick gauge.  Before using it I checked the calibration with boiling water--it's accurate.  The outside air temperature is the dash reading of the Stelvio; which seems accurate--regardless; it will be the best guide for when the oil cooler should be shielded during cold weather.

[Ad B]

Hi,

I didn't like the a-symmetrical headers of my G12, I rebuilt my exhaust system, using Stelvio headers.
Because of that, the oil cooler lump had to move from the right side to  a "normal" oil cooler the central front.
Result:

Not knowing what the result would be of moving the oil cooler, I put on a oil temperature gauge on my G12.
As you can see 2 posts above...

 :pop  :BEER:
I recognize the results from Daniel...
In (for us in Holland) hot summer weather, about 30 C (86 F), in a traffic jam on the highway, the oil went towards 105 C (220 F)
Riding in normal summer condition, the oil goes to the temp of 85 - 95 C (185 - 205 F).
2 weeks back, nice weather, around ~7 C (45 F) outside temp, during a 1,5 hour ride, the oil didn't get more than 75-80 C (165-175 F).
As Pete is writing, these numbers are not good conditions for my tappets...
But I think, the story is even worse....
We are measuring the oil temp in the sump.
But the oil first is going through the oil cooler before it goes up the camshaft and tappets. :o
Once up the oil will be at nearly freezing temperatures... (just kidding)
But the temperature will be a lot lower once it gets up.

Pete, will it be also that worse for roller tappets?
I think I also have to make a nice kind of baffle, to get the temp of my oil in better condition.
Pete, question: can a thermostatic switch do that job...?
Than the oil will go up by-passing the cooler.

Ad B

[Vasco DG]

Cams and tappets are fed from the high pressure circuit that doesn't pass through the cooler. Your supposition there is wrong. Doesn't alter the fact that the engine is grossly over-cooled.

Pete

[Ad B]

Oeps,

sorry, I thought all the oil was going through the oil hoses from the cooler to the heads... :-\
I will think about a baffle in front of the cooler or a thermostatic switch between the lines.
Also I'm going to fit a (plastic) sump protector, I have (from a Stelvio).
So wet roads and rain will influence the temperature less.
Thanks for your input, Pete.

Ad B

[GearheadGrrrl]

I'm looking for a new sidecar tug in the next couple years, and I kinda like the Stelvio's "excessive" oil cooling...

[lucian]

Very sweet looking griso Ad b, Curios if the digital gauge you have could be had in the usa? Would love to add one on my 09. Thanks Dave

[youcanrunnaked]

While a baffle over the oil cooler is a cheap and simple solution, it requires setting up the bike to precisely monitor oil and ambient temperatures, and the operator now has something else to monitor and adjust.

How about putting in a thermostat to bypass the oil cooler up to a pre-set oil temperature?  I am not sure what aftermarket parts can be adapted to this application, but I am curious if anybody has tried this on an 8V model.

[leafman60]

Each point represents at least 45 minutes of steady running under point conditions.  For continuous running with the air temperature below 50 F (certainly, under 40 F) It might make sense to shield the oil cooler.

Looks like the oil temp in this sample is running about 85 C  (185 F) in ambient conditions around 40 F. Most of the oil thermostats that I have referenced open at 180 F so this actually looks like the Stelvio is reaching that temp okay in conditions pretty chilly for most riders.

If you want more than 180-185 F oil when riding at 40 F then, yes, covering the cooler looks like the best option although one of the thermostats was a 190+ F unit.

Experts say optimal temp is 180-210 and that's what the Stelvio is doing in stock form apparently.

http://www.elephantracing.com/techtopic/oiltemperature.htm

Having said that, an in-line thermostat valve would bring the oil temp up quicker than not having a thermostat. Sounds like, if you do ride in cold weather with a stock bike, you need to ride it a ways to allow it to come to proper temp for an adequate period of time to burn out moisture.   


.

[pyoungbl]

David, I don't think the 180-210F temp range is enough to burn off moisture in the oil.  You need at least 220F.  The Stelvio won't get hot enough under normal riding and ambient temp much below 70F.  A 190F thermostat sounds like a good idea to me, one at 200F would be even better.  High quality full synthetic 10W60 can easily take those temps.

Peter Y.

[nikwax]

But the oil temperatures are not uniform throughout the engine. Oil will be much hotter coming off of the piston than the oil in the crankcase, for example. One study says that the instantaneous oil temp is 50 degrees F higher than the oil going into the engine. So 180-200 would get the oil plenty hot (when it is 50 degrees hotter) and keep you out of the danger zone of overheated oil.

[Vasco DG]

The places where the oil is going to get momentarily very hot are likely the oil galleries around the exhaust valves and the under piston sprays when the contact the piston. While the oil is in the galleries there is nowhere for any impurities to evaporate to. By the time it gets back into the crankcase it will of likely cooled to the point where purging itself of water will be marginal or incomplete.

Then there is the fact that even if the water does sublime off it is liable to condense out, with oil particulates, in the breather box and end up being returned to the engine via the condensate return. It has always been thus. It's the reason Tonti frames that use the spine backbone and Spineframes which also use the frame as a condensor tend to fill their frames up,with rusty mank!

Pete

[leafman60]

David, I don't think the 180-210F temp range is enough to burn off moisture in the oil.  You need at least 220F.  The Stelvio won't get hot enough under normal riding and ambient temp much below 70F.  A 190F thermostat sounds like a good idea to me, one at 200F would be even better.  High quality full synthetic 10W60 can easily take those temps.

Peter Y.

I think 180 degrees has always been a benchmark oil sump point to insure moisture burn off.  That's why all the thermostats, e.g. the H-D versions, tend to be gauged at 180.  I realize water boils at 212 but that is misleading when determining motor oil temp.  As already mentioned by others, 180 in the sump is not the highest temp throughout the engine.

Many sources cite 180-200 as best.  Here's another regarding airplanes engines-

http://www.reiffpreheat.com/Article-Visser3.htm

"By running at 180° during cruise, the oil should be hot enough to boil off the normal condensation in a one-hour flight."


Having seen that empirical chart, I am not so worried about too-cold oil and I have a little more confidence in the Guzzi engineers.


.

[Spuddy]

SO, who is going to come up with a thermostatic fix so we can all feel good about our hotter oil?

Spuddy

[brlawson]

I have to ask why the factory thought it was appropriate to add 25% more cooling surface to the oil coolers on the New Stelvio versus the original. I have even heard of folks putting the bigger cooler on older bikes.

[leafman60]

SO, who is going to come up with a thermostatic fix so we can all feel good about our hotter oil?

Spuddy

http://wildguzzi.com/forum/index.php?topic=73346.0


.

[pyoungbl]

Campfire friends, I understand the issue of peak temp near the pistons and such.  That's not my concern. We have two oil pumps.  One is high pressure/low volume, the other high volume/low pressure.  On my Stelvio the high volume/low pressure oil goes from the pump, out the crankcase, and to that huge cooler and then to the valve covers.  The oil going through the cooler is only starting out at a maximum of 180F and is then being cooled well below that.   Next the oil is sent to the valve covers where it has to lube the rockers, lifters, and cams.  That's where we are seeing all the mayo and where I fear for excess wear on the high cam and lifters.  Remember, the 8V is not getting lube to those parts high on the head except for what comes from the cooler (Pete Roper, feel free to correct me).  Daniel's chart shows the temp in the sump.  I think those temps are too low.  What is coming out of the cooler will be even lower.  If I have explained clearly you can see why I believe we need a thermostat to bypass the cooler until oil temp gets up to about 200F.  The engineers at Guzzi may well have figured all this out to a perfect solution, I don't claim to be smarter than them.  I'm just recognizing some problems from the field and my experience with my Ducks, which were over cooled.

Peter Y.

[Vasco DG]

Peter, the oil for the cams, rockers etc. comes from the high pressure circuit. The low pressure circuit only supplies the cooling galleries around the exhaust valves. Even the under piston sprays are fed from the high pressure circuit.

Pete

[Wayne Orwig]

I noticed that the oil cooler pump, has a pressure relief valve in it. I wonder if that is just a safety thing, or if it restricted somewhere and there is higher pressures in there then we might think?

[Vasco DG]

It'll hve a PR valve because if it didn't it might burst the rad when the oil was cold.

[lucian]

Seems like thermostatically controlled louvers on the oc would be a good fix. Similar to what some of the tractor trailers have in front of there radiators. How do we create such a thing? Sounds like a good winter project.

[Ad B]

Hi Dave

Very sweet looking griso Ad b, Curios if the digital gauge you have could be had in the usa? Would love to add one on my 09. Thanks Dave

You can buy it on E-bay in the UK:
http://www.ebay.nl/itm/Stage6-scooter-motorbike-digital-temp-gauge-aerox-runner-zip-SR-Nitro-jog-DNA-/141445379489?pt=UK_Motorcycle_Parts&hash=item20eecd35a1
But watch it, it's not just a easy fix... not difficult, but it's not out of the box to your bike...
You must use the M14x1.25 temperature sender to make M10x1.5 on a lathe.
I couldn't find a temp sender with M10x1.5, so I had to make it myself.

Ad B