Oil Temp Probe Location

[Rick Parker]

I am undecided as to where to locate the oil temprature probe for a new gauge I am adding. Is it better in the oil pan itself or in the remote filter /cooler lines? Some of you that do alot of open track events may be best qualified to answer. What oil temps do you experience?
Inquiring minds want to know!

Thanks
Rick

[Dominik]

rick,

that is good question and you shall receive a lot of good answers.
for the start use mine:

you want to know how hot the oil got around the bearings tofind out if they melt or not. unfortunately it is not very practical to mount a sensor st the crank ...

so my best bet is the oil pan, not at the bottom but close to it ...
here is where the engine builders may add a good spot.

the bearing manufacturer will give you a maximum oil temperatur that the bearings are supposed to experience.
unfortunately the oil itself may not be capable at all of that temperature.

mineral oil is suppposed to last up to 300°F for a short while.
that is: go on when you are leader in the last lap ...

synthetic oil is supposed to last to 350°F +, but are the bearings?

for the track we try to keep oil temperature at about 230°F to 260°F.
do not cool it too much (below 200°F), water and other residues (sulfur?) will stay in the oil and you do not want that.

engine builders, race drivers, oil and bearing engineers correct my temperature values, but they should be in the ball park!

dominik

[Bob Putnam]

Nice 80% Dominik.

Oil temperature is an indication of how much heat is generated by bearing friction - how well they're keeping metal-to-metal contact down. (There is some shear energy dissipated, but it's relatively minor.) Always measure the oil temperature in the pan, just after it has left the bearings.

[Dominik]

thanks bob,

i just found out that your 80% "engine weight link" is working properly again ...

i hope somebody lets me know if i am writing b.s.

dominik

[Dave Samson]

Dominik,
I don't have an oil cooler and I measure the oil at about 4 cm from the bottom of the pan. When cruising at around 100 kph I seldom see the temperature rise above 85 deg. C = 185 F. After several hot laps on the track it only reaches 110 C = 230 F. Are these temps. really too low ?

[Dominik]

dave,

good to see you on the forum again. as soon as you exceed the 100°C (212F) at least for a little while you are okay.

Mercedes Benz and Porsche used to let their cars cruise at 82°C (180F) all day and are fine. 180F is the opening point of the thermostat for the oil cooler.

My 964 sees more 110°C (230F) during racing and 90°C at normal (autobahn) driving.

4 cm (1 5/8") above the pan seems quite high to me. Depending on the oil which is circulating at high revs - more in the heads, less in the pan.

you may get a false reading at high revs.

I am not sure though (80%?).

dominik

[Dave Samson]

ok so I measured it, actually it's 2.5 cm from the botton and that's 100%.

[Bob Putnam]

Guys,

I wouldn't worry too much about the height of the probe. Since the pickup is right at the bottom of the sump, there will be a constant flow from the top surface toward it. Not to mention probably a fair amount of sloshin' back and forth as you have altogether too much fun!

[Dominik]

bob,

imagine racing at daytona, all the oil stuck to the other side of the oil pan where no sensor is located ...

just kidding, you're right - my thinking was too overcautious.

dominik

[Mike Braddock]

Funny Dominik

[Dave Samson]

Hey Dom,
That's not so stupid....do they drive clockwise or anti-clockwise at Daytona ? You could position the sender accordingly.

[Cobranut]

On the Cobra, I have it in the oil filter adapter, and it seems to respond well there. The oil temp shouldn't change much between the pump and the filters, as they are ahead of the cooler.

On my Legends racecar, the probe is in the pan.

Either place seems to work fine.

The highest I've seen on the Cobra is 120* C.

The Legends runs as high as 300* F on occasion, but it is seeing a lot heavier usage, up to 10,000 rpm.

Later,

[cobish]

Oil temp at 110 deg C is about normal, as long there is enough flow to the bearings. Remember, temp high, less press, press is not related to flow. Oil pump must deliver the flow to the bearings to prevent meltdown of bearings.

[Dominik]

dave,

I am not sure about daytona, but there are track you go left and others you go right. best is to use two sensors

Oo four, the third one for braking the forth one for accellerating ...

Serious question:

I lost some bearings the other days in spite of having enough pressure.
I did not use any by-pass for the filter. Not in the block, not in the filter.

How do I know if the volume of oil to the bearing is sufficient, when the pressure is fine, but the filter maybe not capable of the flow?
I.e. at cold conditions when the oil is very thick.

Dominik

[Dave Samson]

Dom,
And that is the exact reason for running the right oil for the climatic conditions and allowing the engine to warm up before making it work too hard.

As for the senders - in a rollover situation, I guess gravity will take care of the oil flow !

[Dominik]

Guys,
there is a company that does research on this topic:

"performance unlimited", Hartford, Wisconsin (262) 673-4077

They placed a nice chart from AATCorp.

The bearings are about 75°F hotter than the oil in the pan. Bearings are supposed to wipe out at 375°F.

That is 300°F in the pan.

Best mileage is at 195°F in the pan. Unfortunately they do not list a value for best performance.

Sorry, I do not have a weblink for this company.

Dominik (95%?)

[Dave Samson]

here it is:

http://performanceunlimited.com/docu...tempguide.html

[Dominik]

dave,

perfect teamwork: 100%!

Dominik