M758

Motor build oil temp with no issues on the track, but the oil does not really go up in the sump very fast from idle. The cooler stays cold as well. I just don't think idling puts enough heat in my motor. It can 20 mintues for the t-stat to open at all when idling on cool day.

There are ways to improve ventilation. I understand that there are ways. I just don't know them. I would like suggestions. Now i can apperciate if you find somethng proprietry. I will not be offened, but just now you can't share them for business reasons. Better than winks and nudges.

GregBBRD

And do you have data on what the oil temperature is, in the pan?

M758

My temp gauge sensor replaces the drain plug so I reading oil pan temps. No data, but I do watch my gauge. I don't have one on my stock street cars so no idea what they do.


With the turbo oil cooler racing on track in 105F air temps oil temp peaks at 260F in clean air. Too may laps tucked up close does increas temps. Plus I know water temps run lower without the load from the oil/water heat exchanger.

GregBBRD

I'm not here to tell you guys how to do this stuff. I'm sure that you are far better at this stuff, than I am. I've got no proprietary stuff going on here. Not trying to make/sell pieces to 944 guys.

I just saw this thread and thought some additional insight on bearing failures might be nice.

I didn't realize that you had installed the stock 951 block adpator and thermostat assembly. When I was doing 951 engines, we had those thermostats fail...but usually closed, not open. Might be worth a look. That's a very "neglected" part of the 951 engine. That thermostat area packs lots of debris whenever there is an engine failure. We had a couple engines come in, that had this very problem....no one had bothered to remove that thermostat and clean that area, after an engine failure, causing the "new' engine to fail immediately.

GregBBRD

That's pretty hot, in my book.

However, if it works for you, then it is obviously fine.

67King

A great many race oils (not all) perform better at 260 than at 200. For example (green is film thickness, temperature is in degrees C):



I was surprised to see this curve, and that it is a pretty common trend among race oils, though this is one of the more extreme examples.

GregBBRD

Very interesting. I guess the next step would be to ask that oil supplier if they "prefer" 260 degree oil, or if they are just saying it still has decent properties.

It would be interesting to know how this compares with the "supermarket" oils that most people use....

Doesn't look very good cold, does it?

Thanks for that data. Who's oil is this?

67King

I can't say, but it is a race oil that you know. A friend and I recently started a company to start importing Millers Oils, and we sent them samples of race oils we either have used or that are typically used around here. The results were pretty shocking. We hope our budget allows us to become site sponsors in a couple of months, but until then I should refrain expanding. Millers has some really, really cool stuff we are very excited about.

GregBBRD

Good luck!

Hope the business works, for you.

And the oil helps all of us.

GregBBRD

I requested some information from Torco, which is the oil that I run and prefer.

I found this information, coming directly from Redline:

Prefered oil temperatures: 220-230
Look into how the oil is being cooled and see if there is anything wrong with the system: 240-250.
Need to make some changes: 260-270

ptuomov

My main comment on this thread is that there's a bit of an apples to oranges comparison going on here. I think that the racing oils are designed to lubricate the best at something like 285 F temperature. And I also think that the oil that you feed to the engine needs to be about 235 F to get there. That's because I think that the oil inside the bearing heats up by about 50 F. I think this because I recall seeing a study by one of the big three car companies that measured how much the oil heats between the entry to the block and the operating temperature between the journal and the bearing.

ptuomov

One comment on the bearing options:

Take a look at the ACL race bearing 8b8091h. The shaft minimum diameter according to the ACL specs is within 0.001mm of the average crank journal diameter across the used 928 cranks that I've seen. I assume similar journal sizes are found in used 944 cranks as well. That's a fit in my book. There's no unneccessary oiling holes either in those bearings. Tang location is not an exact fit, but that's a relatively cheap mod.

The reason why I am bringing up this bearing is that of all the mentioned "race" bearings in the thread it would probably require the least amount of crank grinding/polishing and rod big end bore sizing to fit with a correct clearance. Some of the bore resizing you'd have to most likely do even with the stock bearings to get things to fit the way you want.

The ACL 8b8091h may not be the best solution. It is likely not nearly as good a solution as say a Clevite bearing of correct eccentricity for the rpm range on a turned down journal size and custom rods. But it may be an economical solution and still a very good solution, as not everyone playing with 944's has the "full Monty" budget.

Haven't tried it, so the first one trying will be a guinea pig...

333pg333

Good thread bump.

Humboldtgrin

I like this thread too. What about this idea. Using two oil temp sensors and have a switch for one gauge. One sensor can be made to sit where the drain plug is and monitor the hot oil in the pan and the other mounted in a custom fitting coming off the oil cooler to monitor the cool oil.

odonnell

Do "aftermarket" Glyco bearings have the yellow/blue/red coding on them, or is that only on the "OEM" Glyco bearings?