Oil pressure puzzle - Page 2

winders · 08-09-2020, 02:03 PM

Quote:

Originally Posted by r lane

A diverter of sorts has to be down in there.

My 964-based race engine has a 965 oil filter console in place. So the stock 964 crankcase sensor cover (96410176800) is replaced with the 965 crankcase sensor cover (93010776702).

Here is 96410176800:

Here is 93010776702:

r lane · 08-10-2020, 06:13 AM

Walt, thank you. Was hoping someone had been there, had that information. Can you tell me how that differs from the early RSR diverter piece. Bob

winders · 08-10-2020, 06:49 AM

I found this:

That is the EB Motorsport version of the RSR diverted. I can’t find a photo of the Factory part.

Walt Fricke · 08-10-2020, 10:47 AM

r lane: Is this what caught your attention: (and modified an old engine oil thermostat to work the same way)?

I can't remember what I did, other than to remove, I think, the steel barrel with the wax in it and the little "nail' which the wax moves out with heat. I figured out a way to block things in the always hot/open way. With the unit in hand, and the engine on the stand so you can look in at where the various passages are, it is fairly intuitive.

From memory, the factory RSR (the guy who gave it to me said it was a 935 part, but probably the same?) part looked like Scott's picture, just a bare aluminum or mag machined casting - no anodizing. I think the oil comes up from the bottom, exits to the former cooler port via the U shaped area, and on the return side goes to the main oil gallery. Or the other way around, but easy to figure out when making a substitute, especially since they cleverly only can be inserted in one orientation.

If I could figure this out, you can probably figure it out faster and better.

stownsen914 · 08-10-2020, 01:06 PM

My diverter looks like the one Winders posted, which I assume is a copy of the factory RSR/935 part. JB Racing makes one too. I got mine from a local machinist.

winders · 08-10-2020, 01:13 PM

Here is the JB Racing diverter:

winders · 08-10-2020, 01:14 PM

Those last two diverters are supposed to have smoother oil flow....but the Porsche Factory wouldn't put a part in a 965 Turbo that sucked....

r lane · 08-11-2020, 10:43 AM

Thanks for the info. Have been meaning to make one of the diverters, but is down on my list. The motor presently in the car has the 2nd oil filter and I have installed the OE thermostat in its stock configuration. Though it has to heat up to get oil to that 2nd cooler, it Seems to work.

Walt Fricke · 08-11-2020, 11:44 AM

I've forgotten what the failure mode of that thermostat is. I once knew. But I think failure means little or no oil through the cooler - or whatever you put there. So putting in a failed thermostat (the wax quits doing its magic, and the plunger never gets pushed out), alas, isn't going to do what you want.

winders · 08-11-2020, 12:35 PM

I don't think you want a thermostat in there....you want a diverter.

Walt Fricke · 08-11-2020, 04:03 PM

I was a bit surprised to see switching to a filter and not diverting the oil all the time. A filter there is last ditch defense - the guck has gotten through your other oil filter or filters, and through the pressure side of the oil pump, too. I suppose a big blowup is more likely with a hot engine, so there it protects. Diverter doubtless best, but converting a thermostat you already have costs nothing, and moves the oil as well as it moved when you had an oil radiator in that system, just only one way.

r lane · 08-12-2020, 05:25 AM

I am obviously past left field on this. I have ordered the 965 piece and waiting for it to arrive. How is it that the thermostat can manage the oil cooler, but not the oil filter in the same location. I realize there is a delay as the thermostat has to open to bring the 2nd filter into the oil circuit. I am missing something here very basic. I do have a spare thermostat and will disassemble it today for its repurpose. That may illuminate me as to how this should work. Any one out there have a diverter they would be willing to part with. Grateful of all of the input. Bob

r lane · 08-12-2020, 12:19 PM

Walt, I have a thermostat with the snap ring on the bottom and have removed it along with the inside steel barrel. I plan to machine a plug the same diameter as the steel sleeve that will slide up inside the thermostat housing. The plug will be deep enough to block the upper window in the thermostat housing, but leaving the lower window exposed. That should allow instant oil to come up into the thermostat, go horizontal at the lower window into the oil filter. The oil then exits the filter into the oil gallery junction of pressure switch, relief valve and main gallery. Does that sound right? Thanks, Bob

JoeMag · 08-12-2020, 06:33 PM

Scott -- Are you saying that with the oil filter consol that hangs off the right front of the motor, the temp/pressure sensor cover should be part 93010776702?

winders · 08-12-2020, 08:02 PM

Quote:

Originally Posted by JoeMag

Scott -- Are you saying that with the oil filter consol that hangs off the right front of the motor, the temp/pressure sensor cover should be part 93010776702?

Yep!

...or one of those RSR-style diverters with the stock cover.

r lane · 08-14-2020, 07:15 AM

A picture of the 965 thermostat cavity piece and a picture of a modified thermostat for the same purpose. For the thermostat mod, an aluminum plug to slip fit into the gutted thermostat that will block off the upper port in the thermostat. The 965 piece does the same thing. This allows the pressure side oil that comes up into the bottom of the thermostat cavity to access only the lower port going into the 2nd oil filter. At least this is how I understand it presently. Thanks again for the input by all.

stownsen914 · 08-14-2020, 09:24 AM

@JoeMag - did you sort out the pressures at Point 1 vs. Point 10?

JoeMag · 08-15-2020, 02:44 AM

Well... just looked and I have part 93010776702 (965) cover on my motor.

Stownsen914 - ...well I would not say it’s sorted out. Data is on first page of post. Still confused.

stownsen914 · 08-15-2020, 04:01 AM

I realize I didn't get much support for my assertion

but I still say Point 1 from the first post and Point 1 in post 16 are not the same. Point 1 in post #1 is at the thermostat (pre-filter), and Point 1 in post #16 is post-filter. I think this is contributing to the confusion, because for the pressure graphs in post #8, which "Point 1" are we looking at?

r lane · 08-15-2020, 07:11 AM

stownsen914, I agree that pic 1 and pic 16 are configured diff., actually opposite. We are dealing with apples, oranges and possibly bananas. The #1 pic must be a 964 and the #16 is a 993. The 964 has no 2nd filter, the 993 does. My perspective says the thermostat area is pre filter for the pressure side if there is a pressure side oil filter as in the 993, but is always post filter for the scavenge side oil filter. Joe mag should not be using #1 diagram as it does not apply to him as the picture of his engine shows it be 993 or configured as such.