JohnKoaWood

With all the conversations going on I am finding it hard to get my bearing....

magcuda

Run Mobil 1 20w-50
That's what Jerry woods told me to run in my old Firehawk 944 and never had a problem
Almost lost #2 in a 6 hour at Sebring running Kendall 20w-50 be fore he told me that
He also told me not to put an oil temp gauge in the car, it would only scare me

speedjw

Our Chumpcar/Lemons 944 has run 3 races (24hr, 16hr, 14hr) and multple trackdays without any failures. All in the south (HOT CLIMATE!)

Our recipe so far:

We installed a used turbo oil/air cooler and cassette for the car, that seems to keep our oil pressures high (1.5bar at idle hot, a 4.5bar at 6000 hot).

We short shift between 5500 and 5800.

We run Mobil 1 15W-50 oil.

We welded in a baffle setup (like the lindsey setup).

We change the oil and filter before and after every race.


This said, we'll probably have to look at doing bearings soon, and might just have to look into the clevites mentioned above....

whalebird

mobile 20/50 is currently labeled as a motorcycle oil and perhaps a good choice for our cars. I've run 15/50 M1 until it was recently hard to get in my area. I switched to Amsoil 20/50(premium) and am surprised at how much more consistent my oil pressures are at temp, ~3.25 bar on the dash gauge. This is my DD and I'm not racing.
However, when whatever bearings you're running are starved of whatever oil you're running, damage will occur. I'm not sure this is an oil/bearing-material issue altogether, although those may be secondary issues.
The windage relief observation is curious, but wouldn't #1 suffer the same issues? Does the AOS at the rear offer some relief back there? could the front 2 (or each cyclinder) be ported through the exterior of the block or the webbing inside?
Some theorise (logically) that the balance shaft galleys bleed oil from the crank...so replace those bearings too.

M758

I moved away from mobil 1 many years ago. The AMSOIL I used since then got me less pressure drop aftere 15 min on track. I run the AMSOIL racing forumulation in 15-50

Strosek Ultra

Here is an extensive thread of oil control from the 928 community. It might give you guys some interesting inputs.
https://rennlist.com/forums/928-foru...8-engines.html

Ake

Strosek Ultra

The picture in post #124 https://rennlist.com/forums/924-931-...r-400hp-9.html will give you a good idea of what con rod width Michael Mount is running. This is not a factory Glyco rod bearing. The rod big end is 27mm or 1.063" wide.

Ake

bebbetufs

Thanks Åke.
Very informative. I had heard that the head was not draining efficiently enough when running extended high RPMs, but never seen it confirmed. I am definitely cleaning up the drains to remove casting defects, and I will take a deep long look at increasing drainage from the head. I wonder if the windage ports could be related to this allowing the pressure from the pistons to move away and not pressurize the drainage channels... armchair engineering is so easy

fortysixandtwo

There are some good points in this thread and certainly some things to put into consideration.

One thing I would like to bring up are some of the devices that are suppose to help with oil management that, in my opinion, could very well hurt oil distribution or I don't see actually performing the job they were intended to do.

Skirt around oil pickup screen:
Has anyone noticed the oil pickup has an inlet horn? Adding a collar around the pickup is essentially adding a restriction. In addition to this, most of the ones I've seen installed are only tack welded around perimeter. In order for it to function as intended, this would need to be a full perimeter weld, otherwise the pickup will still suck air through the weld gaps, if the oil level exposes them.

Hinged oil baffle:
Hot oil flows almost like water. A butt hinge isn't exactly liquid tight. This device will help keep oil slosh down, but I suspect during long, high g corners, the oil will have time to flow through the cracks and normalize as if the baffle was not there. If it does seal tight, does the returning oil, that now favors returning to the non-pickup side of the baffle, start to starve the active side of the sump?


Have I tested any of this? No, I'm going by what I would expect to see if tested. I also don't believe the people that came up with these solutions tested them either.

bebbetufs

^^agreed

john gill

Hello ALl
The Clevite high performance Nascar rod bearings CB-1628HX that have been mentioned here , the link mentiones toyota specifiic ,this leads a couple of obvious questions ?
Are the 944 968 928 conrod bearings the same ?

Will these toyota specific bearings fit the above given that they are all the same ?

I was not aware that the conrod bearing in the 928 (being specific) was similar to anything else ?

john gill

Has anyone tried to buy these bearings ?

I understand they are no longer made ?

944meister

Ordered a set of the clevites to see if they work, otherwise I'm just throwing in a std set of glyco bearings. Figured id try the clevites since my a bearing is failing in my car, anyone else try them yet?

944meister

Update: got the bearings in today, the clevites look visibly identical in diameter to the stock glyco bearings, I will hopefully find out if that they work this weekend when I have time to work on h

944meister

On the car