Thrust Bearing Contour

[87GN&98VET]

I'm working on integrating a contour to the rear thrust face of the 3.8L turbo Buick crankshaft thrust bearing to withstand additional loading due to ballooning of high stall torque converters. Can someone please confirm which side is the rear (that will react the thrust load from the converter) with respect to the locating tang - I believe it is the same side as the locating tang but need confirmation. These improved parts will be available in the near future. Part numbers are 107M (entire main set) and 7117CH (flange set only).

Sean Welch
Federal Mogul Bearing and Bushing Engineer
87 GN
98 Corvette

 

[Crazi]

Doing research on this, I found a site that said to make a small, 1mm groove in the rear side of the bearing to increase oiling to that side. I will see if I can find it again.

I can't remember which side is which unfortunately. Anyone???

 

[87GN&98VET]

Actually, I talked to Jack Merkel and he gave me the correct orientation - same side as tang in the upper and opposite side as tang in the lower.

I would not recommend modifying the thrust bearing. There's a lot of engineering and experience that goes into these designs. The bearing already has three 3/16" grooves. Adding another groove takes away bearing area which has a negative effect on the load carrying capability of the bearing.

 

[Ormand]

I saw the recommendation for the slot, and it won't affect load carrying capacity. The "slot" is actually just a chamfer of one edge at the bearing parting line. There should be very little load in that direction. It (theoretically) allows for more oil to the thrust surface, toward the front of the engine. There was some discussion of why it wouldn't affect oil pressure, but I can't remember the details.

 

[KendallF]

Did any of you notice where he works in his signature? Sounds like a good idea..I'd buy some. I read a link that someone put in the last thread on thrust bearing failures. It talked about heavy duty diesel thrust bearing design that incorporated multiple ramps to allow for an oil wedge..are you looking at something like that?

 

[87GN&98VET]

I'm not aware of the article that talks about adding an extra slot. If it were a chamfer on the thrust face near the parting line, it would probably be o.k. Just make sure you don't touch the parting line of the main bearing portion. It wouldn't affect oil pressure because it uses the oil already discarded from the main crankshaft journal / bearing interface.

As for the contour, yes it is typically used in heavy duty diesel applications. Actually, we incorporate contours on all thrust bearings in the OE automotive market and have been doing it for years (we own exclusive patent rights). The contour is essentiallly a ramp-flat shape of each pad. The ramp originates at the slot and it's purpose is to squeeze the oil as the crankshaft rotates to build an oil wedge. This wedge increases the oil pressure at the crank / thrust surface interface. A higher oil pressure will be able to support higher loads and maintain a minimum film thickness. I just signed off on the prints so the improved design should be available within the next month or two.

 

[KWIKR 1]

Sean , your email is bouncing back .......Tim.

 

[87GN&98VET]

I read that article on the chamfer. I believe it will reduce the oil pressure for the main bearing. I talked to one of our most experienced bearings engineers here (over 35 years) and they had an issue with failing thrust bearings on Ford motors in the past. They tried the chamfer and that didn't work. They even tapped the main feed galley to distribute oil directly to the flange and that didn't work either. Best results were obtained by using a contour.

My excite mail is crap. You can try my work address. swelch@fmo.com

 

[tminer]

Did this ever come to fruition? I search FM's site for the 7117CH part and didn't get a hit.

Thanks,
Tom

 

[KWIKR 1]

In Canada you can not purchase the thrust bearing (OS or std) separate (#7117CH) . you have to purchase in a full main set (#107M) . Maybe different for you guys .

 

[tminer]

I don't see 107M either, just 7144M & 7144MA series.

tom

 

[KWIKR 1]

far as I know107M is considered the performance set . there are also the FM 4263M and the 7150M main sets . different types for different applications . Best to drop 87GN&98VET a email I'm sure he'll be able to tell you what's right for you. . and let you know exactly what FM bearing main sets come with the contoured thrust flanges

 

[87GN&98VET]

Main set numbers 7288M, 7288MA, 7277M, 7277MA, 7144M, 7144MA, 7150M10 and 7150MA10 all use a contoured unplated aluminum flange bearing. The unplated aluminum offers excellent seizure resistance and works well with the stock iron crankshaft.

Main set number 107M uses a contoured overplated copper-lead flange bearing. This bearing works better on steel cranks and offers greater strength over the aluminum part and should be used for extreme applications. However, this material is more sensitive to debris so the oil should be changed more frequently. I would recommend this part for a race motor, but not necessarily a regularly driven street motor.

So to sum up, all the flanges should now have contours (the contour for the 107M was added in May '03).

 

[ijames]

THANK YOU. It sure is nice to see a major manufacturer making product improvements for such old vehicles.

 

[disco stu]

Bumping a very old post because it is relative.



87GN&98Vette, I saw your sig and figured you might be able to help me out.
I have an engine that was pretty fresh, but due to a lifter failure I had to pull it. Since there was no damage to the rotating assembly, little machine work was needed. So I proceded to put the same bearings I had in it because there was no need to machine the crank. I then realized (AFTER I got the bearings coated of course) that the thrust bearing was larger than what I had in the car before. These are the numbers as they are on the back of that bearing.

7117CH U
F/m
STD
07 02
447Q

Is this bearing available separately?
Is a coated version listed?
And what is the part # of the separate bearing if available, and also the part # of the complete kit with this bearing?

If you could help me out it would save me alot of hassle. TIA

This was also sent via PM and email.