65tripleblack

...........but there's no Eye of Providence.

Both the flywheel and pressure plate have matching patterns of three round 2" diameter blue hot spots spaced on a perfect equilateral triangle, or, 120 degrees around the circumference of both parts. All 6 hot spots are dead center radially between the outside and inside of the rub area of the clutch disk.

R66

Uneducated SWAG.
You have a Borg and Beck three finger PP?? 120 degrees apart on the fingers.
Now, if you straight edge the PP surface, are the hot spots higher than the rest of the surface?
As I started out, Uneducated SWAG. Maybe a real mechanic will chime in.

65tripleblack

It's not a B&B. It's a diaphragm type. I'll get some pictures after surgery.

65tripleblack

Pictures

GTOguy

Those areas got HOT....and the surrounding areas didn't. That tells me that there's uneven contact being made. One or both surfaces are not true to each other. I suspect high spots in the flywheel, disc, or pressure plate. If all parts were flat, you would not have isolated hot spots.

TJefferson2020

This. I don't think there is any other source of heat with a clutch plate other than friction. I wonder if there is some irregularity on the mating surface?

Easy Rhino

Totally agree. Those three spots appear to be absorbing the heat load that should be distributed across the entire surface of the pressure plate contact area.

R66

Looks like the original grinding marks are still on the PP surface between the hot (high) spots. My guess if the PP was somehow warped during fabrication or the adjustment bolts for the diaphragm spring pressure were not properly set.
Is that a RAM pressure plate?

65tripleblack

Yes. It's a 401......2800# pressure.

Rich Yanulis

I will take a stab at this.
I know very little about clutches, however I have a lot of common sense.

If you look at the outside perimeter of the pressure plate........
You will see that it is broken down into three identical segments.
The three hot spots line up exactly with the same "center" flywheel mounting bolt.

So, if I had to GUESS.....I would say that the pressure plate is defective.
It seems to be applying uneven pressure, concentrating the force inline with those three mounting bolts.

65tripleblack

What I don't understand is how/why the same exact hot spot pattern appears on both the wheel and the PP. And why a perfect equilateral triangle? Coincidence?

Both were installed brand new. I remember a thread a while back where somebody said that a flywheel they bought new was recommended SURFACED out of the box before installing!!!!

65tripleblack

Maybe R66 was onto something in his early post because there is the same symmetry in a diaphragm as in a B&B PP:

The PP has three equally spaced arms which connect the friction surface to the diaphragm spring. The hot spots are lined up with the three arms on the clutch cover. Maybe there's flex in the plate? Far fetched? Defective out of the box?

And that still leaves the question as to why that same pattern shows on the flywheel?

Westlotorn

Looks like the clutch was very hot and then parked with the hot spots radiating where the pressure points were. The clutch turns separate from the pressure plate/flywheel but if the pressure plate was heated in those spots and then you parked the heat would transfer to the flywheel in those spots.
I have seen this in brake discs. Someone drives down a long steep hill and parks at a red light. Sitting at the red light the heat concentrates on one spot since there is no rotation.
If it was mine I would be wondering why the pressure plate does not distribute pressure evenly, it would make your clutch much more effective.

pop23235

First, I don't know. Having established that, I'd be curious to see the clutch disc. A hot PP should not burn the FW like that. If the FW is flat (?) I'd rule that out and suspect the disc may not move freely on the input shaft or the PP is defective. (or the disc is installed incorrectly?)

ejboyd5

Send the pictures to the clutch manufacturer.

R66

The disc is going to wear against the surface it is spinning against. My guess (really dumb and not an expert) is that the disc should show a groove on the side that has the high spots but, then that the heat then was transferred to the PP or FW as those were the points of most contact.

Did you mark the PP location on the flywheel before disassembly? Is the clutch disc worn unevenly on one side or both.

I have seen discs worn on the PP side due to the PP diaphragm springs being weak, or the PP surface warped and resulting on more pressure on the outside of the disc and less pressure on the inside of the disc, but never symmetrical hot spots.

Lay a straight edge across the hot spots and with a .001" feeler gauge and up, see what you find.

Bottom line is to get the FW resurfaced and dump the PP and disc regardless of the visual inspection.

I used a couple of cheap RAM setups in the 70s and 80s in drag cars and was never really happy with them. Spend a few more bucks and find something better if you are dumping the clutch and expect it to hold.

Westlotorn

At least with brake discs and drums we instruct to never try to grind out blue spots because even after grinding those spots while they look fine they will have uneven hardness compared to surrounding areas on the flywheel and cause problems.

67vetteal

Can you give us anymore info such as symptoms during operation? Was there any Chattering, gear grinding during shifts etc.. It looks like a 'new" install and the Housing of the PP looks suspect to me. Either the Housing is not fully releasing from the Disc or a wrong Thickness Disc was installed. It's got to be something weird, (no Offense), to the average "Back Yard" mechanic. See if there is a rebuilder who can look into this nearby. Always something "NEW" to learn when your a Gearhead! LOL Al W.

GTOguy

A straight-edge, micrometer, and dial-indicator should be able to pinpoint the problem in about 2 minutes..............

65tripleblack

You can bet I'm going to raise hell with them!