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Burn marks on new pressure plate and resurfaced flywheel at 450 miles


'41 Fat Bottom Girl

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First I need to thank everybody that has given me advice and their experiences. The best thing that has happened for my old Dodge is this forum. I sure appreciate all the help. Amazing! 

In my journey to rejuvenate the old '41, in pulling the engine and tranny out again, I noticed burn marks on the new pressure plate and resurfaced flywheel. Having used both three finger and diaphragm style pressure plates in past years, I don't remember seeing this at low miles. I don't ride the clutch, either. As most of us do with no synchros on first, I always go to neutral at a stop and before proceeding, up to second briefly before engaging first gear to avoid grinding.

I have about 450 miles on these parts and wondering if this is a concern, or if I just don't remember noticing this happening in the past. I wonder about the spring count. Looking at the face of the pressure plate, I see two compression springs to the right of each finger and one spring to the left. The burn marks are above the two-spring areas, which intuitively seems to make sense- the two springs exerting more pressure there? I don't have my old pressure plate to compare...

Is there a problem here I should address?

864016599_PPlateandFlywheel450miles.JPG.82ca7588668d75bc452775e78ef0ff78.JPG

1699504000_PressurePlate450miles.JPG.184b6528b1df2188e45fff1d2d280ed3.JPG

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   It looks like a spring is missing in the pressure plate. Causing uneven surface tension. The spring spacing just looks wrong, in that picture. They should all be set in a pattern around the circumference. Two are next to each other.

Edited by 9 foot box
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I suspect the uneven spring pressure also.  Maybe the rebuilder didn't have the right springs to fully load it without making it too stiff, so just left some out.    It is also possible that the plate itself had too much material removed when it was resurfaced, making it flex from the spring issue.   In any case, it probably is not facing an imminent failure.

 

Long ago I had a Pontiac 389 with a standard.  Not surprisingly for a young guy, I had a problem with clutches.  A rebuilder 'fixed' the slipping issue for me by upping the spring pressure.  Worked.  But I couldn't hold the clutch down at red lights!  Had to back off the springs selection a bit.  But we did all of them, not just remove some.

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Others have said in the past here that if a flywheel is turned on a lathe as compared to ground flat on a surface grinder that some hard spots can remain in the surface and cause this issue. I personally have never had a flywheel surfaced as none seemed to need it bad enough to have done. A sanding was all I ever felt was needed. Just lucky maybe.

Just have read that here many times before.

???

 

DJ

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Thanx, guys-

The flywheel was ground, I can tell by the surface swirl marks.

The flywheel was inspected and resurfaced to eliminate small cracks that radiated out from the center; they apparently were not deep and the flywheel could be salvaged. There were no burn marks on it before resurfacing, and the old plate surface looked pretty good too.

My old pressure plate was sent  in for a core, so I don't have it to compare the plate thickness.

 I guess I'd like to know if the localized heating could eventually warp the plate or flywheel, or cause cracks on the flywheel surface.

 

Would you expect any issues down the road? Should I find another pressure plate with a balanced spring arrangement?

 

 

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Sorry to say ?, but radial cuts from center out out would say to me a cut from a lathe is indicated. Where a surface grinder is used where the flywheel is laid out out flat (horizontal)  and a large stone wheel about 1"-2" ( possibly more ) wide is run across the face multiple times. Others have a large grinding wheel also laid on horizontal plane that move across not centered on the flywheel. Hope I make some sense?

 

From past machine shop experience only!

 

DJ

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i just looked at my old Bork and Beck pressure plate that came out of my 39 Desoto and there are three sets of three springs three spring between each lever and the model number is a B&B 10A7  this is a 10 inch PP.

 

The dodge might be the 9 1/4 PP.

 

Rich Hartung

desoto1939@aol.com

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Thanx, guys. Great input.

To be more clear, the flywheel was definitely ground, not turned. Can easily tell from swirl marks from the rotary stone face. The shop uses a fairly large Blanchard type grinder with a 6 inch dia. cupped stone. Parallelism of the face ground surface to the mounting surface is tightly held, verified for no run-out, and then balanced after grinding. I think we can eliminate the flywheel. Good thought, though.

The Pressure Plate is a 10".

Got the PP from Andy B.  I will talk to them to see if I can get a one with an even spring arrangement. If not, I will try to return it and will look for the Bork and Beck or similar. Thanx for the part info.

I also had noticed that the clutch engagement wasn't quite as smooth as it should be, as it would grab a tiny bit part way through the release travel. Not much, but occasionally I noticed it. In the beginning I thought it might be the new disc and surfaces mating in, but after 450 miles of driving that would have been long gone. I suspect that was from the PP too. I will find out.

 

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Looked in my Bork and Beck Borg warner clutch catalog:

 

1941 Dodge  D14 uses the B&B presure plate number  360957  for 10-1 inch  fits 39-50 dodge, plymouth and desoto type 10a7

 

if an export or canadian model then 9 1/4 inch PP  and the number 926  Bork and Beck type 9A7  fits 1940-50 Dodge plymouth

 

hope this helps you,

 

rich hartung

desoto1939@aol.com

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If you live in a highly populated area look up a semi truck transmission and clutch rebuilder and take your pressure plate disc and flywheel to them and tell them to do it to it. Living near Chicago there are companies that do this, which is exactly what I did. Perfect result. Turnaround in an afternoon.

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Des1939- That is a big help if a rebuild or proper replacement doesn't pan out. Thanx for those part numbers.

DG- Living an hour from Phoenix, I am sure I can find one. I'll check out going that route too, especially if Andy B won't take the PP back.

It cost me $43 to ship the first incorrect pressure plate back to AB, so I may just forget about them giving me a remedy. But I will definitely let them know.

Great info, thanx!

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  • 4 weeks later...

This was resolved.

AB took care of me right away, and sent me another Pressure Plate/ Clutch Cover quickly and on their dime. Great response.

I sent the new PP to a truck Brake and Clutch place as recommended and they shipped it back to me within a few days of receiving it. The full count of 12 springs now provides springs in all 12 locations.

Well worth the extra $ to have it rebuilt and the plate parallelism tuned in at throw-out bearing travel distance.

The forces will be now be more even all around the disc face and flywheel dace when clutching, with no localized hot spots...

This will be smooooooth clutching.

Thanx for the help.

Merry Christmas, all!

Bruce

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