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Brand new throwout bearing and clutch smashedsad smiley

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ice Avatar
ice Gold Member Larry Ice
Lawrenceville, GA, USA   USA
Ok guys, seems the jury is still out on graphite vs bearings. When on of the guys (Gerard?) mentions about the arc being different and not good for the bearing it seems like the graphite TOB goes thru the same arc when the clutch is pushed in. Ok, if both types of bearings move thru an arc across the pressure plate bearing surface it would seem to me having a bearing that spins would at least cut down on the heat generated as the bearing moves across the pressure plate flange? Just some thoughts!



Iceman

Atlanta GA

60 AH MK1
62 AH MKII
67 Midget
71 Midget

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dickmoritz Avatar
dickmoritz Gold Member Dick Moritz
Philly 'burbs, PA, USA   USA
Graphite bearing works just fine a little off-center because it is still pressing against the flat disc on the pressure plate. It runs cool because it is self-lubricating. With the roller bearing, the disc on the pressure plate is omitted, such that the bearing bears against the pressure plate diaphragm fingers, and off-center will result in uneven release of the pressure plate's friction surface...

Dick

In reply to # 3553552 by ice Ok guys, seems the jury is still out on graphite vs bearings. When on of the guys (Gerard?) mentions about the arc being different and not good for the bearing it seems like the graphite TOB goes thru the same arc when the clutch is pushed in. Ok, if both types of bearings move thru an arc across the pressure plate bearing surface it would seem to me having a bearing that spins would at least cut down on the heat generated as the bearing moves across the pressure plate flange? Just some thoughts!



Errabundi Saepe, Semper Certi
(Often wrong, but always certain)

AN5L8016 Avatar
AN5L8016 Mark Haynes
Nederland, Colorado, USA   USA
Where did this come from, Dick?
In reply to a post by dickmoritz With the roller bearing, the disc on the pressure plate is omitted, such that the bearing bears against the pressure plate diaphragm fingers,
If you remove the plate for the back of the pressure plate, you change the contact point of the TO bearing such that, as you said, the bearing now contact off-center. The bearing-style TO should be made to the same distance from centerline dimensions as the original, so use of the plate on the PP is mandatory, and therefore retains the contact pressure as a distributed load on the PP fingers rather than a momentary load on the point of the fingers which would cause undue wear and premature failure of the PP fingers, No?



'58 Bugeye
'05 Mini Cooper S

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dickmoritz Avatar
dickmoritz Gold Member Dick Moritz
Philly 'burbs, PA, USA   USA
Thanks for the note, Mark. I may well be mistaken on this point, as I always use the clutch kits with the carbon bearing. I know with the 'murcan cars I've worked with over the years they've all used mechanical linkage and a ball/roller bearing riding directly on the diaphragm fingers, with no disc for the bearing to abut. I'll welcome you or someone else confirming that the pressure plate used with the roller bearing is the same configuration as that used for the carbon bearing.

Errabundi saepe... cool smiley

Dick

In reply to # 3553650 by AN5L8016 Where did this come from, Dick?
In reply to a post by dickmoritz With the roller bearing, the disc on the pressure plate is omitted, such that the bearing bears against the pressure plate diaphragm fingers,
If you remove the plate for the back of the pressure plate, you change the contact point of the TO bearing such that, as you said, the bearing now contact off-center. The bearing-style TO should be made to the same distance from centerline dimensions as the original, so use of the plate on the PP is mandatory, and therefore retains the contact pressure as a distributed load on the PP fingers rather than a momentary load on the point of the fingers which would cause undue wear and premature failure of the PP fingers, No?



Errabundi Saepe, Semper Certi
(Often wrong, but always certain)

refisk Avatar
refisk Rick Fisk
Frankenmuth, Michigan, USA   USA
Mark,

Cars with roller type throwout bearings usually do not have the disc on the pressure plate. The roller bearing rides concentrically on the "fingers" of the spring mechanism in the pressure plate. Because the throwout bearing is concentric with the transmission input shaft there is no grinding between the fingers and the throwout bearing. Our Spridgets use the disc on the pressure plate because the throwout bearing is not concentric with the disc and slippage has to occur throughout the life of the clutch.

Here is a Chevy pressure plate with no disc.....


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PeterC Avatar
PeterC Platinum Member Peter Caldwell
Madison Wisconsin, USA   USA
Couple of terms.... the "plate" on the pressure plate for the bearing is a thrust plate.
The sleeve that some cars use as a guide for the bearing to ride on over the input shaft is a quill.

Peter


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ice Avatar
ice Gold Member Larry Ice
Lawrenceville, GA, USA   USA
thnx for setting us straight Pete.



Iceman

Atlanta GA

60 AH MK1
62 AH MKII
67 Midget
71 Midget

S1 Elan Kurt. Appley
Akron, Ia., USA   USA
Hap has been using them for years on race cars with, I presume, heavier duty pressure plates. That may be a good substitution in that case but I would still like to hear from someone that has put 40K miles on one. With the arrangement of the TO bearing in a Spridget I can see no way that the ball bearing wouldn't be turning all the time. Even if you tried to retract the Throw out the bearing would tip against the pad on the pressure plate fingers.

Kurt.

AN5L8016 Avatar
AN5L8016 Mark Haynes
Nederland, Colorado, USA   USA
I was asking to be sure that Dick was not advocating removal of the (to be correct) Thrust Plate from the pressure plate if one is using a roller TO bearing, and that if such was the case that he had some reason for advocating so. As you can see from my thought process, I wholeheartedly believe that even with the use of a roller bearing, one needs to have the thrust plate in place.



'58 Bugeye
'05 Mini Cooper S

dickmoritz Avatar
dickmoritz Gold Member Dick Moritz
Philly 'burbs, PA, USA   USA
Thank you, Mark. I don't know enough about these roller bearing setups to advocate one way or another. I just know that the old-school American cars I've worked on do not use such a thrust plate, and I'm just uncomfortable with the lack of a proper pull-back mechanism, coupled with my good experiences with the carbon bearings, so I just stick with what works for me...

Appreciate the insights... smileys with beer

Dick

In reply to # 3554453 by AN5L8016 I was asking to be sure that Dick was not advocating removal of the (to be correct) Thrust Plate from the pressure plate if one is using a roller TO bearing, and that if such was the case that he had some reason for advocating so. As you can see from my thought process, I wholeheartedly believe that even with the use of a roller bearing, one needs to have the thrust plate in place.



Errabundi Saepe, Semper Certi
(Often wrong, but always certain)

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