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03-30-2024, 10:05 PM | #21 |
Junior Member
Join Date: Sep 2020
Location: Goose Creek, SC
Posts: 23
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Re: V8 Clutch in Model A: Something is not right
note on the second picture I removed the nut that was originally on that side, backed out the screw, and added a nut on the other side (which may or may not end up as the final configuration -- but at least this way I would not drive the fingers into the clutch disk, all other things being equal)
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04-05-2024, 08:13 AM | #22 |
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Join Date: Apr 2021
Location: Central Illinois
Posts: 528
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Re: V8 Clutch in Model A: Something is not right
Lyle, what is the status of your project? Any luck?
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04-05-2024, 11:30 AM | #23 |
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Join Date: May 2010
Location: on the Littlefield
Posts: 6,194
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Re: V8 Clutch in Model A: Something is not right
get a disc that is the proper thickness, then no modifications are needed
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04-09-2024, 09:23 AM | #24 |
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Join Date: Sep 2020
Location: Goose Creek, SC
Posts: 23
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Re: V8 Clutch in Model A: Something is not right
The measurement from the flywheel plane to the pressure plate plane (with no clutch disk installed) is ~ 0.140". I got a friend to measure the same dimension on his V8 pressure plate and it was 5/16 (0.313). I called Bratton's and the person measured one off the shelf and it was 0.185". And so if I take the bratton's measurement, that is still 0.045" more than the one I have. And the design of the fingers give about 5:1 ratio on movement of the throwout bearing to movement of the plate...which means my throwout bearing would have to move 0.225" farther towards the engine to get the same release of the clutch. And so this is enough to explain why the fingers were having interference with the clutch disk.
Bottom Line -- I think the V8 Pressure Plate Assembly that I have is not right. Bratton's agreed to exchange it for a new one, but I have already had this one balanced to the flywheel and so I am inclined to just shim the pressure plate out from the flywheel using some precision washers. I have not started that process yet, but that is what I plan to do at this point. |
04-09-2024, 09:48 AM | #25 |
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Join Date: May 2010
Location: Southern Maine
Posts: 1,513
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Re: V8 Clutch in Model A: Something is not right
It works.
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04-10-2024, 06:03 AM | #26 |
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Join Date: Apr 2021
Location: Central Illinois
Posts: 528
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Re: V8 Clutch in Model A: Something is not right
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Balance your Model A flywheel at Home! The portion of interest starts at ~ 14 minutes in. George mentions the relationship of the range of pedal movement as it relates to the range of the pressure plate finger movements. He is discussing the stock Model A setup, but it applies to the non stock, customization of using a modified flywheel dimension along with a V8 pressure plate. I've read that the collar on the end of the pedal shaft is not the sole player in the travel of the clutch pedal. A senior guru stated that the upper floorboard had a role in limiting that travel. I believe this is true of our coupe's functioning and a friend's coupe with a stock setup. Without the floorboard, the pedal goes all the way to the firewall metal. This may be further than with the upper board installed. Just a thought. Our coupe's functioning, with new Bratton's clutch disc measuring ~.375-.380 thickness with the used V8 pressure plate required additional free play at the top of the pedal to work correctly. When I had it at 3/4" free play, I had the same result that you had, and I could watch it happening via the inspection window. I'll be interested in your experiment moving the pressure plate farther away from the flywheel. I suspect that you will simply diminish the pressure that the pressure plate exerts on the clutch disc when the pedal is at the top of its range. A stock setup exerts 1200 pounds. I don't have enough experience to speak with any authority, but in IMHO, I'm thinking that the proper operation of your setup will require a proper adjustment of the free play. In other words setting the max forward position of the throw out bearing in the correct position of the min and max travel of the pressure plate fingers. I'll be learning with you as you report your findings. Luck to ya.
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"It ain't what you know for certain that gets ya in trouble. It's what ya know for certain that just ain't so!" Last edited by Rob Doe; 04-10-2024 at 06:30 AM. |
04-27-2024, 05:49 AM | #27 |
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Join Date: Apr 2021
Location: Central Illinois
Posts: 528
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Re: V8 Clutch in Model A: Something is not right
lyle: where'd ya go, any progress?
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"It ain't what you know for certain that gets ya in trouble. It's what ya know for certain that just ain't so!" |
04-30-2024, 07:40 PM | #28 |
Junior Member
Join Date: Sep 2020
Location: Goose Creek, SC
Posts: 23
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Re: V8 Clutch in Model A: Something is not right
So...my analysis is that the pressure plate was not allowing the clutch to properly release -- not enough stroke to adjust the pressure plate to release the clutch disk...
I could have just swapped out the pressure plate, but since this one was already balanced to the flywheel I was reluctant to do that. And so in the end I simply installed washers between the pressure plate and the flywheel, adjusted the fingers according to the specs, and put it all back together and everything is working fine. Per the guidelines, I adjusted the pedal so that there is about 1" pedal travel before the throwout bearing is contacted. The clutch totally releases with the pedal down to the floor, clutch is fully engaged when the clutch pedal is released...so all good! |
04-30-2024, 07:59 PM | #29 | |
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Join Date: Sep 2020
Location: Goose Creek, SC
Posts: 23
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Re: V8 Clutch in Model A: Something is not right
Quote:
I bought more washers than needed, then checked thickness of each one to make sure they were all within 0.001" -- most of them were and so not much sorting was required...(the washers were from Lowes btw). |
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05-01-2024, 09:55 AM | #30 |
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Join Date: Jun 2015
Location: Red Deer, Alberta
Posts: 5,109
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Re: V8 Clutch in Model A: Something is not right
How thick was each stack of washers?
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05-01-2024, 03:13 PM | #31 |
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Join Date: Sep 2020
Location: Goose Creek, SC
Posts: 23
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Re: V8 Clutch in Model A: Something is not right
as mentioned, the washers were 0.069" thick -- I only used a single washer at each screw and so the effect was that the pressure plate was 0.069" farther out from the flywheel vs. what it was previously.
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05-02-2024, 10:28 AM | #32 |
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Join Date: Jun 2015
Location: Red Deer, Alberta
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Re: V8 Clutch in Model A: Something is not right
Thanks
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