Clutch disc diameter?

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French demon

French demon

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Hi guys

I would like to order a new clutch disc and I would like to know its diameter before removing the gearbox.
FSM tells 9 1/4 (standard) and 9 1/2 (optional) disc diameter for slant-6 and A230 transmission.
How can I know the correct one for my transmission?
:thankyou:
 
First we need year make and model - engine size and transmission size before we can help.
 
IDK what size clutch your 1971 Demon with a 198/A230 has,
but since the 198 is the smallest slanty available in '71,
I'd guess it has the smallest clutch;
But I'm just guessing, lol
 
AJ/FormS said:
IDK what size clutch your 1971 Demon with a 198/A230 has,
but since the 198 is the smallest slanty available in '71,
I'd guess it has the smallest clutch;
But I'm just guessing, lol
Click to expand...

Yes, it's logical :). But an optional 9 1/2" disc is mentioned in the FSM for the 198ci.
So, I suppose that it's impossible to determine the disc diameter without removing the transmission... :rolleyes:

Clutch disc.jpg
 
Call Brewer Performance. They used to sell a scalloped 10" clutch to replace the 9 1/2" one,
 
French demon said:
.............So, I suppose that it's impossible to determine the disc diameter without removing the transmission... :rolleyes:
Click to expand...

Not sure you can but maybe it's possible to get a measurement from the disc OD to the input shaft spline.
4" and less would be a 9" I believe.

1713363240580.png
 
or see if you can identify the trim/options

looks like you car could be "L" or "J" if yours is "J" whatever that means it at least had a 9 1/4 when it left the factory

if its an L and was a Europe assembled car we often got "special" equipment.. don't know why probably local environment or different servicing routine specified

look at barracudas many got high end trim and the formula S suspension and brakes i.e stuff optioned in just for export (CKD) Kit assembled or exported US assembled cars.

if in doubt get the 9 1/4 i doubt it will make much difference for this application and will work with both pressure plate

70.8 square inches of plate both sides vs 67.2 both sides

141.6 vs 134.4
6% reduction
Is your motor still producing 100% of the torque and power it made on day 1? 500-1000 miles after day one :) when it was run in.


Dave
 
Last edited:
Dave999 said:
or see if you can identify the trim/options

looks like you car could be "L" or "J" if yours is "J" whatever that means it at least had a 9 1/4 when it left the factory

if its an L and was a Europe assembled car we often got "special" equipment.. don't know why probably local environment or different servicing routine specified

look at barracudas many got high end trim and the formula S suspension and brakes i.e stuff optioned in just for export (CKD) Kit assembled or exported US assembled cars.

if in doubt get the 9 1/4 i doubt it will make much difference for this application and will work with both pressure plate

70.8 square inches of plate both sides vs 67.2 both sides

141.6 vs 134.4
6% reduction
Is your motor still producing 100% of the torque and power it made on day 1? 500-1000 miles after day one :) when it was run in.


Dave
Click to expand...

Hello Dave
"L" is for Dart, and "J" for Challenger.
And it's not an Europe made car. It has been assembled in Hamtramck, Michigan.

I also think that the 9 1/4" will fit... I saw that Rockauto has this kind of disc for sale.

Thanks all.
François
 
French demon said:
Hi guys

I would like to order a new clutch disc and I would like to know its diameter before removing the gearbox.
FSM tells 9 1/4 (standard) and 9 1/2 (optional) disc diameter for slant-6 and A230 transmission.
How can I know the correct one for my transmission?
:thankyou:
Click to expand...
Measure it Like Dave69 described or take it apart then order what you need.
 
I cannot take the transmission apart and wait for the delivery. I'm in Europe and deliveries from USA take at least one or two weeks.
 
French demon said:
I cannot take the transmission apart and wait for the delivery. I'm in Europe and deliveries from USA take at least one or two weeks.
Click to expand...
Then you'll have to get crafty and measure it through the inspection cover. @Dan Brewer do you have any information for this member to help him out?
 
122 tooth wheels have 10.625" bolt pattern. You could measure from the edge of the disc to the CENTER of a pressure plate bolt.

If it has a 9.25" disc, measurement should be around 0.687". 9.5" disc = 0.562" 10.0" disc = 0.312"

pressure plate bolt pattern.jpg
 
I got some help from a friend here, and following his advice, I upgrade my clutch to 10"
I wasn't sure that my bellhousing and flywheel would accept it, but this friend has a '71 Barracuda with the same 198ci than mine and he has a 10" OD clutch.
I ordered this one from Rockauto :
More Information for M-PACT 05004

:thankyou: all for your help and your time
François
 
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