Clutch disc diameters?

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njcar757
Posts: 79
Joined: March 4th, 2009, 4:00 pm
Body Type: closed cab
Model Year: 1929

Clutch disc diameters?

Post by njcar757 »

I own a 1929 AA, when I took it apart, it had a 10" clutch disc in it. I also own a 1930 AA swamp buggy, when I took it apart, it had a 10' clutch disc in it. It is my under standing that all the A automobiles feft the factory with 9' clutch discs. Is it safe to assume that all the AA's left the factory with 10' clutch discs? Some model A'ers seem to think a 10" clutch work in a model A automobile pressure plate and flywheel? I hope someone can clear this up for me.
Thanks Nick c
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Neil Wilson
Posts: 3062
Joined: February 5th, 2003, 9:42 pm
Body Type: 82-A/89-A
Model Year: 1930
Location: Boulder, CO
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Re: Clutch disc diameters?

Post by Neil Wilson »

The August 1, 1929 Ford parts price list has AA parts for the clutch disc clutch disc assembly and clutch pressure plate and cover assembly. No dimensions are given. And, I don't know about interchangeability. Hopefully someone can explain.
Regards, Neil Wilson
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Reds34
Posts: 603
Joined: May 15th, 2010, 2:34 pm
Body Type: dump
Model Year: 1930
Location: Eastern, CT

Re: Clutch disc diameters?

Post by Reds34 »

I thought that was the difference between the truck and car engines? I think the 10" would work in a car, but don't quote me on that one.

Red
E.Moore
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Joined: April 15th, 2005, 5:35 pm
Model Year: 1930
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Re: Clutch disc diameters?

Post by E.Moore »

The flywheel is the same in the A car & AA truck after the introduction of the single disc clutch. The car can use the 10" clutch disc which was in the AA. My 31 AA has the 10" clutch disc. There was approximately 1/4" clearance from the outer diameter of the clutch disc to the flywheel inside diameter.

The pressure plate completely covered the 10" clutch disc. During Model AA production, the 10" clutch disc was used with pressure plate springs of a thicker wire diameter in order for the AA clutch to prevent slippage under heavy loads.

With the AA trucks these days not being used to haul really heavy loads, either the 9" clutch disc or the 10" clutch disc should be fine. The 10" clutch disc would be fine in the A car, especially ones that have modified engines. The pressure plate springs should not really matter that much unless the truck is being used to haul heavy loads.

If heavier pressure plate springs are desired, take the pressure plate apart and get springs that are the next wire size thicker and use them. Be aware that heavier pressure plate springs would cause the clutch pedal to be harder to push.
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Chris Haynes
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Joined: September 7th, 2003, 5:18 pm
Body Type: 82A
Model Year: 1930
Location: Camarillo, CA

Re: Clutch disc diameters?

Post by Chris Haynes »

I would like to find a 10" with the spring loaded center section. That takes the lurch out of start ups.
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vtwinsideways
Posts: 452
Joined: March 19th, 2010, 6:37 pm
Body Type: 82-A, 88-A
Model Year: 1929
Location: Taylorville IL

Re: Clutch disc diameters?

Post by vtwinsideways »

A'ers who trim some weight off of their flywheels (in some cases 20-30 lbs) often look for the 10 inchers to get a little more grab. It's nearly as easy to just switch to the v8 set-up which is more commonly available. Luke
"I get all my exercise jumping to conclusions."
Luke in Illinois
SHELBY MESSER
Posts: 752
Joined: March 9th, 2009, 8:06 pm
Body Type: 75-A
Model Year: 1930
Location: Sacramento, Ca.

Re: Clutch disc diameters?

Post by SHELBY MESSER »

Anyone wanted a spring loaded center in the clutch center. Bring your old clutch to a local auto parts house and ask them to match you up with a clutch dic. Don't ask for a clutch for an 30 AA ford truck. They won't have one. Tell them it's for a FORD. Make sure the splines are the same. 10" clutch is fine, and a 9" clutch will work well. Most of these old trucks will never work hard as they were in their days. Most of them may still have the factory clutch after 80 yrs not bad hau! Shelby, Sacramento.
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Erskine48
Posts: 68
Joined: April 9th, 2008, 9:20 pm
Body Type: 82a/3axle
Model Year: 1929
Location: Huntingon Beach Ca.

Re: Clutch disc diameters?

Post by Erskine48 »

My clutch shop had a new disc made for my 27 Erskine by a race clutch shop! Bob E.
Reds34
Posts: 603
Joined: May 15th, 2010, 2:34 pm
Body Type: dump
Model Year: 1930
Location: Eastern, CT

Re: Clutch disc diameters?

Post by Reds34 »

I took the transmission out of my '34 and looked at the clutch. It is a 10" diameter spring loaded center section. The splines do line up with a model A car and truck and V8 3 speed. I looked in the Macs catalog and they have a 10" clutch for a 3 speed V8 that I'm am going to get. I thought I'd let you guys know if you were thinking about getting 10" clutches.

Red
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