Clutch Question

40fordpu

40fordpu

Well-known member
I realize there are different size clutches...probably for different years and probably for different applications ie. pickup, standard, etc (correct me if I am wrong). So here are my questions...

1. How is a clutch measured? ( I hear 9 1/2 and 10 all the time for example)

2. If I am running a 1940 what is my clutch size? (if application matters let say pickup vs. standard)

3. If I am running a 1949 what is my clutch size? (if application matters let say pickup vs. standard)

4. Does engine determine clutch size?

Thanks
 
A stock '40 used a 9" clutch. That is the diameter of the disc. Unless you are building up your engine (increasing HP / torque), the stock clutch will serve you quite well.
I most often modify my set-up and use a 10" diameter clutch.
I'm not certain what diameter was used in '49. It seems to me both 9 1/2" and 10" depending on the specific vehicle application.
 
Further to Kube's post, application does effect clutch size. The larger the disc diameter, the more square inches of clutch lining there are. More square inches od lining, the more torque can be transmitted. So, bigger engines need bigger clutches. Similarly, heavier loads - like in trucks - need bigger clutches. Fort Wayne Clutch in Fort Wayne, Indiana is a great source of clutch parts, service and technical advice. Hope this helps.
 
To add to Henry and Kube, vehicle weight also plays a factor. Lighter vehicles can use smaller, lighter clutches. Hence, an aluminum flywheel works well in a light car but perhaps not as well in say a coupe or a sedan.

If you are staying stock, no question, go with what came in the car originally - Henry had it right for many, many things in these cars. However, if you are going for more performance or "over the road" kind of vehicle say with a 5-speed or perhaps a nostalgia hot rod, that changes things.

The stock 9" flywheel has a heavy metal lip on the outer edge - the 10" does not. On my 32 in my avatar I'm using a 9" clutch setup but I had the heavy outer lip shaved off to lighten it. I basically used it because I had it, the matching p-plate was good, and I didn't have anything else. It's basically a stock 40 engine with headers and 2 deuces that run progressive. This has a 5-speed in it.

In my 40 coupe however, I used a 10" setup with the 5-speed as it is a heavier car and the engine does have some modifications like 4" crank, hot cam, 2-deuces, hot(ter) ignition, headers.

So again, you fit your setup to your application, weight, and intended use.
 
The stock 9" flywheel has a heavy metal lip on the outer edge - the 10" does not. On my 32 in my avatar I'm using a 9" clutch setup but I had the heavy outer lip shaved off to lighten it. I basically used it because I had it, the matching p-plate was good, and I didn't have anything else. It's basically a stock 40 engine with headers and 2 deuces that run progressive. This has a 5-speed in it.

In my 40 coupe however, I used a 10" setup with the 5-speed as it is a heavier car and the engine does have some modifications like 4" crank, hot cam, 2-deuces, hot(ter) ignition, headers.

So again, you fit your setup to your application, weight, and intended use.[/QUOTE]
Hey Tom,
Like you, I always shave the bell off of my stock flywheels. I see no advantage to maintaining that extra weight. I also re-drill my flywheels to accept a 10" clutch. No need really as my cars once completed, are rarely, if ever driven. Just something "I do" :)
 
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