Clutch Questions

RAF

RAF

Member
Finally got around to pulling the motor and ****** out of my 40 Ford coupe so I can repaint firewall and inner fender wells and also repaint motor. While the engine is out I figured it would be a good time to see what shape the clutch was in. The car has a 59AB flathead with a 39 floor shift transmission and this is the first time the car has been apart since I bought it. I was surprised to find an 11" clutch in the car, not that familiar with flatheads but from what I have read most cars have 9" or 10" clutches and trucks have the 11". My questions are should I just by a new 11" pressure plate and disc or look for a 9" or 10" flywheel and clutch set. Do all the flywheels have the same outside diameter and number of teeth so my starter will work? Thanks for any help you can offer.
 
It depends on what you are wanting to do with it. If you are wanting a little increase in performance/acceleration then the smaller diameter clutch/pressure plate is worth the effort. If you could care less and are OK with the current clutch pedal effort that leave it as is.
 
Not looking to tow or for hi performance use and I don't want a hard pedal looking more to the stock setup.
 
RAF said:
Not looking to tow or for hi performance use and I don't want a hard pedal looking more to the stock setup.
Click to expand...

You currently have the stiffest pedal setup, so anything else (9 or 10) should be a lot softer
 
The '40 originally came with a heavy flywheel and a 9" clutch. Assuming that you still have passenger car gearing and that Ford engineers knew their stuff, then the smaller clutch is the one well suited to the car. The 59A engine at 239 cubes may have a bit more starting torque, so a later 59A (lighter) flywheel would be no practical problem, most of which are flat and drilled for a 10" clutch, but can be redrilled. I am pondering the same issue with my '40, expecting to use a higher gear ratio and a 59A engine. Part of my fix is to use the 15-29 "pickup" trans gears to bring things into a practical expectation. It's all about the numbers. If you have a super strong motor stupid combinations are harder to detect and less likely a problem. Flatheads are still better off with smart gear choices. You might wonder how the choice of clutch works in with the gearing. Just ask your left leg if ignoring physics is a good idea. Good Luck: Fred A
 
Again this is mostly a matter of your objectives. If you drive your car a lot, drive at highway speeds and are concerned about gas milage, then a higher gear ratio might be a good option. On the other hand a lot of intown/stop and go driving, hilly area and less MPG intrest might favor a lower gear selection. So what does this have to do with flywheels and clutchs? The heavier the car and the higher the rear axle ratio the more you might lean toward a heavy flywheel/clutch combo. The lighter the car and with lower gearing you might consider a lighter flywheel/clutch. If none of this matters much and you are just interested in a little pedal feel, go with the smaller clutch and whatever flywheel.
 
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