TR4/4A Coil Spring Clutch vs. Diaphragm Clutch

[RJS]

Hey

My car is a '66 TR4A. The TR4A uses the diaphragm clutch, not the coil spring clutch used on the TR4 and earlier cars.

The PO replaced the clutch but, I do not now if he replaced it with the proper diaphragm clutch. Short of removing the transmission, is there any way to tell which is in there? The reason I ask is b/c I am trying to confirm if I should be using the slave cylinder return spring or not. My understanding is the return spring was used on the spring clutches but, not on the diaphragm clutches.

When I received the car, it had the slave cylinder return spring attached. I have driven the car both with the spring on and removed - and it seems to work better with the return spring in place. If I can't determine which clutch is in there, is there any harm in leaving the return spring attached?

Thanks

Bob

 

[TR3driver]

Either clutch should work fine either with the spring or without. But it needs to be spring loaded one way or the other, so if you remove the return spring, you should probably add the spring inside the slave to keep the pushrod extended.

I'm guessing that the 4A flywheel is visibly different and that difference should be visible through the starter hole. But since it is possible to redrill either flywheel for the other clutch, that doesn't guarantee which clutch you have in place.

I've got maybe 80,000 miles so far, on a 4A pressure plate with a TR3A slave setup (return spring plus adjustable pushrod). So far it seems fine. I had it out at about 50,000 (to move from the wrecked 3A to the current 3) and it all looked good.

 

[charleyf]

I do not believe that the differences between the TR3/4 and the TR4A flywheel and ring gear are noticeable to the casual observer. One would likely need both flywheels in front of them to be able to see the difference. The ring gear should be the same on both. The bolt pattern for the two pressure plates/ flywheels are the difference. And it is not a big difference unless you are trying to mount the wrong pressure plate to a flywheel.
Sounds like you should just enjoy and not worry about which one you have.
Charley