Clutch confusion - please help!

[Bob_D]

Question 1. Does the flywheel in the attached photos look to be correct for a TR3A?

Question 2. Does the pressure plate and release bearing look correct?

The pressure plate doesn't match the flywheel. My thought is TRF shipped the wrong clutch kit, but since we purchased the flywheel seperate from the engine we are rebuilding, it is possible that the flywheel is the problem.

Any other information I could provide to help? Dimensions, etc.

Thanks much

 

[TR3driver]

Flywheel looks slightly wrong to me; clutch & TOB look fine.

Is the bolt circle on the flywheel just slightly smaller than the clutch? If so, it might be a 4A flywheel. The single dowel hole tends to indicate that too.

 

[martx-5]

I put a TR4A flywheel in my TR3 because I put in a HVDA trans conversion. That looks like the one I put in. The pressure plate you have shown looks just like the one that came out of my TR3.

Edit: I had to use a TR4A flywheel, because the trans conversion requires using a TR6 clutch pressure plate.

 

[Bob_D]

Thanks for the quick feedback -- sounds like you may have nailed it. One more piece of data- I just measured, and the mounting surface of the flywheel is 11" in diameter while the pressure plate is 11 3/8" diameter. Does this help confirm? Thanks

 

[DNK]

Gees Bob, since you got the flywheel might as well change to a 5 speed.

 

[TR3driver]

One more piece of data- I just measured, and the mounting surface of the flywheel is 11" in diameter while the pressure plate is 11 3/8" diameter. Does this help confirm?

It at least confirms you don't have a 3A flywheel there. I just stuck a tape measure on what I believe is the original flywheel from TS39781LO, and it's 11-3/8" edge to edge. The clutch only measures 11-5/16", but that's likely within the manufacturing tolerance.

 

[fogdot]

I have a 3A, and this exercise might be in my future.
Are flywheels interchangeable? Between the 3A and 4 flywheel diameters, what happens with ring gear/starter compatibility?
Dave

 

[TR3driver]

Well, the short answer is "It depends"

For the TR2-4A, there are 3 different flywheels, 2 different ring gears, 2 different clutches, 2 different starters and 3 different gearbox castings. Some will fit others, some won't. But the crankshafts were all the same, so all the flywheels will fit all the cranks. The two major change points were at TS50000 (more or less the middle of the TR3A run), and at the TR4-4A transition.

Early (TR2-TR3A/TS50000) flywheels had a pressed-on ring gear and will only work with the early starter and early clutch (although it's possible for a machine shop to redrill them for the later clutch).

Middle flywheels (TR3A/TS50001 - TR4) take the bolt-on ring gear, later starter, but early clutch.

Late flywheels (TR4A) take the bolt-on ring gear, late starter, and late clutch.

The late clutch also requires a different TOB, TOB carrier, and gearbox front cover (but an early cover can be modified to work).

The early gearbox (3 synchro, to TS50000) will not accept the original late starter; but will take the gear-drive aftermarket starter that is compatible with the late ring gear.

All clear as mud ?

PS, forgot to mention that the early gearbox can be modified to accept the late starter, by cutting a big hole in the side.

Also, the 3A transmission tunnel was modified at TS50000 to clear the later gearbox, but again early ones can be modified to fit.

 

[Bob_D]

Thanks TR3driver - I have a pre-TS5000 car with a post-TS5000 engine, and have just purchased (after realizing that I have a TR4A flywheel) a post-TS5000 flywheel. I also have a new gear-reduction starter. From what I read in your post, it all should fit together and might even work!

 

[TR3driver]

Yup, as long as your starter is the post-50K type, you should be good to go. Only difference is the pinion gear on the starter, as I recall the early flywheel takes a 9 tooth pinion, while the later types take a 10 tooth.

 

[Bob_D]

Beautiful -- Just opened the starter box and counted the teeth. 1,2,3,4,5,6,7,8,9...10! Thanks for the help TR3driver and everybody else who pitched in.

 

[Bob_D]

Just to close the loop -- received my new (used) flywheel and it is, indeed, correct! Thanks again. Who knows, we might actually get this thing on the road this summer after all.