Clutch disc - which side goes towards flywheel?

[blueskies]

This is on the early 100-6. The car came with a new clutch disc and pressure plate, with no brand name marked on the parts. The clutch disc has no markings indicating which side goes towards the flywheel.

One side of the clutch disc has the center spline section protrude about one inch from the disc surface. The center spline area on the other side is more flush with the clutch disc.

Any help appreciated.

 

[trrdster2000]

The protruding side goes toward the transmission. The other way will make a **** of a noise for a one time shift.

Wayne

 

[blueskies]

Thank you. That's the way I installed it, to the rear, towards the pressure plate. Just to be clear, the protruding section I'm talking about is the center splined section, about 1/4 inch larger than the transmission output shaft. It may protrude 3/4 inch or 1 inch more than on the other side.

I started second guessing this when reading other posts, including for Triumph cars, where the protruding center should go towards the flywheel. Apparently even the factory manual is wrong on this point for Triumphs. So since Austin Healeys and Triumphs are somewhat related, I started wondering. It would be a lot easier to reverse the clutch disc before the engine and transmission go into the car than later on.

 

[steveg]

Thank you. That's the way I installed it, to the rear, towards the pressure plate. Just to be clear, the protruding section I'm talking about is the center splined section, about 1/4 inch larger than the transmission output shaft. It may protrude 3/4 inch or 1 inch more than on the other side.

I started second guessing this when reading other posts, including for Triumph cars, where the protruding center should go towards the flywheel. Apparently even the factory manual is wrong on this point for Triumphs. So since Austin Healeys and Triumphs are somewhat related, I started wondering. It would be a lot easier to reverse the clutch disc before the engine and transmission go into the car than later on.

With the disc installed incorrectly, would you even be able to bolt the pressure plate up to the flywheel?

 

[blueskies]

With the disc installed incorrectly, would you even be able to bolt the pressure plate up to the flywheel?

Not sure, as I just tried it the one way that seemed right. The internet is full of stories about people who installed the clutch backwards. They often don't notice problems until they try to shift with the engine running.

Admittedly, this seems like a dumb question, but it would not be the first time I had to do something twice. The last two clutches I did were on my Kubota tractor (after the clutch/flywheel housing broke - the Kubota thought it was a D8), and on the Chevelle SS. It always helps with reassembly when one also took things apart. In this case, the 100-6 came in many pieces.

 

[Keoke]

With the disc installed incorrectly, would you even be able to bolt the pressure plate up to the flywheel?

-----------------YES-See what Wayne said :excitement:

 

[steveg]

With the disc installed incorrectly, would you even be able to bolt the pressure plate up to the flywheel?

-----------------YES-See what Wayne said :excitement:

I see what Wayne said; not sure he actually did it the wrong way on a Healey, or if he is surmising that is what would happen. From the previous comment it would seem the Triumph setup wouldn't be exactly relevant to the Healey.
If I recall correctly, with the clutch disc incorrectly oriented, its surface would not be able to seat against the flywheel, due to hitting the pilot bearing, and I would guess it would feel pretty strange when one was bolting the pressure plate in place, if indeed the bolts were long enough.

 

[Keoke]

P.S.
not sure he actually did it the wrong way on a Healey,

Steve____I DID---:glee:

 

[Randy Forbes]

Healeys and MGBs are the same, in that the protruding sprung hub faces the pressure plate (as blueskies installed his), but the other cars I work on the most, the '98-'02 BMW M Coupes/Rdstrs, theirs are installed the opposite way (and instead of a sprung hub, The Germans engineered a twin-mass flywheel__ever the ones to provide the most complicated and expensive alternative to a condition...).

Here's thread about a recent BMW clutch installation gone wrong (in the Philipines), just in case you needed anything to support your choice in British cars AND doing the work yourself
https://www.bimmerforums.com/forum/showthread.php?2180468-Z3M-Roadster-Clutch-Replacement-Gone-Wrong