[tazandjan]

For the 456 through the early 612 (pre-Sessanta/OTO) it is possible to do a visual inspection of the clutch and determine wear. Once the pin reaches the end of the slot, time for a new clutch. Especially important for F1 cars, where one day, the clutch may quit working and strand you.

Brian Crall:

There are several ventilation holes.

On either version what limits clutch life is how far back the TO bearing sleeve or slave cylinder housing can travel rearward before coming to rest on the seal housing flange. Once it gets to the end of its travel the spring pressure starts going down and the clutch's days are numbered.

On a stick shift car there is an anti-rotation device with a pin riding in a slotted steel bracket which is easily seen through the bottom vent hole. The location of the pin in that slot gives you a very effective and accurate guide to remaining clutch life. It should be in the middle of the slot when new and will move to the rear as the clutch wears.

The F1 is a little more difficult. The guide pins for the TO bearing give you the same visual cue. But to really know remaining life looking at the distance between the rear of the sleeve and its distance to the flange of the seal hosing will tell you. It is a little harder. With a bore scope you can get a really good look.

[Bill]

Originally Posted by tazandjan

For the 456 through the early 612 (pre-Sessanta/OTO) it is possible to do a visual inspection of the clutch and determine wear. Once the pin reaches the end of the slot, time for a new clutch. Especially important for F1 cars, where one day, the clutch may quit working and strand you.

Brian Crall:

There are several ventilation holes.

On either version what limits clutch life is how far back the TO bearing sleeve or slave cylinder housing can travel rearward before coming to rest on the seal housing flange. Once it gets to the end of its travel the spring pressure starts going down and the clutch's days are numbered.

On a stick shift car there is an anti-rotation device with a pin riding in a slotted steel bracket which is easily seen through the bottom vent hole. The location of the pin in that slot gives you a very effective and accurate guide to remaining clutch life. It should be in the middle of the slot when new and will move to the rear as the clutch wears.

The F1 is a little more difficult. The guide pins for the TO bearing give you the same visual cue. But to really know remaining life looking at the distance between the rear of the sleeve and its distance to the flange of the seal hosing will tell you. It is a little harder. With a bore scope you can get a really good look.

Terry, when my clutch got a little heavy they showed me the pin, I had new clutch put in... so nice!
Bill