erljive

My 1st belt drive OHC engine was the 1st to use the Gates belt drive. A 67 Firebird with the 250 OHC . Ran great and had a ton of miles on it when I bought it and still running when I sold it. Had chain drive M-B's, 4.5 & 3.8 that I changed the copper tubes and fittings for the cooling oil and to make sure they had the double rollers and the sliders weren't toast. I fear chain drive far more than belt drive!

steveoen

At what point did the TT issue become an issue? I have read that it is "later model automatics" but is it truly the later model cars? Or is it ALL automatics? Certainly doesn't look like a complex repair/adjustment - but is it a known issue on the earlier cars as well?

Thanks!

dprantl

Earlier cars had a driveshaft circlip setup that did not allow TBF to happen. Also, earlier cars had less power/torque than the later 32-valve ones.

Dan
'91 928GT S/C 475hp/460lb.ft

Landseer

Thru 1984 they have the driveshaft with an end that accepts a circlip. But it has been said that some mechanics eliminated the circlip during service. That's the way I found mine. I put on a constantine.

1985/6 is another version, without clip. Both of mine are torqued highly and loctited. Will Porklamp or Constantine them later. They get moderate to light use and are frequently checked.

IIRC 1987 began another with a thicker shaft but a deeper taper neck. The 89 TT in my basement has this.

Vilhuer

'85-87 have same shaft as earlier 4sp automatics. With them its possible to use circlip like factory did up to end of '84 MY.

Jfrahm

My 4runner and Audi and my Ducati all have timing belts. It's no big deal really. The only issue I have with the 928 tbelt system is well sorted by the PorKensioner. If it really bugs you, Buy an Audi R8

As for the torque tube, you need to connect the engine to the trans or rear axle somehow and this way, while heavy, is great for stiffness, balance and low CG. Yes TBF is a problem but every car has it's foibles.

-Joel.

JHowell37

I've had several cars with timing chains, and I've never had an issue. I've had a few cars with timing belts. Again, I've never had an issue because I replaced them at the manufacturer's suggested replacement interval. I prefer a chain just so I'd never have to deal with a belt change, but as was already stated, most car owners will have the car long enough to have to change one belt, and then they get something else.

The torque tube has been around for decades. It was used in many different vehicles up until the Hotchkiss or Cardan drive became more popular in the 1950s. It has been used in the Corvette for over ten years now. Lexus will be using it for their exotic LFA which goes into production at the end of this year. Mercedes plans to use it for one of their AMG models. TBF gets a lot of publicity here because it's a catastrophic failure that can send an otherwise good car to the junkyard. But I don't think it happens as often as it seems.