I was talking to a guy who, who supplies uprated clutches. He reckons that on the six speed box, the flywheels give up the ghost around 20-30,000 miles! He said that tiny cracks form and when the wheel gets hot, they open up and cause slipping. Also he said that well lane turbo, won't change a clutch, without changing the flywheel as well, on a six speed. How true is this?

 

Does anyone know?

 

You'll find that nearly "all" OEM flywheels will get surface crazing over time, if they are pushed hard. This has nothing to do with the gearbox, just the type of material used to make the flywheels.

If the flywheel is abused enough, then these surface cracks can turn into proper cracks, which will wreck the clutch plate.

You have two choices, one is to change the flywheel for either a billet one, or another orginal, or, you could just have the original re-surfaced/lightened, if it's not too bad.

Billet flywheels will last longer, shouldn't craze, disipate heat better, and normally come lighter (4.5>7kg) stock being circa 10.5kg.

Can't comment on what Well Lane do.

Mark.

 

Ditto Mark above,

If the flywheel is allowed to deteriorate the cracks can open and it may shatter, then it'll have your ankles off at speed. That floorpan is not as thick as you think when a bomb goes off close by........

Moderate cracks can be overcome by surface grinding - they cannot usually be removed by lathe work as the surface work hardens and effectively becomes heat treated. That is evidenced by shiny patches on the clutch friction disc face. These can only be removed by grinding.

Once flat and lightened sensibly, a cast flywheel will go again for a number of miles.

Billet steel flywheels are the long term answer but my not suit the pocket.

Well Lane's position on flywheels is laudable and protects them from any comeback, but I'd prefer to advise you and discuss it rather than just add it on anyway.

David APi Engines / APi Impreza