CVT-7 - Flywheel

[guest5033]

Can someone please provide some info about the Jazz with CVT-7 transmission.

What sort of flywheel does it have ?

Dual Mass or the old-fashioned sort ?

Thanks

David

[VicW]

The CVT transmission has a normal flywheel.

Dual Mass Flywheels are fitted to manual gearbox diesels to dampen engine pulses.

Vic.

[culzean]

Dual mass flywheels are the devils own invention - as Vic says they are necessary on diesels to stop the roughness of the Diesel engines power delivery destroying the gearbox.  Where a petrol engine has a solid flywheel with springs in the clutch plate to give a bit of 'shock absorbing' when you drop the clutch etc a dual mass flywheel has a metal part that is attached to the engine side and a separate disc (that the clutch plate grips onto) with springs between it and the engine flywheel.  They fall apart on a regular basis and are one of the costs of owning a Diesel that petrol owners don't have to worry about.

[Eddie Honda]

Vic's right in that it's not dual mass, but I wouldn't call it normal or very solid.

The CVT-7 / SWRA transmission has a "springy flywheel"*. That is, the middle of it is like the middle of a dry manual clutch plate with the torque damping springs.

Looks like this:


How to repair Honda fit Cvt flywheel
Honda fit L15a CVT flywheel repair remove the tension sprin

*I don't know what the correct technical term is as my technical knowledge of things fizzles out after 1982. Damper flywheel? Not quite a dual mass? Rattly when broken?

[lexi]

  It looks like the springs are in the 2 part flywheel, rather like in a standard clutch plate. Is he going to change the double springs and rivet it back together?
  Standard auto torque converters are similar in that the clutch plates can be reached by cutting the sealed converter in half.  Specialists and reconditioners have a machine that welds it back together in a precise manner.

          The remarkable thing with Honda is that they had to design an auto box from scratch with the first of their cars way back. All the patents were being used by the other players. They designed and made the Hondamatic without epicyclic gears.  Probably the only company to make their own auto boxes really, in house.

[Eddie Honda]

Is he going to change the double springs and rivet it back together?

Your guess is as good as mine as to what a Chinaman's bodge might be. Hats off to him though for recycling parts rather than discarding. 

Having given it more thought, there has to be some torque damping in the driveline otherwise take-up would be rather rough and jerky.

In ye olden days the DAF driveline had a drum clutch with 8 shoes in it. Four of them gradually grabbed the drum followed by the second set of four. Further back, the propshaft had splines bonded in rubber at either end of the shaft and the belts would of added a bit of damping too. Later DAF / Volvos had a single dry plate clutch with 4 or 6 springs in the middle as per a manual clutch and again the bonded rubber prop couplings and the belts.

Anyway, from all of the above, with age/abuse/mileage the springs can probably tire/break/become sloppy and the thing goes rattly and needs replacing/repair.

[culzean]

The clutch on a Fiat Punto Selecta (auto CVT box) that my wife had a few years ago was a magnetic powder trapped between two plates, and a electro-magnetic  coil.  To take up the drive on the car the current in the coil was gradually increased which turned the powder from almost a liquid to almost a solid.  It worked very well and the take up was always smooth - unfortunately it was the best part of the car,  the rest of it was nothing but trouble.