Flywheel Machining?

[1340]

When doing the clutch, can the flywheel be machined?
Thanks.

[Rabbit TD]

What do you mean by machined, resurfaced?  If you just want it to have a good surface for the disc all I've ever done is take some fairly coarse sandpaper like 100-120 and just clean it up a little as long as it's not cracked or warped.  The little sanding marks don't hurt a thing and I think actualy help. You can use a sanding block and go in a circular motion and create a pretty even pattern on the surface.

[arb]

The current thinking in brakes is to not turn the rotors with each pad change... OEM's now recomend only turning them if they are no longer flat. The new pad will do its own resurfacing... The clutch could be the same if your flywhyeel is still flat. Are there deep groves? Most machine shops can have your flywheel blanchard ground for a nice flat smooth surface.

[Zulfiqar]

if its smooth - leave it alone - if its shiny use some sand paper to unglaze it - dont machine it - its made like a tub and machining it will render it useless

[dieselsmoke]

How can machining it render it useless??? I had mine machined at a machine shop. I have not put it in yet but I don't want to if machining it renders it useless.

[arb]

if its smooth - leave it alone - if its shiny use some sand paper to unglaze it - dont machine it - its made like a tub and machining it will render it useless

This is news to me... Every manual flywheel I've seen was cast iron (steel) and required machining operations at the factory. And post production, re-surfacing with proper machine operations are acceptible. Can you explain why you think it would be rendered useless ? I've known professional racers who had their's blanchard ground as this makes them perfectly flat with respect to the crank flange.

[Zulfiqar]

VW umwelt flywheels are mounted on the pressure plate not on the crank - thats the biggest reason, if you machine the contact surface you also need to cut the mounting hole bosses - them only holding 6mm bolts you dont have much to machine on

[1340]

I guess I should have asked if it was really necessary.
I know on big truck flywheels you have to maintain the proper distance from the disc surface to the pressure plate mounting surface. Is that what you mean?

[Zulfiqar]

the great thing about the VW clutch setup is that the pressure plate forces are not inverted like on regular setups - this is basically a pull type clutch fit the other way round - it is genius I would say and the insanely stupid miles these motors go without crank damage is certification to it..

anyways if you have a machinist that can rework these flywheels its pretty good but I would rather source a new wheel because of the tiny screws holding it to the pressure plate - the bosses may become weak. A regular crank-fly-frdisc-pressure plate setup has a very very meaty flywheel with thick bolts holding it in place on the crank - machining that would work without failure

just my 2 cents tho

[Rabbit TD]

Whatever you do or whatever flywheel you end up with make sure the TDC mark is the same as where it is on the one you have now.  Also avoid using a cheap autozone pressure plate especialy if you are putting the engine together the first time with it unless you are positive about the TDC mark.  Remember the pressure plate locates the flywheel and if it's not clocked right during it's assemblyat the factory your flywheel won't be either.  I discovered that last Summer after I put a cheap clutch in the Rabbit.

[GypsyR]

Resurfacing flywheels is standard practice whenever a new clutch is to be installed. "Stepped" flywheels that need two separate cuts are hardly news to a machine shop, all kinds of flywheels are made that way. Clutch companies like LUK publish guides in the back of their catalogs that list the specs for such offset cuts. Lacking that info, usually if you remove X amount from the flywheel surface, you then remove the same amount from the pressure plate mounting surface.
Generally older VW flywheels must be ground very little to clean them up. I took only .008" off mine. Hardly enough to "weaken" anything. Since they wear and warp so little, lots of folks get away with just deglazing the flywheel surface with some sandpaper or something.
It can be a problem finding a shop that has the setup to do VW flywheels as they are very non-standard. 

[monomer]

to de-glaze.



I use 320 grit paper on a DA.


Keep the patterns random. takes off VERY little material.