[Fwd: [syncronized] On flywheels]

[roccit_53 at scirocco.cs.uoguelph.ca (C Boyko)]

On 9:20 pm 03/09/07 "Mark F." <mk1mark@gmail.com> wrote:
> On 3/9/07, Nate Mellom <doubt@inwave.com> wrote:
> >   From my Syncro list.
> >
> >  Anyone have any thoughts about lightening a flywheel? This would
> >  be for my '85 4 cylinder Quantum, whose clutch and flywheel will
> > be replaced soon.
> >  Also, I know about machining or facing the flywheel, which I will
> >  have done in advance, but how do they lighten it?
>
>
> I lightened a few VW flywheels in my previous life as an automotive
> machinist wannabe...  The most common thing to do is remove the metal
> that's beyond the ring gear (the flywheel is spun on a big-ass lathe
> and is turned down flush to the ring gear).  This mass is furthest out
> from the center, and is the most desirable mass to remove.  If further
> lightening is required material on the back side of the friction
> surface can be shaved down (removing the "bumps") BUT I wouldn't
> recommend going this far for a street car, since you're reducing the
> flywheels "heat sink" area which can lead to overheating - which can
> contribute to cracking of the friction surface...
>
> HTH,
>
> Mark.
> 75
> 82
> 82 Caddy
> 91 Jetta Coupe

I have one of Mark's splendid efforts on my 16V, and it's held up well
since it was done, it revs up faster I'd say, (and obviously revs down
faster too, LOL) Mine wasn't the extreme version, and I did get it balanced
after the lightening was done. I have seen one at the drags blow up in
spectacular fashion, but that wasn't on a VW, and that car saw a lot of
abuse. I suspect the key is to not go overboard with how much gets removed,
and to find the right wannabe machinist ;)
Cathy