Voith

Thanks for the pictures, it does look like it could be it.

Actually machine shop that did the job destroyed my first block, this is the second one.

They are in business since 1950, but obviously alusil boring, honing and lapping is not in high demand.

Otto Mechanic

I'll weigh mine when I get it out. As far as I know it has a stock clutch, but it's worn so the weight may not be exact. I'm planning to lighten the FW f I can find a shop that knows how. I'll weigh it beforehand. If the clutch has springs in it I'll make a note.

Voith

There are many turbo experts here, how does this match looks to you for 3.0 8V 8:1 engine?

http://www.turbos.bwauto.com//afterm...6_wrsin=92044&


Otto, thanks.

Otto Mechanic

I have the clutch & FW out, did you want the weight with or without the ring gear? Usually that moves to the new clutch (I've already moved it but it's easy to take back off).

Voith

Just FW and complete clutch. Ring should be the same weight on all cars I guess.

Otto Mechanic

OK. I should mention that after removing the clutch I discovered mine isn't stock. The clutch itself doesn't have the rubber center, it has 4 springs. I don't know who the manufacturer was. Is it still interesting?

Voith

I don't think S2 came with rubber center clutch. Im trying to figure out the balance of S2 engine, if the clutch with flywheel is of significantly different weight than 951, that would be an interesting piece of front harmonic dampener puzzle.

Otto Mechanic

I'll weight it tomorrow then and I'll weigh the starter gear ring separate. All I have is a bath scale so it may not be real accurate.

From what I've found out, the S2 flywheel weighs 16 lbs and experiments Porsche ran with lighter flywheels didn't all work out well. I'm interested to know what it weighs too. I've heard there was a custom aluminum billet flywheel made by Porsche Motorsports, and I'd first heard rumor it was 16lbs and they only made a few, now NLA. I've also heard attempts to use the 8-9 lb. flywheels (an Italian name, can't remember exactly) haven't been all that successful because of vibration. There's a separate harmonic balancer on the front of the crankshaft and if you lighten the flywheel you need to put more weight up front to compensate? These are just stories I've read here and other places, not personal experience, but I thought I'd pass on the gossip anyway, maybe someone else will comment?

Voith

I want to replicate bottom end S2 engine mass relations on my 3.0T build, I think 951 FW is heavier.

Bath scale should be good enough.

Otto Mechanic

The parts weigh as follows, +/- .5 lbs.

Flywheel: 12 lbs.
Pressure Plate + clutch disk: 18 lbs.
Ring Gear: 3 lbs.

That's using an end of life stock clutch plate. I'm surprised the flywheel is as light as it is since a "light" FW is 8 to 9 lbs.

Voith

So fw is aprox. 5.4kg vs 951s 6.8kg.

Thanks!

Otto Mechanic

As I understand, the lower weight of the FW is compensated by a harmonic balancer built into the crankshaft pulley on the front of the engine, so the net rotating mass may be roughly equivalent.

Voith

Ill replicate that with lightened 951 flywheel and cup clutch disk.

Voith

I lapped the cyl with sunnen paste and got the desired dull finish.

Maybe it was exposed enough when I got it, but the difference is very obvious..

Left after AN30 treatment, Right as I got it from the shop..

Voith

Got my new Turbo delivered today