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rsrmike rsrmike is offline
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Join Date: Jan 2008
Location: Birmingham, AL
Posts: 538
Thanks Les,

I'm thinking the best thing is to order a new flywheel. I wish I had more time but this is a daily driver for this guy and he needs his car.

There aren't any heat cracks in the flywheel just a lot of hot spots and a very rough surface. I could almost swear I had the flywhel machined and replaced the disc when we built the motor years ago.

I have battled with a really stiff clutch pedal on this car for years. It has sheared more than one roll pin and at one point the clutch shaft in the pedal assembly nearly broke in half!!! It cracked on one side of the hole for one of the roll pins and bent!!

Everything seems fine in the linkage/hydraulic dept. Pedal helper spring is good/adjusted(those are weird). It has the later release arm w/ external bearings(they are fine) The guide sleeve and release bearing are good. Even the poly liner in the release bearing looks new. I think I replaced it too years ago. It's had a slave cylinder at some point as well.

The one thing that sticks out to me is that the pressure plate looks concave when bolted up w/disc to flywheel. Which typically means a worn out disc or a flywheel that wasn't machined properly. I know Porsche says not to machine the g-50 flywheels for fear of interference w/ the flywheel bolts. I guess that's why they don't give a measurement in the little spec book. I sure would love to know what it's supposed to be. Does ANYONE KNOW?? Does anyone have an unmachined 89 turbo flywheel laying around that you could measure?

Like I said before, the disc was not that worn out but the the pressure plate barely had any pressure when unbolting from the flywheel. It wasn't slipping though which is even weirder considering this beast is far from stock. I can't help but convince myself his stiff clutch is from the flywheel step being wrong and possibly a "work hardened" pressure plate though I tend to lean towards the "step" issue.

I guess we may have to bite the bullet and spend $1,600 on a flywheel, disc, and pressure plate! OUCH

On a lighter note, you can bet I'll measure that virgin flywheel and post for future reference.

The flywheel crank trigger is cool. You can't see it, it's where Porsche put it, and it uses a very robust Porsche sensor readily available should it ever die.

I've heard that about the sensors before, I've even used the later 3/8"? sensor on a few cars. One guy has changed his later style 3 times in 4 years on his 3.6t. I think it's just a bad spot to put it on a turbo, personally. I'm not criticizing Clewett though. He makes damn nice stuff and is very sharp! If he used custom flywheels instead of crank pulleys that setup would be far less practical. Not to mention all the different flywheels he would need. Our problems have most likely stemmed from Alabama weather combined w/ guys that probably don't cool their turbo's as much as they should upon shutdown. I guess I should mention I know a couple of guys that haven't had sensor trouble on their turbos. They are both very particular about how they treat their cars as well... hmmm (they still keep a spare sensor, an allen wrench, and some feeler gauges in their glovebox though)
Old 04-30-2008, 03:44 PM
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