Hello fellow Porschephiles,

Just a quick word to those of you who already have or are thinking about a lightened flywheel for your 997 GT3 (the non-RS version). If you get the lightweight flywheel be sure to get the proper pulley on the other end that is designed to go with the lightweight flywheel if you haven’t already. Apparently, it’s a different part and there was a TSB issued to this effect (if anybody has the TSB, would love to read it). You can stop reading here because there no other useful information that I have to share, but here’s how I came to learn about this for those who are interested.

I was driving home last Friday night and all of a sudden I get a beep and message telling me to check the generator, or something along those lines. My immediate reaction is that I lost the belt that drives the alternator and I’m sure of it as soon as I come up my first turn because the steering is heavy. Anyway, I’m close to home so I just drive it home versus risk leaving it on the side of the road late at night. I kept my eye on the water and oil temp gauges to make sure that the engine did not get too hot because I suspected the belt might also drive the water pump. This was verified because the engine was starting to get warmer than usual, but not dangerously so.

Once home, I pop the engine lid expecting to see a broken belt or none at all, but to my surprise it looks completely intact. This cannot be, because there’s no way I lost the alternator, steering, and water pump all at once. I get the flashlight out and then I see the belt “pushing off” the tensioner. Now this is weird because with the engine running the belt should have shredded or melted. The only answer is the belt was not being driven at all so, to verify, I fire up the motor and sure enough the belt is static.

Finally, I took even closer and then I see the problem. Turns out, the bolt for the pulley that drives the serp belt backed out of the end of the crankshaft and the pulley is just lying there. I’m not a mechanic, but I have built my share of cars and this was a new one on me.

I made arrangements to have the car towed to the dealer this morning. They called me back before lunch and asked me if I had a lightweight flywheel. The suspected it was the case when they started the motor and heard how much more quickly it revved Anyway, so much for warrantee on this one . Luckily, there was no damage as a result of the pulley coming off (e.g., marring up the end of the crankshaft, damaging the keyway, etc.). In fact, they had the car ready to go but when they started it that they suspected the lightweight flywheel.

I’m accepting that the bolt backing out had something to do with the wrong pulley being on the car given the LWFW (in fact, I want to believe this is the case because then there’s at least a good explanation). I’m not entirely convinced of it but I don’t have much of a leg to stand on and am going to have to eat this one myself in terms of the repair cost. The service advisor mentioned “that’s why your car was noisy so I’m assuming he was referring to the gearbox chatter when in neutral. Perhaps there’s something about the different pulley what helps reduce the amount of chatter, not that it bothered me. Anyway, there you have it.

Love my car. 6k miles now and I’ve had zero issues with it up until now. I use it as my daily driver, it’s the best car I’ve ever owned by a long shot, and I can’t imagine driving anything else. Should have it back tomorrow or the next day (they’re just waiting on the part).

 

thanks for the info roland...


hey alex, do you guys change out the pulleys when doing the LWFW upgrade?

 

We've had this happen to a local GT3'er (1 out of 9) with the LWF. There's actually a lot of info about this (I listed the part numbers needed since it's not just the pulley) on the rennlist thread:
http://forums.rennlist.com/rennforum...d.php?t=413519
I will say there's currently no TSB that I'm aware of as of yesterday (so thanks for the heads up) and we're not sure that's what's doing it but we already have the part numbers to do the conversion to the RS pulley (has two holes). Trying to find out if earlier cars were torqued differntly as well (we've seen different pulleys on these cars- both RS and GT3). We've had several guys go miles and miles and/or track so we're still watching the subject closely It's not that hard to do while doing the flywheel etc... You'll be back on the road soon I hope

 

Good info Alex. Thanks. Good to see I'm not alone and some validation.

 

This happened to me and it was after getting the LWFW done.
I was driving and all of a sudden the engine temp went to the moon.
Pulled over immediately. Engine compartment looked normal. No fluids and belt intact.
When started up the motor and looked the belt was still.
As it turned out the crank pulley had become loosened and damaged.
This was followed by an eternity wait to get a crank pulley from Porsche.
At the time none was available. The wait was about 4 weeks.

The cars been fixed since and no problems or sequelae. I was concern about internal damages but apparent all was okay and the car run fine.

I was not aware of a change needed to the crank pulley with the LWFW conversion.

Juan

 

thanks for sharing that info.

 

rja, can you clarify on the warranty? did the dealer voided the warranty work even though it's an OEM LWFW? after they mate it with the proper pulley, is the warranty back intact?

-joe

 

Roland sorry to hear about your problem, and sorry to hear that you have to eat it. Hear is my problem with that. Porsche has to establish that the problem was due to the modification of the LWF before they can make you eat it. I would be interested in knowing the connection. If you bought an Aftermarket LWF and the design of the mod required a different crank pulley then the seller should have antisipated that and provided it or recomended it in a kit. Otherwise they are putting you in a dangerous situation. could you imagin the damage at 8400 rpm on the track for example. So either its unrleated and its a porsche problem or it was an oversight by the after market supplier. What if the damages were more significant?
I did read the same problem on Rennlist. one of the incidents was with a guy during track event. could have been expensive. Hopefully someone figures it out and takes the precautions necessary. On the other head, it can be argued that you assume the risk when you install mods on your car but hay this stuff is not cheep so I hope the figure it out. quick.

By the way what kind of beer are u drinking in the pic. better have two.

 

part number on the RS pulley....anyone???

 

I spoke to three different dealers and they all stated that Porsche has issued no TSB on this (just an FYI).

 

was this or has this been an issue on the 996-3 or does this just pertain to the 997-3?

 

996-102-017-95 thats it...

 

Thanks for the comments. To clear one thing up, I had the GT3 RS LWFW and clutch assembly installed, so it was Porsche OEM equipment and not aftermarket. I'll see if I can get the TSB info from my dealer and post -- they said there is one.

As for being covered by warrantee, I don't see how I have much of a leg to stand on here given I had the wrong pulley on the car for the flywheel, TSB or not. Even if the wrong pulley had nothing to do with bolt backing out, it would be difficult if not impossible to prove. This is the risk you take when you start to mod things. Now that the proper pulley is on the car I should be covered if it happens again but there are no guarantees when you mod, especially with a GT3.

I'm looking at this whole situation positively. No damage came of my car, so I got lucky. It would have been a lot worse had the pulley chewed up the crankshaft end. Also, I had the wrong pulley one the car for the flywheel so that could have led to long-term damage to the crankshaft if not caught early. Also, my dealer was able to expedite getting the part from Germany and my car is already fixed (Porsche originally told them 4-8 weeks when they called earlier this week!)

As for the beer, I forget what I was drinking. I was in Venice and asked for a Pilsner. It was something I had never heard of before, and it was good. I believe I had two

 

It happened to me today at Pocono. LWFW went in last week. Got through 2 sessions this morning and late in the 3rd session at about 120mph I went to turn into a sweeping right hander and had no power steering. I was fortunate that it happened where it did. Water temp was red lined and power steering fluid was leaking.
The crank pulley was not changed out when the rs lwfw went in.

 

Might be a stupid question but I'll risk it anyway: how does the flywheel have a cause to effect relationship with a pulley which is located at the opposite end of the crank ?