GT3 Chuck

I thought this was important enough for it's own thread...this is a copy of the service bulletin issued October 15, 2008.

Technical Information
Service
36/08 ENU 1360 1
GT3 Engine: Flywheel and Pulley
Vehicle Type: 911 GT3 (997)
Model Year: As of 2007
Concerns: Flywheel and pulley
Information: Replacing dual-mass flywheel with single-mass flywheel.
We have discovered that the dual-mass flywheel, which is installed as standard in the GT3 engine (vehicle type 997810/-811), is being replaced in the dealer organization with the single-mass flywheel from the GT3 RS engine (vehicle type 997850/-851).

Information

Due to an increasing number of reported faults, we expressly wish to point out that the installation of the single-mass flywheel (from the GT3 RS) in the GT3 engine is not approved by Porsche.

Since the 911 GT3 (997) engine application is designed for the dual-mass flywheel, conversion to the single-mass flywheel results in the following problems and consequences:

• The single-mass flywheel causes fluctuations and vibration in the lower rpm range, thereby reducing the smooth-running performance of the engine.

• The crankshaft is subjected to one-sided loading, causing stress peaks that can result in damage to the crankshaft.

• The one-sided loading of the crankshaft can cause the pulley to come loose, resulting in damage to the belt drive and engine.

• Any damage relating to conversion or damage that can be attributed to conversion is not covered under warranty.

Please advise your customers of this information accordingly.

©Porsche Cars North America, Inc.

October 15, 2008

Targa Tim

very interesting...I always thought they are the exact same engine.

sharkster

They are the exact same engine Seems like a nice way to not warranty the RMS

flash1034

Everyone, including Porsche, is tightening their money belts.

Flash

GT3 Chuck

Alex, do you have to put a new RMS when you switch flywheels? If not, how could they blame RMS leak on flywheel mod....

sharkster

I think Flash is right... they need to cut warranty claims and expenses down... Well everyone that gets an RMS leak basically drives over to their nearest dealer who is good enough to put in a LWF while they're replacing it Funny thing is the 996TT/GT3 seal in a local car that we did the LWF and RMS fix on 6 months ago is dry as a bone...

todinlaw

I am sorry for being a bit off topic but I think the difference between 997 that leak and the ones that don't is some microscopic flaw in the block that causes the leak. can't be just the back pressure issue or all would leak. all have the same seal some leak some don't. But yes Alex I agree convenient way to get out of repairs. If the LWFW and new front pulley can work in the RS why not in the 3?? I do agree that the change in the drag of one end of the crank could change dynamic forces and vibration, I just assumed that since the LWFW allows the motor to rev quicker it was loading the front pulley more and the upgrade to the RS pulley should do the trick.

996FLT6

I remember one poster changed out from his 6gt3 to a more restrictive crankcase breather and maybe it's an isolated incident or coincidence but car developed a leak thereafter. Maybe too much crankcase pressure since 7gt3 is rated 415(probably moreso) vs our wimpy 381 hp 6gt3's(still fast though). Is crankcase breather on 7gt3 ne different then 6gt3? Someone mentioned that 6gt3 cupcars have the more restrictive breather which on dyno can increase between 5-8 hp. Regards. Mike

NJ-GT

Alex,

Which seal seems to hold better in the 7GT3? the 6GT3, 7GT2, 7Turbo, 6Turbo?

sharkster

6GT3 and TT....

tcsracing1

this makes the RS worth the extra $$ for already having the good stuff installed from the factory....

NJ-GT

Is that 996TT or 997TT?

PET shows me the same part for the 996GT3, 996GT2 and 996TT: 999.113.426.41

Snowboarder54

I agree 100%!! I had my LWF installed by Alex and James at 16,000 miles. I believe James mentioned that when he had the old clutch out that he noticed the RMS was just starting to “weep” slightly. There was never any oil showing on the outside of the motor. Today I have nearly 28,000 total miles on the car and still no sign of an oil leak. There are more then a few people on this forum who can attest to the fact that whenever I drive my car it is driven hard, the way it was designed to be driven and on a daily basis. If I were to buy another GT3 I would not hesitate installing the LWF first thing, even after knowing Porsche would not warranty the motor afterwards. That’s how much I like it!! Oh and I would follow it up with the Sharkwerks exhaust bypass.

NJ-GT

Seriously, the LWFW awakes these cars. I drove a bone stock 996 GT3 for two days last month at Pocono racetrack. Very, very nice car, but the engine response was sluggish on my transitions (autoX).

The GT3 is one of the best performance cars for the money out there (996 & 997), the LWFW makes it better.

OldGuy

I had my 996 GT3 done under warranty by my Porsche mechanic.
This one is a cheapy on Porsche part. Which lead to the new Porsche Motto

"Porsche Dual Mass-There is no substitute.......part"