All that said, I really don't think I'd be losing sleep over it if I didn't have a 997.2. And even having a .2 I rarely think about it. Every engine fails eventually.

 

Ordered a dampener from Jaime before my car even arrived. I plan on having it installed before my first real drive. I've been told there's a way to have a look at the actuators without dropping to motor to see if the bolts look fully torqued, but I have yet to confirm that.

I would consider paying some seriously wacky numbers to CPO. If it were possible...

 

Started reading that thread. Not a mechanical engineer but still an engineering PhD here (with good grasp of harmonics and Fourier analysis) and had hard time following the OP's description of the problem and the "dampener" solution. So Porsche has been making and racing Mezger engines for decades -- hundreds of Porsche engineers dumbfounded for decades about how to resolve a known "harmonic" vibration problem, then someone solves it by putting a "dampener" to dampen these vibrations? OK, let me continue reading the thread...

 

Jaime never claimed to have "solved the problem" with the dampener. I think there's some science behind it to suggest it does mitigate some of the harmonic vibration issues. From what I've read, it's more of the low to mid RPM range that's really an issue, which could be the reason it's not a concern for race cars that are spending majority of their time over 5K.

 

So Porsche has been unaware for decades that they could change the harmonic (frequency response, resonance) properties of a dynamic system by adding, removing, or redistributing mass around? No one told them...

 

I would guess the Porsche engineers are not dumbfounded, but I would wager they don't care. If the whole IMS debacle wasn't something that warranted attention from them, I doubt a handful of 10+ year old Mezger engines are causing them any lost sleep. Porsche did their due diligence to have the factory service documentation updated to say that the Dual mass flywheel must not be replaced with the single mass version from the RS counterpart. These are torsional vibrations. If you read the link I shared from Performance Developments he outlines instrumenting an engine to measure the crank wind up at various RPM ranges. Maybe you should start at the ATI website since it seems like you don't understand what a crankshaft damper is actually for.

Example of flywheel shedding on older models:
http://forums.pelicanparts.com/911-e...ing-loose.html

 

So please bottom line your best guess if you could ... for those of us regular GT3 owners with DMFW, as well as street drivers who could spend a lot of time (over thousands of miles & many years) in the harmful 4k range. Do you think cracking open the covers and re-torquing at some specified mileage point? ... or going even further for bolt replacement (M6 to M7) or damper?
(... don't want to seem panic here, but have only owned this GT3 for a year now. still uncovering aspects/nuances)

Btw, I have read through this thread from back in 2013-2015: https://rennlist.com/forums/997-gt2-...ing-out-3.html

=Steve

 

This base 997.2 GT3 had the camshaft bolt failure, so it can happen on base cars.

https://bringatrailer.com/listing/20...he-911-gt3-25/

 

From that thread, from the maker of the dampener:

https://rennlist.com/forums/997-gt2-...l#post12035556
"3.6L in the 996 and 7 are fine. Haven't heard of any issues unless you bore it out. Even bored to a 4.0L from a 3.6L is fine. It's the extra stroke that gets you..."

Reading on... At this point, I've banished any thoughts about "upgrading" my 6gt3 to a single mass flywheel or other RS bits in that area.

 

i don’t see it mentioned in the auction, but if it has an RS flywheel installed it will have all the same problems as the RS. Current owner might not even know what flywheel it has..... or the dual mass flywheel could have failed. One of my autocross friends has broken the guts out of his flywheel with lunches.

 

i don’t have a good answer for you. For me, installing the damper would be enough to sleep well. I’ve driven a base GT3 before and after the damper install, and it’s much smoother at 4,000 rpm with the damper installed. It did seem to be a little more noisy at 2700 rpm, but the car spends almost no time there. Jaimie says you should check the torque, so he’s the expert there. I will check the torque any time my engine comes out for service. I really like ATI dampers. They have been a major improvement on everything I’ve experienced them on. It’s an easy sell for me on a part that’s not very expensive compared to the car. As far as whether the bolt upgrades are really required we would want to know if anyone has installed the damper and still had a failure. If no one has the damper and a failure, you’d have to be the unluckiest owner in the world. With any luck these failures get overblown.

 

My 2010 RS had the plastic intake part suck into the engine and blew it up. Porsche fixed it under warranty. Got rid of the RS nightmare before warranty ended. Too many possible problems past warranty. Too much $ liability for me to enjoy it.

 

As an engine engineer I look at the problems in front of me and come up with my best engineered solution. Solutions never include what I might think Porsche could have done, or should have done or that no one ever told them about a problem. The solution has to be based purely on what I see and figure out what caused the problem.

I can tell you that I was involved in the rebuilding of the Porsche 3.0L and 3.2L water cooled engines used by Porsche back in the mid to late 1980"s. These are the base of the GT3 engines. The GT3 engine is not new. Those engines had individual cylinder heads welded to the Cylinder liners. The GT3 uses a single 3 cylinder head with removable cylinder liners. The base engine including the bottom end are pretty much the same. Those engines in both the 3.0L, 95.00mm x 70.40mm and the 3.2L, 95.00mm x 74.40mm strokes broke their cranks. They had single mass flywheels and a simple small crankshaft pulley. Did Porsche know about this back then. Absolutely they did. Did they do anything about it? No not really, they ran lower and limited the RPM only.

So come forward to these more modern engines, we have a longer stroke, long rod CCL, and a larger and heavier piston. Did they do anything about the harmonics, I guess not. You have to make up your own mind why or why not. But for me, I have to look only at the fault, the cause and come up with a solution.

If you think this is not required, you should make that decision based on engineering data, multiple failures, and what solutions are available.

As a PhD, I'm somewhat surprised in your demeanor. The PhD's I deal with daily are skeptical for sure but all have an open mind and ask many questions before they show any sort of dismissive opinions.

 

Has anyone thought of simply spot welding each bolt on the variocam actuator to the actuator cover thus eliminating any chance of any of the bolts coming loose? Seems like a simple solution and could probably be done with the engine in the car. Yes, the variocam adjuster would never be able to be disassembled after that but that's never needed anyway.

 

a quick tack weld could do it.
maybe the heat could be an issue? Could also wire it up
or just do what bbi has done, a better bolt and red loctite

they did testing on the installed bolt from factory and found it was torqued beyond yield for the bolt. So, a Higher spec bolt and loctite. They do this fix on any engine opened up. Part of the routine like welding the pipes.

i agree with you in that this is not something worth over thinking too much.