RAudi Driver

What about the .1Rs with the single mass flywheels.

sirringo

As I say - nothing is “proven” to be a permanent fix!

Thanks guys for all the info. Keep it coming…

Auto_Werks 3.6

The failure rate isn't astronomical, so you're not exactly going to be able to use science in a practical way to assess the fixes that are on the market. You would need a statistically meaningful quantity of engines in a control group and engines in a modified group, and you would need to run them with different flywheels etc. You're not wrong that no one has proved the damper solves the cam bolt issue, and that bar will likely never be reached. In the same way that the damper is not a proven fix, your shop having a car with a damper and failed bolts is not evidence that the damper doesn't help the situation. The dampers are sold as a separate item from Dundon. They are not part of an installation package or a new build engine. If the damper is installed after the bolts have already started to work loose, it won't do anything to stop the process of failure. I purchased a damper and ignored Dundon's recommendation to tear down all the covers and check the bolt torque. If my car suffered a failure, I wouldn't be able to say the Damper didn't do its job, because I didn't start from a fresh bolt installation. Im sure your shop would say the damper doesn't do anything, and their fix is more adequate. There's little proof for either scenario. What there is plenty of is evidence that these engines have some harmonic issues, and that those issues are more acute with larger displacement. 911 Engines have had those issues since the early days when the flywheels would shear off the six bolt crankshaft. There are photos of cracked alternator mounts, and other broken parts on the last gen of Mezger engines. My personal hypothesis is that the harmonic issues contribute to the screws falling out in the 3.8 RS intake, and even with the breakdown of the effectivenss of the glue in the coolant pipes. Again, hypothesis, so yes, I have not proved this out.. Just as it has not been disproved. As far as the damper; I have used ATI dampers on other vintage engine builds and the difference was night and day from the driver's seat. When I bought the Dundon damper it was closer to $1600, and I considered that a no brainer for an engine that again, does have readily evident issues that are (or could be) related to harmonics. The installaiton on the GT3 wasn't as night and day as the last build I used one on, but I still consider it a good piece for a car that I intend to keep for the long term. When my engine comes out eventually I will look into the other bolt fixes, because I think its prudent to improve the fasteners as well. I don't see myself getting rid of the damper at that time. If I just got a 997 and I was only planning on putting 5 to 10k miles on it before selling for something else, I probably wouldn't spend a minute thinking about any of these fixes... If you're going to be unlucky, you're going to be unlucky.

TLDR: I don't think the damper is a cure all for the cam bolts, but I think it's still a reasonable upgrade for these cars.

Burren

Paging John; you just welded the bolts on my car, right? Can't back out that way.

Spyerx

53k miles on mine. The cam bolt issue is a .2 issue.

lawrence1

I’ve seen a few cars where the description of the fix said the bolts were safety wired. I’m assuming that would require different bolts to allow for a drilled head to run the wire through. I can try and dig through my notes to see where it was done.

Jupp

The 996 Gt3 Mk1 was delivered with a harmonic balancer.
Partnr is: 996 102 115 93
But not available at the moment.

The 2.5k$ price tag is even more ridiculous when you compare to the usual ATI prices for other cars.

bonehead

The Sharkwerks fix is proprietary. Alex understandably won't divulge the info. I bought the Dundon ATI unit 2-3 years ago. Think it was $1000 at the time?? Prices have obviously gone up along with the value of the cars.

Auto_Werks 3.6

Dundon stuff is expensive, I'm not saying you're wrong. When I bought my damper I thought it seemed expensive, so I contacted ATI and priced out having their custom department make one for the GT3. At the time the savings of buying direct from ATI was small enough that it made zero sense to be out on my own doing a design when the Dundon part existed on the shelf. I believe it was also goign to take months to have a part in hand. Anyone can buy dampers from ATI at any time... there are probably at least several reasons why Dundon is able to keep selling theirs.

Spyerx

There isn't magic here. I'm sure what Sharkwerks does works. They aren't the only ones that figured this out. You need to secure, modify, or change the holding properties so the bolts don't back out. If people are worried about this they need to work with a shop that builds enough of these engines that they know what they are doing and how to address it. FWIW, I don't think sharkwerks, and I know BBI don't use the dampers.

Robocop305

No issues with my .1 with a LWFW. 30k miles plus.

lawrence1

can anyone enlighten me on why the 4.0 clutch and LWFW plus the ATI damper is a better package than replacing with stock 3.6/3.8 components? I get the LWFW benefits of quicker revving but doesn't the heavier ATI damper kind of eliminate the benefit? It seems like the 4.0/LWFW combo + ATI damper cost 2x if not closer to 3x as much as the stock 3.6/3.8 parts, and you can still vibrate your cam bolts loose. If one was to get the cam bolts secured also, well, that would be thousands more. Would love to hear the cost /benefit rationale for this "upgrade" from those that are smarter than I am.

Auto_Werks 3.6

There is no rationale. People like the sounds, and conflate that with big performacne gains. The .2 RS is only 0.1 or 0.2 second quicker to 60 and it has the lightweight flywheel, ~10% shorter gearing, and a little more power. I'm neurotic about things like vibrations and bolts falling out, so I added the ATI damper on my stock engine. The moment of inertia of the damper is much lower than the flywheel because of the small diameter, so adding it didn't cause the revs to get any more lathargic to my butt dyno.. and the real dyno still registers 392 at the wheels.

jreifler

So, for those inclined to add a damper as a preventative measure - If you're of the view that we're not sure whether any of these fixes does in fact fix the issue, will you still visually inspect with some regularity? And if so, why not just bolster up with better hardware and call it a day ? Not slighting any approach; genuinely asking because I'm still considering what to do myself.

Auto_Werks 3.6

50% I think the damper helps, 50% I embrace the placebo effect it has... No plans to check the bolts unless the engine is out for other service. If it fails in the mean time, so be it.