jphughan

Ouch. Have they ventured any guesses into root cause yet based on what they're seeing in the engine or DME? And you were NOT running an ECU tune, correct? That's even more worrisome to people who are tracking stock GT4s....

In terms of the mis-shift into 1st discussion, even if it wasn't mechanically engaged by letting the clutch out, moving the lever into an inappropriately low gate is enough to over-rev the transmission. That may not matter in this case since I don't think that could even indirectly cause camshaft, cylinder head, and possibly piston issues, but just fyi for the people who seem to believe that a mis-shift is completely harmless as long as the clutch isn't released.

Pep!RRRR

There's always this:
http://www.flat6innovations.com/inde...09-dfi-engines

jslee225

No ECU tune thank god. BTW my dealer not once mentioned anything about an over rev, so I'm definitely not going to be the one that brings it up.

Just got an update from both my dealer and ATXauto that they have been seeing cars with failures of the camshaft adjusters. In fact one the cars ATX services had this exact problem.
Apparently its been a problem starting with 997 GT3 Mezgers and also late model cayennes and now they are starting to pop up in newer sports cars.

needmoregarage

Sorry to hear but from what you've said so far it may be a service bulletin if there is enough documentation of the issue in other cars? (I'm asking - not stating, as I don't have nearly enough experience to comment). Staying tuned....

Vintage72

and is there any warning sign from the car/engine your SA or ATX could clue us in on before this happens?

Archimedes

Aren't the internals on this motor identical to the 991S, just a slightly lower tune? I haven't heard of any 991s with the 3.8 suffering this problem, tracked or not. Not saying it isn't happening, but can't recall anyone mentioning it on the 991 boards.

zedcat

Sorry to hear this is looking serious and wish you the best in getting things resolved favorably. I doubt the dealer techs would get into block/ pistons themselves. I've seen cases where they have replaced top end parts (heads, etc. ) but seems rather than get into a lower end rebuild they just replace the motor. I assume cam adjuster means the chain tensioners (not variocam). I haven't heard of broad issues with these across multiple engines before. Overall the 9A1 seems very reliable including track use. More so than the earlier M96, M97 which had oil starvation issues on track (and the IMSB in the M96). The GT4's motor has been around since 2009 and many have been tracked in Carreras, Caymans/Boxsters with few reported problems. Hopefully we'll learn more from your case. Again, best of luck.

trebien

Agreed, a rather proven design... and the OP's car is rather stock, not pimped on track suspension and slicks... so the data points to an isolated incident.

Underblu

I know the 991 GT3 engines are modified from the standard 3.8 block but there is a long running thread about similar problems especially with the top end: cam etc. of these engines on the track. I believe a lot of this has to do with insufficient oiling of one or more of the cylinders so not sure if applies here but check out the GT3 board as this seems to be a recurrent issue.

zedcat

Yes, a long thread over there, but I think that's something different. The GT3 motor has many differences including a true dry sump and the 9k redline. The leading theory is the E and F (model year code from the vin) motors have insufficient oil flow in the heads at high rpm such as track use and that leads to cam lobe wear. The cars show misfire codes but I don't recall reading of any that shut down and don't restart. There is some evidence the G code engines (MY16) have different oil pumps, galleries, programming. of course Porsche is tight lipped on the issues. OPs description of cam adjuster sounded like tensioner to me (I could be all wrong) which is a different part of the valve train. I'm sure we'll hear more and hopefully it's a one-off and gets fixed/ replaced promptly under warranty.

kitwetzler

Auto blip uses the gas pedal, so no it can't.

jslee225

Just to clarify I have tarrett suspension bits, fabspeed sport exhaust, and RE71r's

jslee225

just to clarify, this hasn't been confirmed that this is what happened to my car, just an assumption. I'm hoping to hear the root cause over the next couple days.

trebien

Good to know, but I was alluding to aggressive suspension tuning and Hoosiers... the RE71 are similar grip to the OEM PSC2 or Dunlops... so no worries there about running "slicks" on the track, from the point of view of a warranty issue... where the GT4 warranty specifically excludes the use of slicks.

I just hope we end up learning the root cause, as opposed to PCNA shipping off the engine to corporate for analysis, and we never get an in-depth answer.

BGB Motorsports

Any update? i would love to see the video but it's private!