sharkster

We don't just build GT3 engines here... but this is seriously the stuff that keeps James awake at night! If any of you guys also have either a 996 or 997 GT1 based Twin Turbo and are experiencing more engine vibration/noise than you'd think was normal we've unfortunately seen our fair share of this nasty symptom. It's not the same IMS failure you here/read about on the M96/97 engines (that is more common too).


How many degrees of play in that crank shaft?!?! At first you won't even get any check engine lights/codes either. This type of set up is in all the 996/997TT GT1 engines but luckily NOT I repeat NOT in our GT3s- phew. One has to wonder why... The only other thing I can say is of the turbo engines we've seen with this failure there seems to be a correlation of a light weight flywheel into play as well which _could_ be exacerbate the problem due to additional transmitted vibration.

To check for this if you're worried you can rotate the crank shaft back and forth and it it feels loose at all then the next step is to remove the driver's side upper cam cover and observe the relation between the crank shaft movement and the cam shaft movement. Obviously you want to nip this in the bud before it gets bad and leads to a total catastrophic failure.

The noise is most noticeable at idle and when gently increasing the revs to 2000 and then releasing the throttle pedal. It's kind of frustrating that the Turbos don't have the same design as the GT3 but there you have it (or hopefully not!).

savyboy

Sheesh.

Is this the same engine in GT2 and GT2RS Alex?

sharkster

gt2 yes.. gt2RS I suspect/hope not But won't know until we pick one apart...

malmasri

Is the failure related to mileage or is this similar to the coolant pipes failure.i:e can occur regardless of wear?

sharkster

Right now it's not what I'd call common like the coolant pipe failure but it does happen. Talking with other shops (EVOMS for example) we've been building Turbo engines with fixes for this since like 06?

I'd say mileage yes.. and over time. But a LWF seems to also maybe accelerate the issue.

kosmo

LWF- as in cars with non factory flywheels?

Serge944

What exactly is the failure? Looks l ike it is at the gear to shaft interface, but the video isn't very clear. Can you provide photos showing the difference at the gear connection on the GT3 vs the turbo? Thanks.

F1CrazyDriver

Alex,

You have a PM on the other site : )

Hmmm I think. Here me out; most Porsche owners lug their motor. Which is incredibly bad for the crank on a flat 6 motor, and having a lwfw makes it even worse. I was told by my good friend who owns an older 911, that always keep the RPM's above 3,000 when the engine is warm, always- since before i acquired my car 6 + years ago, and he let me drive his car. I read in the 996 T manual that Porsche states the same. I HIGHLY doubt 95% of the owners out there do this ( this includes GT2's /GT3's) . Specially the Turbo owners, as lets face it, most don't drive a Porsche properly IMO, which looks to be more prone. Yes it is a weak link on the turbo cars though.

Regardless, can I stop by so you can take a look at my car, please !? : )


p.s. Pete, money going your way.

sharkster

It's just a qucikie FYI iPhone video but your engine builders will know. If you look closely at the turbo one in the first part you'll see the bolt heads which is how it is held into place vs the one you are familiar with like on your gt3 engine (second one). The failure is with vibration/use/mileage and/or inferior design the bolts back out. There's no way for the gt3 one to start having play like that and it's too bad the turbos don't get the same treatment. Hence for anyone doing an engine build on those it's not a bad idea to perform some sort of fix or indeed raid the gt3 parts bin. There's different ways to do it but as long as its addressed then it won't crop up later is all

sharkster

At a hospital with limited connectivity and an iphone so it's hard to expand upon that more but unless you're planning on buying a TT you don't need to worry. It's not a super common failure but has happened and we've been fixing this in turbo engines since 06. I've read and seen a good few people suffer from this on various forums tho...

I'll post a picture later of a turbo one so you can see the difference if you haven't seen one before.

sharkster

I actually have a picture of a turbo one on my iPhone. But I can't attach it using an iPhone lol I can email it to one of you guys and you can put it up. Else it'll have to be tomorrow...

F1CrazyDriver

Alex, hope all is well with you .... and nothing bad at the hospital. You can shot it over to me at info@ebwerks.com I can post it up for people to see here.

F1CrazyDriver

Here is the pic I got from Alex:

sharkster

Thanks man can only do so much with an iPhone and 4g lol If you look at the bolts it'll have you scratching your head... All good here and will be back at work tomorrow baring any ims failures

PAULUNM

Fairly discussed issue on the 996tt board. My understanding is that the 996tt motor uses a multi piece IMS shaft, held together by a wodruff key that sometime backs out.

All GT3s use the single piece 959 IMS shaft, which does not have this key. I'm also told that the 997tt went to the 959 IMS shaft.

These motors are noisy at idle, which many confuse as an IMS failure.

Search the 996tt board for more info. Kevin has a lot of knowledge about this issue.