I already posted the failure for the stats, but I had a dual row failure found during a routine change. Luckily didn't have any engine damage. Maybe the dual row gave me more time? Still cost me $10,000 but that's better than $20,000.

 

No damage but it still cost $10k? What was being done on the repair? I'm just curious.

 

Been posted somewhere here before, so you get the short version. $2000 for the IMSB. Tons of metal around the bearing and in the pan. Car ran perfect. Car could not pass certification. Had it buttoned back up and flushed frequent oil changes. After a few thousand miles metal started to show up again in the filter/plug. Rennlist panic set in and I send the car to UFO in California for the $7500 refresh/rebuild. Diagnosis was engine/bearings/IMS/cylinder heads all perfect. Was just some of the old shavings showing up after the engine being used. I guess there are places you can't really flush without taking the engine apart. 20,000 miles later car is perfect.

 

Hi all

My 1999 C2 coupe with 113000km on it has just undergone its second IMS bearing replacement.

The first one done under the first owner at 80000Km. At that time they also replaced the liners with 3.6L nikkies and also did the RMS.

Now, 6 years and 33000kms later I've just replaced that one with a new dual row version. The reasons for doing this are based on the advice from a long term Porsche workshop who state - "the IMS bearing MUST be replaced every 4 years regardless of distance travelled in that time".

So, being 2 years over this advised period, I did as advised... my workshop initially tried to install the "IMS solution", which when fitted was sitting 2-3mm proud and wouldn't fit properly... many calls/emails later it was removed and sent back. They then used the dual row option which, again, will have to be redone in 4 years time... personally, I find this a serious drag and a clear design fault from the get-go - and I think most would agree!

Interestingly, the IMSB that was removed was 100% fine - no bits missing and no metal in the pan or anywhere else that it shouldn't be either!

However, I don't have to keep the car, theres always the option of selling it etc. But, I'm prepared to do it so far as I love the car.

Anyway, no real gripes here, I just thought I'd share my story with you all to see if anyone has had a similar experience.


AT

 

You need to find a new shop.

 

The fact that they tried to install an IMS Solution on 3.4l engine would further support your statement, Alp.

 

Looking back you are indeed correct if the shop put 3.6L nikkies into an original 3.4L block.

 

OP here. F6I/LN had not made the offer clear at the time I posted. I'd simply notified them of the information provided to me.
Glad to have a spare IMS and bearing.
I am getting the the IMS bearing back so that I can send it to F6I/LN.

Re: engine damage -
Current theory is the Seattle based mechanic installed the single row IMS incorrectly causing it to fail prematurely (@6,000 miles).

In discussing the failure with Vision Motorsports, the bearing seized at high RPM. The exhaust valves were stuck open during "valve float" and struck by the pistons. The valves then struck the exhaust cams. The exhaust cams were broken on both sides of the engine.

EDIT - to clarify, Vision tore the motor down to make this diagnosis. - OP

I purchased a rebuilt motor from Vision Motorsport and shipped the car to their shop to have the dead motor removed and the new motor installed.

Drove it back to Seattle over the weekend. Happy to have the car back.

Dwain and the team were exceptionally knowledgable, helpful and professional. I highly recommend them.

 

Oh yeah, I remember your thread now but my impression was there was some damage. Interesting to learn that it was just residual debris. At least now you know for sure you got a healthy and long lasting engine after the rebuild.

 

Nope, no damage. I guess the concern was that the shavings would cause premature bearing wear or get back in the replacement IMSB and cause it to fail early. I am interested to see if this bearing fails. Knowing the first double row failed early I wonder about whether my car has an IMS "alignment" issue and whether this was a factory build problem or a defective part problem that can't be fixed by a rebuild or whether I just had bad luck. I don't worry about it anymore and just drive the car like I stole it.

 

Hi

I bought a 1998 996 Tiptronic with 92 000 km on. (about 50 000miles)

I have no way of knowing if the IMSB has been changed as the car has had multiple owners. I have been panicking about the bearing ever since i bought the car and i am even tempted to just replace the car with a 997.

This response regarding a 3.4 engine not needing the IMS solution caught my attention.

Please explain. Are there 996 models that are immune?
Where would my 1998 fit in this picture?
Do you need the VIN to determine this?

much appreciated

 

I remember that thread and I believe I was on the side of the fence of people to suggest not jumping the gun and letting things play out.

 

I should have listened to you. Live and learn.

 

1998's all had double row bearings. The only replacment from LN is a dual row ceramic bearing with I think a 75,000 mile replacement life. The solution and single row pro will not fit.

The double rows have a 1% or less failure rate. So don't panic. Drive the car. Check and change the oil looking for metal.

The 997.1's also have an upgraded IMSB, but still have a 1% or less failure rate - so unless you upgrade to a 997.2 with the 9a1 engine you are going to be in the same place.

 

Yeap and yeap. Was going to do the solution in our 01 until they pulled it and found a perfect dual row. If we had known it was a DR I would have left well enough alone, but oh well.

I now have a nifty desk toy though

I was told 5yrs/75k on the new LN bearing. We'll see how I'm feeling 5 years from now (it won't be near that milage unless something significant changes ).