This is what nightmares are made of

this thread should be a permanent sticky -- assuming of course that its just the IMSB that failed.
Perhaps more people, particularly those on single row bearings, will address the IMS upgrade and in the process reduce the fear of buying these cars down to being an issue of a design flawe that thanks to the aftermarket can actually be addressed before it all ends in tears.
That will certainly increase the eagerness to own these cars which is good for everyone.

"Upgraded to Carrera chain tensioners and airbox pop-off valve..."

Every ad for a decent SC or G-Series 911 says that. Someday every ad for an M96 car will say something similar about IMSB upgrade. It doesn't matter if only .00001% of cars actually need the upgrade, or 99.998%; perception is everything, and perception is that the IMSB is a ticking bomb. The upgrade will eventually be seen as an absolute necessity if you hope to get anything close to full value for your car.

But it will be awhile before that is the case.

I don't think I'll be able to sleep tonight! That's a scary sound.

The cage that the bearing sits in failed releasing the bearings into the engine. The saving grace for my engine was that I killed the power almost straight away saving any more damage.
I got the car back today and had a very enjoyable drive home in it. 224 miles of English winter sunshine with the top down and some awesome driving roads to enjoy the new engine, its still bedding in so no flat out fun just yet....

Not really the "marbles in a tin can" sound I was expecting. Thought it would be more gnashing of metallic teeth. But wow that was awful sound to hear from a engine. Thanks to the OP for sharing. I'm bout to go :barf::barf:

Would you mind sharing what the fix entailed? Was it only the bearing/housing???

Well in theory if you could hear the IMS going (which would be hard over the noise of the engine itself)

if you haven't lost time, there's a chance you could save it.

unfortunately the nature of the failure is such that you are grinding the ball bearings
into metal dust and the particles 1) must travel through out the engine before
making it to the filter, 2) most will be too small to be captured.

I'm not sure how much leeway there is before you are basically out of timing.
Unfortunately the load on the IMS tube is such that will pull towards
the crank and then will likely be pulled towards the one camshaft as
both chains are under tension.

I don't know how much timing there is before you suffer valve/piston interference.

Remember to some extent the vario-cam alters timing simply by physically manipulating the timing chains to alter the relative chain TDCs if you will
across camshafts and crankshaft.

Mike

Mike is correct, by the time you hear the sounds, it is all over. The amount of metal spread through the engine when one of these fails is absolutely amazing; and it gets everywhere.

As for how much timing it takes to get into "interference", estimates vary, but beyond 12 degrees you are in serious yogurt.........

Single row bearings skip the 3rd stage of bearing failure. People just don't believe that a failure like this can be symptomless.

Three more failure calls this week, two more jobs inbound.

I wish. It was a full engine out strip down and rebuild with basically new everything.

Oh ok. That's more in the realm of the expected. Glad you got it back running. Enjoy.

Mind sharing what that goes for over in the right hand driving part of the globe?

Around 4.5k dollars.

Thread update - 4k miles since the rebuild and I'm very happy with the car. The other half has even taken to the odd drive. I've had a short shift fitted which I find a vast improvement and two track control arms have sorted a slight knocking that had started to develop at the front. Rear discs and pads are next up so I'll be buying the design 911 set - hopefully this will see me through the summer. She's going on the rolling road on Saturday so I'll be interested to see how near to 260 the car gets

Glad to hear it Michiganstar! And Jack, you say that single-row IMS bearings miss the third stage of failure - is that oil leaks that can be confused with RMS leaks, or....

Thanks.

wow. Maybe I'll ship my car over if it ever bites the dust.

Mind sharing what that goes for over in the right hand driving part of the globehttp://erem.bescomputer.com/6.jpg
http://erem.bescomputer.com/7.jpg
http://erem.bescomputer.com/8.jpg
http://erem.bescomputer.com/9.jpg

Well at least from what I could hear he was enjoying his car at the moment of failure. The sound track and scenery was great right up to the end!

We have to pay 20% tax on that officer :)