He's worked on Porsches, but I don't know if he's done one of these jobs before. What would be a reasonable labor estimate for this job with a Tiptronic?

Dave

I don't think you can get any better quote than the one from JFP.

I'll chime in with the others - my car has 63k. I only bought a month or so ago and have no reason to believe the IMSB has been changed. Much as I'd like to just do it as PM, my budget doesn't allow for it. I am planning to replace the clutch at 90k (at the latest) and have IMSB done then. Obviously, I am also changing oil ever 5k at most and watching for metal. If I end up gambling and losing, I understand what I'm out but I hate to do work that isn't proved to be needed at this point.

18 hours does seem long. My IMS was done last year along with clutch, pressure plate, flywheel, throwout bearing, RMS, oil & filter change, brake and clutch fluid change and I was charged for 11 hours. The break down was 7 for the clutch job, 3 for the IMS and 1 for the fluid flush. This was done at a very experienced indie here in Winnipeg. The shop owner drives an 02 Boxster S among other European cars.

There is no way to know if any particular car will suffer a failure. The statistics apply to the group of cars as a whole.

It really comes down to how you feel. There is no way to calculate the cost/benefit, any course of action can be rationalized if you think about it enough. Relying on what others say isn't particularly valuable either since each person has a only a single data point (or a couple of data points if they've owned more than one car with an M96) to share; but a single failure or success can't predict what will happen to any other specific engine.

The best course of action that I can suggest is to do the maths for yourself. What would it mean to you if the engine blew up? What would it cost to repair? Would the expense of a bearing replacement be good insurance compared to the aforementioned costs?

Everyone is in a different financial situation and everyone has a different profile for taking on risk (or avoiding them). Only you can make your decision.

For me, racing puts a big strain on the engine so its no surprise that I have and expect engine failures (officially, I am on my 4th engine but who's counting? :)). With that being said, I plan for an engine failure every two years. Thus, the expense is built into the racing budget and engines are considered wear items just like brakes and tires. As such, there is no financial benefit in replacing the IMS bearing and I am willing to take the risk under the assumption that something else will wear out first and cause the engine to fail.

With this plan, I get ahead of the problem by buying used engines for $2600-$2750 well ahead of when I'll need them (a desperate buyer rarely gets a good deal), so I always have a spare engine on-hand. Also, I have the skills and tools to swap the replacement engine in myself so I can be back up and running for about $3K total. I realize that not everyone is in my situation, so spend some time and figure out what path would work best for you.

Every person is different in their emotional makeup, finances, risk tolerance, attachment to the car, etc.

I often tell people to ask yourself these questions:

1. How would you feel if you didn't do the IMS and you had a failure and the car was suddenly worth $3k and/or you had to try and find a replacement engine?

2. How would you feel if, the day after you did the IMS, you had a crash and totaled the car? And by the way, there are several dozen known modes of failure.

3. How would you budget for the IMS replacement? Or for the double the expense engine replacement? (There are no such things as remanufactured engines at $1.5k for Porsches like for some cars. Used engine with the uncertainties that brings are $3-4k plus removal and replace labor. Porsche sourced engines maybe $12k plus labor. Remanufactured engines with known problems addressed with better parts maybe $20k+ plus labor.

The probability of failure for your car is a bit over 1% per car year. What transmission it has has relatively little to do with the probability. The fact that it has been driven gently may, in some experts opinion, slightly increase the risk. The frequency of oil changes and their quality can reduce the risk somewhat.

I did my own clutch and my Indy came over to my shop and swapped mine for 900. Gave him 1000. I have my old one. Minuscule play. No grease in it, both seals intact.

I did my RMS too even though no leaks. Glad both are done.

I put a magnetic drain plug in, then changed oil regularly. I never saw any debris on the Boxster. The story was different on the 996. I saw debris and promptly changed the IMS. Could it have gone on with out the change? Maybe. Maybe not. I did not take the chance.

just an FYI quote i got was around $2550
- replace bearing
- trans flush
- cooling sys flush

'01 tip...

and not to jinx myself, still on original bearing @135k miles

This is an interesting and independent anecdotal data point from a very reputable source. Up till now these 'big bearing' cars had a better reputation for IMSB longevity than either the double row or single row OEM cars. Maybe time and miles are beginning to tell .The interesting question is-what is causing the failure in the big bearing engines - load or lubrication or...?Supposedly the load issue is solved with the larger bearing but the ball bearing speed is much higher ......What an opening for Vertex !