Zookie

I don't know, I have Cut open the Bearings yet

thebowl

I just had a failure in my 2003 C2 at around 37000 miles. The end of the shaft has sheared off (I was forced to drive it for a while; it's a long story), so the process is beginning for me.

I will probably scroll through all of the pages of this thread, but any advice on the rebuild will be appreciated. I have a mechanic who is extremely competent, honest and experienced. A bit of dark (VERY dark) humor- he kept the box and packing materials that he used to send off the block from the last Carrerra he rebuilt, to the folks who had to bore it out and sleeve the cylinders. I am hoping that I don't need that box...

alpine003

Pics or it didn't happen.

mklein9

My advice from having had 2 IMS bearings get very close to failure (you didn't say if yours was IMS related or not, do you know for sure??):

1) If anything has failed inside, the engine MUST be torn apart, all the way down to the bare case and all metal removed. Don't even start this project if you will not do this. Or, like my PO, you can do a half-a$$ed job, replace the bearing (if that's what failed), and pass it off on an unsuspecting n00b (like me) who will have the replacement fail again.

2) Replace known risky parts with better ones than factory. There is quite a menu depending on what your goals are.

3) The cost to do it right doesn't vary a lot, I believe. The cost to *not* do it right can be all over the map, with the top end being a new engine from Porsche (although apparently those are no longer available??).

The key for you is to decide what your goals are with the car. I plan on keeping mine a long time and drive it every day including occasional moderate track days. So I went with the best I could find and added a few reliability options. I would love to drive it to 150k like I did with my '87, or more. There are many lower cost options if you just want to put lipstick on the pig but then you have to live with that.

You are right to look over what others have done and decide what you want to do.

FYI, I also have a very good and experienced Porsche specialist mechanic that I've been going to for over 17 years. He even took a rebuild class from Jake Raby and rebuilt one engine. He's not doing any more because he says it takes so long that he will never make money on it unless he gets really experienced at rebuilds specifically. This is something to keep in mind, IMHO.

thebowl

Thanks for the info. Yes, it was the IMS bearing that failed and seized. No warning at all. My mechanic has 30 years of experience. I live in a densely populated and relatively affluent area, and this guy is the "go to" resource for German cars. He has (sadly) done many re-builds, and even more pro-active bearing jobs.

He has explained to me that everything has to come out, to see the extent of the damage. In a best case, there will be no cylinder wall damage. In a worst case, I get to decide if I want to increase the displacement when it gets bored out for sleeves. It looks like upgrades are available for the timing chains. The clutch will get new plates, throw out bearing, etc.

I plan to keep the car forever. I actually need to drive it more than I do. I don't like driving it in traffic where I live, so I have only been driving it down in the Appalachian highlands, which is like being in Bavaria, but not easily accessible for me. My guy is very familiar with the ceramic bearings, and is steering me in that direction, but I am intrigued by the "Solution". It looks more permanent and, as a non-engineer, it seems more intuitive to me as a proper fix. I am not thrilled by the recommendation to replace the ceramic bearing at 50K. That seems like the main decision I will have to make. I am interested to know about available upgrades, particularly for stuff that will have to be replaced anyway. At this point, my loyalty to Porsche factory parts is less than total...

thebowl

I wish.

[IMG][/IMG]

Flat6 Innovations

I'll be awaiting your call. This week goes down in history, WOW!

ChicagoSpeed996

There seems to be a lot of information that can be gained from these failures. I am probably restating something someone else has brought up, but wouldn't it be beneficial to ask the persons with failures to fill out a questionnaire with thins such as:
Year, model
Any modifications
Miles driven per year
Style of driving
Typical mileage of daily drive
Time between drives
Oil change intervals
Oil used
Oil Filter used
Minor major maintenance performed, when?
Any leaks near engine/trans housing
Any oil filter inspections done prior to failure?
What were you doing when it failed (vehicle speed, vehicle RPMs, temperature of vehicle, miles into drive, temperature of environment, accelerating/cruise/decelerating?)?
I would think a standard form would be able to extract trends.
I am sure I am restating this, but worth a shot.

alpine003

Well there you go. Jake or anyone else will tell you, you shouldn't have driven it at the first signs of any trouble. Who knows what kind of collateral damage you've done and what the original issue could've been initially.

BTW, I still do not see a pic of the end of the shaft that's sheared off, unless you mean the IMS bearing.

alpine003

This whole poll is unscientific and useless so nothing can be gained except wasted time reading this and then worrying about this, which will keep you up or accelerate that ulcer you may already have.

Who's also to say someone didn't create multiple accounts and voted multiple times. Not to mention we have no where near 130k+ members on here which was the rough production numbers of the 996. So based on the total count of the poll, this equates to 0.003% of the owners chiming in which can hardly qualify as a "trend" in any sense. OK, rant off.

mklein9

I got four significant upgrades on mine:

1) IMS Solution and full-flow oil filter
2) Billet steel connecting rods to eliminate both the loosening bolt and rod strength issues
3) Improved timing chains and new rails
4) Improved intake valve seats (two were loose)

These address my interpretation of the top reliability issues of the M96 engine to produce a reliable daily driver with modest and occasional track use. If I couldn't do that, then to me there is little point in having a Porsche, period. Even still, track use will require a high-temp shear-resistant racing oil (e.g. XP-9).

My cylinders, crankshaft, cam shafts, and most peripheral components were healthy. I got a new water pump, AOS, RMS, belt/roller, plugs, thermostat, heat exchanger, lifters, some hoses, and got the clutch inspected (had 50% left so I didn't replace it). So a load of 40-50-60k type maintenance items were also taken care of and I won't need to touch those for quite a while.

210k911

1999 996 210000 miles on chassis. New engine at 86K. 130K on original crate IMS.

Copilot

Just out of curiosity, what specifically did the shop do wrong in the installation that caused it to go bad?

mklein9

The shop basically did not follow any of the steps listed on LN Engineering's site. The worst is that they replaced a bearing that had already been damaged and was shedding metal debris without cleaning out the debris. Or, maybe even worse, they did the replacement with an obviously non-qualifying engine according to LNE's qualification process. Even if they had qualified it, they should have gone through a massive oil change program to try to clean out as much debris as possible and replace the oil filter with a full-flow filter (without the pressure bypass valve).

I could go on about more things the shop did like replace the RMS which was discovered 12k miles later to be hanging out of the engine block. And forgetting to tighten a suspension piece. Comedy of errors. It appears they just wanted to collect the repair charges and foist the car on a new owner (me) who didn't know better.

Flat6 Innovations

Put simply, this engine should never have been retrofitted.

Too many shops treat the IMSR like a brake job these days. They don't pre- qualify engines and they don't care. We've carried out 399 IMSR procedures and have never had a post- process failure. The reason why is because we won't retrofit every engine that comes in the door.
Pre- qualification separates the men from the boys. We developed the procedures, we can sniff out a bad engine a mile away.