mklein9

Thanks for the response, Jake, but even if every failure shows metal debris, it is not the same as saying every time metal debris is found, there is (or will be) a failure. The latter is the case I have to assess (and the former is the data you have in spades). Clearly there is some correlation, but without a different kind of data set I can't conclude much about my case with certainty.

Thanks very much for this advice. That is really useful and I will definitely follow up on this.

Flat6 Innovations

If that debris finds its way between critical clearances, at minimum you'll experience accelerated wear. These are very tight clearance engines, and that reduces the margins of error. Often times the primary failure found with these engines is NOT what takes the engine out, its the collateral damage with secondary and tertiary impacts that equate the bigger issues.

One has to live a life of working with the failure of these engines for a decade to understand that its the same story over and over again. See a few hundred scattered specimens and its all pretty clear.

This is how I take the words out of the mouths of owners routinely when answering the failure hotline.

MiamiC70

The sky is falling

Flat6 Innovations

No, thats tomorrow… Monday is the day when the failure calls roll in.

DaveCarrera4

I believe you are taking the right approach. Be vigilant, take a few low cost precautions, and enjoy the car. Keep us appraised of the future filter inspections.

2003 Carrera 4S Speed Yellow / 1955 356 Continental 1500 Rust Red

CJWessing

Appreciate your input on topics like this, Jake. In trying to talk myself out of thinking my 2002 Targa with 82k miles on original IMS is going to blow up every time I start it (mainly because I monitor this forum), I googled how many 996's (non-turbo) were built, looks to be around 150,000. Would you mind telling us how many catastrophic 996 failures you've seen? Trying to get to an estimate of the failure rates. Or would you have an estimate yourself?

Thanks,
Chris

Flat6 Innovations

There's no way to calculate the failure rate, because the information to support the equation does not exist.

Today I had 4 failure consultations.

mklein9

Update: after 500 "spirited" miles on the new oil and filter, I went in again today and we inspected the filter. Same issue: many (I'm guessing 100-200) small, shiny metal bits. So something is clearly an ongoing problem that requires attention.

Mechanic's assessment: failing IMS bearing (rings or bolts are other possible sources but much less likely). Given that the bearing was replaced 12k ago with the LNE part, it could mean either the new bearing's steel parts are failing, or there's metal debris left from the original bearing. Either way the next step is inspecting the IMS bearing area for damage or debris. This is the likely problem area. If not, something else is failing and a rebuild is called for.

Flat6 Innovations

The most likely case is the original bearing failure process created material laden oil which has attacked the replacement bearing and is forcing its failure through greatly accelerated wear.

Read this page, all the info is here. There are things that MUST be done if ANY material laden oil exists prior to an IMS Retrofit procedure, but shops are not oing this and they are even retrofitting engines that should be disqualified.
http://imsretrofit.com/bearing-already-failing/

This must be taken seriously, as the foreign debris could also be from another failing component that was damaged by the material shed from the original bearing failure process, or otherwise. This is especially true with camshaft and lifter materials as their material fits the description of what you have described.

Engines filled with debris consume themselves. The chances of natural selection occurring are much greater after a failure if the correct regimen is not followed verbatim, and common sense is not applied.

As it stands now, we could save the engine, (more than likely) keep driving it, and no one can save it.

mklein9

Well folks, the car is now on its way to Jake for a rebuild.

Reasoning:

1) There is something creating new or recirculating old metal bits, and not a transient problem of one thing that got shaken loose or something like that. It could be parts of the old IMS bearing, the races of the new one, cams, lifters, or other components. So in the "game of chance" I described above, the likelihood of failure is high. This tilts the probabilities strongly toward doing the rebuild -- not to diagnose only, but to go in and replace everything that is needed.

2) One question was why is the oil pan clean? I figured it is an easy calculation. If I found 200 visible small metal bits in the filter after 500 miles of driving, that's one metal bit every couple of miles. I don't know how often the oil gets recirculated but I'm sure it runs a good number of full circulations in 2-3 miles. That means that at any point in time, there are likely to be zero visible metal bits in the oil. So a clean oil pan is not inconsistent with 100-200 bits in the filter.

3) As part of the rebuild, Flat6 will replace known weak parts in the engine with better reliability parts, based on their experience with these engines. If I want to keep this car for 100k - 150k miles (which is my intent, and was from day one), this seems like the best way to do so.

4) If the engine fails, the cost to repair is (more or less as I estimated) maybe $5k - $8k more than doing it now, but there is also a chance that it would be too damaged to rebuild at all in which case the cost would jump by $20k or more.

I am not happy about this, I am pained to be spending this on a nearly new car, and not have the car as my DD for anywhere between 3 months to a year (depending on what needs to be done), but this is to my eyes the best way forward.

CJWessing

Can I ask how much an engine rebuild costs?

If its still running well, another option would be to dump the car at a place like Carmax before it dies. You'll take a loss on the car but financially it might make more sense.

Thanks,
Chris

Gonzo911

I am sure the next owner would appreciate that.

5CHN3LL

Deleted.

/

mklein9

And then what? Start the whole process over again with another car whose odds are the same for developing an engine related problem? I'll guess that the financial difference is less than you may think, between the sales price to Carmax (or other) and what it will be worth again after the rebuild.

No, the idea here is that I get (or, have forced on me) the opportunity to make substantial improvements in long term longevity of the car. The color, X74, and tweaks I've made to it are of significant value. After rebuild, the car will be far more of a known quantity, I believe.

BTW I had an '87 for 16+ years before this one. That year range developed "in a small percentage of cars" loose valve guide seals that eventually produce extreme oil usage, smoking, and failing smog tests. Guess what, mine got it starting at 90k, burned a quart of oil/200 miles, and smoked like an 18 wheeler until it finally failed smog. I had the heads rebuilt at 122k to fix that problem along with some part improvements for reliability. Maybe I have bad luck, or maybe it's a typical thing to need a rebuild on these engines before you can take them to 150k - 200k.

DaveCarrera4

****ty luck Mike. I'll be very interested to hear the exact diagnosis on what was scraping loose inside, and what parts are replaced. Please keep a good list for us. Are you shipping the car to GA?

2003 Carrera 4S Speed Yellow / 1955 356 Continental 1500 Rust Red