Hypothetical question about IMS vs. engine replacement (2006-2008)

This is related to the recent discussion about Jake's (LN's?) development of a non-bearing replacement for an IMS. From what I understand pre-2006 engines can have either of LNs replacement IMS (bearing or non-bearing model) done along with a clutch change or as preventive maintenance for a reasonable cost. It sounds very reasonable if you do in fact need to replace a clutch. On the other hand, to replace the IMS in 2006-08 engines the engine must be pulled and taken apart. I wrote to Jake about the cost of doing this and he estimated $10,000. Not recently, but in some old posts, I recall that new or factory rebuild engines run about $15,000. With on 08 engine, it might make more sense to wait until I have an engine failure (or NOT), and then replace the engine.

This line of thinking leads me to a more interesting possibility: If my 08 engine fails, I wonder if I could replace it with an 09 or later non-IMS engine?

This is all hypothetical as my car is 4 years old with 20k miles and I don't expect or fret about an engine failure. I drive the car as if it will last forever, or as long as MarcW's, which ever comes first But, in case it does fail, or if it happens to some one's 06-08, it is worth considering.

My first thought is you would need a DME that would work with the DFI engine, but will defer to the experts.

engine wiring harness that of course connects all the various engine sensors to the DME is a must have.

Then there is the issue of the fuel supply. The new DFI engines require 2 fuel pumps one a low pressure pump to feed fuel to the high pressure pump.

But of course, nothing is impossible and it would not surprise me if this engine swap isn't worked out at some point, but I'd sure not want to the first to attempt it.

I have to add regarding engine swaps. To me for a swap to be considered the final result should be in-distinguishable from the factory result. IOWs, after the swap I should not have any inking the car is not as it came from the factory.

The engine should behave as the original engine from start to WOT and every where in between. Emissions should be at least as good as before. (Which brings up another issue. The engine MY determines what the car's emissions compliance requirements are and to put a newer engine in an older car raises the stakes regarding emissions so those that live in a state in which emissions compliance is periodically tested have this to worry about. If the car doesn't pass emissions it can't be registered. If it can't be registered it can't be insured. Thus the car becomes useless and worthless.)

Anyhow, back on track... I do not want to deal with phantom CELs (which given where I live would cause the car to fail emissions testing), jerky power delivery, cold or hot weather starting, idling or running issues.

In short the final result should be at least as good as the car was as it was from new.

To this end the factory has unimaginable resources to call upon. To believe someone in a garage or even a well equipped shop will produce something equally as good... Like I said I would not want to be the first person to attempt this nor the first person to fund such an undertaking.

For the 2006-2008 you have only a few choices I know of:

Do nothing
LN replacement IMS shaft which requires engine teardown on a bench
Complete engine rebuild including IMS shaft

No one but LN that I've seen offers an alternative.

As the 2006-08 3rd generation IMS design has seemingly been doing lots better than the prior generations, the odds seem better at this time remembering that it was only later did we realize that there were statistically frequent problems with the first two generations. Only 10 or so of the LN shafts had been done last time I checked with the maker and there weren't any figures offered on how many of those had been done as the result of failure of the initial part or how many as pro-active measures. On the forums I frequent, I'm not seeing lots of claims of IMS problems on cars of those years and certainly some are out of warranty by now when is when the reports start to surface.

No idea of the complexity of the 987 engine into 986 swap. Maybe by the time you need one you won't be a pioneer. Or there will be used engines from wrecks available.

... leave them alone. Preventative maintenance makes no economic sense, and the bearing is about twice the size of the old one, and likely to last much better anyway. If and when it blows up, put another in.

If the mean lifespan of G1 and G2 M96s is, for argument's sake, 85k miles, the new may well be 170k. So it begins to approach "who cares?"

Grant

Grant

gee-lenahan-at-gee-mail-dot-com

As we have seen some go at 10k and some not go at 250k+.

I can only point, with absolute certainty, at about 5 failures. All were M96 pre-2005 cars. All occurred after 40k.
I know the condition of the two i took out of motors myself. One was Ok, but slowly going at 40 k. The other was farly tight, although devoid of grease at 150k.

Got a better figure, pick it. I presume 10k failures point to other conditions that led to early demise. I cant prove that,. but i feel fairly comfortable with the assumption.

Grant

Grant

gee-lenahan-at-gee-mail-dot-com

someone could read it and assume that up to 85k they were safe. Yes it might be the high point in the bell curve of reliability against miles but the truth is we just don't know. If we did know the shape of that curve, we could make a much better educated guess at when or if to make the major expenditure that is an IMS bearing swap. Just as, if we knew for certain how long we'd live and/or how long we are going to keep the car, we could better figure out which of the several differently priced options we should use for the bearing replacement.

Roll them dice.

Yeah, roll those 50,000-sided dice. Hope it doesn't come up with a specific number.

The number of engine failures due to IMS failures is unknown. But with over 500,000 relevant cars and a lot of people attributing other internal engine failures to the IMS bearing, we can infer that the chance of IMS failure is extremely low.

It has been posited by me and others that driving style contributes to IMS failure. Mathematically that is the only sane explanation as to why some people have had 2 or 3 failures. So if you get to 85k and you have not had a failure, the chance of your getting one is even lower than the already low possibility of a low-mileage car.

To spend thousands of dollars on avoiding such a small chance is silly IMO. Check the bearing when you replace the clutch. Unless you've had an IMS failure in the past...

... what that driving style is. I actually agree, to a point. Nearly across the board i have better luck with my cars than many others. I attribute this to good maintenance, general care with machinery, and lack of abuse (not to be confused with lack of hard use).

Audis are known as money pits. Mine have never been so. Expensive when they break? yes. But they don't break that much.

But without numbers - even estimates with very wide variations, we have little to go on.

Grant

Grant

gee-lenahan-at-gee-mail-dot-com

Quote
grant
... what that driving style is....
But without numbers - even estimates with very wide variations, we have little to go on.

Porsche unfortunately, and irresponsibly IMHO, likes it that way. May be something about American litigation responsibility shifting.

Driving styles like perhaps, break in technique, driving it like you stole it right away, letting it warm up before getting into it, oil and filter frequency and quality, times and distance driven per week, following scheduled maintenance recommendations and time intervals, storage inside or outside, climatic conditions, the list is endless.

I'm glad some previous doubters have realized most reported IMS failures are anything but.....it's just such an easy label.

"A mile of highway will take you one mile. A mile of runway will take you anywhere."

Quote
Gary in SoFL

Quote
grant
... what that driving style is....
But without numbers - even estimates with very wide variations, we have little to go on.

Porsche unfortunately, and irresponsibly IMHO, likes it that way. May be something about American litigation responsibility shifting.

Driving styles like perhaps, break in technique, driving it like you stole it right away, letting it warm up before getting into it, oil and filter frequency and quality, times and distance driven per week, following scheduled maintenance recommendations and time intervals, storage inside or outside, climatic conditions, the list is endless.

I'm glad some previous doubters have realized most reported IMS failures are anything but.....it's just such an easy label.

No automaker publishes this info for obvious reasons.

Thus the only thing that makes sense from Porsche's point of view, and this point of view has be held by every automaker, is to keep mum.

The only time we may get a hint as to the severity of the problem is if the automaker does a recall or offers some public extended warranty for a specific condition like sludge in Toyota engines and BMW engine cylinder walls wearing out to list a couple that come from distant memory.

The worst-case scenario is not that your engine blows up.

The worst-case scenario is that you pay for an expensive (possibly-unnecessary) preemptive "fix" for one problem and then the replacement engine dies because of a different problem.



Edited 1 time(s). Last edit at 02/04/2013 04:21PM by Boxsterra. (view changes)

... that point) - your worst case scenario is likely, from what i have personally witnessed.

That said, i still think the $1200 incremental cost of doing the LN bearing while the flywheel's out or in front of your nose is probably a good idea.

Grant

Grant

gee-lenahan-at-gee-mail-dot-com

on the preventative maintenance you should do?

A ship I served on had a $3M shipyard refit, ran aground on its sea trials just out of the yard and ended up being used as a gunnery practice target. So just because it could happen, we shouldn't what?

I do preventative maintenance to give me a feeling of confidence in the car. Immediately after buying my second Boxster, I spent well over $2k on preventative maintenance. The result was a reliable car for the next 5 or 6 years.

Sounds about right; the notion of opening a 987 case preemptively to get replace a bearing assembly that may go 100k (or more) sounds like a financial non-starter.
From my experience with the 06, after 7 years and many tracks days, my cam deviation was practically zero, nothing in the filter and my oil analysis -done annually- always came back indicating minimal wear.

"As the 2006-08 3rd generation IMS design has seemingly been doing lots better than the prior generations, the odds seem better at this time remembering that it was only later did we realize that there were statistically frequent problems with the first two generations."

While I wish everyone with pre-06 Boxsters (I had a 1999 for 10 years) good odds with their IMSs, hopefully the "fix" that Porsche made for the IMS for 06-08s will result in fewer failures. I think I was told at one shop that they knew of at least 06-08 failure, so I am not out of the woods. As I wrote, I don't plan to fret about it. Why distract from all the fun?

... that its too big to fit through the access hole. Like the LN, part of the fix was to make a bigger bearing, with more surface area and more ability to distribute wear, pressure and heat.

So all things equal, it better last longer.

Grant

Grant

gee-lenahan-at-gee-mail-dot-com

but the critical question for this discussion is did they go inside the engine and determine the root cause of the failure?

Recall how few shops are qualified to really tear into a M96/M97 engine. Lots attribute any failure to IMS when the reality is that other failures that really cause the failures go unexplored and the failure gets glibly attributed to the IMS.