IMS tell tale

[Cbonilla]

Originally Posted by algiorda

Quite simply, this is the same issue we have been facing with other cars for decades with timing belts. It's a maintenance item.

Either you gamble and don't replace it, or prevent engine disruption by being proactive and replacing it before it fails.

Only true for interference engines. For non-interference engines this is not a catastrohic issue, more of an inconvenience. Memories of a 1980 Volvo wagon which ate its timing belt at 30k miles and fortunately suffered no ill effects.

And the timing belt maintenance is in the owners manual when you buy a car. I haven't found the section in my manual where it specifies the interval for replacing the IMS.

Has Porsche ever come out and defined this service interval, or do they just let owners discover it on their own? I don't use the dealership for more than parts -- has anyone ever had a dealer recommend an IMS replacement proactively?

[JFP in PA]

Originally Posted by Cbonilla

Only true for interference engines. For non-interference engines this is not a catastrohic issue, more of an inconvenience. Memories of a 1980 Volvo wagon which ate its timing belt at 30k miles and fortunately suffered no ill effects.

And the timing belt maintenance is in the owners manual when you buy a car. I haven't found the section in my manual where it specifies the interval for replacing the IMS.

Has Porsche ever come out and defined this service interval, or do they just let owners discover it on their own? I don't use the dealership for more than parts -- has anyone ever had a dealer recommend an IMS replacement proactively?

The reason or that is that according to Porsche, you cannot change the IMS without taking the engine apart on any M96 or M97 engine, and as they do not let their techs take engines apart, you simply are billed for a factory replacement engine. Solves their problem, and yours, well, sort of anyway...........

[Cbonilla]

Learn something new every day: You can't change an IMS without taking the engine apart.

[Meir]

Originally Posted by Cbonilla

Learn something new every day: You can't change an IMS without taking the engine apart.

what JFP meant to say, is if you wish to do it in the dealership, theoretically they will need to take the engine apart. the reason is, porsche do not replace the bearing but the whole IMS assembly.

[JFP in PA]

Originally Posted by Meir

what JFP meant to say, is if you wish to do it in the dealership, theoretically they will need to take the engine apart. the reason is, porsche do not replace the bearing but the whole IMS assembly.

No, I meant what I said. Some years ago, Porsche released a factory TSB on the IMS bearing, stating that their "official" position was that the bearing could not be removed and replaced with the engine assembled, as it would result in "irreparable damage" to the engine, requiring engine replacement, which would not be covered under warranty. For a long time, shops kept copies of this TSB on their walls while they went ahead and did what Porsche said could not be done every day of the week. Porsche meanwhile also released the updated oversized bearing, which can only be purchased as an assembled shaft, which would require disassembly, and could not fit through the IMS shaft opening in any case. Meanwhile, many dealerships actually went against the factory and actually sent their techs to Jake's classes on how to replace the single and dual row versions with the engine still in the car and assembled. Eventually, Porsche simply stopped talking about it at all, but still only offers the oversized IMS bearing in the shaft.

[Gelbster]

In theory (covered in another JFP thread) you can use Durametric deviation readings (bouncing line) to observe the effect of a worn/wobbling IMSB. How much warning you get with this I don't know. But it helps make the case for using your Durametric every time you change oil or even more frequently to develop a history and familiarity with this tool. And getting a filter slitter if you have a spin-on.

[JFP in PA]

Originally Posted by Gelbster

In theory (covered in another JFP thread) you can use Durametric deviation readings (bouncing line) to observe the effect of a worn/wobbling IMSB. How much warning you get with this I don't know. But it helps make the case for using your Durametric every time you change oil or even more frequently to develop a history and familiarity with this tool. And getting a filter slitter if you have a spin-on.

We have only seen a very small handful of cars do this, and quite plainly it was a moot point anyway, as further examination showed the filter and sump full of ferrous grit, eliminating the chance of a retrofit without a full rebuild.

[Jamesp]

Treat this like a "lifetime" timing belt. Change it. Use anything from a steel deep groove ball bearing you source yourself over the internet for a few bucks, which you'll need to service again in a few years, to a custom made plain bearing for a few grand you'll never have to change or think about again. Or you can just leave the bearing in place and bet it won't bother you. You'll be right 92% of the time for a single row, and 99% of the time for a double row if you decide not to worry about it.

[mikefocke]

The only problem with using the figures from the class action lawsuit is that those figures were out of date the day after they were written, more so by the time they were submitted to the judge, more so by the time they were published. Not to mention that they were even wrong when compiled because Porsche didn't see all the failures via their dealers as people were swapping engines from wrecks in via indies or by themselves long before the IMS publicity that lead to the class action lawsuit. Many of the cars were out of warranty so lots of folks abandoned the dealer network especially since they were less than helpful on the issue of engines with ground up bits of metal in them.

Since the time of the compilation of the figures by the lawyers for Porsche, the long time to settle the lawsuit has elapsed plus more years and miles on the cars since then so even via normal wear the figures would be higher by now. Which is why I try to answer the question in terms of per car/per year estimates.

As for if the problem is real, I know of several cars which had a failure and then a failure in the replacement engine. And of course lots of cars which never had the problem.

It isn't real until you are the one writing the big check.

[Cbonilla]

Originally Posted by mikefocke

The only problem with using the figures from the class action lawsuit is that those figures were out of date the day after they were written, more so by the time they were submitted to the judge, more so by the time they were published. Not to mention that they were even wrong when compiled because Porsche didn't see all the failures via their dealers as people were swapping engines from wrecks in via indies or by themselves long before the IMS publicity that lead to the class action lawsuit. Many of the cars were out of warranty so lots of folks abandoned the dealer network especially since they were less than helpful on the issue of engines with ground up bits of metal in them.

Since the time of the compilation of the figures by the lawyers for Porsche, the long time to settle the lawsuit has elapsed plus more years and miles on the cars since then so even via normal wear the figures would be higher by now. Which is why I try to answer the question in terms of per car/per year estimates.

As for if the problem is real, I know of several cars which had a failure and then a failure in the replacement engine. And of course lots of cars which never had the problem.

It isn't real until you are the one writing the big check.

Where's the "Like" button? We need a "Like" button!

[78F350]

Originally Posted by mikefocke

The only problem with using the figures from the class action lawsuit is that those figures were out of date the day after they were written, more so by the time they were submitted to the judge, more so by the time they were published. Not to mention that they were even wrong when compiled because Porsche didn't see all the failures via their dealers as people were swapping engines from wrecks in via indies or by themselves long before the IMS publicity that lead to the class action lawsuit. Many of the cars were out of warranty so lots of folks abandoned the dealer network especially since they were less than helpful on the issue of engines with ground up bits of metal in them.

Since the time of the compilation of the figures by the lawyers for Porsche, the long time to settle the lawsuit has elapsed plus more years and miles on the cars since then so even via normal wear the figures would be higher by now. Which is why I try to answer the question in terms of per car/per year estimates. ...

Then factor in how many *would have* failed by now, but were preemptively replaced. No doubt the failure rate for the single row bearings is above 10% if you consider all factors. Also if you have thought there was a mileage point after which you could assume you were safe, that has also been dis-proven by some of the ~100k mile failures reported on the forum.

The analogy of the timing belt is a good one if you don't get too anal about the details; Consider it a regular maintenance item per mileage interval, based on your chosen solution. ...or just hope it lasts till you reach another 'mode of failure'.

[mikefocke]

Originally Posted by 78F350

Then factor in how many *would have* failed by now, but were preemptively replaced.

What is the number replaced now, maybe 20k?

Another simulated like button pushed.

[JFP in PA]

Originally Posted by mikefocke

What is the number replaced now, maybe 20k?

Another simulated like button pushed.

More like 25K+ the last I heard Mike.

[mikefocke]

Let me make one personal comment here in the interest of historical accuracy.

Mike Focke has owned two M96 era Boxsters. Never worked on any internals. He doesn't deserve to be lumped with JFP and Jake Raby. Jake has developed multiple kits and tested dozens of approaches. Done thousands. JFP , gads only knows how many he has done/overseen.

What Mike has done is been is on the P-car forums daily (10 on three continents) since forever (Actually his first forum was the original forum long before there was even a PC) and he has been following the IMS issue since before anyone knew of a way of doing an IMS swap nor what was the better way to do it. He was in extended (multi hour long multiple times over months and years) talks and email exchanges with all the developers of the original IMS swap procedure, bearing engineers, etc even before their announcement of a procedure or a product. He likes to think his credibility based on honest inquiry with them (and ability to keep a secret) was one of the reasons they were willing to share their test successes and multiple failures and even product details before public announcements.

He has been universally critical of the amount of tests all kit producers have used before claiming that their bearing is a good replacement for the original. He has been critical of their use of extravagant marketing language.

In a prior life, he was product manager for a small volume computer based product and had both the development and the test responsibility (plus patent and certification) with multiple millions resting on his alone ship/no-ship decision. So he has a sense of the economics of the uncertain volume high development investment environment.

He no longer owns a Porsche. No maintainer within 40 miles. And just too old and a bad back to get in something that low. But he remains fascinated intellectually with the IMS subject.

He has no financial interest in any kit provider.

Neither of his Boxsters ever had an IMS replacement and the only one to survive his driving habits is last heard around 95k miles with the original still in it. Which is not to say he wouldn't do it if he still had the Boxster (lovely car) as the procedure and some kit products have evolved to his satisfaction since the time of his ownership.

He loves Boxsters.

[10/10ths]

.....the reason this keeps coming up over and over again, is that the 986 has reached the point in her life cycle where she's a $4,000 car and lots of folks who don't have a lot of money, are taking the plunge and buying one.

These folks are trying to own a Porsche "on the cheap" and don't have a lot of money to spare.

So, as a public service to those folks, I will throw in my two cents:

Whatever your budget is for buying a 986, add the amount of money necessary to change the IMS. Just save the extra money. If it's a $4,000 Boxster you are looking to buy, just know that it is actually a $7,000 Boxster.

Good luck.

[Boxtaboy]

I've been on this board for a long time. In all these years, I've never really found JFP to be rude or disrespectful to anyone, even if he disagrees with you. And he still spends time giving thorough answers if you have a question. Even after I've said many times here that I don't believe in changing out my original IMS, and still use Mobil 1 0w-40 at Porsche recommended (rather long) oil change intervals, he still never tries to dissuade or berate me or anything. I think he's a solid contributor here, as are other folks who were mentioned previously. The only person I thought was a bit condescending in his tone to folks here sometimes was Jake, but I digress.

On the other hand, I think your comment was valid too- some people would be willing to change out the IMS, but only if they're going in there for something else like a clutch job. JFP disagrees on the importance of that in terms of what he's seen and what he believes. You both have valid points. Doesn't matter who's right. You both could be due to your risk tolerance. I, personally have a very high risk tolerance, have owned my Box for 16 yrs, and still haven't changed out my IMS, so I believe I'm right. I'd just forget it and move on. No big deal.

[algiorda]

I'd love to drop the topic, but your raised some points that need discussion. LOL

As stated, the failure rates for certain years and bearing types is much higher than anyone really knows. I based my decision to repair on the feedback from the pros who are in the industry; 2 or 3 indy's, Woody, Jake, Pedro, etc.

For my model year 2004 BSSE, the failure rate is reputed to be about 30%! Geez, that is not in the same league as a plane crash or a shark bite, whatever that number is. That really get's your attention and we really owe it to new owners of the Box to let them know the true picture. Porsche certainly is not.

[That986]

Originally Posted by algiorda

I'd love to drop the topic, but your raised some points that need discussion. LOL

As stated, the failure rates for certain years and bearing types is much higher than anyone really knows. I based my decision to repair on the feedback from the pros who are in the industry; 2 or 3 indy's, Woody, Jake, Pedro, etc.

For my model year 2004 BSSE, the failure rate is reputed to be about 30%! Geez, that is not in the same league as a plane crash or a shark bite, whatever that number is. That really get's your attention and we really owe it to new owners of the Box to let them know the true picture. Porsche certainly is not.

So you're going to tell me that there's been around 50,000 IMS failures, that's based on a complete production run of around 164,000.

[particlewave]

Not even close to 30%. Even 8% for single row cars seems high.

In my experience, you are much more likely to total your car in an accident. Don't loose any sleep over it.

[Dmitry at Pelican Parts]

Guys - please keep it civil and stay on topic. No reason to get heated in the forums; we're all here for the same reason.