the reason for ims /bearing failure

bobrestore · 08-19-2013, 02:40 PM

IMS/BEARING ... Ok my 2005 boxster s is outside the class. The class(2001 to earlier 2005) used specific bearings that the plastic failed on. Alright hears my theses. 1970 karmmann ghia convertible tops melted. Vw blamed the cars being washed with soap that had a chemical reaction.... My upholstery instructor informed me that it was really the plastic manufacturer of the convertible top material did not have proper UV component. ...OK .... in the 1970's anyone use feather fill primer? Some people after block sanding found little pimples.... the paint jobber said it was the acetone that sucked water molecules out of the air and trapped then in the finish. .....no ...according to featherfills own scientist.. it was that the supplier of the resin to make feather fill was below grade and created resin pools that then gassed off that created the pimples.... this rhymes....the plastic seal of the ims bearings were probably made of a plastic resin component that was not to "intended" design standard.

Zeke · 08-19-2013, 03:02 PM

Add to that the fact that the IMS bearing was not in the circulating oil system. What kind of permanently sealed bearing can live in that environment plastic or no? Also, it's never been shown what the actual percentage of failures are, just that enough have failed to warrant a law suit. Well, if 2 thousand Ford trucks had catastrophic failures out of any year's total production (hundreds of 1000's), that would be too many.

It was a bad design.

BTW, in certain shop conditions primer flashed cold and drew water in.

bobrestore · 08-19-2013, 03:40 PM

Zeke ....yes with you all the way. But there may be a plastic that would withstand that. I don't know. I am hoping to ferret out info.... More is coming out. I am not in the class but the lawyer told me of the percentages for 2001- 2005 is 4-10% for each production year in class...........................ok.... commence breathing again......and he mentioned that the failing ims recipe had the plastic in common..... this amounts to just hear say coming from me........I would like to find out what the rate is for my out of class late 2005. and if there are failures,is it once again the plastic.

bobrestore · 08-19-2013, 03:45 PM

I ment to say ... he also said the out of class cars on both sides earlier/later was less than 1% but I would like to know specificly late 2005 boxster s

bobrestore · 08-19-2013, 04:06 PM

You know what...... I may have been streaching it a bit to say why the plastic part failed. Its still posible that it ....the plastic failed because the bearing parts inside were failing...I would like to know if the plastic was ever anyalised and then we could exclued the plastic quality

bobrestore · 08-19-2013, 05:37 PM

IF it matters..... Have owned 1954 1500,1959 1600,1966 9/11, 1966 9/12,1969 9/12 targa, 1970 9/11 t, 1971 9/11t, 1972 9/11 t targa......I now have 1961 roadster, 1966 9/12, 2005 boxster s.

steveng1993 · 08-19-2013, 06:30 PM

Probably fails because too much pressure is exerted on the bearings and the hardness or ductileness whichever just can't take it. Cars that sit too long get pressure unevenly internally on the bearing.

bobrestore · 08-19-2013, 08:54 PM

It all reminds me of the first 9/11. The chain tensioners would get weak; chains slop around and break chain ramp and if you were lucky you were the proud owner of a hunk of screwed up aluminum. Lukes/ Shorman of Albany ca. came up with the solid fix...... they simply gutted the Porsche tensioner and put a nut and bolt in it at a set hight..... only problem was that you had to pull off the covers to adjust.I really admire the flat 6 solution.........

bobrestore · 08-19-2013, 09:14 PM

I dont know..... Im a civil engineer expert not a mechanical engineer...I dont no poopie balls from maltballs when it comes to bearing standards. however LN and some timmkin bearing guy did a study on the bearing and al they could difinitivly say is that not being properly lubed was for shur a reason for failure. There was anecdotal mention of bearing surfaces inplay at certain rpm and oil liking certain rpm to get the lub distributed .......but they could not definativly point to the failure (cause) other than the lube.

mreid · 08-20-2013, 07:01 AM

Quote:

Originally Posted by bobrestore

It all reminds me of the first 9/11. The chain tensioners would get weak; chains slop around and break chain ramp and if you were lucky you were the proud owner of a hunk of screwed up aluminum. Lukes/ Shorman of Albany ca. came up with the solid fix...... they simply gutted the Porsche tensioner and put a nut and bolt in it at a set hight..... only problem was that you had to pull off the covers to adjust.I really admire the flat 6 solution.........

Interesting. I recently upgraded my 74 2.7 to hydraulic tensioners. When I removed the old tensioners, they were as described. A bolt with a nut used to hold it in position. Worked just fine, but...

mikefocke · 08-20-2013, 07:02 AM

I follow IMS issues on about 7 forums. Just saw the first 2005.5+ failure I had seen reported the other day. Another data point was LN had sold less than a dozen 2005.5+ rebuilt IMS shafts. From this one infers low failure rates reported so far. But people only complain when it hits them in the pocketbook and the 2005.5s haven't been out of warranty as long as the earlier ones and we only realized the full magnitude of the 2000s after about 6-8 years.

matt demaria · 08-20-2013, 07:22 AM

In 3 years I've seen about 20 failures. The latest model was an 08 boxster with 60K. I had an 05 with 19K on it that was failing. And it was curious that in the records the dealer fixed the ims seal at 9K. This I believe was due to fretting wear from vibration of the failing ims bearing.
It is also curious that the front ims bearing under the oil pump never fails. Clearly it seams that the loading from 2 chain drives has an effect on the failures.

bobrestore · 08-20-2013, 10:24 AM

Oh yeah... If Porsche could do it over again there is no doubt they wood do the flat 6 plain bearing oil feed set up...... just like when the early 911 tensioners failed and us Yankees found fixes Porsche followed . Please don't take that statement as a knock on Porsche.... i love there stuff..

randy_k · randy_k's Garage

Simple answer is. It was a POS bearing design. Farmed out to questionable, at best manufacture's. Porsche was about ready to go broke, due to lack of sales. The Boxster was going to be there savior. It was hurried on the market place to accomplish it. Little research and development was done.
For what ever reason. The general consensus is. These cars need to be driven. Another words. Drive the piss out of it. I guess is some ways, it may keep the bearing moving and may prevent the crap materials from absorbing the containments in oil to deteriorate it. In any case. It is was poorly done. Some are lucky. The one in there car are ride on. Some suck. To ponder why, is irrelevant. Hope yours does not go bad. Mine has 106,500 miles on it and lives. A bunch of other crap parts have failed. But not that fatal one... I love to drive it. But that failure is always in the back of my mind.
Now off to fix taco's for dinner. With a proven method.
Randy
PS, The LN bearing still seems the best answer to prevent this. But at what cost? I'm not spending 3k to prevent an 8k car from blowing up. I can part it out and break even...

bobrestore · 08-20-2013, 01:04 PM

Thanks enjoy your meal.... Call me a skeptic ...but... It could be a joke that its the guys that sell maintenance parts say the cure is to drive it like its stolen... that comment is not intended for you , bye the way

big911fan · big911fan's Garage

I'm with you on the "drive it like it was stolen" theory. While not impossible I find it hard to believe that a bearing of any type actually has a better life span with hard or abusive use.

I can believe driving a car frequently stops deterioration on some parts like seals, gaskets, etc., etc. but not a bearing.

Sure the grease in a sealed bearing might get hard but I would think any type of use would soften it up. It's easier to believe the IMS bearing fails because of poor design. poor quality materials, or poor manufacturing. Or perhaps the stress from the bearing having non-centric stresses on it from the timing chain.

Bearings are mechanical items and subject to the laws of physics. They are affected by stresses, usage, wear. and thermal cycles like anything mechanical.

I'm not an engineer but I'd like to hear from either a mechanical engineer or bearing engineer that "drive it like you stole it" actually lengthens bearing life.

If an IMS bearing was defective from the factory in design or implementation it was going to fail at some point. Some earlier than others. At least that's my theory....

Zeke · 08-20-2013, 02:37 PM

911fan, I don't think driving hard is a proven preemptive measure. But if you are in the habit of driving until the thing is plenty hot and then parking it for a month each time, the grease doesn't do the job. I don't know what kind of grease they used, but if it didn't come from an F1 car bearing, it's probably not good enough.

mikefocke · 08-20-2013, 04:54 PM

Quote:

Originally Posted by matt demaria

In 3 years I've seen about 20 failures. The latest model was an 08 boxster with 60K. I had an 05 with 19K on it that was failing. And it was curious that in the records the dealer fixed the ims seal at 9K. This I believe was due to fretting wear from vibration of the failing ims bearing.
It is also curious that the front ims bearing under the oil pump never fails. Clearly it seams that the loading from 2 chain drives has an effect on the failures.

You've seen 20 where? I don't follow the Cayman forums but I sure have read all the Boxster ones for years. Am I just oblivious?

tcora · tcora's Garage

Quote:

Originally Posted by big911fan

I'm with you on the "drive it like it was stolen" theory. While not impossible I find it hard to believe that a bearing of any type actually has a better life span with hard or abusive use.

I can believe driving a car frequently stops deterioration on some parts like seals, gaskets, etc., etc. but not a bearing.

And therein lies the crux of the matter. As I've followed this for some time now, I'm fairly convinced that seal failure allowing the grease out and oil in is the bottom line failure mode.

Quote:

I'm not an engineer but I'd like to hear from either a mechanical engineer or bearing engineer that "drive it like you stole it" actually lengthens bearing life.

BS and ME degrees in Mechanical Engineering here. See the above for why drive it like you stole it ain't so bad.

big911fan · big911fan's Garage

Tom- Are you saying the bearing seal deteriorates from non-use? I can see that on soft gasket or rubber material but what about the hard plastic bearing seal?

Also, why do you think that some of the solutions offered up for solving this problem involve removing the seal and letting engine oil do the lubricating? Do you think that solution is a disaster waiting to happen?

Last, I was trying to rationalize why driving a car to near abuse was inherently better for the bearing than just normal usage or maybe even occasional use. I'll accept the premise that sitting for months on end might be an issue.

My logic is that once a vehicle is up to normal operating temperature for a reasonable period of time, driving it "like you stole it" serves no useful purpose, other than pure fun, except to increase wear and tear on the bearing.