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Old 09-27-2016, 07:03 PM   #1
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Thumbs up 1999 with double row ims vs single row

Is it safe to say the '99 has a low incidence of ims failure. At less than 1%.
The rate of failure with double rows looks to be over 8%.

I'm having a ppi done on a '99 boxster this weekend Been reading up on the common issues Not sure but it seems like less than 1% is almost a non issue . Less than 1 out of 100. I may be misinterpreting these statistics ??

Preventative measures are frequent oil changes , proper viscosity , quality filters,
Magnetic drain plug , driving at rpm's 2500 & up checking filter for metal.

Any others? I was ready to look other choices for sports car BMW etc. but think the
Internet may have induced ims panic ! I don't like to gamble but the odds seem pretty good

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Old 09-27-2016, 07:32 PM   #2
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I'm no expert, but I have been pretty busy with Boxsters over the last couple years. Since August 2014, I have owned five 1999s and a pair of '01s that all have dual row bearings.
The '99s range in mileage from 80,000 to 175,000. As far as I know only one of them has had the IMS bearing replaced and I did it because the seal was leaking. The bearing itself was still good at 129,000 miles. I got the dual row LN ceramic replacement.
One of the '01s had a failed engine at 124,000 miles with a broken rod/rod bolt. The IMS bearing still looked good, but had lost the grease. The other '01 was a parts car for the replacement engine. While I had it out, I replaced the bearing (which still looked good) with the bearing from Pelican Parts. After five years or so, I may replace it again.
Dual row bearings have failed, but lots of other parts are more likely to fail first IMO. Continue to search and read, there's lots of good info and much of the info here on the forum is experience and reality based rather than hype. If worrying about it is likely to ruin your enjoyment of the car, don't buy it, or simply have the bearing replaced.
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Old 09-27-2016, 08:09 PM   #3
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Be sure you are comfortable with spending more than the old car is worth in repairs. If you want a cheap, reliable, easy to fix roadster, there are more prudent choices than an older Boxster.If you do buy, a Boxster make sure you don;t overpay. Good Luck- they are great cars if you have the skills,tool,equipment, facilities, time and funds to keep them.
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Old 09-27-2016, 08:46 PM   #4
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99s came with double row bearings and these had failure rates if <1%. It was the single row cars that saw higher rates.

Your maintenance suggestions are spot on, but you face a double whammy.

The root cause of the problem seems to be when the bearing seals allow the lubricating grease to wash out over time but don't allow enough oil back in to adequately lubricate the bearing. When this happens, the bearing - whether single or double row - will fail.

Seals can degrade on high AND low mileage cars. Whammy 1: seals in high mileage cars just plain wear and eventually leak. It's a question of when. Whammy 2: seals in low mileage cars start to leak when acids in the oil degrade them when part of the seal just sits in the oil.

If your buying a high mileage car, you'll probably need a clutch soon so just replace the bearing at that time. If your buying a low mileage car, the calculus is harder b/c you just won't know the condition of the seals. Then you just hope the <1% stands up
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Old 09-27-2016, 11:29 PM   #5
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Hi,

there are lots of causes why theses engines can fail. IMSB is only one. My personal POV: there are some people interested in making money by spreading fear.

And as long as you have oil sucked in the IMS you have a kind of lubricated IMSB – just think about it – it rotates.

I have a 2003 S (US = 2004) and i'm very happy with it, because it hasn't the old variocam camshaft mechanism with the green seals and the camshaft rails that desorientate.

Also it has the better designed cylinder heads.

On the downside there are the weaker open deck 3.2 cylinders. But with the right oil, permanent oil changes and slowly warming up the engine i think that is manageable. We'll see when it fails.

Also think about that an IMSB can be installed the wrong way. It was not intended to be changed by factory. So if somebody does it, he needs to know what he is doing and i'm pretty shure it is important to use the right tools and methods and be careful to get a durable result. And in general: if you find magnetic parts in the oil it's too late for just doing an IMSB. Maybe it's a good idea to install a new IMSB with every new clutch.

Don't see why i should only drive at 2.500 rpm and above.

And if the engine fails it fails. That's life.

Also agree what Gelbster said. The expensive part is the proper maintenance of the car. Even if you don't buy every replacement part at the Porsche d(st)ealership – which you have to do sometimes and if you do repairs yourself.

BTW: we've had a lot of 2.7 FL engine failed, but no 3.2 FL in the last months in the german Porsche forum. Fingers crossed.

Regards, Markus
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Old 09-28-2016, 04:49 AM   #6
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The failure rate is quite low as has been written already. I did a major refurb on our 2000 and replaced it as a preventive measure when replacing the clutch. There are many threads about what to look for on a new buy and what the fix might cost.

Deferred maintenance on these cars can be quite expensive if you can't do it yourself. Does the car have service records?
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Old 09-28-2016, 06:17 AM   #7
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the current owner has had car for over 10 yrs . says he changes oil every year , he averages less than 3000 miles / yr . I'll see what other records he has

I can see how things will wear or rot on a 17 year old car [ sounds old !]
that being said it's hard to find a car with so much upside for under $10k
I've had -MG, Miata , corvette , BMW 330Ci, new Boxster [2004] -
Boxster was the best handling with plenty of power [it was an S]

I may need to become more involved with maintenance- oil / brakes etc. Maybe there is a Porsche club in my area [long island NY ]
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Old 09-28-2016, 11:32 AM   #8
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When I purchased my red boxster I chose a 99 because it seems to be the IMS proof one and it has a few upgrades over 97's and 98's for me a 99 is the best option in terms of longevity but is it my opinion and based on my research.
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Old 09-28-2016, 12:02 PM   #9
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1% was reported as part of the settlement with car owners years ago. Yet people show up here every week with bearing failure (mine is dual row and failed).

It's not 1% any more.
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Old 09-28-2016, 01:09 PM   #10
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1% was reported as part of the settlement with car owners years ago. Yet people show up here every week with bearing failure (mine is dual row and failed).

It's not 1% any more.
Correct..........
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Old 09-28-2016, 01:15 PM   #11
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A different perspective is interesting.

Markus,
Your perspective is interesting because you are involved with a Porsche M96 world that is closed to most of us because of language. The English-speaking world gravitates to the American based forums so we seldom discover differences and nuances in say Germany/Austria/Switzerland
A specific example is the IMSB issue. From what little I can read on German Porsche forums, the cylindrical roller bearing is quite a popular alternative and was used much earlier than here in the Anglo Porsche world. Is that true? And which specific version of the cylindrical roller bearing is used? Do they all use the SKF NUP204 bearing or local equivalent? I ask because we all made such a fuss about "thrust control" when Vertex introduced it here.But I do not find that issue discussed in Germany. This is interesting because RND in the U.S.A. make a big deal about this.
Roller Bearing IMS Retrofit Kit – RND Engines
Here is the alleged German alternative with no mention of thrust control from a "colorful" source:
http://www.mbmotorsportsrepair.com/items-for-sale.html
The vendor has a questionble reputation on Forums but perhaps his German-sourced products are indeed good?
Quote:
Originally Posted by Smallblock454 View Post
Hi,

there are lots of causes why theses engines can fail. IMSB is only one. My personal POV: there are some people interested in making money by spreading fear.

And as long as you have oil sucked in the IMS you have a kind of lubricated IMSB – just think about it – it rotates.

Also think about that an IMSB can be installed the wrong way. It was not intended to be changed by factory. So if somebody does it, he needs to know what he is doing and i'm pretty shure it is important to use the right tools and methods and be careful to get a durable result. And in general: if you find magnetic parts in the oil it's too late for just doing an IMSB. Maybe it's a good idea to install a new IMSB with every new clutch.

Don't see why i should only drive at 2.500 rpm and above.

And if the engine fails it fails. That's life.

Also agree what Gelbster said. The expensive part is the proper maintenance of the car. Even if you don't buy every replacement part at the Porsche d(st)ealership – which you have to do sometimes and if you do repairs yourself.

BTW: we've had a lot of 2.7 FL engine failed, but no 3.2 FL in the last months in the german Porsche forum. Fingers crossed.

Regards, Markus

Last edited by Gelbster; 09-28-2016 at 01:19 PM.
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Old 09-28-2016, 01:19 PM   #12
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Does the way people drive effect the longevity? I think of my neighbor with his new ford f150. Son blew the motor a couple months into ownership. Father blamed ford, I blame son. I see how he drives and know of other things he had destroyed. He's a maniac.
I don't think Boxster's are 0-60 cars but if they are treated as such, could that negatively impact the motors life. I thought I read some place that it was designed with the u.s crowd in mind so maybe I so could be wrong.

It's a tough choice to drop 2k on an ims for a 10k car.

David
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Old 09-28-2016, 01:26 PM   #13
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I'm thinking the ims bearing should be a routine replacement at xxx miles
like a timing belt .
I'm sure after a certain amount of miles anything can fail . Bearings fail & the imsb was obviously not well thought out as far as lubrication goes .
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Old 09-28-2016, 01:43 PM   #14
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I ask because we all made such a fuss about "thrust control" when Vertex introduced it here.But I do not find that issue discussed in Germany. This is interesting because RND in the U.S.A. make a big deal about this.
Huh. That's odd.
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Old 09-28-2016, 02:11 PM   #15
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Huh. That's odd.
Yup,it is odd. And Markus may be able to give us some insight.
The German EBay kits and the roller bearing kits discussed on the German language Forums do not mention thrust control. Some mention the large washer (you see this in the RND photos) but I have never seen a photo of a German kit with a large washer + a claim for improved function due to thrust control.
We hammered Vertex on this issue and they eventually modified the text of their roller bearing blurb to mention thrust control .
Some of the European kits are just USA imports ,so I am ignoring them for this discussion
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Old 09-28-2016, 03:02 PM   #16
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Markus,
Your perspective is interesting because you are involved with a Porsche M96 world that is closed to most of us because of language. The English-speaking world gravitates to the American based forums so we seldom discover differences and nuances in say Germany/Austria/Switzerland
A specific example is the IMSB issue. From what little I can read on German Porsche forums, the cylindrical roller bearing is quite a popular alternative and was used much earlier than here in the Anglo Porsche world. Is that true? And which specific version of the cylindrical roller bearing is used? Do they all use the SKF NUP204 bearing or local equivalent? I ask because we all made such a fuss about "thrust control" when Vertex introduced it here.But I do not find that issue discussed in Germany. This is interesting because RND in the U.S.A. make a big deal about this.
Roller Bearing IMS Retrofit Kit – RND Engines
Here is the alleged German alternative with no mention of thrust control from a "colorful" source:
Currently for sale - ************ ************ ************ ************ ************ ************ ************MB MOTORSPORTS
The vendor has a questionble reputation on Forums but perhaps his German-sourced products are indeed good?
Hello Gelbster,

to be honest, most independent Porsche engine rebuiders i know in the Stuttgart and Germany area use all ball-bearing ISMBs that are like the OEM design. They say replace it with every clutch and use the right oil and change the oil yearly. Why is that? Because the other solutions are quite too expensive.

Might be different calculation for an AT car. But it also seems that AT cars fail less from an ISMB. But they also fail. Cracked heads, failing tensioners, oval cylinders from overheating, hydrolocking… you know better than me what else can fail.

The roller bearing ISMBs are not that popular, because of the same subjects. They generate more friction, so the generate more heat. And because the IMS is running at the same rpm than the engine, these types of bearings are more at their limits than ball-bearings. Just check the specs of the roller bearing manufacturers. An remember that the engines revs higher than the max. rpm given at max. power. Mine revs up around 6.900 rpm until it hits the rev limiter while max. power is at 6.200 rpm in my S.

Thrust control is another topic. Most people think of engines as a static system. But they are installed in a car with engine part torques, drive train torques, g-forces in cornering, acceleration, braking, road bumps… So you have additional mass moments. And concerning the valve train and IMS most of these masses are compensated by the IMS bearing and IMS bearing mount.

The M96 engines that failed very early from an ISMB had mostly engine case problems (986 and 996). And these engines were all replaced by Porsche with new OEM engines. In general they didn't repair them, they replaced them. So there was a cause for that.

There are IMSB kits with oil feed. From my POV this is more discussed im germany forums. What happens if the oil feed fails and is it useful to use oil pressure for an additional oil feed, when the oil system wasn't designed for that. The overall opinion is not to use additional oil IMSB feeds in this specific engines.

But you also keep in mind that in Germany the cars are used in a different way than in the US. We have also speed limits but we have also parts on the Autobahn where we don't have speed limits. You have the tail of the dragon – mostly with speed limits. We have the alps and the Black Forest with an official speed limit of 100 Km/h on normal roads. But who cares. Maybe race tracks seems to be similar. But there are also climate differences. We don't have that very warm summers like you have in Texas or Arizona. So maybe there is a lot different that can affect an engine oil system and cooling system.

IMSB kits. OK, there is lot of stuff around, because there is much fear and so you can do a lot of money out of kits that contain some stuff you and me can buy and manufacture for 50-100 bucks in a limited edition. Also the guys are Porsche drivers, so the only know Porsche prices and will pay them. The more expensive the better. What does Made in Germany exactly mean. Does it mean the bearing is made by FAG or anybody else in Germany. Or does it mean the whole components are designed and made in Germany. Reminds somehow on Apple. Designed in Cupertino, made in Asia at the cheapest fabrication facility they could find. Which doesn't mean the products can fail because they are badly designed by supplier parts – i know what i'm talking about when it comes to Apple graphic cards with Nvidia or ATI chipsets.

The MB Motorsports IMSB seems to contain parts from NTN which is located in Germany but has production factories all over europe. For example in Romania, Russia - where production costs are cheaper. And if you take a look at the extraction tool i would say go for the latest LN extraction tool.

As for the RND engines kit. The manual looks good. Hope everybody uses it. Heard of some DIY people that didn't lock camshafts/crankshaft and didn't remove tensioners. Saw it lately in a video. You can imagine the results. Don't see why Made in Japan should be less good than Made in Germany.

I know one kit that is really designed and made in Germany. That is by FVD Brombacher and has ceramic ball bearings. But that doesn't mean it is better or less good than others. And it is also not cheap (Porsche drivers don't care about money ) - around 470 Euros without toolkit.

In the end i would say go for a local manufacturer. Because first it is no rocket science. And second it doesn't make sense to pay a lot of money for shipping, taxes and duties to import things. If you have an excellent ball or roller-bearing manufacturer in the US or where you live, why not use local stuff?

And as always, these are just my 2 cents. Maybe other people have other opinions. Maybe other people read other forums or have other sources and background. There is a lot of information (and misinformation) around. So just my 2 cents.

Regards, Markus

Last edited by Smallblock454; 09-28-2016 at 03:07 PM.
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Old 09-28-2016, 03:14 PM   #17
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OK, here is the part that is missing: For some time, it has been known that not all of the IMS shafts were created equal; some spin true, while others have shown significant run out, which causes the shaft to wobble and literally beat the Hell out of the bearings. I think Jake first picked up on this when he examined engines that had multiple IMS bearing failures. Others mistakenly identified the issue as a thrust problem with the ball bearing design, leading to the development of the roller bearing replacements, which in fact have no better load carrying capacity that the ceramic ball bearings, and do not in my opinion really offer any better performance in a high run out shaft.

Unfortunately, the only way to test the shaft for run out is to take it out of the engine and test it on the bench, making testing in the field a non starter. And this run out issue may factor in to why some dual rows fail, while other go on forever. All of this went into Jake's development of the IMS Solution, which is decidedly more tolerant to run out in the shaft than any other style bearings, and which should outlive the rest of the engine as well.
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Old 09-28-2016, 03:24 PM   #18
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And because the IMS is running at the same rpm than the engine
Not so much.

The IMS runs at a much lower speed than the crankshaft, as is evident in this picture I took while I was enjoying the innards.
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Old 09-28-2016, 03:32 PM   #19
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Hello JFP in PA,

this wobbling problem is causal caused by bad engine case adjustment (hope that is the right term). In general these engines were replaced by Porsche completely. Well known problem.

flaps10: you're right. I have to go into this further because i remember there where some differences in different M96 engines. Maybe i'm wrong… have to take a look into the tech docs.

Regards, Markus

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Old 09-28-2016, 04:05 PM   #20
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Hello JFP in PA,

this wobbling problem is causal caused by bad engine case adjustment (hope that is the right term). In general these engines were replaced by Porsche completely. Well known problem.
I'm sorry, but you are not correct. On shafts with this issue, if placed in fixtures outside the engine and then turned while a dial indicator tracks them at the bearing end, the run out can be substantial, to the tune of over 0.010 inches. This is in the shaft itself, with nothing else involved. Over time, the repeated wobble in an assembled engine can reek havoc on the IMS bearing.

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