Another IMS Data Point
03-27-2011, 12:10 PM
#1
Rennlist Member
Thread Starter
Another IMS Data Point
Background:
I purchased my '99 996 two years ago with 53,000 miles. One owner and immaculate with a great service history. Having read about IMS failures, I elected to purchase a 2 year/24,000 mile warranty, the first time I've ever got an extended warranty on a car since I do 99% of my own work. My plan was to install the LN Engineering IMS bearing as a preventative measure as many here have done once the warranty expired. The car is my daily driver and sees about 1,000 miles a month. Since the first oil change, I've been running Schaeffer 9000 5W-40 due to its high shear strength number and changing the oil at 7500 mile intervals. Fast forward to two weeks ago when I noticed an oil spot on the garage floor that was coming from the RMS/IMS area. With about 2,000 miles left on the warranty, this looked like a good opportunity to get the IMS bearing done by a pro and only have to pay part of the labor.
The bearing:
Dropped the car off at Steiner Racing Sports in Houston for the repair. Juergen's inpection showed that it was the RMS leaking, which looked like it had been replaced before, even though I didn't have records of it from the previous owner. So they installed the new RMS and IMS upgraded bearing, as well as the clutch disk, which had about 35% of its life left.
I brought the bearing home with me to disect it and see what I could learn. The bearing felt almost, but not quite, as smooth as new bearings (wheel, transmission, etc, never handled a new IMS bearing). Oil would seep out of the seal when layed on edge. Popping the inner seal revealed that it was full of what looked to me to be motor oil, not grease. After pulling the outer seal & both bearing cages, the ***** showed no pitting or wear, nor did the inner or outer race. Also, there was no sign of any flaking or other wear.
It is worth noting that the outer bearing surface did show a fair bit of residue from the block. I can post pictures of the bearing later today if anyone wants to see them.
I purchased my '99 996 two years ago with 53,000 miles. One owner and immaculate with a great service history. Having read about IMS failures, I elected to purchase a 2 year/24,000 mile warranty, the first time I've ever got an extended warranty on a car since I do 99% of my own work. My plan was to install the LN Engineering IMS bearing as a preventative measure as many here have done once the warranty expired. The car is my daily driver and sees about 1,000 miles a month. Since the first oil change, I've been running Schaeffer 9000 5W-40 due to its high shear strength number and changing the oil at 7500 mile intervals. Fast forward to two weeks ago when I noticed an oil spot on the garage floor that was coming from the RMS/IMS area. With about 2,000 miles left on the warranty, this looked like a good opportunity to get the IMS bearing done by a pro and only have to pay part of the labor.
The bearing:
Dropped the car off at Steiner Racing Sports in Houston for the repair. Juergen's inpection showed that it was the RMS leaking, which looked like it had been replaced before, even though I didn't have records of it from the previous owner. So they installed the new RMS and IMS upgraded bearing, as well as the clutch disk, which had about 35% of its life left.
I brought the bearing home with me to disect it and see what I could learn. The bearing felt almost, but not quite, as smooth as new bearings (wheel, transmission, etc, never handled a new IMS bearing). Oil would seep out of the seal when layed on edge. Popping the inner seal revealed that it was full of what looked to me to be motor oil, not grease. After pulling the outer seal & both bearing cages, the ***** showed no pitting or wear, nor did the inner or outer race. Also, there was no sign of any flaking or other wear.
It is worth noting that the outer bearing surface did show a fair bit of residue from the block. I can post pictures of the bearing later today if anyone wants to see them.
03-27-2011, 12:45 PM
#2
Parts Specialist
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+1 for NO GREASE... never seen one yet with grease in it.. they seem to all be using oil as lubricant....old stinky oil at that...IMO it stems from the shaft itself being sealed (thermal expansion of the air inside)
anyhow, you're good to go now!
anyhow, you're good to go now!
03-27-2011, 01:13 PM
#3
Drifting
I'd love to see what you found.
I'd also love to see any other bearings that have been removed that are in various stages of impending failure, discolored, brinelled, pitted, etc. I hear of lots and lots of these getting replaced on the internet, but when I talk with Porsche techs and parts people in the real world (friends of mine that don't troll the net looking for issues) the problem is almost unheard of. I spoke with an employee of one of the largest P dealers on the West coast that ownes a 996 C4S. He spent over a dozen years as a service writer and moved into sales a couple of years ago. He seemed very familiar with all of the potential 996 ills, and when specifically asked about the IMS, he stated he saw a couple of broken shafts on the earliest 996s and the shaft/ bearing was updated early on.
I can't help to think if the IMS bearing failure is immenent, there would be tons of dead '97, '98, '99 '00 and later Boxsters for sale for scrap prices. Maybe there are? Just my opinions form being heavily into P cars for decades, and real heavy since '97. I'm not denying that there is no intermediate shaft bearing related issue. Just not 100% convinced that there is. Sure lots get replaced, and if it concerns you and helps you sleep better at night, I guess it's worth it. Peace of mind is a great thing, insurance have made billions off of it, lol. Honestly not trying to be cynical.
I'd also love to see any other bearings that have been removed that are in various stages of impending failure, discolored, brinelled, pitted, etc. I hear of lots and lots of these getting replaced on the internet, but when I talk with Porsche techs and parts people in the real world (friends of mine that don't troll the net looking for issues) the problem is almost unheard of. I spoke with an employee of one of the largest P dealers on the West coast that ownes a 996 C4S. He spent over a dozen years as a service writer and moved into sales a couple of years ago. He seemed very familiar with all of the potential 996 ills, and when specifically asked about the IMS, he stated he saw a couple of broken shafts on the earliest 996s and the shaft/ bearing was updated early on.
I can't help to think if the IMS bearing failure is immenent, there would be tons of dead '97, '98, '99 '00 and later Boxsters for sale for scrap prices. Maybe there are? Just my opinions form being heavily into P cars for decades, and real heavy since '97. I'm not denying that there is no intermediate shaft bearing related issue. Just not 100% convinced that there is. Sure lots get replaced, and if it concerns you and helps you sleep better at night, I guess it's worth it. Peace of mind is a great thing, insurance have made billions off of it, lol. Honestly not trying to be cynical.
03-27-2011, 02:49 PM
#4
Rennlist Member
Well, I dont think the bearing fails slowly, So I dont think you would really find pitting unless you were really close to losing that bearing. Its my Opinion the bearing fails due to the seal failing and letting engine oil in to the bearing and not letting it back out.. This also allows oil to build up oil in the IMS tube. It's MY OPINION again... that the oil in the IMS tube breaks down and burns black. This oil in turn then seeps into the bearing as the bearing is left sit at rest while the car is parked.. So this bad, burnt oil is in the bearing all the time.. This causing it to wear from lack of a good lube source. Im not willing to bet my engine on it.. But I feel if you would pull the outter seal off the stock bearing.. It woudlnt fail.
03-27-2011, 02:54 PM
#5
Parts Specialist
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also keep in mind as Kyle states this "bad oil" is contaminated with hydrocarbons and unburned and burned fuel...it therefore is corrosive and etches the *****/races if left too long (which is why running the motor is betyter than letting it sit for long periods
and as Kyle stated - this is my opinion.....
and as Kyle stated - this is my opinion.....
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03-27-2011, 03:10 PM
#8
Rennlist Member
So drill a series of holes in the Intermediate to allow oil exchange and have fresh oil on both sides of the bearing?? No etch no itch everyone is happy and comfy
03-27-2011, 03:23 PM
#9
Parts Specialist
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yes, but you should remove the shaft to drill it out...= tear motor apart while doing so I would advise pinning the gear on the end too - why... because they can turn causing the timing on one bank to shift
yup
wait, this is still my opinion
yup
wait, this is still my opinion
03-27-2011, 03:26 PM
#10
Rennlist Member
Thread Starter
OK, here are a few pictures. It is interesting to note that the seals looked ok, but the oil that came out looked just like the oil you would expect to find in the crankcase. Same color, smell, & feel. The oil on the blue paper towel is some of what came out of the bearing. One could theorize that this is a good reason to do frequent oil changes & use really good oil.
Steiner had a dead 3.6 on an engine stand that the IMS bearing had taken out. The bearing felt a bit rough when you turned it, but not that bad.
Steiner had a dead 3.6 on an engine stand that the IMS bearing had taken out. The bearing felt a bit rough when you turned it, but not that bad.
03-27-2011, 05:01 PM
#11
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This is sure to start a flame fest but this constant chatter about sealed bearings is killing me.
I work as a mechanical engineer in the medical industry, on a past project I needed a "sealed bearing" to prevent fluid ingress to maintain the sterile field. I contacted multiple sources requesting a sealed bearing, all sources stated that the seals are really shields. None would keep fluid out the purpose was to keep grease in. I tested a few but ended up designing in an external shaft seal.
Although the absence of grease is most likely what kills these bearings I think that most of the grease is washed from these bearings rather quickly by the 200+ degree oil.
Drilling holes and getting a lot of oil into the race may not be a bad idea.
I work as a mechanical engineer in the medical industry, on a past project I needed a "sealed bearing" to prevent fluid ingress to maintain the sterile field. I contacted multiple sources requesting a sealed bearing, all sources stated that the seals are really shields. None would keep fluid out the purpose was to keep grease in. I tested a few but ended up designing in an external shaft seal.
Although the absence of grease is most likely what kills these bearings I think that most of the grease is washed from these bearings rather quickly by the 200+ degree oil.
Drilling holes and getting a lot of oil into the race may not be a bad idea.
03-27-2011, 05:29 PM
#12
Rennlist Member
This is sure to start a flame fest but this constant chatter about sealed bearings is killing me.
I work as a mechanical engineer in the medical industry, on a past project I needed a "sealed bearing" to prevent fluid ingress to maintain the sterile field. I contacted multiple sources requesting a sealed bearing, all sources stated that the seals are really shields. None would keep fluid out the purpose was to keep grease in. I tested a few but ended up designing in an external shaft seal.
Although the absence of grease is most likely what kills these bearings I think that most of the grease is washed from these bearings rather quickly by the 200+ degree oil.
Drilling holes and getting a lot of oil into the race may not be a bad idea.
I work as a mechanical engineer in the medical industry, on a past project I needed a "sealed bearing" to prevent fluid ingress to maintain the sterile field. I contacted multiple sources requesting a sealed bearing, all sources stated that the seals are really shields. None would keep fluid out the purpose was to keep grease in. I tested a few but ended up designing in an external shaft seal.
Although the absence of grease is most likely what kills these bearings I think that most of the grease is washed from these bearings rather quickly by the 200+ degree oil.
Drilling holes and getting a lot of oil into the race may not be a bad idea.
03-27-2011, 05:31 PM
#13
Race Director
This is sure to start a flame fest but this constant chatter about sealed bearings is killing me.
I work as a mechanical engineer in the medical industry, on a past project I needed a "sealed bearing" to prevent fluid ingress to maintain the sterile field. I contacted multiple sources requesting a sealed bearing, all sources stated that the seals are really shields. None would keep fluid out the purpose was to keep grease in. I tested a few but ended up designing in an external shaft seal.
Although the absence of grease is most likely what kills these bearings I think that most of the grease is washed from these bearings rather quickly by the 200+ degree oil.
Drilling holes and getting a lot of oil into the race may not be a bad idea.
I work as a mechanical engineer in the medical industry, on a past project I needed a "sealed bearing" to prevent fluid ingress to maintain the sterile field. I contacted multiple sources requesting a sealed bearing, all sources stated that the seals are really shields. None would keep fluid out the purpose was to keep grease in. I tested a few but ended up designing in an external shaft seal.
Although the absence of grease is most likely what kills these bearings I think that most of the grease is washed from these bearings rather quickly by the 200+ degree oil.
Drilling holes and getting a lot of oil into the race may not be a bad idea.
Sincerely,
Macster.
03-27-2011, 05:44 PM
#15
Parts Specialist
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