Who has done an IMS change (New Oil Fed Design Idea)
 

Has anyone that has changed an IMS bearing seen any traces of grease in that bearing? What yr.?
Was there a smelly oil residue associated with it?
I've done 2 and both seals intact and no grease, both 01's
Read on other boards samething.
Just trying to build a theory, bearing shipped dry to Porsche, Porsche loaded bearing with a gear type oil or ?
Thanks for any help

Had mine done in 2010 with new LN. OEM bearing was not leaking, had small amount of play, no grease and heavy, burnt smelling oil in it. Boxster is a '99 and had 82K miles.

We did an IMS job a month ago on our '99 Boxster with 175,000 miles and the OEM came out looking great. No residue. No smell. Still tight. The only oddities was the cover had what appeared to be a poor casting (one ear had pitting) and the factory put a wad of waxy sealant over it. I guess that was to mask the leaking if it did go bad :eek:
If it wasn't for the clutch and flywheel being completely fried - that car probably would have gone another 175,000 miles on the streets problem free. The way we drive it at the autocross is a little different story though :rolleyes:

The burnt or gas smell is hydrogen being pushed out from the oil, through heat and pressure. So in theory, in normal operation, the bearing is building hydrogen pressure, and pushing past the seals. Also, hydrogen will find an imperfection and hook to it so to speak, and build from there, preventing oil or grease from lubing the area causing pitting. Now, does hydrogen fill the IMShaft full of hydrogen then burn causing the burnt smell and heavy oil in it?

Remember, just building a theory here, opinion could change direction at anytime.

Interesting theory. Those crazy germans... so does that mean a Boxster will explode like a Zeppelin?

Interesting comparison. One way to lose your life and another way to lose your wallet with hydrogen as a common thread:D.

Actually, the hydrogen part isn't theory.... and some engines have gone ........poof.......
I don't think there would be enough hydrogen built up to blow anything up...

OK, back to the theory..... I have confirmed that Porsche was shipped the bearings with no lube and only one seal. As back up to this, the DU part of the bearing number means just that... 1 seal on the bearing.
Now if anyone has a good unopened double row bearing, I would sure like to see it to get a sample of the fluid inside it.
Just theorizing again here, but I would bet it is a mobil product that was used... but will have to have some to compare to products that would have been used.

Feelyx - Can you say this in a way I'll understand. You know I took mine apart so I'm familiar with how it is put together...maybe you can reference back to the photo I posted on 986forum. I knew I shouldn't have drained the oil out of the bearing without saving it for you...darn! Looking at everything though, I had about 10 ounces of old oil in the shaft and clean oil in the bearing, are you thinking the oil in the bearing was a mobil product that I drained out? If so how did all the oil get in the shaft?
How much of the oil from the bearing do you need to analyze it. I still have the paper towels I drained it into I think.

Whip, NSK(the mfg) has sent me some info about the bearing. That is why I asked if the seals had the same numbers on ea. side. I did confirm they sent the bearing dry (no lube) with 1 seal attached. It appears Porsche used their own lubrication and installed the other seal on it. Porsche ordered the extra wide bearing so it would have a reservoir for the fluid.

I am still working on how the oil was in the shaft, but my theory involves the heat and pressure in the bearing produced hydrogen which expanded the seal(ignition?) blowing oil past the seal then causing a negative pressure and sucking the seal in and engine oil contamination. Like a pulse jet engine, that would explain the burnt oil. Like I said, it is theory, not "proovin' facts yet".

The oil on the paper towels would be considered a contaminated sample and I can't use it. I would need an unopened bearing, with what oil was used in the engine.

Feelyx - I put my bearing back together and filled it up with oil (Mobil 1 :) ). Put the seals back on and am going to see if it leaks. The seals are exactly the same on each side. I know you know this but the seals are very much the same concept as the RMS, the inner race slides along the seal. The outer part of seal of course is different in that it hooks under the lip of outer race.

Whip, Your sealed bearing filled with oil will need to vent if you run it... just like a flooded transmission or gearbox has a vent on top. I still wonder how Porsche missed this?

I sort of look at it in a more simple view. For the RMS, the distance from the crankcase end and the inner is substantial along with it operating under a vacuum state should suck the lip seal inwards.

Now when we consider the IMS seal and bearing, you would think its the same behavior but its not. For the moment disregard the high volume oil pump of which has no relationship to where I'm going. The original bearing that is sealed in its cavity is being pressurized far greater because engine oil (from a harsh cumbustion environment) is pushing and pushing with no escape in that tiny area. That little area without oil having an escape route or orifice has no choice but to push through the bearing seal, mix and wash out the grease and we all know what happens from there. Apparently bigger bearings and ceramic type are enough to take the abuse but if the bearing housing had an orifice relief or cavity return, it might be all that is needed.

Also, from what I've read and guessing, Wayne's design has a beveled shield. Who knows what the best will be when we read these post years from now?!

A couple of points that need to be explained before too much time is spent of fine theories. FIt was suggested that H2 is produced in some process within the engine. I have fiddled with engines for 60 odd years and I have yet to hear any process that would produce H2. H2 forms strong bonds, making it difficult for it to be freed from other chemicals.

H2 is odorless, so no one can smell it. It is possible that some process is going on that somehow produces H2 and at the same time makes the smell that has been described.

cheers,

Joe Stephenson

Oh I'm not going to run it :)...already have the LN in and running just fine. Since my bearing was so nicely filled with clean oil when I took it apart and not leaking I thought I would put it back together and see how well it still held oil...just curiosity :).

http://www.jp.nsk.com/app01/en/ctrg/index.cgi?rm=pdfView&pno=e1256a
Joe,
Here is some info on h2 intrusion, kinda basic with flaking bearings.

After much thought on the info I have received, I cannot prove beyond reasonable doubt or confirm an exact conclusion to what happened with the IMS bearing.
But, with what I have gathered my best guess and its only a guess is "Porsche" screwed up. Did Porsche sub any work on the bearing out? This I could not find out.
I know as fact the bearing was shipped with 1 seal installed, I know as fact the bearing was shipped dry, I know the bearing should of been filled about 1/2 way with oil or grease, this being dependent on rpm the bearing will be running/and max speed the bearing can handle. The seals shipped with the bearings would handle the task in the engine.
Here is where the info gets sketchy, Porsche, or whoever Porsche had subed the work to, was careless when filling the bearing with oil and snapping on the second seal. The bearings where "probably" filled to the top, an unmeasured amount, and "if" the seal was nicked, even the tinyest nick could form a rip in the seal.
So in "MY opinion" this isn't a bearing problem or lubrication it was just carelessness in quality control on the build line. So depending on the size of the nick, or how full the bearing, or if it was done perfect, will determine the longevity of the bearing. Which we can tell that some bearings failed real early, some midway, and some over the 100,000 mi. mark and maybe some will last the life of the engine.
My best suggestion would be change the bearing, but everyone already knows that. SmileWavy

I opened my twin row bearing to provide information for Feelyx and did not find any sign of grease, only oil residue. I also found that half the sealing lip on one side was broken away. It did not look burnt off. I would say that it was fractured. When I removed my bearing there was not much oil that came out of it and this could suggest that it was draining itself but was it being replentished with use.
I originally changed the bearing for insurance at about 30K miles but seeing the seal was damaged, I am happier that I went through the exercise. The car needed a clutch and the IMS was leaking but the clutch dust was absorbing the leakage so no drips from the car.
Thanks Feelyx for your bearing info.
Ron Jackson in Canada

Ok, after more research and finally being able to have a disassembled engine that didn't suffer a IMS failure, a few things stand out.
1. The IM shaft was approx. 1/3 filled with oil, not motor oil but it appears to be syn. gear oil by feel. I won't know for sure until a sample is tested.

http://forums.pelicanparts.com/uploa...1331266946.jpg

2. The bearing has BOTH seals on it, I have confirmed earlier with NSK that the bearing was shipped with only ONE seal and no lube. I have written proof of this thru Emails with Eng.'s from NSK.

http://forums.pelicanparts.com/uploa...1331267293.jpg

3. After a quick inspection, the inside of the bearing is like new, smooth rolling, but very little lube (oil) inside, no grease anywhere, as I am pretty sure porsche did not use grease, as no bearing yet has been found with grease.

http://forums.pelicanparts.com/uploa...1331267591.jpg

4. Which leads me to this new theory.... Porsche filled the IMS with an oil, which was to lube and cool the bearing, but, for some reason Porsche filled the bearing with oil and put the other seal on the side missing one and installed the bearing.

5. So... did the original design of the IMS require the inside seal to be removed from the bearing and have the IM shaft 1/3 full of oil to lube and cool the bearing while having it sealed from the engine oil?

6. To me, it appears Porsche had a break down between Designing and Production of the engine. Somewhere something was changed to the bearing.

7. After handling a perfect IMS, I have no doubt that the oil in the IMS design with the inside seal removed, would be trouble free if installed correctly. But who am I to say? :p

8. Unless my microscope finds damage or I come across more info contradicting this theory, this is how I will intall THIS bearing or mine if it is in the same condition into my '98. (no seal on the inside and IMS 1/3 full of oil.)

A sealed bearing back in 2001 ie ( 2RS) was never intended to seal against the ingress of oil, it was only required to handle grease and was about 30% full of grease. A new sealed bearing such as the SKF ..RSH series however, with a line contact seal on the inner race will have a far better chance to seal against oil ingress than the old RS series.
Just a suggestion

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2001 Boxster --- retired Mech Eng 40 yrs