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

[feelyx]

Ok, Thanks, Not to sound like an interrogation, but did you purchase any replacement bearings in 1997-98 from porsche? Why I ask is I have information from NSK that Porsche purchased from NSK the bearings dry with 1 seal. Also the original bearing seal DAU17 decifered off the NSK site states 1 seal, the 17 has yet to be decifered. Thanks for any info you can provide on this.

[cnavarro]

Sorry, we've only been in business since 2002 (R&D in 2001) and didn't start on the M96 engine until much later, so that would be a no.

I had a discussion about the seals and their meaning with one of our bearing engineers years ago, but I'm in GA at Flat 6 Innovations doing some R&D work and I don't have access to all my notes, if I can even find them. It's been a while...

[feelyx]

Thanks Charles,

[randy_k]

I have been watching discussions about the IMS for, well about as long as I have owned my 99 Boxster. One thing I have never seen mentioned is. And this may be a stupid question? Could it be the shaft of the intermediate shaft is wearing and causing it to run in an uneven way and putting stresses on the bearing. Wether designed properly or not. Or other stresses that the chain may put it thru that were never thought of.

[feelyx]

randy, Anything is possible, and chain pull could cause enough deflection to tear the bearings apart.

Here is my theory on what happened, Porsche placed an order for custom bearings from NSK. NSK then built said bearings, and inadvertantly put the 1 seal on the wrong side and shipped the bearings. Porsche received the bearings and sent them to assembly where the shafts were filled with oil, and the bearings were installed correctly, but with the seal incorrect.(seal on the inside of the shaft) The shaft is then sent to production. Production catches an error as a missing seal, sends it back to assembly. Assembly orders seals from NSK (and here it could go 2 ways, as NSK could of said, or Assembly could of said, "fill bearing with oil and add seal on the outside." So the seal was put on some correct some not so correct and into production it went. The rest is history.

This doesn't explain why the single row, and the 6305 bearing. I have a whole 'nother ufo sighting for that.

[seventythree]

Not to hijack this thread but since we have some IMS experts here, I can't resist to ask:

My 2002 base is reading out of spec cam deviations, -7 & -8 respectively.
The deviations are constant, with no fluctuation, at idle or any other RPM.
Both deviations get slightly larger with engine warm-up.
There has been no junk in the oil or the filter (I've checked at every oil change).
There is no start up noise indicating failed tensioner(s).
The engine is running fine!

What is cam deviation? Camshaft, both intake and exhaust, deviation relative to crankshaft?
How is the deviation measured?
What could cause cam deviations to change?
How can it be corrected?
Can the car be driven in the meantime?

TIA

[randy_k]

TIA, I did a search regarding your question. There are several threads on the subject. Although you will probably get an answer here as well. Here's the link to my search.
Randy

Pelican Parts Technical BBS - Search Results

[JFP in PA]

Originally Posted by seventythree

Not to hijack this thread but since we have some IMS experts here, I can't resist to ask:

My 2002 base is reading out of spec cam deviations, -7 & -8 respectively.
The deviations are constant, with no fluctuation, at idle or any other RPM.
Both deviations get slightly larger with engine warm-up.
There has been no junk in the oil or the filter (I've checked at every oil change).
There is no start up noise indicating failed tensioner(s).
The engine is running fine!

What is cam deviation? Camshaft, both intake and exhaust, deviation relative to crankshaft?
How is the deviation measured?
What could cause cam deviations to change?
How can it be corrected?
Can the car be driven in the meantime?

TIA

Cam deviation values are how far off they are from ideal (zero degrees). The values are measured by the DME using the crank and cam position sensor signals and a simple algorithm. Why they are out of spec can come from several different issues (or combinations of issues): Stretched chains, worn tensioner paddles, worn or sticking tensioners, problems with the VarioCam system, the cams simply not being correctly timed in the first place, weak or dying position sensors, etc., etc………

When the cams are too far off their ideal timing, you definitely give up performance, and generally speaking, these problems do not get better with age. All of the above conditions are eminently fixable, just takes some time and money to sort it out. Time to start doing some in depth diagnostics………..

[showbiz]

Feelyx,excellent article on the IMS bearing.I could remove the IMS bearing I have,do a measurement of the oil in a beaker and let you know with pics the seal and bearing numbers if this helps you with your project? Greg

[feelyx]

Hi Greg,
Yes, That definitely would help out, I look foreward to your information.
Thanks

[MikenOH]

Originally Posted by feelyx

randy, Anything is possible, and chain pull could cause enough deflection to tear the bearings apart.

Here is my theory on what happened, Porsche placed an order for custom bearings from NSK. NSK then built said bearings, and inadvertantly put the 1 seal on the wrong side and shipped the bearings. Porsche received the bearings and sent them to assembly where the shafts were filled with oil, and the bearings were installed correctly, but with the seal incorrect.(seal on the inside of the shaft) The shaft is then sent to production. Production catches an error as a missing seal, sends it back to assembly. Assembly orders seals from NSK (and here it could go 2 ways, as NSK could of said, or Assembly could of said, "fill bearing with oil and add seal on the outside." So the seal was put on some correct some not so correct and into production it went. The rest is history.

This doesn't explain why the single row, and the 6305 bearing. I have a whole 'nother ufo sighting for that.

Feelyx:
so your theory is that the bearing should have had a shield on the outside o fthe assembly ( the side toward the case wall) and no shield on the inside toward the IMS, where the shaft's oil supply would have continually lubed the bearing--right?

The first question that comes to mind is whether or not the outside seal would have held oil in this loop so it all didn't just run out into the engine? It doesn't look like a setup that would keep all the oil within this assembly forever.

[feelyx]

Originally Posted by MikenOH

Feelyx:
so your theory is that the bearing should have had a shield on the outside o fthe assembly ( the side toward the case wall) and no shield on the inside toward the IMS, where the shaft's oil supply would have continually lubed the bearing--right?

The first question that comes to mind is whether or not the outside seal would have held oil in this loop so it all didn't just run out into the engine? It doesn't look like a setup that would keep all the oil within this assembly forever.

MikenOH,
Yes, that is correct, that is my theory, unless any verifiable info to the contrary can be produced.

Yes, I verified the seal will hold oil in the tank so to speak, even in boiling water for 2hrs. with no oil leaking. I know 2hrs. isn't long enough for a test, but long enough to see if the seal will ripple. I too think the seal will fail but when and why is my questions.

The next test will start today and see if the bearing/seal will do the length of time in mileage. The shaft will be spinning at 3500 rpm which ='s 7000 rpm engine spd. with a final gear ratio of 3.44 = 152 mph approx. top spd. So every 24hrs run will = 3648 mi. a day x 100 days = 364,800 total mi. Granted, no chain pull on the shaft, but I am looking for a used lathe right now to set up a rack to run chains.

[feelyx]

Ok, as of 2:00pm pst the test has started. A few things have changed, I started with the 1.95$ cheap bearing removed the seals and added a seperate seal to the outside. I figure if a bearing was going to scatter it would be the cheapo.



The RPM is set at 3500, the gear oil I am using is an EP 80/90wt. The temp of the bearing is a steady 82 degrees and the shaft is 65 degrees after 1 hr. in service.









I thought the oil in the tube was going to cause an imbalance and fling the shaft right out of there, but there isn't any measureable flex at 3500rpm.

Onward...

[showbiz]

Tim, had some time today ,made up a puller and was careful taking out a very good IMS bearing from the 1997 2.5, was ready for oil in the tube but there was less than 1/4 oz , the bearing as seen in pictures is sealed both ends,taking seals off found engine oil? not grease ? spins and looks like new. hope this helps you,let me know if I can help out with more pics. bearing # is Japan NSK 6204DUA17 sorry some of pics are not that clear Greg

[feelyx]

Thanks Greg,
How many miles on the engine? Did you notice if the oil had any foul smell? Awesome puller you made there. I am still interested in the IMS and all the parts including the seals.
Tim

[feelyx]

Updadate, on the first 8.5hrs. bearing temp at 85 degrees tube temp at 70 degrees. The lathe head bearing at 106 degrees. Quiet as ever, no oil leaks. This is = to 1292 mi.

[showbiz]

Hi Tim,
Unfortunately Mileage unknown on this engine , no smell other than normal engine oil,bearing came out with a loud snap at first (release of lock ring?) then ease out under light puller pressure,but no oil in tube to speak of, my 1st estimate of 1/4 oz is off when I turned tube over to pour out only a few drops came out. The bearing inners were wet with oil but how would it stay lubricated over heat and time? , IMO after seeing a sealed bearing both ends I was at least expecting to see a hi temp grease inside Greg

[feelyx]

Greg,
Welcome to the world of IMS confusion. I think the oil in the tube was leaking out over time through the seals and the bearing was on its last hoorah before failing. If you can... can you pull the cages out of the bearing and pop the balls out to inspect? I am quite curious if there is any discoloration in there. Like I said earlier in the thread, I believe Porsche didn't use grease in the earlier bearings, if the bearing was submerged in engine oil I could see oil washing in, but there is only an oil spray at best. so oil must of been washing out of these bearings.
Tim

[feelyx]

11.0 hrs. no change, 1672mi.
15.5 hrs. no change, 2356mi.
18.5 hrs. no change, 2812mi.
23.0 hrs. no change, 3496mi.
1 day complete, no bearing problems, 3648mi.

[feelyx]

Video test of IMS running..... I had to take the side panel off of the lathe so the lathe head bearings would cool down, as the lathe was never intended to run at this speed.