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Old 04-09-2014, 02:47 PM   #1
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Metal Shavings Behind LN IMS Bearing - Need Advice!

I'm totally devastated right now. I was in the process of pulling IMS bearing out of my engine to replace as well as install the DOF kit. The existing bearing is an LN dual row ceramic that was installed by the PO (at an indy shop) 8000 miles ago, and here is what I find:



There was about a cup of oil that came out from the IMS tube. I drained the oil several days ago, so it didn't come from the sump. I inspected the filter tonight and see a few metal specks in it, but nothing like what is in the IMS tube. I taped paper towels to the handle of my breaker bar and cleaned the inside of the tube several times like the barrel of a gun. Lots of small sparkles came out on each paper towel.

I'd like to believe the metal came from the IMS bearing because of the buildup on the seal. Anyone have any opinions? I have been looking at engine parts drawings to try and see if there is a ball type bearing at the other end of the shaft, and if so, how do I test it to see if the metal flakes were coming from that end? When the bearing was still installed, I could feel ever so slightly some play. Once it was removed I felt it again, then rotated it and couldn't feel it. Not a big surprise, but turning the bearing gives a slight "crunchy" sound.

What do I do next?
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Old 04-09-2014, 03:07 PM   #2
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The other end of the IMS is a one piece integral bushing, that fits inside a larger bushing formed by the front coolant manifold behind the oilpump. This design is basicly trouble-free & not the source of the shavings. I'm guessing those shavings came from the oem IMSB & were not properly removed during the LN retrofit. If I were you I would send a e-mail to LN & try to consult with them. LN may want to know who installed the retrofit.
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Old 04-09-2014, 03:07 PM   #3
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Quote:
Originally Posted by Benjamin View Post
I'm totally devastated right now. I was in the process of pulling IMS bearing out of my engine to replace as well as install the DOF kit. The existing bearing is an LN dual row ceramic that was installed by the PO (at an indy shop) 8000 miles ago, and here is what I find:



There was about a cup of oil that came out from the IMS tube. I drained the oil several days ago, so it didn't come from the sump. I inspected the filter tonight and see a few metal specks in it, but nothing like what is in the IMS tube. I taped paper towels to the handle of my breaker bar and cleaned the inside of the tube several times like the barrel of a gun. Lots of small sparkles came out on each paper towel.

I'd like to believe the metal came from the IMS bearing because of the buildup on the seal. Anyone have any opinions? I have been looking at engine parts drawings to try and see if there is a ball type bearing at the other end of the shaft, and if so, how do I test it to see if the metal flakes were coming from that end? When the bearing was still installed, I could feel ever so slightly some play. Once it was removed I felt it again, then rotated it and couldn't feel it. Not a big surprise, but turning the bearing gives a slight "crunchy" sound.

What do I do next?
Are the metal bits ferrous (can they be picked up by a magnet)? Do you have a photo of the other side of the bearing?
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Old 04-09-2014, 03:11 PM   #4
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Originally Posted by BYprodriver View Post
The other end of the IMS is a one piece integral bushing, that fits inside a larger bushing formed by the front coolant manifold behind the oilpump. This design is basicly trouble-free & not the source of the shavings. I'm guessing those shavings came from the oem IMSB & were not properly removed during the LN retrofit. If I were you I would send a e-mail to LN & try to consult with them. LN may want to know who installed the retrofit.
I would tend to agree as if the bearing itself were tearing itself up, the metal would be in your oil..........
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Old 04-09-2014, 03:14 PM   #5
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looks ferrous; actually looks magnetised in the image.
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Old 04-09-2014, 03:15 PM   #6
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If there is a bushing at the other end, then I am all but convinced the shavings came from one of the IMS bearings. One would think that the installer of the LN bearing would have noticed such a thing and cleaned things out or something along those lines.

No matter which one it was, it's not going back in the car as I have a new bearing. My real worry at this point is how to effectively clean as much of the flakes as I can, hopefully without doing a complete tear down.

Yes, they shavings/flakes are ferrous.
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Old 04-09-2014, 03:18 PM   #7
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Also, 8000 miles ago any oil in the tube would have all but drained out when the LN was put in, so all of the oil that drained out this time is "new". Can oil get in from the bushing side, or is it only possible to get in from the flywheel end? (ie, through the bearing and past the seal?)
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Old 04-09-2014, 03:22 PM   #8
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Hmmm, a Black 2000S? I seem to remember a Black 2000S last year with a DIY IMS retrofit that just turned into a massive train wreck with the owner in well over his head. I wonder if this is the same car.
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Old 04-09-2014, 03:24 PM   #9
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looks ferrous; actually looks magnetised in the image.
Yes, the bearing is actually slightly magnetic. I think the back of the bearing was acting like a magnetic drain plug.
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Old 04-09-2014, 03:27 PM   #10
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Hmmm, a Black 2000S? I seem to remember a Black 2000S last year with a DIY IMS retrofit that just turned into a massive train wreck with the owner in well over his head. I wonder if this is the same car.
Well, as I understand it, Porsche made more than one black 2000S. I have owned it for a year and the PO I have become friends with since the purchase and she had it for a year and I know she didn't do any work on it herself, it was all Stealer work that she had done. The previous PO had the bearing work done.
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Old 04-09-2014, 03:48 PM   #11
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OK, I've been sitting here trying to make myself feel better and have thought of two points (rather, clarifications of points that you guys have made).

IF it were the current bearing making the flakes, most, if not all of them would be in the oil and oil filter since that is the path of least resistance, and not push their way through the seal to end up in the tube.

IF the original bearing began to fail, and the inner seal (since the originals had two seals) failed, it would introduce flakes into the tube (and perhaps not into the oil/filter, but we will never know). Those flakes might not be that noticeable if the original bearings weren't magnetic and if the outer seal didn't fail, thus no or very little oil in the tube. The flakes would just migrate around in the tube and not be attracted to anything in particular. Introduce the magnet and the single seal bearing, and you have an opportunity for the flakes to float around and make their way to the weak magnet of the bearing.

Sound plausible?
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Old 04-09-2014, 04:01 PM   #12
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The IMS drive is loose and creating wear debris as it chatters on the IMS assembly. This is allowing the debris to get inside the IMS tube.

Not new, this is mode of failure #25, first noted in 2012 and seen 3X since then here.

I could be wrong, but the symptoms are exacting what we've seen before.
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Old 04-09-2014, 04:09 PM   #13
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Thanks for the input, Jake. How do I confirm this? I don't understand what you mean by IMS drive. Is this the sprocket that is connected via chain to the crankshaft?
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Old 04-09-2014, 04:12 PM   #14
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That IMS bearing appears to have plastic seals on it. Don't genuine LN bearings have NO SEALS on the sides?

The bearing race is marked "SPC". I did some Googling and SPC generally notates a ROLLER bearing. I'd guess a roller bearing with considerable side load would generate metal chips.

To quote General Buck Turgidson, I hate to judge before all the facts are in, but I think your PO may have been had by an unscrupulous shop.
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Old 04-09-2014, 04:31 PM   #15
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It's not a roller bearing, I can see the balls in it. It also doesn't say SPF. It looks like JAF, Japan, and 5204 Here it is with the debris wiped away:

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Old 04-09-2014, 04:33 PM   #16
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Quote:
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It's not a roller bearing, I can see the balls in it. It also doesn't say SPF. It looks like JAF, Japan, and 5204 Here it is with the debris wiped away:

When did LNE outsource to Japan?
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Old 04-09-2014, 04:42 PM   #17
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If I'm reading the numbers correctly, it would be this:

Amazon.com: 5204 Nachi (JAF) Angular Contact Bearing 20x47x20.6 Japan Bearings: Industrial & Scientific

Definitely NOT an LN bearing.
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Old 04-09-2014, 04:47 PM   #18
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Link to get JAF full line catalog here.

JAF Bearings Catalog | AST Bearings
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Old 04-09-2014, 04:57 PM   #19
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Thanks for the input, Jake. How do I confirm this? I don't understand what you mean by IMS drive. Is this the sprocket that is connected via chain to the crankshaft?
The IMS shaft is 4 pieces that are lightly press fit together. The drive can separate from the driven components and when this occurs the precursor is wear debris like this. There's no way for this to get out of the shaft, until the shaft separates, or the bearing is pulled.

Or a hack installed the bearing and left debris from a previously failing bearing in the tube/ engine.
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Old 04-09-2014, 05:06 PM   #20
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I know JPF doesn't like the Dempsey "set screw" method of locking down the IMS sprocket. IIUC he thinks the sprocket can be pushed loose from the shaft, as it's a press fit.
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