IMS show-n-tell - 986 Forum - The Community for Porsche Boxster & Cayman Owners

j.fro · 02-13-2014, 09:30 AM

I pulled the IMS from my 996 (1999 C4) and thought I'd let everyone have a look. The dual row bearing spins smoothly and has zero play. The shaft it rides on looks good, too. The cover has a rough edge inside, but that surface does not contact anything. Strangely, the cover has no markings. Most that I've seen photos for had "Germany" or a part number on them. The rubber o-ring is flattened and definitely shot, which I'm sure contributed to the leak I found. I've got the LNE kit to replace the bearing.
So, jury of my peers, what are your thoughts on this...
Did I just spend $$ to replace a good part?
Did I just save my engine?
Does the personal learning experience alone justify the similar-to-3-credit-hours cost?

LNE wants the old bearing in order for the warranty...I really wanna pop the seal and have a look inside. What would Jesus do?

Dlirium · 02-13-2014, 09:44 AM

Dude! That thing is SHOT!!

or, maybe not...

:-)

Bigsmoothlee · 02-13-2014, 12:25 PM

LNE wants the bearing? For what, warranty? That is not an LNE bearing, its original.

Pop the seal off and have a look. Also, theres another recent thread where the bearing was cut open and all the deep grooves in the bearing race were visible. Check it out.

Bigsmoothlee · 02-13-2014, 12:27 PM

heres the link

Autopsy of a "good" IMS bearing

san rensho · 02-13-2014, 12:36 PM

Cut it open so you can see the bearing surfaces and the balls, then you will know the condition. And please post pictures. Then send the bearing to LNE if they really want it. Makes sense to do so, because they analyze the bearings and use the data to come up with failure analysis trends. It would be nice if LNE shared the data with us.

Steve Tinker · 02-13-2014, 01:33 PM

The "rough edge" on the bearing inner cover in picture #1 is interesting - looks like the steel has been acid etched.
Was this section of the cover positioned at the bottom - I seem to recall the the lower edge of the IMS is immersed in oil when the engine is stationary, so if the bearing was sitting in old, acidic oil for long periods, etching could occur.
It would be interesting to see if the bearing races were in a similar condition, but that would mean cutting it open to inspect .....

Jamesp · 02-13-2014, 02:06 PM

A Dremel tool with a cutting disk works nicely

Now on the down side if you want an LNE bearing, and your old bearing intact is part of the trade, you have a decision to make. Additionally the bearing carrier you took out of the case is the old style which tended to leak, the new style has a different seal. I think the new one is about $150. And don't tell anybody, but I ran a bead of 5900 case sealant around the outboard edge of the seal before I installed mine as a little "belt and suspenders" for a seal area renowned for leaking. I wonder if that would work with your old style bearing carrier? It is important where the sealant goes. It has to be on the outboard surface of the piece you are installing so none of the sealant gets pushed into the case when you push the piece back in. Additionally any surface you apply sealant to has to be completely clean. No old sealant, no water, no oil. I favor brake cleaner followed up with acetone. In fact, I've got to get my hiney back out to the garage and install my oil pan and new O2 sensor (Thanks Pelican Parts! Great price on this part!)

Jamesp · 02-13-2014, 04:21 PM

Just back from a top down ride through the neighborhood to make sure the oil pan would stay on.

Walter White · 02-13-2014, 05:06 PM

You can take the seal off, take a look, then snap it back in place.
I use a very small screw driver, like those sold for eye glasses. Carefully pry the seal off from the outside edge, the edge at the outer race.
You can then just snap it back into place.

The rough area on the flange seal looks like a casting flaw to me. It is a cast piece. Doesn't look like it would be a problem to me.

Jake Raby · 02-13-2014, 06:22 PM

Quote:

Originally Posted by Bigsmoothlee

LNE wants the bearing? For what, warranty? That is not an LNE bearing, its original.

Pop the seal off and have a look. Also, theres another recent thread where the bearing was cut open and all the deep grooves in the bearing race were visible. Check it out.

To ensure that the engine was not quipped with a failing IMSB at the time of retrofit, sending in the OEM bearing is a requirement to complete warranty registration. Its been that way since day one.

You can't judge a used bearing by its cover, unless its cut open and measured, you can't judge it's health- period.

Oh, and by the way, that bearing was running VERY loosely n the housing. I can tell by all the fretting on the OD.

stephen wilson · 02-14-2014, 04:54 AM

Quote:

Originally Posted by Steve Tinker

The "rough edge" on the bearing inner cover in picture #1 is interesting - looks like the steel has been acid etched.
Was this section of the cover positioned at the bottom - I seem to recall the the lower edge of the IMS is immersed in oil when the engine is stationary, so if the bearing was sitting in old, acidic oil for long periods, etching could occur.
It would be interesting to see if the bearing races were in a similar condition, but that would mean cutting it open to inspect .....

That rough spot is just the raw casting, a low spot that wasn't touched by the machining operations.

Steve Tinker · 02-15-2014, 12:04 AM

That will be a relief to the owner, though I have seen steel surfaces that have been etched by acidic oils before. Isn't a good sign if it happens to be a bearing surface.....

Walter White · 02-15-2014, 07:31 AM

Quote:

Originally Posted by Jamesp

I ran a bead of 5900 case sealant around the outboard edge of the seal before I installed mine as a little "belt and suspenders" for a seal area renowned for leaking.

It may be a good thing you did. That Nachi seal has a small notch molded into the outer sealing area for ventilation.

Jamesp · 02-15-2014, 09:02 AM

Quote:

Originally Posted by Walter White

It may be a good thing you did. That Nachi seal has a small notch molded into the outer sealing area for ventilation.

Do you have a picture? The NSE is a full seal.

Walter White · 02-16-2014, 07:14 AM

I looked but I could not find a seal I have not destroyed. I will get a pic next time I have one I will get a pic.
I think I saw two notches on the outboard side of the seal at the perimeter.
I thought they were just part of the molding process and not intended for anything. Then I saw the details on this page, near the bottom

6204-2NSE Nachi Bearing 20x47x14 Sealed C3 Japan Ball Bearings:Nachi-Bearings

"Breathing mechanism (on seal OD)".

j.fro · 02-17-2014, 02:51 PM

I have earned my IMS merit badge! Got the car together yesterday, but needed 3 litres of Delvac 75W-90 to fill the trans. Filled up the trans and got it running this evening. Since I had to pull the chain tensioners, there was some racket on start-up, but that quieted down right away and the car runs smooth. I replaced the clutch with a Sachs unit. The clutch pedal is nice and light, and with the new trans oil and new engine mounts, shifting is like butter. A while back we had an Infinit G35 6MT coupe, and now my 996 shifts as well as that car did.
All in, replaced :
the clutch, pressure plate, and throw out bearing
IMS with LNE dual row IMS kit
Rms with Pelican PTFE RMS
Engine mounts with new stock units
Flushed clutch with Ate gold