DennisAN

I've been looking around and haven't found replacement OEM type IMS bearings available from Porsche.

I'm no expert on bearings, but do know that manufacturers such as Timken and SKF (Swedish Ballbearing Factory) have standardized on many standard sizes and configurations. On doing some searching I believe the double-row IMSB has a generic part number of 5204 and the single-row IMSB is a 6204.

5204 Specs.
OD 47 mm, Bore diameter 20 mm, Length 20.6 mm*

6204 Specs.
OD 47 mm, Bore diameter 20 mm, Length 14 mm

* variously given as 20.6 mm or 13/16" = 20.6375 mm.

Naturally if these basic specs are wrong everything following is wrong too.

To order a bearing, you have to add some suffixes to the base part number, such as "ZZ" for metal shields or "RS" for rubber shields (actually plastic). Guessing that Porsche buys from SKF, orderable bearings from SKF have exemplary extended part numbers:

Base part 5204
SKF 3204 A-2RS1TN9/MT33 $53 at the Atmus online store.

Base part 6204
SKF 6204 2RSJEM $12 from Amazon.com, $7 from USABearingsandBelts.com .

I don't know why SKF calls their 5204 a 3204.

I'm starting to view an IMSB as a "wear part" just like brake pads or motor oil. I'm a retired guy with more time than money, and don't mind tinkering with non-essential cars in my garage. Would it make sense to put one of these generic bearings in as a replacement IMSB every 40K miles or so?

Most respondents to my previous thread about replacing a double-row IMSB with a single-row IMSB reinforce my thought that it would be a dumb idea to do that specifically. But buying the LN tool set for $250 and the SKF double-row bearing for $53 sounds like it could be a low-cost insurance plan, especially since the tools are a one-time sunk cost.

Macster

Porsche doesn't offer the IMSB as a separate part. The IMS is available with the bearing but of course requires the cases to be split to install.

I guess you could remove the existing bearing from the engine and then using the numbers on the bearing order a comparable replacement from some bearing maker: SKF or *** or Timken or ?.

If you want to tinker and if your idea of tinkering is replacing the IMSB every so often that's up to you, provided the generic bearing is up to the task. I know I know an argument can be made the OE bearing is not up to the task but you want to make sure you are not jumping from the frying pan into the fire and in grabbing a generic bearing downgrading the bearing.

You have to consider infant death syndrome that is the new bearing is at some risk from failing early, in its "infancy". You have no warranty on the bearing so if the bearing does fail prematurely you have inflicted this upon yourself. How likely is the new bearing to fail premature? My WAG is about as likely as an existing bearing is to fail. Remember Porsche covered that OE bearing with a new car warranty for up to 50K miles and 4 years.

zedcat

The single row imsb from my 04S is marked "NSK 917 6204DU17 Poland". Was intact but a bit wobbly. Just me of course, but given all the effort of dropping the trans etc, I'd lean toward the LNE bearing.

mikefocke

There are loans or used tool sets sales. Or, if you buy the tool set, you can sell it on to decrease your cost.

Given that you'd have to fabricate/borrow/acquire some of the tools no matter what bearing you use..

Given that most of the double row IMS bearing kits contain perhaps a dozen parts beyond the simple bearing and you would have to source some of those as non-reusable original parts and some of the parts in some of the kits are improved on the originals...

And given that LN tells us that there are no reported failures of properly-installed current-design double-row LN bearings in cars that have not had previous failures...

And given that LN tells us that they think their double row bearing kit may well be life of the engine based on thousands of installs and accumulated mileage and samples examined...

Given that the skill and care of the installer matters...

And given that you want to decrease risk, not increase it...

(There are other threads some on other forums where people give part numbers of an individually sourced bearing that they used. and there is the Pelican kit which is cheaper, OEM in design and materials (but we know that isn't the greatest or we wouldn't be talking about replacing the OEM part) and contains many parts but depends on the LN tool kit.)

Good luck ...

amagalla

This is a link to an OEM style kit:
Pelican IMS Kit

But I agree, as long as you're down there, put the LN unit in.

Tony

DennisAN

Tony,
See my other thread where I discuss the wisdom of putting the one-row Pelican kit into a two-row bearing engine. Nobody seems to like that idea much.

It sounds better to replace a two-row bearing with another two-row bearing. Maybe I could get the Pelican kit just to use the "improved" center bolt and nut with a two-row bearing sourced from someplace else. That would only be about $200 for both.

Since Pelican suggests replacing their single-row bearing at 40K miles anyway, and since they don't sell the bearing by itself, getting one for $12 from Amazon sounds like a deal to me. In fact if I bought their kit to use the center bolt with a two-row bearing, I could sell their single-row bearing to someone else who was already at the next 40K replacement mileage.

Dave H.

you're making this harder than it needs to be.

Flat6 Innovations

+1.

Because the IMSB was never considered a replacement component from Porsche as it was tauter to be a "lifetime" component that was to never be changed. There is no Porsche part # for an IMSB, because a replacement OEM bearing was never offered.

There are different ways of doing this retrofit. The life of your engine, and the status of your bank account both are heavily dependent upon your decision. Go with truly developed and proven components, or risk everything. The quicker way to spend thousands is to try to save a few hundred. The margin of error is near zero and the learning curve is 90 degrees. To some its worth the risk, to others it isn't.

DennisAN

Gee whiz, what's the fun in doing things the easy way?

I'm just trying to figure out the options open for this situation. I'm now targeting the purchase of a 2000 car since it's got the 2.7l with a double row IMSB. Data presented in the lawsuit says the OEM double row IMSB has a reported failure rate less than 1%, whereas LN says they have a 0% failure rate with their double row IMSB. Not much difference there statistically.

I'm not sure what I'd do if I found a desirable 2001 offered for sale since there seems to be no a priori way of determining which IMSB it has.

mikefocke

And there isn't much of a difference between the 2000 and 2001 except that risk of getting a single row engine. (my '01S had 58k when I passed it on with original IMS. No idea which it had. And it was all the bad things. Third owner. First and second owner maintained with longer change intervals. Sat around a lot. Not a daily driver for 4+ years. Used for some short half mile drives. Used in colder weather. Tip.)

These are 13-14 year old cars. Lots can go wrong besides IMS.

(Hint. If you are just now shopping, you might want to wait a few weeks.)

GVA-SFO

How to know for a given car if it is single or double row ?
Would the vin number tell ?

DennisAN

I'm in no rush at all. I have plenty of money in savings to buy pretty much anything, but I've found that I actually prefer to drive a beater car rather than a shiny new one. My personality is such that I worry too much when I drive a new car to really enjoy it. With an older one I can drive up into the mountains and not worry about getting a rock chip.

Right now I'm in the reading and studying phase. I've found resources such as your web pages, Mike, and others. I've bought Wayne Dempsey's book and the Bentley shop manual. I'm learning what parts are available or not. Biggest surprise is how expensive a 986 flywheel is, since is serves as both flywheel and harmonic balancer.

I've found that many used cars are in bad shape for the asking price, and thus languish for months in their advertisements. Then the "good deals" tend to sell in 48 hours so you have to be ready to rush in with the cash.

terbiumactivated

Then the "good deals" tend to sell in 48 hours so you have to be ready to rush in with the cash. Finding this true with houses I'm trying to buy.

Stephen Tinker

No - only real way is to remove the transmission and flywheel to inspect the IMS bearing cover.

Macster

One way -- how conclusive this is is open for discussion/debate -- might be to see if your car's VIN is excluded from the IMS settlement. Cars equipped with double row bearings I think are excluded as these bearings do not fail often enough to be a concern. My 02 Boxster -- built 10/2001 -- is excluded and it has a double row bearing (shallow dish on the IMSB end plate/flange).