Re: Need some advice on IMS preventive maintenance (replacement).......

Mine is a 2000 S with about 50K on the motor. I drive it about 6000 miles per year. No tracking, but occasional aggressive twisty drives. I change the oil at 5000 miles or annual intervals. I do mostly city driving in my normal commute and personal travels. I do not drive real aggressive on the city streets (Very infrequent visits to red line). I normally upshift when in the 4000 to 5000 rpm range.

I love this car and have no plans selling or upgrading. I see that Marc W. has upwards of 200K miles on his without an IMS issue.

I have been quoted ~$2500 to install the ceramic ball bearing version and $3500 for "The Solution".

I have the funds to do either and I am not personally fond of the bushing design of The Solution.


What are the board opinions?

Either is sufficient, so i'd go with the regular LN replacement. While the "solution" may be superior ( we don't actually have evidence either way), both vastly extend the service life of the IMS bearing. At that point you need to ask yourself "what is the weak link now?". It may well be that either will exceed the life of other motor components, primarily the chain guides - but who knows?

Both fix the major issue: a sealed bearing that, once the seal breaks down and the grease leaves, has minimal lubrication from motor oil. one simply catches splash lubrication, the other provides stream of oil. I expect both are well designed so i don't have any issues with the bushing design of the solution, i simply would not pay extra for it, since i begin to doubt it is the weak link any longer.

$2500 sounds a bit high to me. I'd estimate 3 hours (leisurely) to get the tranny and flywheel out, 2 hours (leisurely) to get the IMS done and 2 more (leisurely) to get it back together for an experienced 986/987 mechanic. Plus the part ($600-700) plus markup, plus the RMS (might as well) and you should be at ~7 hours plus $600-1000 or about $1700-2000, in my opinion, tops.

Maybe others will disagree.

Now, you spent a lot of time basically saying you don't drive the car too hard. History says that is no advantage: hard driven, but well; maintained cars have the fewest failures. The main exception are those driven so hard on the track that they starve a cylinder. That requires slicks and a very good (well, fast) driver. Once the motor is warm, revving seems to be just fine - and creates more splash lubrication. Caution is suggested when cold.

You also noted short drives. They are bad, allowing buildup of water, fuel and acids that don't boil off sufficiently or frequently enough. Make sure you get regular trips that have the motor fully hot > 15 minutes.

Grant

Grant

gee-lenahan-at-gee-mail-dot-com

Thanks Grant. When I use the car, the trip is always more than 1/2 hour. I take my bicycle when a close trip is needed. But, yes I do not drive hard. I usually save that for freeway onramps and offramps.

I would wait a week (or come to BRBS!)

Pedro Bonilla
1998 Boxster 986 - 311,000+ miles: [www.PedrosGarage.com]
PCA National Club Racing Scrutineer - PCA National HPDE Instructor - PCA Technical Committee (Boxster/Cayman)

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Racecar spelled backwards is Racecar

"Racing is life. Anything before or after is just waiting" ... Steve McQueen as Michael Delaney in "LeMans"

"If you wait, all that happens is that you get older"... Mario Andretti

"Being second is to be the first of the ones who lose" ... Ayrton Senna

Have fun at BRBS!

Grant

Grant

gee-lenahan-at-gee-mail-dot-com

Pedro Bonilla
1998 Boxster 986 - 311,000+ miles: [www.PedrosGarage.com]
PCA National Club Racing Scrutineer - PCA National HPDE Instructor - PCA Technical Committee (Boxster/Cayman)

---

Racecar spelled backwards is Racecar

"Racing is life. Anything before or after is just waiting" ... Steve McQueen as Michael Delaney in "LeMans"

"If you wait, all that happens is that you get older"... Mario Andretti

"Being second is to be the first of the ones who lose" ... Ayrton Senna

Grant

gee-lenahan-at-gee-mail-dot-com

I remain eager to hear about Pedro's "unveiling".

I completely agree with Grant on this. Had mine done with the LN improved bearing at 40K an my '02 S and now have peace of mind. My highly experienced and regarded Indy in Tucson said they have replaced more than 50 original bearings and many were on the way to failure. They have also experienced a few blown engines. $2K sounds about right and, while in there, your mechanic can do other things like replace the AOS, inspect or replace clutch items, service the starter, etc. This is a good compromise solution if you plan to keep the car. In my opinion, of course!!

I plan to do the LN replacement next winter. 2001 S with 73K. I track the car and plan to keep it so seems worthwhile for the peace of mind. Will do clutch and RMS while I am there. Clutch doesn't have any issues currently but parts are cheap relative to the labor so will do it anyway.

Hi all,
I think I have provided this info in the past, but here it is again.

Precision bearings are made in several precision/quality levels from class 1 to class 9 (best) Automotive ball and roller bearings are class 1 ($), Instruments will have class 7 or 9.($$$$)
Bearing ball separators can be stamped steel (pennies), to hardened, silver plated 4340 steel or bronze. ($$)
Lubrication can be grease or oil. Grease is soap or clay holding some oil. Grease is used when it is difficult or too costly to lube with oil

The IMS bearing is a class 1, with a stamped steel separator, grease lubricated, sealed.

To have a long life, a ball bearing must have a load within the yield limits of the steel, adequate surface finishes and lubricant film thickness to prevent metal to metal contact and temperatures within the limits of the materials.

The IMS bearing:
Max temperature before the steel begins to soften, 250F. Engine oil temps can reach 250F. Grease has no cooling effect. Oil, splash or pressure fed does.Seals harden from temperature, regardless what causes it. Assuming a 100# load on the bearing, 0-40 does not have enough film thickness to prevent metal to metal contact. Neither does grease. 15-50 is a little better. Higher speeds help. The oil will build up in front of the balls, separating the surfaces. (aquaplaning)

The LN bearing uses ceramic balls. High temp capability and accelerate easily, putting less stress on the ball separator. Splash oil is better than grease.

I could go on but I have an appointment.

Ed
The Bearing Engineer

Grant

gee-lenahan-at-gee-mail-dot-com

When's the unveiling?

while i have tow LN bearings, i'm still very curious too!

Grant

Grant

gee-lenahan-at-gee-mail-dot-com