Ok I was ignoring the fact that the IMS is in the sump so that makes sense. Crank journal and big end rod bearings are what I was thinking of that need the constant feed of oil under pressure. While Porsche decided to go with the grease packed sealed bearing at the flywheel engine and there is no internal oil gallery there, I don't see why they couldn't have put in a galley and a journal bearing, it is right below the crankshaft's rear main bearing. They had no problem getting an oil galley to the journal bearing on the front of the IMS. PS, I am sick of the IMSB too, having had
a preemptively installed ceramic one fail and going through a rebuild!

Every high performance car.....
 

....has some sort of catastrophic failure mode.

Corvette 427 engines have thrown lots of rods.

BMW M5 V10 engines supposedly grenade at 60,000 miles. All of them. The internet said so.

Mazda RX-8 engines explode if you fire them up and only drive them for ten minutes. Kills the apex seals don't ya know?

E39 M5's all have bad cam phasers that need replacing.

1990 Miatas with the "short nose crank" all break their crankshafts.

Lotus Elise engines will oil starve their cams if you track them with sticky Hoosiers.

The list goes on and on.

Just add $3,000 for a professional IMS aftermarket install to the purchase price of any 1997-2004 Boxster and just spend the money on yours to get it R&R'd if you are trying to sell her.

It's just the world we live in. Complaining about it will not change the perception out there on the ground.

It IS what it IS.

Get busy livin', or get busy dyin'.



http://986forum.com/forums/uploads02...1554611382.jpg

Paul,

It doesn`t make much sense to me to use a pressurized oil lubricated journal bearing in a place that`s overwhelmed with oil anyways. I`ve never seen anything like this in any engine. I think a ball or roller bearing is perfect for this application, just the original, the single-row in particular, is undersized for this job. The dual-row still lasts for over 100k miles, which is not that bad in a performance car. The larger, non-removable bearing that`s installed in the newer Boxsters lasts pretty long too, at least I`ve never heard of any of those failed, but feel free to chime in if anyone have heard about such a bearing that failed.

Ceramic hybrids are not really good for this application because they are made for constant high speed and high temperature, that`s not really typical for a shaft that spins in the sump in oil at lower speed than the crankshaft. What the IMS is exposed to is the intermittent radial impact coming from the camshafts and transmitted by the chains. As the ceramic ball is much harder than the hardened steel races, eventually the intermittent radial load will make the races wear prematurely.

Or don't, quit worrying about what might happen and just drive. ;)

Investing $3k in a $6k car doesn't make much sense to me, but whatever floats your boat.

.

This.
So much this.

Sent from my SM-G970U using Tapatalk

Amen to that.... I’d rather save toward $10K upgrade to 996 3.4 swap, should the original double-row IMSB goes on my daily driving 97.

Owners of single-row cars may have tougher decisions to make but end of the day the risk is still relatively low enough that I won’t put that much money in just to sleep better.

I believe that keeping oil fresh and driving hard more often keep the bearing happy and lubed, and I drive mine daily and never worry about IMSB. This is probably not practical for garage queens and maybe they could get back that much investment after huge appreciation of their mint 986’s with number-matching original motor someday...

Yep. I don't understand why people (mostly non-Porsche owners on general car sites) make a bigger deal about IMS than any interference engine timing belt failure. Doing nothing about it is far less risky than not changing a timing belt, and if you do choose to address it, it's probably going to be only once AND at the same time as some other major maintenance.

Open seal ball bearing IMS are lubricated by splash and mist, not immersion once running. They have gaps through which the oil mist can penetrate. But solid bearings don't have the gaps spaced the same way.

There have been large single bearing engines that had failed bearings. Thankfully not as many percentage wise as the smaller 1st and 2nd gen bearing engines. And smaller total numbers of failures because fewer cars with those bearings were sold.

I always liked Pedro's DOF for the IMSB.

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I think its just cheap bearings being sourced from the purchasing department,You order X amount of bearing's from a vendor they show up you stock them and use them up,then order more and maybe their as good as before maybe not, otherwise they would not be so hit and mis some engines go forever some trash at 40K I think the mechanics of the engines don't change but the bearings sure could:confused:

Hey! let's discuss bearing failure on 16-21 year old cars!!!
Subscribed (not).

It's just a car. Drive the damn thing.

I pushed my clutch in today. Made a weird sound like a metal coil stretching. You guys think it might be the IMSB?

Absolutely. Stop driving it immediately.

Next year will see the introduction of the all new "Totally Serious This Time Permanent Fix Final IMSB Solution", starting at only $5999.

Fix it then, and from now on budget an extra $6k into the purchase price of any future Boxster.
I'm totally serious.

.

Ha ha you joker.

Monty, from what I have gathered, you will not hear anything different before the IMSB goes. So I don't suspect what you heard had anything to do with the IMSB.

I did some checking on Pedro's DOF system and to date no failures that I could find. Much cheaper cost, with excellent results.

Its a good thing the IMS Bearing is THE ONLY THING that ever fails on a Boxster. The symptoms of a pending IMS catastrophe range from a burnt out headlight to low tire pressure to a loose licence plate bolt.

The safest thing is to never drive these cars since the engine will grenade if you get behind the wheel.

Manufacturing tolerance variability between the crankshaft and the IMS may have a bearing on which bearings fail and when. Not that any will go forever, parts wear.

[QUOTE=mikefocke;592605]Open seal ball bearing IMS are lubricated by splash and mist, not immersion once running.

Out of curiosity, how do you know that for a fact?

I think he was joking, too :)

Some of you guys are crack ups lol.

I really like the painted silver center console and trim around the radio and climate control or your car. Did it come from the factory like that? I've been thinking about painting mine.

Today I inspected my IMSB without removing it (2000 Boxster 5-speed, 115,500 Mi.). First, it is a dual row bearing and it looks perfect, turns smoothly and there is no looseness. I pulled the rear bearing seal and oil came out... I was surprised that it didn't smell burned and it looked relatively clean. The grease was totally gone.
At this point the plan is to change the seal on the IMS flange and put it back together. I watched the PCA videos with Jake Raby again and he explained the logic behind removing the seals to help lubricate the bearing. I feel confident with this procedure on this car at this time.

With the seal in place
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With the seal removed
http://986forum.com/forums/uploads02...1554843400.jpg