04-07-2019, 06:32 AM
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#1
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Registered User
Join Date: Apr 2016
Location: SE Michigan
Posts: 496
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Quote:
Originally Posted by particlewave
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.
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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...
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1997 Boxster arctic silver/ red, XNE riveted mahogany/ leather steering wheel & 917-style wood shift knob, Ben’s short shifter, PSE, 996 TB, UDP, stereo/ center console delete, hardtop and speedster humps, daily driver rain or shine or snow!
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04-08-2019, 09:05 AM
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#2
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Registered User
Join Date: Jun 2017
Location: Madison, WI
Posts: 114
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Quote:
Originally Posted by 10/10ths
....has some sort of catastrophic failure mode.
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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.
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'99 986 Ocean Blue Metallic
'87 924S, winter beater
'17 VW Golf Sportwagen, for when I need extra seats
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04-06-2019, 09:22 PM
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#3
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Registered User
Join Date: Oct 2018
Location: North Cali
Posts: 833
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Quote:
Originally Posted by PaulE
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!
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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.
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04-08-2019, 12:14 PM
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#4
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Registered User
Join Date: Aug 2005
Location: Sanford NC
Posts: 2,583
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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.
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04-09-2019, 09:02 AM
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#5
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Registered User
Join Date: Oct 2018
Location: North Cali
Posts: 833
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[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?
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04-09-2019, 01:46 PM
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#6
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Registered User
Join Date: Feb 2017
Location: North Eastern US
Posts: 646
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...post deleted...
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Rgds, Fred
#317 550 Spyder Anniversary Edition 2004 Boxster S, 3.8L Flat Six Innovations engine, PSS9s, etc, etc . . .
The contents of my posts are for entertainment only. As confirmed by my many motor sports fails, I am not qualified to give product endorsements or mechanical advice
Last edited by Oldcarguy; 04-09-2019 at 01:49 PM.
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04-08-2019, 12:48 PM
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#7
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Need For Speed
Join Date: Feb 2013
Location: Funville
Posts: 2,114
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I always liked Pedro's DOF for the IMSB.
__________________
2003 Boxster S
| 987 Air Box | K&N Air Filter | 76mm Intake Pipe| 996 76mm TB | 997 Distribution T | Secondary Cat Delete Pipes | Borla Muffler | NHP 200 Cell Exhaust Headers |
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04-08-2019, 05:00 PM
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#8
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Registered User
Join Date: Aug 2017
Location: Tucson,az
Posts: 759
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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
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04-09-2019, 08:47 AM
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#9
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Registered User
Join Date: Aug 2005
Location: Sanford NC
Posts: 2,583
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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.
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04-08-2019, 05:23 PM
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#10
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Registered User
Join Date: Sep 2008
Location: Florida
Posts: 2,497
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Hey! let's discuss bearing failure on 16-21 year old cars!!!
Subscribed (not).
It's just a car. Drive the damn thing.
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04-08-2019, 07:06 PM
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#11
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Registered User
Join Date: Oct 2014
Location: California Central Coast
Posts: 1,476
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I pushed my clutch in today. Made a weird sound like a metal coil stretching. You guys think it might be the IMSB?
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04-08-2019, 11:04 PM
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#12
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Custom User Title Here
Join Date: Mar 2012
Location: Ft. Leonard Wood
Posts: 6,164
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Quote:
Originally Posted by 911monty
I pushed my clutch in today. Made a weird sound like a metal coil stretching. You guys think it might be the IMSB?
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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.
.
Last edited by particlewave; 04-08-2019 at 11:07 PM.
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04-08-2019, 11:15 PM
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#13
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Need For Speed
Join Date: Feb 2013
Location: Funville
Posts: 2,114
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Quote:
Originally Posted by particlewave
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.
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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.
__________________
2003 Boxster S
| 987 Air Box | K&N Air Filter | 76mm Intake Pipe| 996 76mm TB | 997 Distribution T | Secondary Cat Delete Pipes | Borla Muffler | NHP 200 Cell Exhaust Headers |
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04-09-2019, 04:57 AM
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#14
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2003 S, Arctic Silver, M6
Join Date: Oct 2014
Location: Winnipeg, MB, Canada
Posts: 1,346
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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.
Last edited by paulofto; 04-09-2019 at 05:03 AM.
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04-09-2019, 09:05 AM
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#15
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Registered User
Join Date: Oct 2018
Location: North Cali
Posts: 833
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Quote:
Originally Posted by KRAM36
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.
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I think he was joking, too
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04-09-2019, 01:04 PM
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#16
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Registered User
Join Date: Sep 2018
Location: Laval QC
Posts: 840
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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
With the seal removed
__________________
Grant
Arctic Silver 2000 Boxster S - bought with a broken engine, back on the road with the engine replaced
Green 2000 Boxster 5-speed and 1978 928 auto
1987 924S 5-speed (Sold) - Blue 2000 Boxster 5 spd (Sold)
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04-09-2019, 01:38 PM
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#17
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Need For Speed
Join Date: Feb 2013
Location: Funville
Posts: 2,114
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Quote:
Originally Posted by elgyqc
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
With the seal removed

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I'd keep that seal on it. Watch what happens when the bearing spins with no seal. All the oil is thrown out of the bearing. I'd packed it back with some lifetime lubricant before putting the seal back on.
__________________
2003 Boxster S
| 987 Air Box | K&N Air Filter | 76mm Intake Pipe| 996 76mm TB | 997 Distribution T | Secondary Cat Delete Pipes | Borla Muffler | NHP 200 Cell Exhaust Headers |
Last edited by KRAM36; 04-09-2019 at 02:29 PM.
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04-09-2019, 04:19 PM
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#18
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Registered User
Join Date: Sep 2018
Location: Laval QC
Posts: 840
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Quote:
Originally Posted by KRAM36
I'd keep that seal on it. Watch what happens when the bearing spins with no seal. All the oil is thrown out of the bearing. I'd packed it back with some lifetime lubricant before putting the seal back on.
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I saw that video and that is one point of view. Jake Raby still recommends removing the seal on the m97 (987 997) engines, which have the bearing that can't be replaced without disassembling the engine, and before his various replacement bearing kits were developed he recommended removing the seals on m96 engines. I'm no expert... but it seems to me that in throwing all that oil around the balls, races and cages are going to be coated with it. I have a bit of experience with 2 stroke engines in which the bearings are entirely lubricated by a mist of oil that enters the crankshaft diluted in the fuel. I don't want to argue the comparative reliability of 2-stroke kart engines and Porsche Boxsters but misting does work and running the IMSB without seals has a history.
As I said, I am confident with my decision... on this car at this time. When I get to my other Boxster I may decide differently.
By the way I totally destroyed the seal getting it off. I am impressed that you were able to remove and reinstall yours.
__________________
Grant
Arctic Silver 2000 Boxster S - bought with a broken engine, back on the road with the engine replaced
Green 2000 Boxster 5-speed and 1978 928 auto
1987 924S 5-speed (Sold) - Blue 2000 Boxster 5 spd (Sold)
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04-09-2019, 04:32 PM
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#19
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Need For Speed
Join Date: Feb 2013
Location: Funville
Posts: 2,114
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Quote:
Originally Posted by elgyqc
I saw that video and that is one point of view. Jake Raby still recommends removing the seal on the m97 (987 997) engines, which have the bearing that can't be replaced without disassembling the engine, and before his various replacement bearing kits were developed he recommended removing the seals on m96 engines. I'm no expert... but it seems to me that in throwing all that oil around the balls, races and cages are going to be coated with it. I have a bit of experience with 2 stroke engines in which the bearings are entirely lubricated by a mist of oil that enters the crankshaft diluted in the fuel. I don't want to argue the comparative reliability of 2-stroke kart engines and Porsche Boxsters but misting does work and running the IMSB without seals has a history.
As I said, I am confident with my decision... on this car at this time. When I get to my other Boxster I may decide differently.
By the way I totally destroyed the seal getting it off. I am impressed that you were able to remove and reinstall yours.
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Oh I never took the seal off my bearing. I'm not even worrying about it anymore with 127k miles on the engine. I got a price check on having the "Solution" done to my car and was quoted a little over $4,000 as the Tiptronic transmission adds more labor to the job. Forget that, I'll let this engine die one day and pick up a low mileage engine for about the same price and get either Pedro's DOF or Flat 6 Innovation's Solution done to the engine while it's out.
__________________
2003 Boxster S
| 987 Air Box | K&N Air Filter | 76mm Intake Pipe| 996 76mm TB | 997 Distribution T | Secondary Cat Delete Pipes | Borla Muffler | NHP 200 Cell Exhaust Headers |
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04-09-2019, 06:16 PM
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#20
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Registered User
Join Date: Jul 2010
Location: California
Posts: 1,859
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Sick of IMS Bearing?
Sick of IMS Bearing? Do you want to know who is sick of IMS Bearing? I AM SICK OF IMS BEARING. After replacing the IMS Bearing two times in my first Boxster, and getting over 304,000 miles out of it, I purchased a 997 4S with the larger (never fail) IMS Bearing. Guess what happened? THE IMS BEARING FAILED IN MY 997! My 997 has been at Flat 6 Innovations since July. Jake said he had never seen an IMS Bearing go out on a 997 street car. As you all know the repair/rebuild is not cheap. So let me tell you again who is sick of IMS Bearing. I AM SICK OF IMS BEARING!!
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Jäger
300K Mile Club
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