Go Back   986 Forum - for Porsche Boxster & Cayman Owners > Porsche Boxster & Cayman Forums > Performance and Technical chat

Reply
 
LinkBack Thread Tools Display Modes
Old 08-09-2019, 09:47 AM   #1
Registered User
 
Join Date: Jan 2005
Posts: 18
Is there truly no way to tell that it’s time to replace the IMSB?

There has to be some tell tale sign that the bearing must be replaced otherwise, 100% of Boxsters and 911s of a certain vintage have to get this work done. Didn’t Porsche claim only a minority of cars are afflicted with this issue? How can they know that if there aren’t signs to foretell doom ahead?
cantdrv55 is offline   Reply With Quote
Old 08-09-2019, 10:13 AM   #2
Custom User Title Here
 
particlewave's Avatar
 
Join Date: Mar 2012
Location: KC
Posts: 5,812
Garage
You have A LOT of reading to do.


.

Last edited by particlewave; 08-09-2019 at 01:17 PM.
particlewave is offline   Reply With Quote
Old 08-09-2019, 12:52 PM   #3
2003 Base 5-speed
 
grc0456's Avatar
 
Join Date: Jul 2015
Location: Stoneham, MA
Posts: 884
Garage
Cut open your filter to check for ferrous particles, start doing used oil analysis......this is the way to tell.


Sent from my iPhone using Tapatalk
grc0456 is offline   Reply With Quote
Old 08-09-2019, 03:19 PM   #4
Registered User
 
Join Date: Aug 2018
Location: Woodland Wa
Posts: 111
An issue that has been blown way out of proportion by the web.
blue62 is offline   Reply With Quote
Old 08-09-2019, 03:54 PM   #5
Certified Boxster Addict
 
Join Date: Nov 2010
Location: Los Angeles
Posts: 7,429
Correct.

There is NO WAY TO KNOW.

Its a lot like the Heisenberg Principle - if you actually look at (inspect) the IMSB then you might as well replace it anyway.

Cutting the filter open or oil analysis will provide information about the entire engine, not exclusively the IMSB.
__________________
1999 996 C2 - sold - bought back - sold for more
1997 Spec Boxster BSR #254
1979 911 SC
POC Licensed DE/TT Instructor
thstone is offline   Reply With Quote
Old 08-09-2019, 04:01 PM   #6
Registered User
 
Ciao's Avatar
 
Join Date: Dec 2015
Location: Denver
Posts: 706
Garage
Your conscious is your guide
__________________
5280 Cruising @High Altitude
Seal Gray & K&N Filter
Ciao is offline   Reply With Quote
Old 08-10-2019, 05:29 AM   #7
1998 Boxster Silver/Red
 
Join Date: Sep 2017
Location: 92262
Posts: 1,071
Quote:
Originally Posted by cantdrv55 View Post
There has to be some tell tale sign that the bearing must be replaced otherwise, 100% of Boxsters and 911s of a certain vintage have to get this work done. Didn’t Porsche claim only a minority of cars are afflicted with this issue? How can they know that if there aren’t signs to foretell doom ahead?
Remove your airbox and cut it open. There should be a sticker inside that will illustrate where under your car you should look for the hanging tag that will identify which model IMS you have, and how to remove and inspect it.

Or, follow Particleweave's advice.

__________________
1998 Porsche Boxster
1986 BMW 325es
2012 Ford Edge Sport

"Ignore the guilt, and take your turn"
Starter986 is offline   Reply With Quote
Old 08-10-2019, 06:33 AM   #8
2003 S, Arctic Silver, M6
 
paulofto's Avatar
 
Join Date: Oct 2014
Location: Winnipeg, MB, Canada
Posts: 1,001
Garage
Quote:
Originally Posted by Starter986 View Post
Remove your airbox and cut it open. There should be a sticker inside that will illustrate where under your car you should look for the hanging tag that will identify which model IMS you have, and how to remove and inspect it.

Or, follow Particleweave's advice.

File this post under 'Wild Goose Chases'

Starter is just messin' with ya cantdrv55.

There are dozens and dozens of threads here and on other Porsche sites so just do some searches and settle in for a Sunday afternoon of reading. The whole IMS discussion proves the adage 'A little knowledge is a dangerous thing' so educate yourself and gain a lot of knowledge on the subject. In the mean time drive your car.
paulofto is offline   Reply With Quote
Old 08-10-2019, 10:53 AM   #9
Registered User
 
Rickvd's Avatar
 
Join Date: Mar 2018
Location: Indiana
Posts: 75
Garage
Look at your cam deviations as an indicator of IMS health. There was an excellent article in a west coast Porsche mag, I have posted in this forum on this, also check out this link. Cam Deviation to Detect IMS Failure Progression - Pelican Parts Forums here is the url from Pedro’s
http://pedrosgarage.com/Site_5/Good_Vibrations.html
Rick
Rickvd is offline   Reply With Quote
Old 08-10-2019, 11:04 AM   #10
Registered User
 
Join Date: Aug 2005
Location: Sanford NC
Posts: 2,319
Yours could fail with no warning tomorrow. Yes.

And by the time you can detect debris in the oil filter, you have to understand that debris and even smaller and more deadly particles have been circulating within the engine against many bearings for maybe hundreds of hours. Some installers won't replace the IMS bearing at that point because of the probability of future failure. They insist on a $$$$$ total engine rebuild.

Every engine has wear where metal rubs against metal. Your best defense is an excellent lubrication history. But what are the odds that your car had that? Did you see the 3k intervals paperwork proving such a history before you bought?

Cam deviations can be caused by many things. If you see them, get the forensics begun.
mikefocke is offline   Reply With Quote
Old 08-10-2019, 01:38 PM   #11
Registered User
 
Join Date: Jan 2014
Location: New Jersey
Posts: 1,193
I bought a 2003 S new and didn’t know about the IMSB. About 6 years and 42,000 miles into it I learned about it and had the LN single row pro installed. The original IMSB was still fine and I still have it. A year ago at 77,500 miles the LN unit failed. In my case, everything was fine right until it wasn’t. It was caught before any major damage occurred. In terms of failure parts my rebuild only required a new IMS, one broken timing chain paddle and the oil pump internals. The crank, block, cylinder heads, rods and pistons were all fine but I decided to have it increased to a 3.6 for the rebuild. The oil cooler and hydraulic lifters were also replaced as a precaution and all the other usual rebuild parts and gaskets went into it.

So my point if there is one is that the IMSB is fine until it isn’t and if you’re lucky when it goes the engine will be rebuildable.
__________________
2003 S, 3.6 LN Nickies, ARP rod bolts, under-drive pulley, Fabspeed sport headers, Softronic tune, 987 airbox 987 motor mount, Function-First Sport insert & transmission mounts, Ben's short shifter, Nine8Six projector headlights & center caps, ROW M030, stainless flexible brake lines, B-K rollbar extension & fire extinguisher mount, hardtop
PaulE is offline   Reply With Quote
Old 08-10-2019, 05:28 PM   #12
On the slippery slope
 
JayG's Avatar
 
Join Date: Mar 2014
Location: San Diego
Posts: 3,296
Garage
Quote:
Originally Posted by PaulE View Post
I bought a 2003 S new and didn’t know about the IMSB. About 6 years and 42,000 miles into it I learned about it and had the LN single row pro installed. The original IMSB was still fine and I still have it. A year ago at 77,500 miles the LN unit failed. In my case, everything was fine right until it wasn’t. It was caught before any major damage occurred. In terms of failure parts my rebuild only required a new IMS, one broken timing chain paddle and the oil pump internals. The crank, block, cylinder heads, rods and pistons were all fine but I decided to have it increased to a 3.6 for the rebuild. The oil cooler and hydraulic lifters were also replaced as a precaution and all the other usual rebuild parts and gaskets went into it.

So my point if there is one is that the IMSB is fine until it isn’t and if you’re lucky when it goes the engine will be rebuildable.
A LN IMSB failure?
IIRC, there have been claimes than none have ever failed. I could be wrong.....
__________________
2004 Boxster S 6 speed - DRL relay hack, Polaris AutoTop DIY
2004 996 Targa Tip
Instructor - San Diego region, 2014 Porsche Performance Driving School
2013 C300, 2010 Jetta 2011 Mazda 3, 1998 Windstar - Dog van , 2004 F-150 "Big Red"

Last edited by JayG; 08-13-2019 at 05:48 PM.
JayG is offline   Reply With Quote
Old 08-10-2019, 05:37 PM   #13
Custom User Title Here
 
particlewave's Avatar
 
Join Date: Mar 2012
Location: KC
Posts: 5,812
Garage
Quote:
Originally Posted by JayG View Post
A LN IMSB failure?
IIRC, there have been cl;aiomes than none have ever failed. I could be wrong.....
Haha!

I used to keep count...I think I saw around 15-20 different complaints of LN IMSB failures before I quit paying attention. Of course, those failures “had nothing to do with the bearing and was the fault of the installer, crank runout or other engine failure”.

Some of those users reporting failures were even banned from rennlist because they dared to question LNE.
particlewave is offline   Reply With Quote
Old 08-10-2019, 06:05 PM   #14
Who's askin'?
 
maytag's Avatar
 
Join Date: Mar 2018
Location: Utah
Posts: 1,141
Quote:
Originally Posted by JayG View Post
A LN IMSB failure?

IIRC, there have been cl;aiomes than none have ever failed. I could be wrong.....
Oh you're not wrong..... there have been LOTS of claims.... but they're B.S.

As I've done with several other claims made by "the religion", I've read extensively on this topic, and in that reading I've found dozens of failed LN IMSB's.

Don't drink the cool aid.

Sent from my SM-G970U using Tapatalk
maytag is online now   Reply With Quote
Old 08-10-2019, 10:30 PM   #15
Registered User
 
Liamray's Avatar
 
Join Date: May 2019
Location: Australia
Posts: 21
I have owned a 2001 2.7 Tiptronic Boxster for 3yrs now, and I had a major service carried out on it, the mechanic found ‘material’ in the filter, a lot of material. The mechanic thought it was the IMSB, and the material looked like alloy chips, but being a retired Aircraft Maintenance Engineer I did my own investigation. To cut a long story short, I removed the IMSB and it was a factory fitted dual row bearing, and it was in ‘as new’ condition, even the plastic seals looked new. Turns out the problem with my engine was not the IMSB, but another little discussed problem that affects the Boxster engine, my ‘Cam Chain Tensioners & Variocam Tensioners’ were shot. This in turn means that the cam timing is erratic at best, and dangerous at worst, when the Cam Chain Tensioners go it leaves the chains to basically ‘flap’ about untensioned, this in turn can put stress on the IMSB. Porsche should have made the Tensioners a regular service item, but they didn’t, my car with 147,000km on the clock, had three out of the five Tensioners fail. If you’ve heard of the ‘NORMAL’ chain rattle at start up or when the engine is cold, this is a lie! If the Tensioners are operational then there is no rattle. So the IMSB is not the only thing responsible for engine failures.
Liamray is offline   Reply With Quote
Old 08-11-2019, 05:22 AM   #16
1998 Boxster Silver/Red
 
Join Date: Sep 2017
Location: 92262
Posts: 1,071
Quote:
Originally Posted by Liamray View Post
I have owned a 2001 2.7 Tiptronic Boxster for 3yrs now, and I had a major service carried out on it, the mechanic found ‘material’ in the filter, a lot of material. The mechanic thought it was the IMSB, and the material looked like alloy chips, but being a retired Aircraft Maintenance Engineer I did my own investigation. To cut a long story short, I removed the IMSB and it was a factory fitted dual row bearing, and it was in ‘as new’ condition, even the plastic seals looked new. Turns out the problem with my engine was not the IMSB, but another little discussed problem that affects the Boxster engine, my ‘Cam Chain Tensioners & Variocam Tensioners’ were shot. This in turn means that the cam timing is erratic at best, and dangerous at worst, when the Cam Chain Tensioners go it leaves the chains to basically ‘flap’ about untensioned, this in turn can put stress on the IMSB. Porsche should have made the Tensioners a regular service item, but they didn’t, my car with 147,000km on the clock, had three out of the five Tensioners fail. If you’ve heard of the ‘NORMAL’ chain rattle at start up or when the engine is cold, this is a lie! If the Tensioners are operational then there is no rattle. So the IMSB is not the only thing responsible for engine failures.
I've got that startup rattle. Arghhhhh. My reading reveals that I would be ill-equipped to replace the three tensioners.

Think I'll get a Mother Mary to stick on my dash and, no, I'm not talking UFO.
__________________
1998 Porsche Boxster
1986 BMW 325es
2012 Ford Edge Sport

"Ignore the guilt, and take your turn"
Starter986 is offline   Reply With Quote
Old 08-11-2019, 06:41 AM   #17
Registered User
 
jsceash's Avatar
 
Join Date: Aug 2009
Posts: 1,403
Garage
If you had a Durametrics and monitor the Cam Shaft deviation that may give you a perspective on a couple item. Chain rail condition, tensioner condition and IMS. That with oil filter inspections. are a good starting point.
__________________
2003 Black 986. modified for Advanced level HPDE and open track days.
* 3.6L LN block, 06 heads, Carrillo H rods, IDP with 987 intake, Oil mods, LN IMS. * Spec II Clutch, 3.2L S Spec P-P FW. * D2 shocks, GT3 arms & and links, Spacers front and rear * Weight reduced, No carpet, AC deleted, Remote PS pump, PS pump deleted. Recaro Pole position seats, Brey crouse ext. 5 point harness, NHP sport exhaust
jsceash is offline   Reply With Quote
Old 08-13-2019, 10:26 AM   #18
Registered User
 
Join Date: Jan 2014
Location: New Jersey
Posts: 1,193
Quote:
Originally Posted by JayG View Post
A LN IMSB failure?
IIRC, there have been cl;aiomes than none have ever failed. I could be wrong.....
Well all I know is mine failed. Prior to the failure my shop told me my used oil filters and magnetic drain plug were always clean of debris at each oil change and without going through my records I would say that my oil changes were every 5,000 -7,000 miles at most. My oil was always changed at least once a year and always after 2 track events, and always with Mobil 1. In one of my other threads on this topic, someone said ceramic ball bearings in steel races are a bad idea, and I think there is some merit to that. The ceramic balls are much harder than the steel races. Since the bearing is open and relies on splash lubrication, if there are any foreign particles in the oil and they get into the bearing races the ceramic balls are just going to grind them into the races until a failure occurs.
__________________
2003 S, 3.6 LN Nickies, ARP rod bolts, under-drive pulley, Fabspeed sport headers, Softronic tune, 987 airbox 987 motor mount, Function-First Sport insert & transmission mounts, Ben's short shifter, Nine8Six projector headlights & center caps, ROW M030, stainless flexible brake lines, B-K rollbar extension & fire extinguisher mount, hardtop
PaulE is offline   Reply With Quote
Reply


Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is On
Trackbacks are On
Pingbacks are On
Refbacks are On




All times are GMT -8. The time now is 05:17 AM.


Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2019, vBulletin Solutions, Inc.
Content Relevant URLs by vBSEO 3.6.0
Copyright 2018 Pelican Parts, LLC - Posts may be archived for display on the Pelican Parts Website -    DMCA Registered Agent Contact Page