Yeah, higher oil pressure and volume!! That's the ticket!! You've done it now Duezzer. This could start a whole new string of theories and conjecture. Maybe ANOTHER oil pump at the flywheel end of the shaft feeding just the IMS and a secondary oil sump holding another 9 Litres. Of course the oil used would be critical. Only ambergris oil from virgin sperm whales. Yes, that's the answer. Finally a solution to the IMS problem.

Thanks Duezzer!

It all gets a bit tiring, but these are the new folks to the Boxster asking. Maybe we need a sticky to make a listing of must read IMS threads.

Just my .002

Agreed because we need new ideas and info - but NEW ones !

For crying out loud......
 

......Just replace the damn IMS and call it a day.

Why ask "why?"

What difference does it make why they fail?

All that matters is that they DO fail.

So, you either live with the consequences, or spend the money to install a replacement.

Done.

Now get busy living.

:cheers:

The IMS is getting oil from immersion at rest and oil mist when in operation. Not from an oil pump unless some aftermarket bearing assembly has been fitted.

Ball bearings getting too much oil especially at startup is a very bad thing.

Or stop worrying so much and never replace it, other than maybe at clutch change, and never have an issue like 92% of all single row bearing cars and 99%+ of all double row bearing cars. ;)

Already done. :cheers:

Quick, if 8% of a fixed number of people died several years ago, but people are still dying every week, is it still 8%?

For all the people who are annoyed that someone would even raise a question about any option other than LN or sticking your head in the sand, there are a bunch more of us (and will continue to be more) without deep pockets who actually had the problem and had to make a decision.

If oil in the IMS were a problem then all (or a high percentage of) EPS roller installations would fail. My throw down continues: show me a broken EPS roller. I would even like to read about an improperly installed one, or one of the flush 'n go "rescues" they went bad just do i have one to read about.

The only person who has ever said a flooded tube is bad is Jake and i believe he's not posting here currently. Anyone else bringing it up is parroting what he said or theorizing.

Like i stated when i installed my roller, if it ever fails I'll be the first to post about it.

I agree.
I do not recall any Posts about a failure of a roller bearing IMSB. An impressive rebuttal to those of us (me inc.)who were skeptical about the concept as first offered. The first version of the roller bearing IMSB was quickly modified to address the objections about lack of thrust control. This success has been acknowledged several times in the past.Jake has a given his 'benediction' to the design -RND sells it. Dual Row RND Roller Bearing IMS Retrofit kit - RND Store LN Engineering
These roller bearing IMSB kits all(AFAIK) have are *-1RS= rear seal(just like the deep groove ball bearing kits) so the IMS tube will not accumulate foul oil behind it.There must be a reason for the 1 seal?
JFP has also commented on the IMS tube retaining old oil.
The variant that intrigues me and may spawn many pages of hysteria is a roller bearing IMSB kit with DOF. I suggested it on Pedro's Forum - into the Lion's Den ! He would not even discuss it. Which says a lot.Even if the Roller bearing IMSB +DOF kit has no technical merit, it could be a good marketing gimmick :-).

It all boils down to what you think the root cause is. If you think its a bearing load issue then a roller w/additional thrust face, carbide ball or double row ball will improve the life over a single row. Obviously that is not the sole problem otherwise all IMS bearings would fail. If its a lubrication issue(failed grease seal) then bearings open on one side might work. If you think its a runout/vibration issue then they are all temporary fixes if your engine has that defect. Perhaps a plain bearing with DOF will be more tolerant.

Of course it is run-out/vibration. That explain why early failures occurred more often than later ones :rolleyes:

If lubrication 'as per internet theories' then it would be fair to say that everyone's later 9X6 would have died by now. No?!

So.... if you've made it over 60k with your car chances are you'll be doing another 240miles without a hickup :cheers:

Except mine at 120k, and a few that have popped up recently in the PNW with similar mileage.

If have to admit that if I hadn't experienced this design "feature" failing I would probably share the opinion of others.

As it is I got to learn how to disect an M96 and put it back together and spend a few grand in parts and tools.

Sorry to hear man :/

That shaft not being a one piece-machined part, with chains flapping on it all day long, occasionally at above 5,000 RPM.... not sure about your knowledge RE rotor dynamics but I wouldn't look elsewhere for the root cause of the mighty IMS failure.

I've never seen a IMS mind you, however I can tell you that high speed shaft/rotors (>5krpm) ARE and should be machined "one-piece' for an effective and durable TIR. Truly poor of Porsche if they haven't.

** Certainly not caused by a lubrication design flaw otherwise, like I said, most if not all of the 9X6 would be dead today ** Just using common sense here

Again. sorry to hear it happened to you. Not saying that 60k is definitive "passed threshold" but sure you know what I mean by that.

Nine8Six

RE?

TIR?

I collect acronyms. Here.

Sure. Seen your work, pretty cool

RE: regarding
TIR: total indicated run-out


EDIT: Some others that I've recently used on this forum ;)

CFD: Computational fluid dynamics
CAE: Computer-aided engineering
CAD: Computer-aided design
CNC: Computer Numerical Control
GCODE: also RS-274, numerical control (NC) programming language

"Perhaps a plain bearing with DOF will be more tolerant. " You should patent that !

Haha. I think patents run out after 100+ years ;) Perhaps we can do the wheel next.

So what acronym should we use to describe the common IMSB failure caused by the seals deteriorating and allowing all the grease to escape but no splash oil can enter the bearing ?

Its "ICCL" (I couldn't care less)

Do this for fun mate: Run a shaft at 5,000rpm with 'only' 0.1mm run-out, now put a few chains on it to create even more noise, and run it in this condition for let's say 10hrs. Come back to let us know how your bearing seal look like after that.

In fact if it last 2hrs I'd be surprised.

Said 5,000rpm. Not idle at 1,100rpm

Try!!!

One of the contributory factors to IMSB failure is gentle driving - so say the experts.(not me ) So the rev/endurance test seems spurious .The bearings that do survive are generally the -- ones "driven like the Dr. intended" !
Jake has cited IMS run out as a cause of failure for some IMSB's on several forums and at some length in the past. He discovered this while repeatedly testing engines with a history of destroying IMSB's while developing The Solution - a lubricated plain bearing with I 'seal'. Up to that point, nobody had mentioned the run out idea.
Jake & JFP hint that the misalignment issue is not as frequent a cause of IMSB failure as seal deterioration and other causes IIRC. And those two guys have seen a lot of failed IMSB's (unlike you- none or I- I have 2 -so far)!
But you claim run out is the major(or only ?) cause of IMSB failure .
IMSB failure is usually rectified by a replacement bearing with only 1 seal fitted.No correction of run out is measured, made or is possible. Often ,in the case of the double row, the replacement bearing is the same load specification as the original bearing fitted at the Factory.
So , wouldn't these replacement bearings also fail repeatedly because nothing has been done to correct the alignment(Jake's experience).? Answer - it depends how bad the run out is.
If the issue is simply bearings that lost their grease through deteriorated seals and failed, that explains why most upgrade replacement IMSB with *2041RS do not fail ? Some, but not all IMSB kits have upgraded bearings .All have only 1 seal. So, the single seal seems a major part of the solution to the IMSB failure problem.
I am all for a disruptive discovery to upend the IMSB failure story. But your case has no new data nor any field results and does not refute accepted theories from those who have lots of data,experience,credibility and 'skin in the game.' And as you concede ,you've never seen an IMS .
But I am certainly open to persuasion that run out is the main cause. I understand that any source of vibration would 'hammer' the bearing.It might explain the success of the roller bearing kits?
The take home is that an upgraded bearing with just 1 seal (*2041RS) seem to be a generally successful solution . The 'repeat offenders' in the IMSB problem are so few we seldom hear about them. But the cars with slightly (define !) out of round problems may benefit from a higher load capacity bearing - like The Solution.
I have not seen a "Pre- Qualification Test" for out of round in any IMSB kit. Anyone seen this?

Thanks for your explanation. I have no doubt that our IMS industry experts have found the solution and that is; installing a big-arse-bullet-proof-bearing in place of the oem $20 NSK one.

You are spot on by saying that I have no field data nor experience in the matter. All I'm saying (speculating if you prefer) is based on common (general?) knowledge of rotor dynamics and shaft design/performance under torque and angular velocity.

A two-piece pressed fitted shaft (I think) + chains noise, seeing torque curves in the 1,000~5000rpm range?!? Castrol Gold Series Oil or not, if that shaft is not 99.9% precisely running true and balanced under these conditions, I guaranty you its end sides' bearing will fail prematurely. Well known, proven, any engineers would confirm this to you. Toss those bearings as many oil and grease as you want man, it just won't fix it - soon or later they'll eventually explode! I'm repeating this again: "explode".

^ and that is the reason why e.g. AMG, Lamborghini, Ferrari, etc, only utilize one-piece-machined shafts in their engines and run laser precision run-out/TIR + tests on those prior sealing this in their cases. Oh and I'm sure Rolls Royce (Boeing) does the same also, do fly with confidence LOL

The only chance you and I have in a cheap-production engineering problem like this one is to do what your experts recommends: installing a big-arse-bullet-proof-bearing and the problem is so-called solved

But like you said, what do I know! Its a Porsche we drive so all that is unimaginable, right? :D

Jake has a tool for measuring the trueness of the crank and IMS ports in the block that he will protect lest folks steal the design. He has been burned so he takes precautions. I forget if he is patenting it.

this seems like the right place to try to stir-up the hornet's nest.

As some of you may've noticed, I'm elbow-deep in a clutch job. I decided to do the IMS while I was in here, but now I'm 2nd-guessing myself. Help me think this through, will ya? haha

My car is an '03 S, with 148k miles on it. OF which I've only done about 2000 since acquiring it in March this year. I have no history on the car prior to my ownership. So without having so much as a hint of anything wrong with the IMS, I'm hesitant to throw another $800 into this project-creep that I have going on here.

I've found on Pelican's site, an IMS "update kit" for either single or dual row, priced at $189.. https://www.pelicanparts.com/cgi-bin/smart/more_info.cgi?pn=PEL-IMS-1&SuperCat=Y&SVSVSI=1052&catalog_description=Pelic an%20Parts%20M%39%36%20Intermediate%20Shaft%20Bear ing%20%28IMS%29%20Update%20Kit%2C%20for%20either%2 0Single%20or%20Dual%20Row%20IMS%20Bearing%2E

Does anyone have any experience with this? IS this a "good enough" option for u purposes?

The Pelican kit is simply a new OEM style bearing, so if you were worried about your factory bearing, you can also worry about this one as it is no different.

Considering the effort it takes to do the retrofit, why not use something better than you took out...…………...

See, this is the type of thinking that appeals to me. I always try to think of repairs or replacement of wear items as an opportunity to upgrade.
HOWEVER....
I got 148k miles on the factory unit.... so I'm somewhat loathe to "fix what ain't broke".... y'know?

I'm just not convinced yet that the $600 additional cost (the delta between the Pelican kit and the LN unit) is money well-spent.

Is there any merit to the thinking that the new unit is good for at least 20k miles? that's probably 4 years for me in this car. If I said I'm gonna replace it every 4 years.... I can get 16 years out of it before it equals the same cost as the LN unit.

::sigh:: I'm just trying hard to keep the scope-creep from spiraling out of control here. This car is fun because this car is CHEAP. if it ceases to be cheap, then it ceases to be fun.

here's the funny thing about my thinking: if you told me that I'd get 10hp out of the LN unit, or that it SOUNDS AWESOME.... I'd plunk down that additional $600 in a heaartbeat, hahahaha!

Here's the conundrum of using an OEM retrofit: The factory bearing has somewhere around a 10% failure rate; that could happen in the first 5K miles, or the last 5K miles of the next 100K miles. The OEM bearings failure time line is a scatter diagram, meaning some fail after only a short while, others much further down the road. What you do is totally dependent upon your personal risk tolerance, and willingness to do this all over again it 20K miles, or risk catastrophic engine damage, or spend the next couple years jumping at every odd sound the car makes. Unfortunately, peace of mind comes at a price.

My thinking is why use a bearing with the same materials as a original which is known to have a high failure rate.

At the same time, you can go broke trying to upgrade to replace every part that is known to fail.

The classic conundrum surrounding the maintain versus prevent question.

this. SO MUCH this.
great summary of precisely the issue behind my indecision.

Let me preface this by saying that much of what I trust about IMS related issues comes from posts by JFP and Mike Focke. If you have a lot of concern about the IMS bearing, get the "Solution" and be done. If you are replacing a bearing that has already exceeded 100k miles as maintenance and aren't constantly listening for the impending failure, the Pelican kit is probably a 'good enough' replacement. The bearing is same as stock, but it does have an improved center bolt.

My guess it that if it has made it this far on the original, the shaft is balanced and true enough to run another factory bearing until your next clutch change.

Me? ...I have a 99 on the original, one with an LN Ceramic, an '01 with the Pelican, and I think I'll put the solution in my '04 next year. How's that for decisiveness.

then consider engine failure due to ims as opportunity to upgrade to a bigger engine. my thinking, anyway. i can't justify going to 3.4 or 3.6 when i've got a perfectly good 3.2 in my car, but if it were to fail then i have a reason ...

Now you're speaking to me, haha.


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While I'm waiting on parts, I've been studying-up on the procedure.
I found this video tutorial, which seems to be very comprehensive. http://imsretrofit.com/ims-retrofit-procedure-overview/
However it leaves me with a couple of questions I hope y'all can help me with:

1. At about 1:52 in the video, they say "if locking camshafts on left and right cylinder head is desired, a specially modified camshaft locking tool is required". Does that mean it's OPTIONAL to lock left & right side? What am I missing here?
2. Is it absolutely necessary to remove the A/C compressor to do this job, as described at 2:22? I haven't heard anybody else say they've done this? Will I have to vent the system then?
3. Somebody explain to the dummy here (me) why it's necessary at all, to remove all of the tensioners and lock the cams? Is there really that much tension on the chains that they'd pull the shaft out of alignment with the bearing / bore when you remove that bearing? Is that what's going-on here? I mean, why I can't just pop the one out and the next one back in, the way all the rednecks on the other youtube videos do it?

Hit me, will ya? but don't be too harsh. :-)

thanks in advance.

OK, let’s start with the obvious: They are working with a 996 engine out of the car; so left and right are reversed. Because of the type of cam locking tool they are using, this is a three chain motor, which is more susceptible to jumping time than a five chain motor, so more care is advisable, and they are locking the cams on both sides. Realistically, if you are doing a five chain in a Boxster, you only need to lock the passenger’s side cam. Because the “off side” head on the M96 will line up the cams differently than the passenger’s side on a Boxster, you would need to modify the cam holding tool for that side on a three chain retrofit .

Because the 996 is a three chain, they are going full “belt and suspenders” to eliminate any chance of jumping time, including removing the chain tensioner under the AC compressor. If this was a five chain, this precautionary step is not required.

1. You only need to lock the right side on the 5 chain motor. Not sure if it is different on the three chain motor. The first IMS replacement that I did I locked both. The second time I followed the LN instructions (available online) and just locked the right side (bank 1).
2. I've done two IMS replacements in the last six months and have not removed the a/c compressor. The only reason I can think of to remove that would be to access the bank 2 chain tensioner. You can do it without removing the a/c compressor.
3. I have not tried to remove/replace the IMS bearing without removing the chain tensioners. I am guessing that if you don't you may find the IMS shaft being pulled to one side or the other and then not lining up with the engine case.

Thanks, JFP and DLUD. If I'm not mistaken, my '03 S (3.2L) is a 5 chain, correct?

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No.
5-chain: Boxster thru 2002; 996 Carrera thru 2001, 3-chain: Boxster 2003 and later; 996 Carrera 2002 and later

Not that I want to second guess JFP but I thought the 5 chain Boxster went to 2002, 911 to 2001 and then the 3 chain Boxster from 2003 and the 911 from 2002. I'm pretty sure my 03 S is a 3 chain.

You are correct; too much time out in the sun for an old man and I suffered a brain fart...….

5-chain: Boxster thru 2002; 996 Carrera thru 2001, 3-chain: Boxster 2003 and later; 996 Carrera 2002 and later

__________________

Ok.... so.... I'm back to (as you said aptly below) "full belt and suspenders"?

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That depends totally upon your risk adverseness, a lot of people, myself included, have done three chain engines with only one bank locked and the tensioner under the AC compressor in place. That call is yours...…..

thanks! ........