IMS Fix

[flaps10]

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.

[Gelbster]

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 :-).

[356Guy]

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.

[Nine8Six]

Originally Posted by 356Guy

If you think its a runout/vibration issue then they are all temporary fixes if your engine has that defect.

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

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

[Gelbster]

Originally Posted by 356Guy

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.

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

[356Guy]

Originally Posted by Gelbster

"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.

[flaps10]

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.

[Nine8Six]

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.

[Gelbster]

Originally Posted by Nine8Six

I've never seen a IMS mind you,..........
** Certainly not caused by a lubrication design flaw .

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 ?

[Nine8Six]

Originally Posted by Gelbster

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!!!

[Gelbster]

Originally Posted by Nine8Six

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?

[mikefocke]

Nine8Six

RE?

TIR?

I collect acronyms. Here.

[Nine8Six]

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

[mikefocke]

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.

[maytag]

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

Sent from my SM-G930T using Tapatalk

[JFP in PA]

Originally Posted by maytag

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

Sent from my SM-G930T using Tapatalk

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

[paulofto]

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.

[JFP in PA]

Originally Posted by paulofto

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

__________________

[maytag]

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

Sent from my SM-G930T using Tapatalk

[JFP in PA]

Originally Posted by maytag

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

Sent from my SM-G930T using Tapatalk

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...…..