996/7 IMS Failure

[Kelly]

My 98 Carrera 2 suffered the IMS failure a few years back under a different owner, and the car came with a fairly hefty Porsche Centre Melbourne receipt for the replacement engine.

 

A recent service at an Independent said that was no guarantee that this engine would not suffer the same from the same problem.

 

Now I am baffled; would PCM replace an engine yet not fix the fault with the new one, or was the independent trying to make more work for himself (which I find hard to believe given the other things he said I did not have to do just yet)?

 

Is there an easy way of telling whether the upgrade has been done without taking the car to someone for yet another opinion?

The engine fitted by PCM would be with a standard Porsche bearing, hence subject to the same potential failure.

 

You won't be able to tell if it has an aftermarket bearing from an external inspection.

[Broadsword]

The engine fitted by PCM would be with a standard Porsche bearing, hence subject to the same potential failure.

 

You won't be able to tell if it has an aftermarket bearing from an external inspection.

So PA's policy was to charge a significant sum for a new engine that did not even address the fault that caused the first one to fail?

That is appalling.

Interesting; when I had a PPI carried out, the car was on the hoist and they noted it had a new engine immediately and that I did not have to worry about the IMS issue.

[withers]

So PA's policy was to charge a significant sum for a new engine that did not even address the fault that caused the first one to fail?

That is appalling.

Interesting; when I had a PPI carried out, the car was on the hoist and they noted it had a new engine immediately and that I did not have to worry about the IMS issue.

 

I feel your pain Broadsword

 

Here's hoping you have absolutely nothing to be concerned about.

[Broadsword]

Hmmm,

 

Found the receipt and the replacement engine was fitted in June 2009, but no reference in the itemised summary as to whether or not this included single row or double row bearing.

 

By 2009 they should have known better though, surely?

 

Could be an excuse for a visit to East Melbourne perhaps?

[Coastr]

Hmmm,

 

Found the receipt and the replacement engine was fitted in June 2009, but no reference in the itemised summary as to whether or not this included single row or double row bearing.

 

By 2009 they should have known better though, surely?

 

Could be an excuse for a visit to East Melbourne perhaps?

 

if you read the class action thread they basically ignored the problem for ten years.

 

In your case i would be assuming it has the potential to go.  Porsche have not issued a technical retrofit.

[Russ]

and based on the options available in 2009 it's probably time to change the bearing again anyway (based on the pelican kit that they suggest changing every clutch change)

[Orion03]

and here's me resurrecting an old thread....

 

Is the later model 997, with the large single bearing, much better from the IMS bearing point of view?

 

Pro: less likely to have issues

Con: but you can't swap in the IMS Solution bearing system.

 

It seems like the early 997's i.e. the small single bearing M96/97 are the most likely to break?

[JustJames]

and here's me resurrecting an old thread....

Pffftttt! It's three weeks since the previous post. 'Round here we need at least a year for it to count as a resurrection.

 

Is the later model 997, with the large single bearing, much better from the IMS bearing point of view?

Yes it is.

Pro: less likely to have issues

Con: but you can't swap in the IMS Solution bearing system.

Con: You can't swap the bearing easily.

Pro: You don't need to.

It seems like the early 997's i.e. the small single bearing M96/97 are the most likely to break?

Correct. The early 9x7 cars (Boxsters as well as Carreras) had M96 engines.

On a related note, early 9x7 cars also used the brakes that were left over at the end of 9x6 production. For those early cars, the only way to check which brakes were used is to take a look.

[SteamWolf]

Hi all,

I have been doing Preventive Maintenance Optimisation studies for a rail company recently, and a big part of it has been on bearings. This has been quite interesting and can be applied to the IMS issue (Even though I realise this wasn't the cause of WhipIt's engine failure).

 

A bearing operating within its load and speed tolerances if lubricated appropriately will effectively never wear out (ok, it will, but we're talking millions of hours).

 

Things that cause bearings to fail are

• lack of lubrication,
• Impacts,
• Foreign particles,
• overspeed/overload,
• corrosion, and
• Electrical arcing (such as someone welding something and the bearing being in the electrical path back to ground).

There's two things to note here.

1. bearings DO NOT just suddenly fail.  They go noisy until they eventually disintegrate.
2. the only failure modes listed above that can realistically apply to the Porsche is lack of lubrication (sealed bearings) and corrosion.

 

What we have found with rail wagons is the primary cause of brunelling started out as corrosion.  Corrosion is caused by water ingress of course, and moisture can eventually find its way inside a bearing simply by age (thermal changes drawing in moisture out of the air past the seals). 

The primary cause of this turning into corrosion was wagons sitting around not being utilised.  That tiny bead of moisture will collect at the bottom and then cause pitting on the bearing running surface.  When it starts getting used again, that pit turns into brunelling.

 

What this means for the poor old 996 is that low K cars that sit around not getting driven every day may be drawing in moisture into the IMS bearing and causing pitting on the bearing surface. This would explain why well used cars don't seem to be failing.

 

It also means that with a stethoscope you should be able to listen and tell right away if the bearing is showing signs of failure.

[tazzieman]

 

It also means that with a stethoscope you should be able to listen and tell right away if the bearing is showing signs of failure.

 

[SteamWolf]

You are a strange man, Tassieman.

 

[withers]

Very interesting info thanks Steamwolf. Makes me feel good about dropping $3500 on the IMS Solution. I have a car that hasn't been driven a lot and won't get driven a lot! So by removing the ball bearings from the equation and adding a externally lubricated replacement with no moving parts - surely this has addressed the root cause of this issue??

Is it possible that the original bearings P used were faulty or not lubricated correctly during installation?

Also, driving with the revs under 2500RPM is that considered 'overload' ? Or are we talking red lining the engine during say downshift?

[SteamWolf]

I'm not familiar with the specific bearing used (if someone has the make and part number I can look up the recommended life and load ratings) but I doubt it's undersized for the application.  It may simply be a bearing that had the wrong type of seal for the application, or that the environment it lives in is a bit too hostile for it (clutch dust/water pooling/heat rating of the seal material etc).

 

"Overload" is where a bearing may be rated for a certain amount of force which is exceeded in application. A bearing rated to carry say 100nm of load at 20,000rpm can be considered to be overloaded if it's carrying 200nm of load and doing 20,000rpm (but may be fine at 200nm of load if it's only dpoing 10,000rpm).

 

"Overspeed" is where the bearing is rated to run at a certain speed, with a certain load and again this is exceeded.  A bearing rated to carry say 100nm of load at 20,000rpm can be considered to be oversped if it's carrying 100nm of load and doing 40,000rpm (but may be fine at 40,000rpm if it's only carrying 50nm of load).

 

It really depends on what sort of bearing it is, how it's rated by the OEM and the application it's used in. Would love to know the part number so i can have a dig around.

 

 

Removing the roller bearing for a friction bearing should eliminate that problem for sure, as long as the friction bearing replacing it is lubricated appropriately and doesn't have any flaws in its use.  These sorts of bearings have been used in camshafts and bottom ends since Tassieman was a boy ( ) so I doubt it will ever be a problem again.

[Orion03]

My 2 cents on this,

 

1) it's a sealed roller bearing ... but boy talk about a harsh environment, hot oil splashed onto the seals all the time, Hot and Cold repetitions, water getting sucked into the system etc. Gee I wonder how much of the grease is left in the bearing after a while. Didn't think those seals were rated for hot engine oil immersion.

 

2) during my surfing on the internet I've come across a statement that the original bearings were too thin in the shells and had porosity issues leading to engine oil washing away all the grease .... can't proof this of course, joins all the many internet theories.

 

3) load on the IMS .. it's the shaft that runs the oil pump and the cam chain .... really the loads come from the cams and from the oil pump. only right? Perhaps the CAM load on the bearings are higher when the RPM is low? all those CAM lobes slowly opening the valves? it'll be less force at speed right?

 

Anyway it's an issue, and seems to be related to how often you drive the car so fitting an IMS solution seems to be a good way to go. Have to watch out when I look at low km cars. depends on how hot they get the engine when it's actually driven, short trips to the local shops and back will be the worse.

 

sitting in the garage then going for a few hundred km drive on the weekends would be okay I am guessing. Get the oil nice and HOT, get the moisture out.

 

On the good side it's driving cost of 997's down really quick .... so I can afford to get one and just include the cost of the IMS solution into the budget.

[tazzieman]

You are a strange man, Tassieman.

 

 

 

You might be surprised to know that I am trained to use a real stethoscope as well.

Mitral stenosis.

[SteamWolf]

Interesting!

Still wish I hadn't googled it tho

[withers]

Thanks Steamwolf. It's all a bit over my head at the end of the day! I think I might have absorbed all I can at this point

[SteveF]

Looks like the monkey on the right just had his bearing fail!

[Niko]

You might be surprised to know that I am trained to use a real stethoscope as well.

Mitral stenosis.

[Niko]

Just to sort of add to this conversation, I wanted to find out if the retrofitted LN bearing I had done, was a single or double row bearing.

I emailed across to LN ENGINEERING, with the serial number of the bearing fitted to my car.

 

A disappointing answer from them was that they don't keep records of what model bearing the serial number relates to.   WTF?

Why bother giving them a serial number then.....

 

I can obviously ask JOCARO who fitted it, which I will next time I am there but wouldn't you think the people making the retrofit bearings would like to keep records of what they sell in case of any failures in future..

[SteamWolf]

Niko, from what I have read I thought all the LN roller brearing retrofits were double row?

[Russ]

Looks like the monkey on the right just had his bearing fail!

 

they didn't warm the stethoscope before they put it on him!

[Orion03]

There are many types, from single ceramics to triple row to the plain IMS solution.

[Niko]

Niko, from what I have read I thought all the LN roller brearing retrofits were double row?

Hi Jim , no apparently as ORION says there were different types used, have to admit I only thought it was single and double row, to hear there are triple row also is a surprise to me.   There seems to be a fair bit of conjecture as well in regard to which replacement bearing is the better.    

 

I have given up, I replaced it and no matter which one is in it, I would hope it should never be a problem again.....If in the future it goes BANG then so be it..

 

This whole IMS thing is a real bummer, and lets the Porsche name down badly.

In the future are we going to hear that the newest fix the IMS SOLUTION also has a flaw???

Can we look forward to the Solution for the IMS Solution

It just goes on and on...

[withers]

Hi Jim , no apparently as ORION says there were different types used, have to admit I only thought it was single and double row, to hear there are triple row also is a surprise to me. There seems to be a fair bit of conjecture as well in regard to which replacement bearing is the better.

I have given up, I replaced it and no matter which one is in it, I would hope it should never be a problem again.....If in the future it goes BANG then so be it..

This whole IMS thing is a real bummer, and lets the Porsche name down badly.

In the future are we going to hear that the newest fix the IMS SOLUTION also has a flaw???

Can we look forward to the Solution for the IMS Solution

It just goes on and on...

Oh don't say that!

So far my car has been in 3 days. The bearing is in. But the oil filter is turning a half turn more than it should. This means the hose fitting is sitting further away and the fittings no longer fit!!

So they are trying to sort this out. All the other cars they fitted were 986s. So seems come thing is different on the 987. They have gone to LN Engineering for assistance.

Sigh

The single row bearing has the highest failure rate both with the OEM and even with the ceramic LN Engineering retrofit.