Can an IMS be avoided?

[Quickurt]

I had the same conversation with Brucelee.
At the RX8 forum the few guys that had problems freaked out everyone else to the point of my leaving the site, along with quite a few others. I went back a couple of months later to see if things got back to people having fun and talking about things they were doing to enjoy their cars.
I was sadly disappointed that the site had become a "********************ing Post" for those who were unhappy and Mazda was bending over backwards and replacing engines considerably out of warranty.
I'm not saying the problems should not be discussed or Porsche could not be doing more to cure the problem, but someone having 50k miles and 27 speed events calling Boxster motors playing the lotto is not exactly fair. I'm not picking anyone out, just the latest example.
The majority of Boxster owners will enjoy many years and thousands of miles with their cars, with little or no trouble.
My dealer says 8 out of 10 Boxster trade-ins have been for newer Boxsters. That says quite a bit to me.

[JCL12]

Originally Posted by Quickurt

I
I'm not saying the problems should not be discussed or Porsche could not be doing more to cure the problem, but someone having 50k miles and 27 speed events calling Boxster motors playing the lotto is not exactly fair. I'm not picking anyone out, just the latest example. .

Kurt...just to make sure I interpret the meaning of this correctly, you are trying to state that anybody who can get 50,000 regular miles out of their car AND 27 track/autoX events where they abuse the car like hell got their monies worth out of the engine?

[Brucelee]

Lets face it, no one has any real data and as such, this is real speculation on our part. Having said that, how many 50K plus cars should have to work about cratering an engine.

Again, my neighbor was sitting at a light when here IMS let loose. I can ASSURE you this woman did not abuse her box.

She has 12K miles on it.

Nuff said.

[ian wilkinson]

Here is my experience.
2003 Boxster S, 20K miles, purchased 7 monrhs ago from OPC with Poesche Warranty.

One night leaving a car park, heard a light metallic tingling for about 4 seconds whilst idling. Noise disappeared; continued on no problem. One day later; drove car no problem. Next day drove car no problem. Evening of next day; drove car say 300 yards, just entering my drive; car stalls. Starts car; hears the unmistakable terrible sound of marble in coffee can. Noise dissapears, drive for a couple of yards all seems normal.

Next morning looks under car; massive; massive mother of all oil leaks on my drive. Puts some oil in and it runs out like water from a tap! (from the connection between the engine and the g box).

Phones OPC car taken away on transporter. OPC says its IMS failure, no way of knowing when it will happen; its not really milage dependant just bad luck.
OPC replaces engine under warranty; this would have cost £12,000.00 to fix.


What can I say!!!

[chitowndad]

So what's the difference between the RMS and IMS? I'm familiar with the RMS (Rear Main Seal) which I believe is on the block behind the cams, correct? What exactly is the IMS and when it fails why do you have to replace the entire engine?

Thanks,

-Steve

[AddictionRacing]

Originally Posted by chitowndad

So what's the difference between the RMS and IMS? I'm familiar with the RMS (Rear Main Seal) which I believe is on the block behind the cams, correct? What exactly is the IMS and when it fails why do you have to replace the entire engine?

Thanks,

-Steve

The IMS is the intermediate shaft. Unlike RMS it's not a seal. My very basic understanding is that there is a ball bearing in the intermediate shaft that fails and as it fails it comes apart in tiny pieces of metal that you'll later find in your oil and oil filter. Some, like mine, are detected while the car still runs and theoretically you should be able to tear down the motor, replace the bearing and shaft, rebuild, and go on your merry way, but Porsche does not manufacture the replacement parts necessary. Porsche knows they messed up designing it and does not manufacture the identical bottom end any more. They've since upgraded to a larger bearing, which should be better. I hope this helps, and I'm sure others will chime in.

[Lil bastard]

The IMS drives the chains (2) which powers the camshafts (4). The bearing can fail outright, as mentioned, metal bits in the lube circuit, failed timing, etc.

But, it can also fail progressively allowing some flex to the shaft and it's chain sprockets. This flex imparts inconsistent tension on the chains which can then slip a few teeth on the sprockets. This throws off the mechanical timing creating poor running and/or allowing the valves on this 'interference' engine to 'shake hands' with the pistons and it's "Sayonara Motorsan!!"

The funny part is, this IMS issue started after Porsche redesigned the system after '02 to eliminate supposed vibration issues (and IMHO, make way for Variocam Plus). IMS is extremely uncommon on the earlier models, which are more prone to RMS failure due to their early generation seals.

[Quickurt]

Originally Posted by Brucelee

I can ASSURE you this woman did not abuse her box.

She has 12K miles on it.

Nuff said.

I spit coffee all over my keyboard!!

But in all seriousness, this woman has the right to call Boxster motors playing the lotto.
My long, drawn out points being, if you track a car, that is considered abuse, take responsibility for your actions, especially knowing what we know about the possibilities.

[Quickurt]

Originally Posted by JCL12

Kurt...just to make sure I interpret the meaning of this correctly, you are trying to state that anybody who can get 50,000 regular miles out of their car AND 27 track/autoX events where they abuse the car like hell got their monies worth out of the engine?

Yes, that is the gist of it. The car I quoted also has quite a few mods, like a gutted exhaust. How many times was the engine over-revved by someone trying to have a race car/street car combination, and how hard was it run for the 50k street miles? I would say it was not your grandfathers oldsmobile here.
In Formula Ford engines, if you over-rev to 7800 to 8000 rpm, (7000 rpm normal red-line) the crankshaft IS GOING TO BREAK. Period, end of story. It may break next race weekend, it may break in three weeks, it may break next lap, but it is going to break. If you over-rev a Toyota Formula Atlantic engine by 1000 to 1500 RPM, pop. Almost immediately.
What we don't know is what an over-rev may do to the IMS. Harmonic vibrations do weird things to metal parts. The rev-limiter in the Boxster may well protect the engine from an immediate handgrinade, but does it limit harmonic damage to all engine parts? The IMS is a ball bearing supported shaft, as I understand it, so you also have the harmonics of the ball bearings to consider. What shape is the IMS distorting to at 7700 RPM? I'd guess no-one who knows is saying........
Also, on a missed shift situation, especially on downshifts, the rev-limiter is incapable of limiting RPM. Does it take more than one of those to set up imminent failure of the IMS?
How much adreniline (SP?) is flowing at a track day event? I know I've missed shifts, even with tons of track time, it still happens. Part of the game.
What I'm saying is if you want to play, you have to pay. Problem is we don't know the exact bill before we do it. We always know the exact bill after the fact.
There's your lotto.