Well said...you have captured the essence of my thought process here

I know there has been so much discussion on IMS and everyone is probably tired of talking about it but I wanted to get some thoughts on a discussion I had with my local Porsche shop and well respected Porsche guy. .

With 200K miles, I asked him if he thought it was worth replacing the IMS. I had a engine failure at 36k in 2006 due to IMS and had a goodwill replacement engine that has gone 165K now. His shop charges $2700 to do the IMS and highly recommends it be done as he says engine failure are very common. His experience based opinion for dong the IMS was that engines were hard to come by now.

After looking at car-parts. com (thanks Boxsterra for the site reference), I noticed a lot of salvage yard engines available?:

MarkW's quote that there are 20+ other major things that can go wrong with the engine, so putting a lot of money into replacing IMS may not be worth it for a high mileage car resonated with me

Question - how much does it cost to take a salvage yard engine, do the Pedro IMS solution and update AOS, and other components, and install? Or is it worth just getting the IMS done.

BTW, this local indy had a lot of confidence in the LNS bearing, but I also am thinging about all the good work Pedro did in his study and IMS fix that might outlast the LNS bearing?

BarryL
2002 2.7 base, tip
Seal Grey, 200,635 miles
Santa Cruz, CA

bought a used motor
did an IMS (DOF was not available back then, now i would do DOF)
did water pump, coils, timing chain tensioners, a few other things all while out
Put it in
Did all fluids including transmission
all hoses, clamps, etc.

$6k ish in hgih priced land here in NJ (plus motor - this is for all the labor and incidentals)

Grant

Grant

gee-lenahan-at-gee-mail-dot-com

Grant

gee-lenahan-at-gee-mail-dot-com

Quote
BarryL
MarkW's quote that there are 20+ other major things that can go wrong with the engine, so putting a lot of money into replacing IMS may not be worth it for a high mileage car resonated with me

That is not what I said.

First a bit of background:

A noted Porsche engine builder has offered there are a number of failure modes for these engines. I do not know what number he is currently up to but "32" sounds about right. This is right and wrong. Right in that given a large enough population of engines a number of different failures will occur over time.

Given the engine builder is in the business and sees a number of sick engines I'm sure he has seen 32 different failure modes.

The more frequent ones, like IMSB, to the less frequent ones, like a failed crankshaft, all the way down to the one in a million failures. Essentially every critical compoent represents a potential failure point and with enough cars on the road then this just adds to the failure mode count.

But it is wrong in that the majority of engines do not suffer from any of these failures. Thus the "32" failure modes number is to me a bit of scare mongering.

And it was in this context, what I was referring to when I offered up the quote of the number of other major things that can go wrong is in some way when you take care of the #1 problem the #2 problem gets elevated to the #1 problem. Thus if one does go ahead with the IMSB upgrade there are still any number -- I think I said "32" not "20" but no matter -- of failure modes anyone of which can be as fatal to the engine as the IMSB.

But each owner has to decide what's his comfort level regarding risk and if he deems going ahead with an IMSB upgrade or even more upgrades to possibly/probably improve the odds at least the upgraded item(s) will not fail then that's the owner's call.

There are so many doom and gloomers I didn't want to get binned into that category.

...I don't think many folks did fixes on "possible" failures. When things broke, they were fixed. You can be chasing your tail. If you are influenced by reported failures on forums, we all need a water pump, shifter cables and an AOS in our trunks.

Then some other component would go TU.

I totally agree. I read and hear these tales of gloom and doom from engine builders. People who go to them come back with stories of supposedly common failure modes that i have never, ever even heard of. one friend, int he process of building a race 3.8L for his Cayman ( admittedly a costly starting point) wound up spending a total of about $45k on all the goodies. Heck, let it break!

I would do the chain tensioners, DOF (on a known good or new regular old bearing), water pump, and precious little else.

On a track car, ad deep sump is mandatory.
Uh-oh, now i have angered the M96 gods. Did i just hear my windshield crack ? :-)

Grant

Grant

gee-lenahan-at-gee-mail-dot-com

especially expensive items for which there is little or no statistical evidence on how often the problem you are thinking of fixing occurs or when in the engine's life it will occur, I have come to think that it is as much an emotional conclusion as a scientific one that informs the decision for most of us.

If there are 25+ failure modes that would take out an engine, why are we trying to fix one possibility and not another? What statistics do we have that would say you get more probability of success if you do the IMS rather than the lifters (just as an example)? Or for the same amount of money, are you better off doing some combination of others? Stats we don't have. Anecdotes and opinions formed by some experiences but no stats.

Risk tolerance is a personality trait. And ability to afford what may happen is another factor.

You are driving a 14 year old car with 200k miles on it. Economic reasons or sentiment? Gonna keep it forever or is there the probability of some life cycle event causing a sale?

How would I feel if I did it and crashed the car 1 week later? Insurance won't pay any more. How would I feel if I didn't do it and the engine blew up for any reason or even that reason? My decision might be right for me and different than the one right for you.

These thoughts echo MarkW's last paragraph "But each owner has to decide what's his comfort level regarding risk and if he deems going ahead with an IMSB upgrade or even more upgrades to possibly/probably improve the odds at least the upgraded item(s) will not fail then that's the owner's call."

Good luck with YOUR decision.

With Pedro's help, I gained some additional information that has provided more clarification for me....

My goodwill replacement was done in November 2006. I don't have conclusive evidence, but I understand that crate engines from that time might have incorporated the latest IMS bearing, which would mean there is a good chance I have the bigger single bearing version that cannot be replaced 987? without engine teardown. There are ways to find out with a greater degree of confidence, but I would have to remove the Tiptronic transmission to get a visual of the size nut on the IMS, ect. Now, seems like best action forward is to ride it out.

BarryL
2002 2.7 tip
Seal Grey, 200K
Santa Cruz, CA