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YOUR RESEARCHStop Hearing About IMS Failures
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I checked for damage to the old one and it was fine.
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These 3 cars were just transported to our facility on the same truck to be repaired/upgraded..
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For my engine purchasers I require the water pump be changed every 3 years, no matter what pump is used.
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I replaced my water pump when I dropped the engine for the IMS upgrade and all the other stuff, and the new impeller was metal.
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And that's why I replaced my water pump last year when I did the IMS bearing, RMS, tensioners pads, tensioners, AOS, and clutch.
Check rennlist there's a new topic about the ims/rms
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It seems like every time I check Rennlist there's a new topic about the IMS/RMS, so it was funny to see someone asking why they don't see more discussion about it.
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Failed at 51K miles, cost of repair 18K (entire engine compromised due to consequential failures from severe intermix) customer chose my fully upgraded engine as a replacement
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Pic 2= 2001 996 Failed at 34K miles, cost of repair 8,500.00 (engine compromised due to secondary rod bearing failure from intermixed oil) buyer went with our CPO engine program
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When carrying out comparative flow work on the flow bench one is able to see that Porsche greatly altered the intake/ exhaust flow ratios as the engine evolved from the 3.4 to the 3.6 and into the 3.8 and the changes aren't what you'd expect.
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Is it me or have you guys heard much of anything about IMS failures lately. It seemed for a long time there, the IMS was the main topic in this and other Porsche Forums. It is neither not happening as much or people are not reporting the IMS failures. What is your take?
I think as the aftermarket figures out fixes for these common failures we should see less and less of these issues surface. Perhaps its too early to see the results of these fixes but I for one am happy to see the educated owners partake in these updates which should allow one to enjoy these cars with only the odd minor issue.
"Say, why's Jim holding a stick?"
"I don't know... is that a dead horse he's walking towards?"
"Yes, I think it is... Wait, what's he doing? Holy crap, why's he beating that dead horse??"
"Hell if I know..."
To our friend in Baghdad, jfr wertheimber, I get the dead horse analogy. But really want to take the time and THANK YOU for your service to our country in Iraq. Be safe and come home well to your Porsche very soon.
Whats killing the M96 powered cars at the moment are cracked heads...
See this image? These 3 cars were just transported to our facility on the same truck to be repaired/upgraded.. They came from Ohio, Kentucky and Tennessee.
All 3 of them have the same symptoms, and the same mode of failure. Its started at the water pump on at least two of the three cars that we have already diagnosed. Look for an article on this mode of failure soon in Excellence.
So far this week I've only received two IMS failure calls, one from Arizona and another from California.
Jake,
How common are the cracked heads compared to IMS? Must be a convertible thing.... lol
That boxter's front bumper looks awfully close to that ramp...
I don't post any percentages, the actual numbers can't be quantified.
These are 3 cars coming in on one truck all with the same issue. We didn't see these failures at this rate until the Spring of this year, as water pumps aged due to time in service (not mileage) and their impellers began to fail. The failed impellers found a capillary within the cylinder head, which created a hot spot which developed a crack.
The good thing is this MOF is very easy to address and cheap, just requiring a water pump to be proactively installed. When the old pump is removed and visually inspected a cooling system flush may be necessary if one of the impeller blades is found broken. This piece of broken impeller is whats doing the damage thats leading to cracked heads, so it must be removed. If not the impeller will continue floating around in the coolant until it forces a failure even after the pump has been replaced!
Here are some examples of what a failed pump can cause..
Pic 1= 2000 Boxster S. Failed at 51K miles, cost of repair 18K (entire engine compromised due to consequential failures from severe intermix) customer chose my fully upgraded engine as a replacement
Pic 2= 2001 996 Failed at 34K miles, cost of repair 8,500.00 (engine compromised due to secondary rod bearing failure from intermixed oil) buyer went with our CPO engine program
Pic 3= 2001 Boxster failed at 18K miles, cost of repair 7,000.00 (we were able to save this one with crack repair and some effort)
Yes.. What I am seeing supports the fact that the water pumps can fail in 2-3 different ways and it isn't mileage related..
Every M96 on the road is old enough to need the water pump replaced to avoid ending up on that same truck that delivered those 3 cars to me earlier this morning.
BTW- Two of those are dead, the third one was dead before it arrived with D chunk failure.
I feel like the IMS threads are directly related to waves of new and prospective owners, especially since the economic downturn and the very low prices on early 996s we've had a lot of new people coming through all the Porsche forums, and they needed to go hrough the same cycle that any new or prospective internet savvy watercooled Porsche owner goes through:
1. OMG these cars are a a great deal. Does anyone have 84 month financing for these cars?
2. OMG do they all blow up? 99s? 00s? are Mk2s safe? Do 997s blow up? What about 997.2s? Should I buy an M3/Corvette/Honda?
3. Wait, Will my car blow up? I should bump some 3 year old 3rd party warranty threads.
4. Let me create new threads on topics which have been beaten to death and revive 5 year old threads just so they can be beaten to death by a new set of people:
5. Who want to do surveys;
6. File class action law suits;
7. and speculate on the effectiveness of various preventative maintenance measures;
8. only to do nothing about it at all, eventually just changing the oil and driving the car happily like the rest of us.
BTW Jake how on earth did it make more sense for your 2000 boxster S guy to pay 18K for a new motor instead of selling his roller to a spec racer for say 8-10K and picking up a used boxster S for <20? That seems like a very confusing situation to be in.
Hey Jim, thanks for the props, I hope you know I was just having some fun with you... It seems like every time I check Rennlist there's a new topic about the IMS/RMS, so it was funny to see someone asking why they don't see more discussion about it.
Jake, I know you recommend replacing the water pump; do you recommend the Porsche OEM pump, or another brand?
Must admit, Baghdad was a lot more fun back when we actually had external enemies to fight, rather than all the political infighting that's going on now...
He was a classic Porsche owner.. To him the car wasn't a car, it was part of his lifestyle and he planned on keeping it forever. Due to this the amount of money required to achieve absolute reliability and longevity didn't matter. What made it easier for him to swallow was the fact that my version of the engine made 40HP and 55 lb/ft more torque than his stock 3.2. He is a DE driver and that power and reliability was very much worth it.
The one thing that EVERYONE who buys a fully upgraded engine from me shares is the desire to keep their car forever, thats why you never see cars for sale that have my fully upgraded engines installed.
I am the same way, the things related to my Porsches (and even old VWs) come at a cost but that cost is just the amount I have to write on the check.
IF I were running a porsche forum I'd have snubjects like IMS automaticly transfered to a repair section.
How come I never see an IMS failure on the tv show I Can't Believe I Survived?
They need to create a forum section named "If you just bought a 996, read this before your post in the adult forum" and stash all the IMS threads, etc in there..
The big caveat to the steel impeller is the fact that a bad water pump bearing will allow the steel impeller to contact the crankcase and destroy it..
In that situation going to an "overkill" impeller may solve impeller failure issues at the risk of total engine loss if the water pump bearing fails.
Sounds like you have problems either way if the bearing goes. It's a matter of when you would catch it.
I replaced my water pump when I dropped the engine for the IMS upgrade and all the other stuff, and the new impeller was metal. I checked for damage to the old one and it was fine. I just plan on replacing it every 50K. (I'm already 1/5 of the way there)
Are the OEM replacements plastic or metal?
We could use electric water pumps or have a screen to catch the plastic impeller pieces.
Electric water pumps won't work with an M96 due to the design of the jackets surrounding the water pump. We tried this 3-4 years ago with no luck.
Yet again, do not use a mileage point for a service point for the water pump.. Time in service dictates everything. Whether or not the engine is running, the impeller is exposed to coolant 24/7-365 and that time is what makes the impellers brittle and leads to the issues.
For my engine purchasers I require the water pump be changed every 3 years, no matter what pump is used. We had thought about building our own billet impellers from stainless steel, but the liability related to losing a pump bearing and that impeller wiping out an engine was simply too great.. When things go south people like to point fingers and I'd rather not even offer something as give that a possibility of occurring.
[QUOTE=Jake Raby;8028896]
Yet again, do not use a mileage point for a service point for the water pump.. Time in service dictates everything. Whether or not the engine is running,
the impeller is exposed to coolant 24/7-365 and that time is what makes the impellers brittle and leads to the issues.
For my engine purchasers I require the water pump be changed every 3 years, no matter what pump is used. QUOTE]
But this doesn't apply to metal impellers. I would think once the seal starts to fail, the bearing follows. 3yrs sounds pretty safe.
(I replaced the water pump on the 996 @ 100k, and based on my research it was original. I also replaced the WP on my Benz recently, 12 yrs old, 150k+ mi, still in great shape- go figure. Both DD)
I'd rather hear about some company that does a good rebuild of engines with performance parts.
Like mentioned sticking to the sticky would be sufficient for the crowd here instead of waking up the cackling chickens so to speak.
As with many of "these" threads.....I see both sides, one being replace and the other to leave well enough alone.......Im confused...
It seems with these cars there are no constants and results vary with each car......kinda like women. Opps did I say that outloud.
:-)
That used to be our priority.. Now things have changed to "failure control"..Now the only thing we build "New" engine wise are big bore performance engines.. We don't have time for the simple stuff anymore, too busy doing update procedures and repairs.
I figure you do port and polish heads. Do you have any good designs for flowing the head? Have you ever experimented with heart shaped and such at valves openings or is there even room for it in the 4 valve heads? Any better injection system with secondary injectors closer to the head intake for heavy throttle inputs? I just have to figure the stock intake could be made better.
pac996,
Yes, we have learned a ton about the port designs used in the various models of the M96 engine. Along the way we have learned that its very easy to upset the critical balance between the intake and exhaust ports margin wise by just doing port work.
When carrying out comparative flow work on the flow bench one is able to see that Porsche greatly altered the intake/ exhaust flow ratios as the engine evolved from the 3.4 to the 3.6 and into the 3.8 and the changes aren't what you'd expect. When you compare these to the values from an X51 head and consider camshaft differences lots can also be learned.
What I have learned first hand is that the majority of port enlargement is not necessary and will actually impair port dynamics, especially in port velocity. Simply making ports larger is a common mistake made by those who haven't gathered the required data from both the flow bench and the dyno and coupled that to the results of the stop watch before and after enhancements are made.
Due to this my port arrangements are much milder than others, I capitalize on port velocity and chamber filling, especially at lower engine speeds as this enhances every aspect of the engine.
In summary, stay away from big ports, because your 4 valve heads don't need them, even with bore sizes as large as 8mm over stock, we don't see the need for super sized ports, even on race engines.
Very slight alterations to the short side of the intake port along with slight port polishing is all thats necessary to make the heads perform at the next level. These changes don't effect the port balance but they will give solid gains on the flow bench that increases port velocity and those changes will be evident on the dyno and at the track, or even on the street.
Bigger isn't better.
BTW- The fuel injector location in the M96 engine is already less than 2" from the intake valve, perfectly positioned.. Its as far down the intake tract as possible in stock form.
There are lots of performance characteristics of the M96 that are exceptional. Unfortunately to benefit from these one must recreate the engine to be more reliable first.
The M96 is a great foundation, once the problem areas are addressed. If this wasn't true we'd not be using the M96 foundation to build our engines from.
Good thread & good discussion. Thanks for the engine photos, Jake. Nothing like a "visual" to put the proper perspective on a problem.
The water pump/block damage issue (metal vs. non-metal) is not unique to the 996 by any means, but it is great that it has been identified as an item requiring attention during a scheduled maintenance program.
Porsche has an interesting and somewhat problematic history with water pumps.
Good advice from Jake.
The bike industry, specificly the superbike is getting 200hp out of 1 liter engines. One of the newer tricks they are using is injectors that so to say super fog the fuel. Might be something if those style of jets could be adapted to the 911.
In an effort to keep the conversation fresh around this subject, I have taken the liberty of putting AOS, IMS, RMS and MAFS into an anagram generator. I like "Farm *** Is Moms", but you can take your pick.
http://wordsmith.org/anagram/anagram...afs&t=1000&a=n
