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I purchased a 1999 996 Cab from my Dad. He was second owner. He had an issue with a porous engine block and used his extended warranty to replace the engine. The replacement engine was installed at 46199 miles in 2009 with a " 3.4L - 01 Carrera MAN" engine ($13196.50). What are the odds that this new engine had an upgraded IMS? The car now has 78900 miles. SO only 32k miles on this engine. Should I worry about it? I drive the car pretty hard. Any opinions are appreciated.
The consensus is that replacement engines built after ‘05 have the large single row IMS bearing. The only way to know for sure is to open it up to look at the flange. If it is the large bearing, the recommendation is to remove the grease seal that you can access by removing the flange...
I purchased a 1999 996 Cab from my Dad. He was second owner. He had an issue with a porous engine block and used his extended warranty to replace the engine. The replacement engine was installed at 46199 miles in 2009 with a " 3.4L - 01 Carrera MAN" engine ($13196.50). What are the odds that this new engine had an upgraded IMS? The car now has 78900 miles. SO only 32k miles on this engine. Should I worry about it? I drive the car pretty hard. Any opinions are appreciated.
Drive it often and keep those revs up. Change your oil every 6 months or 3000 -4000 miles.
When it's time to do your clutch verify what bearing you have and pull the grease seal if it's the latest big bearing. If not retro-fit with the LN Solution.
As they say "If it's not broken, don't fix it"....or google 'bathtub curve' to understand statistically how to think about it.
You should start following our series on IMS bearing failure. The original owner of this 29,000 mile 996 thought in the same manner. Now he's the one that "took a bath".
You should start following our series on IMS bearing failure. The original owner of this 29,000 mile 996 thought in the same manner. Now he's the one that "took a bath".
If you read everything I wrote you can see I answered the question what to do if you inspect the bearing and it's in perfect condition: replace or leave? In that case you don't try to fix something which is not broken. I guess in your case the owner never did the inspection (as I recommend to do) at all...
If you read everything I wrote you can see I answered the question what to do if you inspect the bearing and it's in perfect condition: replace or leave? In that case you don't try to fix something which is not broken. I guess in your case the owner never did the inspection (as I recommend to do) at all...
I did read what you said
"As they say "If it's not broken, don't fix it"..
As we say, "if it isn't broken, it will be."
A bearing inspection is fairly worthless. When you look at the bearing you are seeing a visual snapshot of how the bearing looks today. You are spending almost as much time to access the bearing for the visual inspection, as it takes to perform some form of IMS Retrofit. The difference is you look at it, think it's good, then expect it to "last a million miles" just because it was "good" today.
It doesn't work like that. Nothing mechanical ever has, or ever will. The only guarantee with anything mechanical is:
-It will wear out
-If it doesn't fail first.
A bearing inspection is fairly worthless. When you look at the bearing you are seeing a visual snapshot of how the bearing looks today. You are spending almost as much time to access the bearing for the visual inspection, as it takes to perform some form of IMS Retrofit. The difference is you look at it, think it's good, then expect it to "last a million miles" just because it was "good" today.
It doesn't work like that. Nothing mechanical ever has, or ever will. The only guarantee with anything mechanical is:
-It will wear out
-If it doesn't fail first.
This is another example of fact over fear.
"A bearing inspection is fairly worthless" - said by NO ONE except you.
Ok mr.expert, If you ever worked (or studied) how to achieve highest possible reliability you would understand this. I mean, why not go ahead and replace everything in your way because it 'looks' good right now but of corse it will fail....every bolt on the car.
Please, read up and study the subject. Aviation literature is a good place to find this information. If you just want fast information, search for "southwest flight 1380" and read about the accident and how they handled the case. Inspection before replacement, always(this goes for 'things' which fail before they time out). Don't just go bluntly replacing this stuff.
And there is more than one example on this forum of aftermarket IMS bearings which have failed and killed the engine. Pulling a perfectly fine bearing and then have the replacement fail and kill the engine. And there is also examples of IMS bearing installations going **** because of inexperienced installers. IMS replacement/retrofit fails also, usually way before the original solution.
"A bearing inspection is fairly worthless" - said by NO ONE except you.
Ok mr.expert, If you ever worked (or studied) how to achieve highest possible reliability you would understand this. I mean, why not go ahead and replace everything in your way because it 'looks' good right now but of corse it will fail....every bolt on the car.
Please, read up and study the subject. Aviation literature is a good place to find this information. If you just want fast information, search for "southwest flight 1380" and read about the accident and how they handled the case. Inspection before replacement, always(this goes for 'things' which fail before they time out). Don't just go bluntly replacing this stuff.
And there is more than one example on this forum of aftermarket IMS bearings which have failed and killed the engine. Pulling a perfectly fine bearing and then have the replacement fail and kill the engine. And there is also examples of IMS bearing installations going **** because of inexperienced installers. IMS replacement/retrofit fails also, usually way before the original solution.
I'm sorry, but a bearing inspection is indeed worthless.
There is no way you can inspect the ***** and races and quantify the wear in any meaningful manner. Pulling the bearing would also render the bearing useless.
If you are paying someone to pull the transmission and go that deep, why not replace it? If you don't want to treat the IMS bearing as a wear item, just put an IMS Solution in it and be done with it. Just matters how you value your time and what your labor costs are.
Jake worked on aircraft in the military (and still volunteers his time to work on them), so yes, he knows some about aircraft.
Last edited by Charles Navarro; 08-05-2020 at 04:50 PM.
Reason: Typo
"A bearing inspection is fairly worthless" - said by NO ONE except you.
If the bearing could be inspected in 5 minutes, and didn't require all the same labor to inspect, as it does to replace (except the extraction/ insertion steps) then it would be a different story. The fact is that the biggest costs with the IMSR procedure are found in the labor to remove, and replace the gearbox, the clutch, the flywheel, and to make sure the engine is properly positioned to allow for safe removal of the IMS Bearing flange. All of these steps are THE SAME whether you are inspecting a bearing, or replacing it.
Ok mr.expert, If you ever worked (or studied) how to achieve highest possible reliability you would understand this. I mean, why not go ahead and replace everything in your way because it 'looks' good right now but of corse it will fail....every bolt on the car.
You called me the Expert, but I'll correct you. Experts have stopped learning, so I'm no expert. Every day is a school day. That said, there has to be a place where you stop replacing components, but that isn't something that pertains to the most problematic component for an entire family of engines.
Please, read up and study the subject. Aviation literature is a good place to find this information. If you just want fast information, search for "southwest flight 1380" and read about the accident and how they handled the case. Inspection before replacement, always(this goes for 'things' which fail before they time out). Don't just go bluntly replacing this stuff.
As a US Marine I crewed and maintained CH46 Helicopters. I worked Flightline, and my job was the drive systems of the aircraft, this included turbine engines, gearboxes, rotor heads, and based- you name it.
It's funny that you mention aviation, because its pretty clear that all you've done is read about it. If you were trained the way I was, and had my experiences, you'd have a completely different mindset, and understanding of aviation maintenance. With aviation, if it is "High time" it is replaced whether it is good, or bad. If the application/ environment is more demanding, the service life can be cut in half from an hourly perspective.
Components are serialized, and they are removed and either rebuilt, or thrown away at certain hour milestones. This does not matter whether these components are good, or bad- they are "high time" and therefore must be removed, and replaced, or removed and discarded. As an example a gearbox that has perfect mag plug checks, and has never tossed a chip light is still removed at a defined interval, and sent to overhaul. With your mindset someone should just look at it, and make sure "its ok", then when the aircraft falls out of the sky, you learn why components have service lives measured in hours. Have you ever had a scenario where one of your friends ate breakfast with you, but you didn't see him for dinner because he fell out of the sky? I have, and it sucks, especially when you had worked on that aircraft a few days before.
Today I am a Crewchief for an organization that keeps Vietnam era helicopters flying, so we can keep a legacy from being forgotten. We throw typical civilians in 50 year old aircraft and take them for what is typically the ride of their lives. I use my mind set, and experiences to keep these people alive, so there's no need to explain to me what you've learned in your freaking "aviation literature" regarding safety, and component replacement In regard to components used in aviation applications. My 8 year old daughter goes flying with us, and she has learned this discipline as we work together on projects with Hueys, and Cobra's.
And there is more than one example on this forum of aftermarket IMS bearings which have failed and killed the engine.
Yep, and behind each one of those you will see the "holes in the Swiss cheese" align, as they do in the old aviation training photograph I have posted below. In all of these someone either did not pre- qualify the engine properly, did not follow the protocol verbatim, or they were using the components as a "repair part" after a failure had already begun/ occurred, rather than using them as they were designed.
Or, they were just an idiot with a wrench, that had no place carrying out the work, or even trying. They probably spent a lot of time "reading about how to do it", which is a fairly common trait with people that fail with these procedures.
Pulling a perfectly fine bearing and then have the replacement fail and kill the engine.
Because something else in the engine led to debris contaminated oil, or etc... Or because they screwed up the install. One time an installer left the bearing retention snap ring out. He reassembled the engine, and the bearing failed.. He said he did everything right.. When he sends me a video of the engine running, making a horrible noise, I noticed the bearing retention snap ring laying on his work bench. He left it out of the engine, and then argued with me later that the snap ring didn't come from the IMS in this engine!
No, you cannot make this stuff up..
And there is also examples of IMS bearing installations going **** because of inexperienced installers.
Of course, just like what would happen if people sitting around reading about aviation maintenance actually decided to go work on an aircraft.
That said, what leads to more IMSR issues is over- experienced installers that try to cut corners so they can make more money. They have done it enough times that they can deviate from my protocol and get it done faster, but less completely, and with less safety.
This is why I have trained,Certified Installers that are tasked with pre- qualifying engines, and ensuring that the protocol is carried out as I developed it. They have check lists, and must use a level of completeness that is normally only fund in Aviation maintenance to document their work, and findings.
IMS replacement/retrofit fails also, usually way before the original solution.
Here's another fact over fear bit of information:
Since the IMS Solution Certified Installer program was created, in 2011 there's never been a single reported case of an IMSR bearing, or IMS Solution failing that was installed by a trained, Certified Installer. Argue with that~
If you want to cut corners, and not look at the most failure prone component in these engines, that is fine- it is your car. Just don't let those holes in the swiss cheese get you.
It's funny that you mention aviation, because its pretty clear that all you've done is read about it
Oooh, please tell me how you 'know' that? I grew up in an aviation family and owned several aircraft myself on which I've done maintenance myself.
I think it's funny how you badly lack engineering skills and then try to re-engineer stuff. It's also funny how you seemingly have been involved with aviation maintenance and then ignore your experience when it coms to cars.
On the picture you can see my 'mode of transportation' for many years at work(this is from a ship off shore from NOLA). I was fortunate to not be onboard this flight: https://en.wikipedia.org/wiki/CHC_He...ice_Flight_241
And back to the bearing discussion. If you stop thinking about the IMSB as some black magic that hold the M96 spirit in place, and instead understand it's just a ball bearing. Things get much easier, because ball bearings have been around for more than 200 years and are well understood. You can inspect it in place: Smooth turning, no excessive play and seals in good condition. This inspection will tell you if the bearing is GOOD or BAD. There is no need to inspect the ***** or races if it passes the inspection. If the bearing is bad and you want to know why, YES, then you need to pull it and destroy it. Before I worked in the off shore I worked at SKF...
I've been curiously investigating the IMSB failures this spring and have come to one conclusion. Because of the extremely short life span(just a few %....compared to the design life) some bearings see, the only plausible failure is either that the bearings was faulty at the time of installation OR that false brinneling occurred during the transportation of the car from the factory to the customer. To reach the USA the cars go on BOAT which is really good at creating false brinneling. Either way non of these failures needs a modification to the bearing, just an inspection and maybe replacement of the SAME TYPE if it is faulty. Debris in oil, wrong lubrication, acid oil, running hot etc is not good but will not kill the bearing nearly that fast.
Jake were you in service when they used walnut shells to clean parts during maintenance and had oil ports clogged with the shells and lost a few birds? Thanks for your service and keeping our history alive.
And back to the bearing discussion. If you stop thinking about the IMSB as some black magic that hold the M96 spirit in place, and instead understand it's just a ball bearing. Things get much easier, because ball bearings have been around for more than 200 years and are well understood. You can inspect it in place: Smooth turning, no excessive play and seals in good condition. This inspection will tell you if the bearing is GOOD or BAD. There is no need to inspect the ***** or races if it passes the inspection. If the bearing is bad and you want to know why, YES, then you need to pull it and destroy it. Before I worked in the off shore I worked at SKF...
I've been curiously investigating the IMSB failures this spring and have come to one conclusion. Because of the extremely short life span(just a few %....compared to the design life) some bearings see, the only plausible failure is either that the bearings was faulty at the time of installation OR that false brinneling occurred during the transportation of the car from the factory to the customer. To reach the USA the cars go on BOAT which is really good at creating false brinneling. Either way non of these failures needs a modification to the bearing, just an inspection and maybe replacement of the SAME TYPE if it is faulty. Debris in oil, wrong lubrication, acid oil, running hot etc is not good but will not kill the bearing nearly that fast.
Not to discount your experience, but we have worked with numerous bearing suppliers, manufacturers, and engineers over the years during the development of our products. Step back and ask why the dual row bearing from the factory had a 1% failure rate versus 8% for the single row under warranty. The simplest explanation is that single row bearing failures are due to insufficient load capacity. Many like to ignore this simple fact.
During development of the IMS Solution, we discovered that due to how the IMS is loaded, all the load concentrates in one spot and that's where we had wear in our earlier prototypes. This would suggest that likely one ball carries most of the load at any given time and the other ***** are free wheeling. This explains why we would see flat spotted ***** and wear to the inner race in the same area on bearings time and time again.
Outer race rotation, average bearing speed, excessive oil temperatures, loss of permanent lubrication, load capacity, and many other factors contribute to these failures. There are many variables to consider and why bearing failures don't always occur at any one given point in service life.
If the factory had continued to use the original dual row bearing and omitted the grease seals, I truly believe they would not have had failures and we wouldn't be having this discussion.
Not to discount your experience, but we have worked with numerous bearing suppliers, manufacturers, and engineers over the years during the development of our products. Step back and ask why the dual row bearing from the factory had a 1% failure rate versus 8% for the single row under warranty. The simplest explanation is that single row bearing failures are due to insufficient load capacity. Many like to ignore this simple fact.
During development of the IMS Solution, we discovered that due to how the IMS is loaded, all the load concentrates in one spot and that's where we had wear in our earlier prototypes. This would suggest that likely one ball carries most of the load at any given time and the other ***** are free wheeling. This explains why we would see flat spotted ***** and wear to the inner race in the same area on bearings time and time again.
Outer race rotation, average bearing speed, excessive oil temperatures, loss of permanent lubrication, load capacity, and many other factors contribute to these failures. There are many variables to consider and why bearing failures don't always occur at any one given point in service life.
If the factory had continued to use the original dual row bearing and omitted the grease seals, I truly believe they would not have had failures and we wouldn't be having this discussion.
I am not an auto engineer but have worked on classic vehicles and newer vehicles and I found it odd that they decided to go with a sealed bearing that is partially submerged in oil. Ball bearings have been used in transmissions for years and have held up fine. They aren't sealed and rely on the transmission oil to keep them lubricated. I really suspect you are correct on this assertion.
07-23-2020, 04:27 PM
