2007 & later IMS brg. removal

[mcfcinusa]

The IMS brg. on the later models is not removable without complete engine disassembly. I am a Machinist with 45years experience in the trade and have recently retired/ been laid off after the San Onofre Nuclear Power Plant was permanently closed. I have been making a machine that can be attached to the engine and then i can machine the bore in the crankcase just large enough to allow removal of the original bearing. Once the bearing has been removed then a replacement IMS bearing can be installed. I can supply a sleeve to fit over the original 3 bolt holed bearing carrier or even a brand new bearing carrier that fits the now oversized bore in the crankcase.

I am putting this idea of mine forward with the knowledge and confidence that it can be done without any detriment to the integrity of the engine crankcase. I can perform this work with the engine in or out of the car. If someone is having a clutch replaced then this would be the perfect time to change out the IMS brg. The style of IMS brg. kit can then be installed by the mechanic doing the job. Some kits are oil fed and some aren't but type used is then up to the owner of the car.
I have been in contact with upper management at Pelican Parts and have been allowed to put the idea forward to see if any owners would want this service. I am willing to travel to where the car is being worked on to do the work. Once the case is machined the owners mechanic can then proceed to install a new IMS kit. If i have got the year wrong please correct me as i have a 97. I live in North San Diego County. Des Young.

[Boiler Inspecto]

Have you tested this on an M97 engine yet?

[mcfcinusa]

Boiler Inspecto, I haven't got an engine case to "Test" it on. If the 3 bolt bearing carrier is the same as the earlier style engine then the bolt circle is the same and the same dimensions still apply.
It would be nice to "Test it out" on a scrap block so that a customer would have the knowledge and "peace of mind" that it works. I personally don't need to do that as the machining is just the same as if i was doing it on a Horizontal Boring Mill or even a regular Vertical Miling machine big enough to set the cases on. The only difference is the way that the tooling is attached to the back of the engine case, the machining of the bore uses the same skill as what i've done for years.

Here's a little background about me.
Born 1955 in Manchester England;
15 yrs old i started my 5 year machinist apprenticeship.
Emigrated to the U.S.A. at 25 in 1980.
Worked for Southern California Edison as a Nuclear Maintenance Machinist from April 1981 till September 1st 2014. Removed and overhauled pumps, motors, valves, gearboxes, steam turbines, The Reactor Coolant Pump mechanical seals stand 30" tall x 12" dia. and the replacement pieces in the seal cost $250,000 alone. Ran Lathes , grinders, miling machines, Vertical boring mills, Horizontal Boring mills, In Place Machining; which is exactly what i'd be doing to a Porsche engine case.
Sounds like i'm "banging my own drum" but i am a highly skilled professional thats been at it for 45 years and when it comes down to designing and making the machine needed to perform this work it's just "what i do best".
Visit aacycleproducts.com to see custom products i have designed and made for motorcycles.
All i really need is someone who wants it done. I welcome anyone who would like to talk to me about this. Call me at (760) 468-6312 cell or (760) 731-2972 home or email me at blymeylymey@gmail.com and be ready for my English accent.
Desmond Young

[mikefocke]

A description of you you propose to keep the resulting debris out of the engine might be helpful. Any IMS kit will fail much sooner if there is debris in the engine at the time the kit is installed.

Also you might want to address how you will align the bore hole as this alignment of the original is now being proposed as one of the issues which causes failure in any IMS bearing, original or kit.

[JFP in PA]

Originally Posted by mcfcinusa

The IMS brg. on the later models is not removable without complete engine disassembly. I am a Machinist with 45years experience in the trade and have recently retired/ been laid off after the San Onofre Nuclear Power Plant was permanently closed. I have been making a machine that can be attached to the engine and then i can machine the bore in the crankcase just large enough to allow removal of the original bearing. Once the bearing has been removed then a replacement IMS bearing can be installed. I can supply a sleeve to fit over the original 3 bolt holed bearing carrier or even a brand new bearing carrier that fits the now oversized bore in the crankcase.

I am putting this idea of mine forward with the knowledge and confidence that it can be done without any detriment to the integrity of the engine crankcase. I can perform this work with the engine in or out of the car. If someone is having a clutch replaced then this would be the perfect time to change out the IMS brg. The style of IMS brg. kit can then be installed by the mechanic doing the job. Some kits are oil fed and some aren't but type used is then up to the owner of the car.
I have been in contact with upper management at Pelican Parts and have been allowed to put the idea forward to see if any owners would want this service. I am willing to travel to where the car is being worked on to do the work. Once the case is machined the owners mechanic can then proceed to install a new IMS kit. If i have got the year wrong please correct me as i have a 97. I live in North San Diego County. Des Young.

Along with Mike's questions about how you intend to prevent machining debris from getting into the engine case while doing this, and how you intend to assure correct alignment of the new bore, exactly what does the car owner do after you have completed this project? No one makes a larger IMS flange or seals for the new opening, and the only available bearing is that size is the one already in the car, which Porsche only sells as an assembly with the shaft itself for around $1K.......

While an interesting idea, I think you need to focus more on the details involved.

[Scnell Gelb]

O.P.
The tool and process you described is already in use and has had a long post covering it's use on another Forum recently.The thread covered problems and solutions.
These later cars seldom need an IMSB replacement .
Sorry.

[mcfcinusa]

Mikefocke, JFP in PA & Scnell Gelb here are the answers to your questions:

Keeping the cutting chips out of the engine is done by installing a "Dam" between the gear on the end of the IMS and case. I would use a borescope to check cleanliness BEFORE and AFTER machining and the borescope also allows pictures to be taken to prove no cuttings or any other pieces are inside the engine.
Alignment to the original bore is guaranteed by utilizing a "alignment plug/bung" that fits into the machine spindle and the engine case. After removing it i would then indicate it to prove it is zeroed in.
The car owner has the mechanic or whoever is working on the car install the new bearing into the IMS gear, an oversize sleeve which i would provide is then installed into the new bore. This would bring the bore back to its original size. The sleeve would be an interference fit so it wouldn't move or leak. The mechanic can then proceed with final installation of the IMS 3 bolt flange.
Even though no one sells a larger diameter IMS flange/3 bolt bearing carrier it doesn't mean it hasn't been done, I replaced an IMS bearing on my friends 2004 Boxster and made the Flange and the bolt that secures the bearing onto the flange. It was made from 4140 (chrome moly) and i increased the bolt diameter to 12mm and put the "O" ring groove in the bore of the IMS flange so the bolt wasn't weakened by undercutting it for an "O"ring groove. Making the OD bigger to fit an oversize bore is no problem and feel that the 3 groove seal would stretch an extra 5 mm to fit a larger OD. If a customer didn't feel comfortable with that idea i could always put 2 "O" ring grooves instead. This kind of stuff isn't "rocket science" and while certainly beyond the scope of the regular owner that does their own maintenance it's what i've been doing for many years and feel confident that i could save people many thousands of dollars from having an engine failure.

[Scnell Gelb]

I'm sure you are a brilliant machinist but your reading comprehension and google searching is questionable. Here I've done some of the work for you.:
Oh man, this is hard to watch... - Rennlist Discussion Forums

[myboxster]

I think you would have to address these concerns about alignment before a driveway mechanic like myself would consider such an untested venture. Not to dissuade you, I felt the same way about the IMS DOF until I watch Pedros from pedrosgarge.com youtube videos explaining the problem and his proposed solution. I feel that you should get in touch with him to discuss your idea. He may even have a donor engine that you could try it out on... u never know... He's located in south florida.

Best of luck to you and please keep us posted on your progress.

[mcfcinusa]

Scnell Gelb, thanks for the video connection. I watched it a few times and then read through the comments made by people and thought about some things that were left out of the video. The presentation of the video could have been better. I have numbered a few points that could be made to improve or explain to the layman about the process used. While looking at some of the tooling it was evident to me a lot of time and thought had gone into this idea. A person who isn't a machinist cannot visualize how these pieces are used. It was plain to me the first time i saw it but then again after 45 years of machining i know a thing or two and certainly understand how it looks "rough and ready" I'm not here to defend the company providing that service but merely making an attempt to explain to the "Layman/Person in the street" why some things look odd or out of place.
I try to present my views to the Non Machinist people so as not to over complicate the description.
If i was to explain all this in Machinist's language it would boggle people's mind. How may people understand these terms that we use on a daily basis: T.I.R. Eccentricity, Ovality, Chatter, Transition Fit, Interference Fit, Clearance Fit, Tolerance, Spfm, Feed/Rev. Parallelism, Top Rake Angle,and Side Rake Angle, Front Clearance, Side Clearance, Rigidity, Overhang and even more that i won't go into. ALL of these terms are applicable to the video.
1 The video showed the tooling in a box and chips all over the bearings and cutter.
The bearings are sealed brgs. so no debris can get in them.
2 Cutting chips/swarf all over the tooling.
This was probably taken AFTER the work had been done.
3 Method of alignment of jig to original bore was not shown.
In the box was a large turned slug which would fit into the bore of the alignment jig and also into the bore in the engine case for precise alignment and then the jig would be locked down in place.
4 The arbor used to mount the cutter on is heavy duty and the locking bolt at the cutter end is the correct type used with arbors.
5 The narration could have explained more about the process to set peoples mind at rest.
The cutter used is a modified Face Mill made from HSS (High Speed Steel)and has a lead ground on the front to reduce chatter. The cutter will give a good finish but over time will dull but it is easily replaced after a regrind. Normally two cutters would be used., a roughing cutter then a finish one but maybe they didn't show that part or didn't feel a finish cutter was needed.
6 The removal of the snap ring using a screwdriver and a pry bar.
Should have been done with the correct snap ring pliers and not with a screwdriver and a pry bar.
7 No explanation of how they were going to "fill in the gap" between the case and the flange.
The replacement flange has to be made to fit the bore with the same tolerance as factory. Some people were suggesting JB Weld being used to fill the gap.

My method of machining the bore would use a Right Angle Head with a variable speed drive and a Boring and Facing Head to mount a boring bar in. This setup is then permanently fixed onto a precision tool slide with 7" of travel that can feed the tool into the bore. All of these parts are then attached to a custom made angle bracket which will span the full height and width of the engine where it mates against the gearbox.
This is all rather long winded but at least explain some of the different ways to achieve the same results.

[mcfcinusa]

myboxster,

Alignment to the original bore is guaranteed by utilizing a "alignment plug/bung" that fits into the machine spindle and the engine case. After removing it i would then indicate it to prove it is zeroed in. This method will guarantee alignment to the original bore within 0.0005" or 1/2 thou which is one sixth of a human hair. Des.

[mcfcinusa]

I rebored two motorcycle wheels for a friend of mine using the same type of tooling. The only thing different is that the spindle is vertical on my milling machine and would be horizontal on an engine case. I can make a "mock up" and then people can see it machining but it's the same exact procedure used in boring the wheel out. This video shows how it's done. Well it will when i figure out how to attach a video!

[mcfcinusa]

Wheel boring.

[mcfcinusa]

maybe this will work.http://https://www.facebook.com/100005144806586/videos/421605548020935/

[mcfcinusa]

Well i put it on Facebook but i don't know how to get it onto this site. I hate computers, they make me feel so dumb, even though i'm smart enough to know i'm not.

[mikefocke]

One item that has recently been disclosed is the relationship of the various "holes" in the engine block and their relationship to each other causing unbalanced loads via the timing chain.

Your boring would have to be located in relation to the existing crank to take away the casting differences and assembly differences in the IMS bearing hole that has been claimed to affect the installation of even replacement IMS bearings and has been said to cause premature failure in replacement bearings.

Suggest looking in the rennlist 996 forum for a series of posts about claimed premature failure of an LN bearing and Jake Raby's posts re this issue possibly being a contributing factor in multiple failures in the same engine.

Given that there are several engines reported on the forums that have exhibited 2 or 3 very early failures and this is statistically improbable, there may be something to the suspicion..

[mcfcinusa]

I wasn't aware of any bores being out of position. Are you saying the spacing of them is "off" what's normally referred to as the "center to center " measurement. The distance from the IMS bore to the Crank bore is easily measured and calculated. Take a vernier and measure the widest spread from bore to bore using the outside of the caliper jaws ( which has a radius) if you had bore of 85mm ( which is what the Rear main seal is) and a center to center dimension of 130mm and the IMS bore is 60mm.Add 1/2 of each bore plus the center to center size and total them up. 202.5 mm would be the size you're looking for. Of course when we use an ID mic. we get an exact size so the 85mm may really be 85.02mm, all this is calculated into the equation to arrive at the correct dimension. Correcting an issue of center to center from the camshafts can be addressed too. Just a little bit more math is involved. Trigonometry is used to calculate the angles and centers. If an engine was way out of spec on one bank there is the possibility of moving the IMS bore over a few thou to bring it back in to specs. If that was done then the IMS shafts plain brg. at the oil pump end would change slightly and change the load pattern along the bearings centerline. If you moved the IMS brg. bore sideways 10 thou. and the shaft was 10" long you have just skewed the shaft sideways 1 thou per inch. if the plain bearings journal is 1" long ( which is about right) you have side loaded the bearing and this will alter how much oil the IMS journal will ride on due to changing the oil wedge the shaft sits on while running. Even though that end has the oil pump gears on it and it basically runs in an oil bath it still has to have the correct wear pattern for the journal to ride on. All of this depends the amount of misalignment found. What happens in real life is the bearing may bed in with no problem and run for years or get hot and wipe the bearing and fail. If an owner suspected a problem then measurements can be taken to see how much a bore would need to be moved and then reposition the tooling to rebore the IMS on center. Lots to consider when issues like this crop up.

[JFP in PA]

Originally Posted by mcfcinusa

I wasn't aware of any bores being out of position. Are you saying the spacing of them is "off" what's normally referred to as the "center to center " measurement. The distance from the IMS bore to the Crank bore is easily measured and calculated. Take a vernier and measure the widest spread from bore to bore using the outside of the caliper jaws ( which has a radius) if you had bore of 85mm ( which is what the Rear main seal is) and a center to center dimension of 130mm and the IMS bore is 60mm.Add 1/2 of each bore plus the center to center size and total them up. 202.5 mm would be the size you're looking for. Of course when we use an ID mic. we get an exact size so the 85mm may really be 85.02mm, all this is calculated into the equation to arrive at the correct dimension. Correcting an issue of center to center from the camshafts can be addressed too. Just a little bit more math is involved. Trigonometry is used to calculate the angles and centers. If an engine was way out of spec on one bank there is the possibility of moving the IMS bore over a few thou to bring it back in to specs. If that was done then the IMS shafts plain brg. at the oil pump end would change slightly and change the load pattern along the bearings centerline. If you moved the IMS brg. bore sideways 10 thou. and the shaft was 10" long you have just skewed the shaft sideways 1 thou per inch. if the plain bearings journal is 1" long ( which is about right) you have side loaded the bearing and this will alter how much oil the IMS journal will ride on due to changing the oil wedge the shaft sits on while running. Even though that end has the oil pump gears on it and it basically runs in an oil bath it still has to have the correct wear pattern for the journal to ride on. All of this depends the amount of misalignment found. What happens in real life is the bearing may bed in with no problem and run for years or get hot and wipe the bearing and fail. If an owner suspected a problem then measurements can be taken to see how much a bore would need to be moved and then reposition the tooling to rebore the IMS on center. Lots to consider when issues like this crop up.

Some of the M96 engine cases suffer from out of round openings on the rear of the cases, which was the subject of an article in Excellence Magazine a couple of years back. When Porsche realized that single engines were suffering repeated oil seal failures on the rear of the case, they developed a tool to measure the opening roundness of the openings. Engine cases that failed that test were replaced with new engines as they felt there was no way to correct the problem in the field without weakening or otherwise damaging the cases.

[Nostril Cheese]

Cool idea, but is it really necessary on a M97?

[mcfcinusa]

JFP, Out of round (ovality) is easily measured with machinist tools. reboring of the seal area can be done with the crankshaft in place ( i can because i have the right tooling AND experience).
The way to correct seal alignment would be to set the machine true to the crankshaft OD.
Bore the oil seal bore 1.5 mm larger which is .060" (60 thou) and make a sleeve/ring to be pressed in position. The sleeve would be .030" wall which is thick enough to support a seal and also loctite it in place. Put a new oil seal in and you're done. Real easy for me to do.
I want people to realize that i would have no problem applying any of these procedures to my own car.