IMS "Eternal Fix", by EPS

[Scnell Gelb]

One way to address the issue of the DOF causing oil pressure drop to the cam shaft bearings would be to install an in-line,adjustable oil pressure relief valve in the DOF line. Yes, this a clumsy way of doing it so I hope it will encourage others to contribute more elegant solutions. The Peterson 09-0160 is -10 AN so requires adapters for the smaller DOF line.Or a whole new line.
Peterson Fluid Systems 09-0160, Peterson Fluid Systems Remote Relief Valves | Peterson Fluid Systems
The flow in the DOF is very small so this may be unnecessary?Pedro claims only a 1/2 psi pressure drop.
The roller bearing thrust issue:
If thrust is the issue, just use thrust a washer on each side of the bearing ? Nope ! It will be too thick for the 6204 single bearing space. Unless someone has a trick part number for a much thinner single row 6204 equivalent roller bearing? Similar problem with the double row 5204 equivalent.
But, perhaps a spherical bearing would solve the problem?

[aftCG]

Originally Posted by Scnell Gelb

aftCG
Thanks for taking the time to add to the discussion - particularly because of your expertise in bearings/loads.
Intuitively many of us liked the roller bearing solution for the IMS but were warned off by the ex-Timken fellow Ed who occasionally contributes.
You mention the DOF oil supply source/pressure loss to camshaft bearings as a problem. If that source was abandoned & the oil supply came from the same source that LN use for their plain bearing Solution, would that help in your view? I ask because that may be an easy mod for those running DOF to make.But did you realise Pedro reduced the diameter of the oil feed in the IMS cover plate? It was a large reduction in flow rate.
I have an LN chromolly driveshaft as an upgrade and share your confusion about why a mild steel shaft is inadequate. Looking at the construction of the oil pump ,you would think that was the weak link ,not the steel drive shaft.
In your study of the oil circulation system, did you ever figure out why/where the Factory diagram is wrong ? Many of us would love to know !
Thanks again for your contribution.

I'm going to carefully word this, but I don't consider myself an expert in bearings. I do have a very long background in manufacturing and design including tool design. I replaced bearings in a lot of vehicles. Mostly wheel bearings but also motorcycle transmission and crankshaft bearings (which were rollers - the crank was pressed together). It is enlightening to pull a really loud bearing out of a piece of machinery and spin it. They usually only have the slightest roughness when they start sounding like hell.

I think Jake's design of pulling oil from a full flow filter housing is excellent. Pretty sure it's probably also protected by a patent, so that is out the window for production. I've queried Jake and he has no intention of developing the "Solution" for dual row cars (it's not economically feasible, so I don't blame him at all).

I took a bunch of pictures to follow the path of oil through the engine and at some point I'll sort through them and post them up (somewhere). I have yet to refer back to the published diagram to see where the discrepancy is. I also missed something related to the way the bearing carrier gets oil for the mains, rods and spray nozzles so I need to back track and figure that out.

[NOTASIX]

I think Jake's design of pulling oil from a full flow filter housing is excellent. Pretty sure it's probably also protected by a patent, so that is out the window for production.

More than one, and included in a patent pending "system" as well. The examoniers have finished their office actions, so we should have the patent documents within the next 6 months. (Call any one else that advertises patent pending on an IMS product and ask for their filing #)

I've queried Jake and he has no intention of developing the "Solution" for dual row cars (it's not economically feasible, so I don't blame him at all).

Big difference here, its already developed and has been. We have not made any production units due to low sales inquiries. I recently had a distributor ask for these and if they'll buy enough units at once, then we'll make them.

The best system, is the simplest system, with the least amount of compromise, and the fewest moving parts. There's a reason why no other IMS components are carried through major distributors, that require true development, engineering and an on site visit to the manufacturing facility before they'll carry the product.

To get the IMS Retrofit products into the Worldpac system took 18 months, it was pretty easy for us, but no one else has been able to make the grade.

[Jeff Alton]

We use the LN products exclusively for this work. We used to buy direct and inventory, now we get just-in-time deliver through worldpac (though pricing could be better through WP )

At any rate, we did have a car in that had the EPS bearing already installed. The car came to us because there was still a leak in the RMS/IMS area. We pulled the gearbox to take a look. We also pulled the IMSB. Now, there was some install issues with this bearing from the previous shop, but the bearing and associated parts did show some significant wear. The vendor sent the car owner a replacement for no charge and did state to us that they had never heard of the issues we saw.

Not sure if the wear was install related or product related. However, if we are doing the job we will source and install the LN part as we know we won't have any issues down the road (and we stand behind the parts we source and our labor to install)

Cheers

[J P Stein]

I've been out of the Porsche loop for a few years. Before I cansider jumping back in, I need some info.

I'm looking at Boxsters. What year did they get rid of the problematic engine.....the M91?

Are the fixes to that old engine effective?
What should I be looking for in a repaired engine? IMS replacement? Whole engine replacement.....kinda iffy ground here considering Porsche's solution.....

How's the newer motor doing? Any major issues?

TIA

[Scnell Gelb]

Jeff,
The wear you saw on this one roller bearing may be what was predicted by some early devotees of this design.Those roller bearing enthusiasts quickly moved on to ball or journal(oil-fed) bearings.
Did you notice in what orientation the wear was most noticeable?
How many miles on the bearing?
Good to hear the kit supplier replaced the bearing but you have to ask why the replacement will do any better - unless it was just an installation problem ?

[chamilun]

Now, there was some install issues with this bearing from the previous shop

lets not start an immediate slander of a company without re-reading the above. If something is installed incorrectly, all bets are off

[Duezzer]

+1 to chamilun

[Jeff Alton]

Originally Posted by chamilun

lets not start an immediate slander of a company without re-reading the above. If something is installed incorrectly, all bets are off

Exactly, and I hope I was clear in stating that we never determined whether the issue was product or install related, and there were install issues...

Cheers

[Duezzer]

Jeff

What were the install issues?

[Sapientoni]

Just a short note to advise of WARRANTY or GUARANTEE. In the bearing box with the L & N Ceramic bearing was a small note that stated "30 day guarantee". Of course I'm guessing they figure any ham fisted mechanic can mess up the install, and that should show up within 30 days.

[Daves911L]

I'm about to replace the IMS in my daughter' 98 Boxster. Preventive maintenance on a car with zero problems and 135K miles. Time for a clutch, and with all the IMS horror stories I've read, decided to do the IMS too. Need to decide which part to buy, and get it ordered. Have spent the past 4 hours this morning reading a bewildering array of posts on various forums. Lots of opinions, many cheerleaders, and what appears to me to be marketing hype from vendors with an interest. Still quite confused, and have yet to make up my mind, but this was probably the most thoughtful post I came across. Thanks.

Originally Posted by aftCG

I queried EPS about the number of installs and failures a couple months back when exploring options.

They responded that they have had over 800 installs in the past two years with zero failures. So it's not millions of miles and hey it could be all lies, right?

Vertex auto installs them in all of their rebuilt engines they sell. Logic says that if they were eating failed engines they would certainly switch to something else.

Also, given the nature of internet whiners, if there had been EPS failures there WOULD be someone on some forum talking about their failure. There aren't any that I've found. Zero. I welcome the corrections because I'd like to read them.

It would be hard to install a worse bearing than the factory did, so anything is an improvement, and I suspect the reason why failures of other options are few (including the Pelican single row into a two row car). Heck there's plenty of people shouting that the bearing problem is just being made up by people selling bearings. I'm not, but I've had a car that has had its a** sticking up in the air for coming up on three months.

Some of us don't have the option of the LN plain bearing solution since we have two row bearings (that supposedly don't fail in any numbers, yet mine and many others are junk).

Look I totally respect the work of Jake Raby and Charles N. If I had a single row car I would pony up for the plain bearing solution. Done. It's not an option for me. It's either stock (no), Pelican single row (no), EPS roller or LN ceramic two row.

EPS doesn't seem to have a presence on the forums to defend their products. I can confirm that they are not a bunch of idiots. If you own a Porsche Cayenne, VW Touareg (I do) or Audi Q7 you may already know of them because they developed a solution to the random failures of the drive shaft support bearing (which requires shaft removal, bearing press and balancing of the finished shaft) common to the types. Instead of $1200-$1400 for a repair you crawl under your car with their $300 kit and are done worrying about it. Even if their kit wasn't a permanent solution it would be way easier and cheaper than the factory route.

Thrust loads:
I do tolerance stack ups and load paths for a living, and I'm getting up there in age. If I had $10 for every time my employer said "yeah we looked at that and decided it wasn't a good idea" I'd own a brand new 981 free and clear. In GTS trim, thank you. Red.

That article linked to about why a roller bearing isn't a great option acknowledges that it has a higher radial load capacity. The criticism of thrust load is actually something addressed with the EPS design.

As long as the inner and outer races are contained between the EPS "thrust control" washer and the IMSB cover with less slop than the rollers have then the bearing rollers themselves will never see thrust loads. I'd have to look closer at the design (hopefully with parts in my hand) to confirm that detail. If they didn't do it that way then all bets are off.

The EPS bearing does not require you to punch the hole and run their oil feed concept, but they do recommend it. Without their oil feed system it is a splash bearing with no grease seals, exactly like the LN ceramic bearing and exactly like LN used to have people do to factory bearings before developing their line of products. And, I'll point out, it was an improvement on the factory version.

I am quite sure I can find a post less than two weeks old where Jake states, as if tired of repeating himself, that the IMS bearings do NOT fail because of lack of lubrication - they fail from load. That would seem to imply that splash lube is just fine for balls/rollers and that we should just focus on that load part. It also supports the claims of makers of the DOF and the EPS roller that a plugged up oil feed won't result in bearing failure, it just reverts to splash oil.

For anyone not clear on how the EPS pressure lube system works, or how the other ones work here's my shade tree version:

The IMS bearing which fails is in the opposite end of the IMS shaft from the oil pump. The oil pump for the M96 is actually driven off the non ball bearing end of the IMS shaft, by using a hex shaft (picture a segment of about a 6mm allen wrench). That same end of the shaft is a plain bearing, just like your main bearings, rod bearings of nearly any vehicle for the past 100 years, and the LN/Flat6 "solution" - except that there is no replaceable bearing.

That plain bearing end of the shaft actually rides in the (soft aluminum) oil pump housing of the M96, and gets lube about as quickly as possible when the oil pump comes on line when you start the car.
The lube oil travels as a "controlled leak" around the spot where the hex shaft comes into the oil pump to drive the gears, to flood that plain bearing on the IMS. Excess oil is driven into the crankcase where it drains to the sump.

What EPS does (and I doubt they invented the idea) is to have you poke a very specific hole with a supplied punch, into the hole where that hex shaft runs. Then they replace the hex shaft with one that has a groove along the side. This causes some (again, a theoretically controlled amount) of the same immediate oil supply that the plain end gets, into the fat, hollow IMS shaft where it eventually finds its way to the opposite end, flowing through the roller bearing and then out a small groove to again drain to the crank case.

Potential problems with this method:
Hole too big. I think first up is mostly the issue with the deft touch of the person poking that hole in the blind end of the IMS shaft. Hole too big and you probably just removed that which keeps the hex shaft from just traveling back (in our 986 or forward in 996 land) and falling inside the IMS. What a riot that would be. No oil pressure, and 100% tear down needed to rectify.

The hex shaft itself. It is known that oil pump drive shaft (the hex thing) is one of the critical modes of failure for the M96. I'm going to admit that I don't know why it fails. It doesn't have that hard of a job other than pumping oil. So either it is a bit feeble (undersize or poor choice of material specification) when oil is cold and thick, or it just shears off when a piece of FOD finds its way into the pump and sticks between the gears. Or maybe there is some harmonic vibration, space aliens, or what have you.

Bottom line, detractors from the punch/grooved shaft option argue that the oil pump shaft is already a problem and that putting a groove in it will make it even weaker, but also probably assume that EPS has done nothing to improve the shaft strength. That may or may not be true, but is worth the question. I will state that it is absolutely possible to create a hex shaft strong enough to allow the oil pump to chew bottle caps if necessary. The one LN sells probably would.

Before moving on, I'm going to say that so far I'm a fan of the roller but not as dedicated to the oil pump modification as outlined by EPS.

The LN oil feed is only available on the single row IMS Solution. Yep, filtered oil. I've recently taken the time to follow the path of oil in the M96 engine. Wow. Okay so it gets sucked out of the oil pan by the oil pump. Some small amount gets leaked to the plain end of the IMS, the rest gets rammed through the oil filter, then up through the oil cooler. The rest of the path, well that's a scream. More on that in a minute.

Bottom line, yes the LN Solution does get filtered (but not recently cooled) oil in what ever the proprietary feed amount is, and it gets fed to the "Solution" bearing in the troubled end of the IMS. End of discussion since that oil feed method is only available to users of the "Solution" and not any of us ball/roller types.

Next up is the DOF (So far as I know Pedro sells the TuneRS system and they are one and the same - just like Vertex sells the EPS roller). The DOF system takes the oil from out on a valve cover..........Regadless of DOF, EPS or LN oil feed methods the basics of where they get the oil from and in what amounts are where they will be successful or fall on their swords.

I personally welcome all the options to the market.

[Scnell Gelb]

I wish aftCG had included the RND roller bearing product in his review.
Single Row RND Roller Bearing IMS Retrofit kit - IMS - Products LN Engineering

Roller Bearing IMS Retrofit Kit – RND Engines

[JFP in PA]

A couple of comments on the various "systems":

Having done our share of IMS retrofits, some observations have developed. Every factory IMS bearing we have ever pulled had a lot of oil behind it in the shaft, that comes flooding out when the bearing is extracted. That bothers me as it means even otherwise perfect factory IMS bearings are allowing oil to at least partially fill the shaft, which can lead to shaft imbalance and harmonics, which cannot be doing the factory bearing any good. Both the EPS and DOF systems do nothing to address this problem; and the EPS actually wants you to punch a crude hole in the sealing plug on the oil pump end to let even more oil into the shaft, while the DOF is flooding the factory bearing with oil, which should also lead to more inside the shaft as well. This somehow does not seem like a good idea.

Every IMS Solution we have done, which while not as numerous as the more conventional IMS retrofits, have resulted in a common comment from the owner the next time we see them: The engine feels smoother. I have often wondered if this is because part of the Solution package is the insertion of a sealing plug behind the new solid IMS bearing, which prevents oil intrusion into the rest of the shaft and subsequent shaft harmonics. While only speculation at this juncture, it is enough to make you stop and think.

And for the earlier poster who commented that there are no dual row IMS Solutions, they are available now, we just finished installing one.

[Scnell Gelb]

JFP,
Interested in your observation about the oil accumulating inside the IMS tube. I have noticed the same thing on mine. Once that oil gets inside, how could it ever drain out ? Maybe through the failing inner seal that allowed it in ? Not good.
JFp - do you know if the RND bearing has a more effective seal ?
For those confused about the Dual Row IMS Solution , here is a link:
IMS Solution for Dual Row IMS MY97-01 - IMS - Products LN Engineering

[JFP in PA]

Originally Posted by Scnell Gelb

JFP,
Interested in your observation about the oil accumulating inside the IMS tube. I have noticed the same thing on mine. Once that oil gets inside, how could it ever drain out ? Maybe through the failing inner seal that allowed it in ? Not good.
JFp - do you know if the RND bearing has a more effective seal ?
For those confused about the Dual Row IMS Solution , here is a link:
IMS Solution for Dual Row IMS MY97-01 - IMS - Products LN Engineering

I know that LN worked on devising a better back seal on their bearings, and as they actually produce the RND bearing for them, it may also use it, but I have no confirmation on that.

The problem with the oil accumulating inside the bearing shaft is that when the engine is off, oil is part way up the bearing itself, so there is no way for it to gravity drain. The ideal fix for this would be for LN to offer the Solution tube plug as an add on option to the ceramic hybrid but then you would also have to buy the IMS Supplemental Tool Kit, which has the driver tool to install it.

[Scnell Gelb]

Very insightful. Thank you.

[sugarwood]

Is there a "no-brainer" solution for the IMS fix? I thought it was LN for $800. Set it and forget it?

[JFP in PA]

Originally Posted by sugarwood

Is there a "no-brainer" solution for the IMS fix? I thought it was LN for $800. Set it and forget it?

Even the ceramic hybrid bearings currently have a life expectancy; the dual row and Single Row Pro LN bearings are currently rated for 75K miles. The RND bearing is 50K miles as is the LN single row bearing. The only permanent retrofit is the LN IMS Solution, but now you are talking a retail of $1725 for parts alone.

As they say, "speed cost money, how fast do you want to go?"

[Sapientoni]

My personally engineered INSITU replacement currently has 33,000 miles. No worries here. If time permits, I'll try to compose an article for Panorama with pics to educate a little on "not all bearings are created equal". Mainly, the factory Porsche bearing is a "high capacity" bearing that has more load bearing balls (8 vs.7) than the average off the shelf industrial bearing. The ceramic Micro Blue I used in mine has only 7 balls.