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.
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