No supporting logic or evidence in that post

Folks, I'm starting a new topic for this, although i mentioned it below.

Three seasons ago, when i put this junkyard motor in my boxster, i put in an LNE IMS bearing. That bearing is already badly deteriorated - it has lots of play and wobble. I cant yet measure the amount, since i have not removed it from the IMS itself yet (missing the right screw on adapter for the puller, sigh), but no matter, its dead. (no its only sleeping!)

The main point of my post is to deliver this data. Under hard use, even with oil changes every what 2000 miles?, even the replacement units can fail fairly quickly. Not only was I surprised, but the shop guys were startled.

I'm strongly considering Pedro's DOF. The basic idea seems like ti almost MUST be right - clean oil all the time. Obviously an overbuilt bearing (LNE) does not solve the problem sufficiently, at least for track use. Any BTDT or other advice along the way? I plan to talk to Pedro next week. I know there has been some impassioned discussion on this topic, but the oil flow diagrams I have seen are pretty convincing.

Grant

Grant

gee-lenahan-at-gee-mail-dot-com

That's what I have, go for it!

The Vertex roller bearing and oiling system is interesting.

Installing a new IMS bearing with an impact wrench will cause it to fail quickly.

Ed B

As i recall the bearing presses onto the the shaft, and then its simply a cover plate and locking (shaft) nut.

What would one use an impact on, and what would be the result ( may be obvious once you indicate "what")

Grant

Grant

gee-lenahan-at-gee-mail-dot-com

Using an impact wrench on the center shaft locking nut can brinell the bearing races and balls. Actually, any impact wrench use on the engine could damage the bearing.

Ed B

Grant

gee-lenahan-at-gee-mail-dot-com

That no competent mechanic would ever do that. Bolts should generally be torqued to spec and if you're going to skip that step on any of them, these are among the last you would do that with.

Grant

gee-lenahan-at-gee-mail-dot-com

Although Ed is correct that you can screw up the installation in those ways I think it is far fetched to believe that that was actually the cause of premature failure. It's human nature of people to vary their caution level based on the consequences of their mistakes. In this case unless the mechanic doesn't know what they're doing they would always torque the bolts.

I've seen too many poor practices, even from people who ought to know better.

Grant

gee-lenahan-at-gee-mail-dot-com

Quote
Boxsterra
Although Ed is correct that you can screw up the installation in those ways I think it is far fetched to believe that that was actually the cause of premature failure. It's human nature of people to vary their caution level based on the consequences of their mistakes. In this case unless the mechanic doesn't know what they're doing they would always torque the bolts.

The LN tool was changed after they found out that a series of 6 very early life failures at a single shop was due to the same mechanic using an impact wrench. They changed the tool design to make it impossible for the tool to connect to the bearing that way. Charles posted that story on another forum just the other day in response to a person questioning the differences in the tool he was using and the one in a video.

Yes, they do fail. Yes they do investigate if given a chance. Yes they have improved the bearings, instructions and tools.

I never understood why just making the bearing bigger and or stronger solved the underlying design problem..... always sounded like kicking the can down the road.

Just feed it good oil... why is this so complex? You can get flowing, pressurized oil from a number of places..... If a flow of good oil won't do the job, then there must be some unexpected forces acting on the shaft resulting in the system not operating as it should. Hey, what do I know? Not much..... (seriously). Relying on "splashing oil"..... hmmm.......

My indy was using a DOF system, don;t know who makes it, where it gets oil from the filter cap.

Peace
Bruce in Philly



Edited 1 time(s). Last edit at 01/17/2017 12:07PM by Bruce In Philly (2000 S Boxster, now '09 C2S). (view changes)

[rennlist.com]

I stand corrected...... assuming Jake is correct.... and at a minimum, a bazillion times more qualified than me.

As a consumer of this avalanche of information and speculation over the years, I have come to a very simple (simple minded?) explanation for all of these failures... IMS being just one...... this engine was hastily designed and or testing was incomplete. Remember, Porsche was failing and rumored to be on the auction block (or about to be put there). The Boxster and the single platform approach was to (and did) save the company.

Most information out here is about the IMS but there are more failure modes.... and if you remember back in 1999 (when I got into this), failures were pretty common..... for reasons not even mentioned anymore..... porous blocks, slipped sleeves (from factory-fixed porous blocks), out-of-round rear main seals as evidenced by leakage IIRC and there was another... maybe it was just the bigger 911 bores..... where some bolt sheared on some shaft that then wagged around the engine (maybe this was actually the IMS bearing... but I don't think so).

It is a pity they blew it with the engine, although not surprised as the engine is the most complex, as the cars were really terrific.

Peace
Bruce in Philly



Edited 4 time(s). Last edit at 01/17/2017 03:25PM by Bruce In Philly (2000 S Boxster, now '09 C2S). (view changes)

Quote
Bruce In Philly (2000 S Boxster, now '09 C2S)
I stand corrected...... assuming Jake is correct.... and at a minimum, a bazillion times more qualified than me.

As a consumer of this avalanche of information and speculation over the years, I have come to a very simple (simple minded?) explanation for all of these failures... IMS being just one...... this engine was hastily designed and or testing was incomplete. Remember, Porsche was failing and rumored to be on the auction block (or about to be put there). The Boxster and the single platform approach was to (and did) save the company.

Most information out here is about the IMS but there are more failure modes.... and if you remember back in 1999 (when I got into this), failures were pretty common..... for reasons not even mentioned anymore..... porous blocks, slipped sleeves (from factory-fixed porous blocks), out-of-round rear main seals as evidenced by leakage IIRC and there was another... maybe it was just the bigger 911 bores..... where some bolt sheared on some shaft that then wagged around the engine (maybe this was actually the IMS bearing... but I don't think so).

It is a pity they blew it with the engine, although not surprised as the engine is the most complex, as the cars were really terrific.

Peace
Bruce in Philly

Understand I don't necessarily agree with Jake Raby on this.

If it were an under-spec'd bearing I think the failure rate would be higher. My opinion is the bearing failures are for the most part just due to bad bearings. Porsche is not necessarily to blame -- although its name is on the car and that obviously includes the engine and everything in the engine, right down to the IMS bearing -- so of course receives the blame. And I'm not necessarily of the opinion that it shouldn't receive the blame.

Not sure I agree with hastely designed or that the testing was incomplete. The failures you listed can be I think attributed to early production run manufacturing woes and at least in one case -- the slipped sleeves -- a bad decision by Porsche to re-work blocks that should have been thrown away.

It is not unknown for early examples of new engines to have problems. Porsche is not alone in this. All of the "failure modes" arise as the problems with various manufacturing/assembly processes surface. It is why every car maker has a new car warranty. This new car warranty also is there to take care of the rather rare event that even though the engine/car has been in production a while the occasionally defective engine surfaces, be it defective due to some casting problem, machining problem, or an outside supplier's component is in some way defective.

We'll never get the full story from Porsche. I'm not sure even Porsche knows the full story. But the narrative we get from all the various purveyors of ISMB solutions are not necesarily the correct narrative. They are just a narrative. The cause and effect is given X or Y, or Z, depending upon whom you choose to listen to. That there are several of these to well, choose from, suggests the right answer could very well be "none of the above." But it is hard to sell an IMSB fix/solution with just a shrug of the shoulders and a "maybe" as an answer to the question "Will this prevent my engine from having an IMSB failure?"

Now, we can speculate. His anecdote about dual vs single rows is somewhat interesting.

but this is a multi-faceted problem. A weak bearing well lubricated will likely endure. A strong bearing poorly lubricated might endure.
My experience says "or not"

But i don't agree with any flat statement, by Jake or anyone else, that lubrication is not beneficial to the life of any bearing.

An aside: This could be a linear programming type problem, with potentially wide variables for things like acidity, rpms, shaft concentricity, blah, blah. In such probelems there is no single cause, but a critical limitation *given a specific set of variables*.

What I do find interesting is a piece of info i heard elsewhere, that there is some evidence that some IMSs (shafts, not bearings) do not spin true, and therefore put a larger strain on the bearing. This simultaneously explains 300k mile bearings and those that fail repeatedly (which, in my case, worries me).

Looking at options that combine both improved load capacity and improved lubrication - cover all bets..

Grant

gee-lenahan-at-gee-mail-dot-com

Lubrication is not just about slipperyness.... it is also about cooling.

Peace
Bruce in Philly

Quote
grant
Now, we can speculate. His anecdote about dual vs single rows is somewhat interesting.

but this is a multi-faceted problem. A weak bearing well lubricated will likely endure. A strong bearing poorly lubricated might endure.
My experience says "or not"

But i don't agree with any flat statement, by Jake or anyone else, that lubrication is not beneficial to the life of any bearing.

An aside: This could be a linear programming type problem, with potentially wide variables for things like acidity, rpms, shaft concentricity, blah, blah. In such probelems there is no single cause, but a critical limitation *given a specific set of variables*.

What I do find interesting is a piece of info i heard elsewhere, that there is some evidence that some IMSs (shafts, not bearings) do not spin true, and therefore put a larger strain on the bearing. This simultaneously explains 300k mile bearings and those that fail repeatedly (which, in my case, worries me).

Looking at options that combine both improved load capacity and improved lubrication - cover all bets..

My takeaway from JR's comment was not that lubrication is not beneficial to the life of the bearing. It is obvious that a bearing needs lubrication.

My belief is the problem is mainly due to bad bearings, bad due to some manufacturing problem at the bearing factory. It could metalurgical in nature, or it could be the lubrication the bearing receives at the factory, either the wrong stuff or even just too little or too much.

That some engines/bearings last a long time strongly suggests the engine and bearing when they leave the factory floor done right are quite up to the task. That some engines/bearngs fail much too soon suggests then they didn't leave the factory floor done right that a manufacturing/assembly problem is at the root cause of the premature failure.

.. but i suspect anything that was in there preceded my ownership, and therefore the LN bearing. I only had this motor 3 years, it had 14 before me.

And those were stock years.

Grant

gee-lenahan-at-gee-mail-dot-com

Assuming it was there before your ownership and before the LN bearing was installed, wasn't the grit going to be fatal to any bearing as it was to so many other parts?

Is this really a good candidate to put more money in? Isn't it the heads that have areas and passages that trap bad stuff especially? Do they clean the block before putting in the nickies?

The bearing wear is not what i would expect from large debris - its more gradual wear, and from talking to several people who have dis-assembled them after years, unfortunately normal for the LN retrofit.

Note i did not say "grit" whatever was in my one cylinder was LARGE (relatively). If its went through the bearing there would be a gaping hole.

Grant

gee-lenahan-at-gee-mail-dot-com

Keep in mind the operating environment your bearing was in. Certainly not typical. It had to have lots is grit in the oil no matter how often you changed the oil. Now which failure came first, the bore scoring, the mains, the IMS. No way of proving that. Were you using a spin-on no-bypass filter?

BTW, the source of the notion that you should measure the crank and the IMS holes in the block for their trueness to each other came from Jake. He now has a tool he uses and if a block doesn't measure true he won't proceed further. This came from his quest to find out why a single block had multiple failures. He destroys engines in testing almost deliberately. Kept asking himself what was different about this double failure engine when other engines would run forever and he measured and quantified until he found an explanation. Manufacturing variations. Yea.

So you might want to question if your block is suitable for putting that much cash into.

I once said splash and was corrected. And immersion at rest.

LN's current thinking re the lubrication of ball bearing IMS bearings is at http://imsretrofit.com/direct-oil-feed/,

so much for his argument.

Sample of one, yes.

Grant

gee-lenahan-at-gee-mail-dot-com

The problem that you encountered is what we've found more than half a dozen times.
The hybrid-ceramic bearing is NOT a permanent solution for this application.
Hybrid and full ceramic bearings are very low friction bearings that get replaced every couple of races in Karts and Motorcycles.
The problem in our specific application with these bearings is the disparity in hardness between the ceramic balls and the steel races.
After some use, the (hard) ceramic balls start to etch a rut in the (soft) steel races until the rut is deep and wide enough for the balls to move around and make contact.
They are really glass balls that are very hard but very fragile. Once they start to move around it's inevitable that they will fail.
For our application if you're OK with removing the tranny and replacing the bearing every 30,000 miles or so, then good for you.
I personally believe that the IMS issue needs to be solved once and for all and that's why I highly recommend the DOF.
The DOF uses an OEM steel-on-steel bearing that when properly lubricated should last the life of the vehicle.
There has never been a DOF failure that I'm aware of and there are vehicles with well over 125,000 logged miles with the DOF.
BTW, the OEM application is correct. I don't believe that it was a poor design. I believe that the manufacturer of the bearing (seals in particular) delivered a product that allowed oil past the seals and you know the rest of the story.
Again, they fail when the seal is compromised and the lifetime grease leaks out, leaving the bearing without the proper lubrication every bearing needs.
Happy DOF'ing,
Pedro

Pedro Bonilla
1998 Boxster 986 - 311,000+ miles: [www.PedrosGarage.com]
PCA National Club Racing Scrutineer - PCA National HPDE Instructor - PCA Technical Committee (Boxster/Cayman)

---

Racecar spelled backwards is Racecar

"Racing is life. Anything before or after is just waiting" ... Steve McQueen as Michael Delaney in "LeMans"

"If you wait, all that happens is that you get older"... Mario Andretti

"Being second is to be the first of the ones who lose" ... Ayrton Senna




Edited 1 time(s). Last edit at 01/19/2017 11:14AM by Pedro (Weston, FL). (view changes)

Grant

gee-lenahan-at-gee-mail-dot-com