Wait until I get to the cam chain wear pads* ... then you'll see suspense.


*a.k.a. Variocam timing-chain guide-rail pilot ramps

I finally found time to pull the bearing yesterday after dealing with other demands on my time, including taking a cat with cystitis to the vet. The bearing puller uses a 24mm nut, but my wrench set only went up to 18mm. Once again, a big metric crescent wrench saved the day. It required considerable force to remove the factory dual-row bearing, as Jake Raby warned. I was expecting to hear a gunshotlike **crack!** when the puller overcame the wire lock, but a soft metallic sigh was the only sound it made. What a gyp!

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A couple ounces of oil seeped out of the hole when the bearing came out. I was prepared and caught it with an improvised catch basin. I'm going to send an oil sample to SPEEDynamix to be analyzed. It doesn't cost all that much and should be informative. An analysis can reveal an engine's entire history, according to oil expert Lake Speed, Jr., the man behind SPEEDynamix.

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As expected, the bearing looked, sounded, and felt perfect. The bearing's wire lock did not break but remained intact.

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Now I need to order the IMS Supplemental Toolkit from LN Engineering, necessary to install the Solution's bushing. (I've stopped calling it a bearing. It's a bushing, folks.) Renting the kit from LN is free for Solution buyers with a hefty deposit, $509.95 worth of hefty. (Which is interesting, in view of the Supplemental kit's list price of $299.) While I'm waiting for it to arrive I'll be busy, carefully measuring and marking the cutout for the notch, and then grinding, filing, and otherwise machining the notch itself. Photos to come. The next installment will also feature my patent-pending method for sealing the IMS opening to ensure that absolutely zero aluminum particles get in there while grinding. Stay tuned.

Have been following along your journey with great interest.
Glad to hear that you went with The Solution instead of the other options.
(That is what I chose without hesitation for my car) Pay once-cry once or whatever that saying is.

But, it is a "plain bearing".
Not a bushing.

Best of luck with the rest of the journey.
The best part of Boxster ownership is driving the car. Hopefully the car rewards you for you perseverance and investment!

cheers

Hmmm... Jake Raby or Charles Navarro referred to it as a bushing in one of their videos. It sure looks like a bushing to me. JFP?

That aside, thanks for the kind words.

While we're on the subject...

A Kansas-based company named Huyett supplies a huge selection of bearings, bushings, and fasteners of every description for a multitude of applications. They consider bushings and bearings to be fasteners... which spins my head around. Anyway, they weighed in on our question on their site:

Bearings and Bushings: The “Difference”

Many explanations will simply state that there is no difference because a bushing is a type of bearing. While this isn’t untrue, it is a surface-level answer because it invites the notion of, “if A is B and B is C, then A is C.” In other words, if bushings were a type of bearing, then subtypes of bushings would also have to be a derivative of a bearing, which isn’t true. Bearings are not the “parent” part.

Bushing is more of a generic term that catches most of the single-component members of this fastener family. Many bushings bear loads or allow for rotational movement, and many bearings reduce friction; all of these parts will alter the size of a bore. So why even distinguish between the two?

There are a few specific fasteners that are definitively a bushing or a bearing based on the definitions above. Beyond these few, the difference between a bushing and a bearing at a practical level is how it is used, not how it is designed. Since fastener manufacturers, distributors, and hardware stores cannot predict how you will use a part, their names for the fasteners are somewhat arbitrary.

https://www.huyett.com/blog/bushing-and-bearing-difference

Interesting, huh? Just out of curiosity, when I get a chance I'm going to email Huyett and ask them what they would term the Solution's application in M96 engines.

EDIT: Emailing them was a good idea. Unfortunately, I didn't anticipate that Huyett would have no email address. That's what you'd call "old school." I guess a website was leading-edge enough for them.

I will opine that to be marketing hype and nothing more. Oil analysis will give you a snapshot in time, so unless you’ve been collecting them periodically, there is no history to be had.

A couple of additional thoughts - if you really want to understand the oil, knowing what was put in the engine at the last change is critical and the number of miles since the last change is equally critical.

Erm. It’s a bearing. Not a rolling element bearing like the one you removed, but a journal bearing. No clue of the essential details of the LN design (dimensional, pressure in the feed line, etc), so I can’t comment on the actual hydrodynamics of it all (and, in the last 35 years, I’ve forgotten pretty much all of the detail I once knew). Unlike rod and crank mains, it sees no impact loads, so a much less complex problem set in that regard.

Lots of flashbacks to closed form calculations, using tensor notation, in that Lubrication Theory elective I took as a grad student. I’m imagining any number of quality software solutions are out there today to make that a whole lot easier to iterate on - LN still had to do the engineering, but the math is less drudgery.

Thanks for weighing in, Tom. I take it you disagree with Huyett that the taxonomy of bearings and bushings is somewhat ambiguous? Huyett and other bearing outlets have convinced me that classification is not cut and dried, so I'm backing off from my position. The Solution's design could be described as a type of bearing. Or a type of bushing. From here on in I will call it a bearing for the sake of clear communication.

Good points about oil analysis. Analyzing the sample I'm sending in can detect wear metals, fuel dilution, and other contaminants that indicate potential issues and reveal whether the engine has any ongoing problems, which is my primary concern.

Mechanically, it is a bushing that is serving as an oil fed bearing.

The picture with the oil is interesting. As the oil level drops when the engine starts, this small amount leaking out is proof that the bearing really only lives from its grease filling during operation.

I do disagree with them. In this application, It’s a hydrodynamic bearing. There is a clearance between the OD of the shaft and the ID of the bearing. The oil which is pressure fed to it, given that clearance and the feed pressure, creates pressures internal to the bearing which are well in excess of what the feed pressure is, hence the term hydrodynamic. The same principle is at play in your mains, conrod big ends, camshafts (journals, not lobes), etc.

Please consider it a data point and nothing more. If the engine was run very briefly, that last time it ran, you will see fuel dilution numbers which are an artifact of a cold start (so over rich combustion) and quick shutoff, for instance. Note: I am a big fan of oil testing and have been doing it for years, across our small fleet of 2 & 4 wheeled vehicles.

I misquoted Lake Speed Jr. when I wrote:

What he actually said was that periodic oil analysis can reveal an engine's history. In my haste to click the Submit button I distorted his words. My apology to Lake and to the forum.

Generally, if there's high speed and/or high load its called a bearing. Think main and rod bearings. They are really bushings, but given their application they're called bearings. The same would apply to the solution.

Think of the small end of the connecting rod on an old style V8 engine: to allow the piston wrist pin to properly float, the small end of the connecting rod has a bronze sleeve bushing pressed into it with annular oil groves in it to permit lubrication; when in operation, that sleeve becomes an bearing.

What it is is all a matter of semantics: a mechanical engineer would call the Solution a bushing because of its design features; in function, it is an oil fed bearing.

I measured and marked the cutout for the notch to my satisfaction. It's 20mm wide, which provides room to put a 13mm deep socket on the oil fitting. Note my aforementioned patent-pending seal for the opening, fabricated from thick, extra-sticky Gorilla tape. How sticky? It took a lot of pulling to peel the prototype off. It seals the opening tighter than a bull's rear end at fly time (one of my dad's expressions, approximately). Not a chance of aluminum particles from grinding getting past the seal, but as belt and suspenders I stuffed a paper towel in the opening before sealing it. I'm ready to grind the notch. Unfortunately, that will have to wait until tomorrow due to a previous commitment.

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Exactly: All a matter of semantics. Like I said about main and rod bearings. They're bushings, but given their application they're called bearings. ;)

I'VE GOT IT! It's a bearinglike bushing. Or a bushinglike bearing, take your pick. Whichever it is, it's unlikely to fail, and that's all I care about.

By the way, my next-to-last post contained proof that I'm getting a handle on my OCD-Lite. There was a time when I would have spent hours carefully cutting out the seal with an X-Acto instead of scissors, and I would have made sure that the marking lines for the cutout were straightedge-perfect. These days I'm deliberately freehanding, and that's an example. I've found that in general it's more fun and doesn't take nearly as much time. (Time, as it dawns on everyone sooner or later, is the most precious commodity of all.) Nevertheless, the notch itself will be as machinelike perfect as I can make it. Because as long as I'm performing the sacrilege of defacing the crankcase, the least I can do is make it look like it belongs there.

Not all bushing are bearings, but all bearings are bushings ;)

Thanks, Captain Obvious. :D :D :cheers:

Not quite finished but getting there. Unfortunately, I have to go out to dinner, so finishing touches will have to wait until tomorrow.

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