S65 Oil reports collation (most with rod bearing photos) - does oil analysis work?

[Assimilator1]

I started this list for myself a few months back when I heard a few comments that bearings had failed or were dangerously worn & oil reports had failed to show any problems. To be honest, I didn't really believe them, how could metal being shed not be picked up??
I expressed some doubt that they could miss problems, but largely stayed quiet about it & decided to gather some data. I was expecting to find that the oil reports were done long before the failure/bearing change, or that the bearings weren't in fact dangerously worn (referring to lead/copper bearings only, & by dangerously worn I mean showing copper). And to start with, that's what I found, although largely I was finding oil reports with high lead levels & when bearings were pulled, their were shot, like these.

Oil analysis confirmed bad bearings

nholmes - https://www.m3post.com/forums/showpo...5&postcount=17 and https://www.m3post.com/forums/showthread.php?t=1237264 - 2 bearings just gone through to copper, 2k miles on oil, pb 97ppm 103k miles.

tom @eas - https://www.m3post.com/forums/showpo...58&postcount=2 , (3 bearings showing copper & 2 of them breaking up!), pb 52, cu 21 106k miles.

tom @eas - oil report https://www.m3post.com/forums/showth...1#post15421907 - bearing photos (Bmw M3 Guy's car) - https://www.m3post.com/forums/showth...5#post15421055, pb 80, cu 36 53k miles.

tom @eas - https://www.m3post.com/forums/showpo...&postcount=389 (surewin's car), pb 106, cu 40, 63k miles.

L4ces - bearing photos https://www.m3post.com/forums/showpo...8&postcount=84, oil report https://www.m3post.com/forums/showpo...3&postcount=89 , pb 24 ppm, cu 2 ppm, Fe 17 ppm. 0/40 was used for last 100k miles) 145k miles.

Richbot - https://www.m3post.com/forums/showpo...&postcount=681 (actually don't look that bad, no copper showing!), pb 21 on an earlier report, 102.4k miles.

Peertwelve - https://www.m3post.com/forums/showpo...&postcount=187 (although oil report not shown, pb 30 ppm) 39k miles.

mmbv1000 - https://www.m3post.com/forums/showpo...&postcount=394 (although oil report not shown, "higher-than-average" levels of lead) 60.5k miles.

tubedreamer - https://www.m3post.com/forums/showpo...&postcount=558 (report shows pb 18 ppm, cu 3 ppm, shells fairly badly worn but no copper showing) 43k miles.

TheBreeze - https://www.m3post.com/forums/showpo...&postcount=563 (report not shown, but pb went from 4 to 10ppm between reports), copper not showing, but bearings quite worn. 87.8k miles.

willie92 - https://forums.m3cutters.co.uk/threa.../#post-2843648 (4 bearings to copper, pb 37, cu 7) 65k miles.

radiognome - https://www.m3post.com/forums/showpo...&postcount=838 - Oil reports 'constantly showed higher than usual metals', bearings quite worn but not through to copper. 68k miles

Imapastokitshc - https://www.m3post.com/forums/showpo...&postcount=858 - 2000km oil report showed pb 19ppm, many bearings through to copper, 1 almost completely. 57k kms, 35.4k miles.

PRJ - https://www.m3post.com/forums/showpo...postcount=1007, pb 19, cu 3, a few just gone through to copper. 41k miles.

LeveragedTiger - https://www.m3post.com/forums/showpo...postcount=1135, pb 18, cu 4, 1 just worn through to copper 3k miles later. 37.1k miles

tom @eas - https://www.m3post.com/forums/showpo...postcount=1338 - alu brgs, report showing slightly elevated levels (including lead bizarrely!), 17k miles.

Yoko22R - https://www.m3post.com/forums/showpo...99&postcount=5, bearings not quite through to copper, pb 35, cu 4, 27k miles.

bvrider1 - https://www.m3post.com/forums/showthread.php?t=1337803, some bearings showing copper, 77k miles at oil report, pb 53, cu 4, bearings changed at 84k miles.

M3MPH1S - https://www.m3post.com/forums/showpo...postcount=1520, 2 bearings showing copper, pb 18, cu 2, 163k miles!

Silos - https://www.m3post.com/forums/showpo...postcount=1583 - elevated lead 66 ppm, copper 7 ppm & iron 13 ppm, changed preventatively, 3 bearings mostly down to copper! 97k miles

amrazM - https://www.m3post.com/forums/showpo...07&postcount=1 , approx 1/2 the bearings worn to copper (run in service missed!), elevated levels of Iron & Lead 7ppm. Advised further investigation due to metals showing over just 500 miles! 40k miles (on that 2nd engine).

Brap///M - https://www.m3post.com/forums/showpo...postcount=2209 elevated lead 19ppm on last OA, cu 3, comments not shown. 65k miles.


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Oil analysis advised caution & to recheck in near future

wfdecon88 - https://www.m3post.com/forums/showpo...6&postcount=24 - oil report, Pb/cu 32/3 ppm. Photos https://www.m3post.com/forums/showthread.php?t=1562310 major wear to lead but no copper visible. 99k miles.

da jemstar - https://www.m3post.com/forums/showpo...postcount=1778 - last oil report, pb/cu 17/2 ppm, bearings heavily worn and some showing copper on the edges.

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Photos &/or oil analysis report, no claim either way

anerbe - https://www.m3post.com/forums/showpo...&postcount=967 - spun bearings, elevated pb (19 and 13 ppm) on 2 reports! High copper (20) on final one. Comments not shown for report prior to spun bearings. 54k miles.

kevin @ eas https://www.m3post.com/forums/showpo...&postcount=429 - high wear & some bearings just showing copper, oil report @75.6k miles pb 6, (note significant gap between report and RB change), bearings changed @80k miles.

XKxRome0ox - https://www.m3post.com/forums/showpo...&postcount=726 - oil report was done 4640 miles before the bearings were changed pb 5, cu 2, the old bearings were very worn, but don't appear to be showing copper. Bearings changed at 58.7k miles.

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Getting close now to missing failures, but not quite!......

Oil analysis stated bearings ok & although they are significantly worn, they weren't through to copper.

blueliner - https://www.m3post.com/forums/showpo...&postcount=937, pb 1, cu 2, preventatively changed @46k miles.

ThatM3guy - https://www.m3post.com/forums/showpo...postcount=1256, pb 1, cu 2, preventatively changed @120k miles.

s14_kev - https://www.m3post.com/forums/showpo...&postcount=777 - high wear, but no copper showing, report lead levels very slightly raised, pb 9, cu 3, comments conclude ok. Preventatively changed @110k miles.

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These 2 could be said as failed & missed by the reports, but I decided they just barely fell into the camp of not dangerously worn, especially subjective these 2 I know!

Oil analysis stated bearings were ok, were heavily worn but not majorly showing copper

lyzmi - https://www.m3post.com/forums/showpo...&postcount=673, 1 bearing showing a little bit of copper, report showed a slight pb (14ppm) spike 5k miles earlier, preventatively changed @66k miles.

kimiraikkonen - https://www.m3post.com/forums/showpo...&postcount=731, high wear, although mostly not through to copper, 1 had a score to copper. Report levels ok, although earlier reports did show elevated lead 7-26 ppm, cu 1-3, comments not shown, 118k miles.

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These 4 are in a grey area if you considered the levels & comments, the comments said ok, but IMO the levels were elevated. If you went by the comments conclusion, you could say they missed bad bearings.

Oil analysis said ok, but pb & Cu levels elevated + shells heavily worn or failed

stevecm3 - https://forums.m3cutters.co.uk/threa...esults.200149/ - although given all clear, report (Millers 5/18) shows pb was 20 ppm & Cu 9ppm, 4 shells to copper! 84k miles.

greg_p - https://www.m3post.com/forums/showpo...&postcount=980 - although given all clear, advised to retest in 1k miles due to raised pb levels. Pb was 22 ppm & Cu 8ppm, a few just gone through to copper, 35k miles.
(Millers 2/19, maybe they tweaked their policy??).

Barnzzz - https://forums.m3cutters.co.uk/threa...2#post-2883365 - no pics or photos there, says report had elevated copper but 'nothing to worry about', shells gave out 2k miles later (had an injector stick open, then another shortly after!, some months prior to shell failure). In a PM he states pb 41ppm & Cu 31 ppm! Post to link to video of shells - https://forums.m3cutters.co.uk/threa...2#post-2885098 80k miles.

Burns - https://forums.m3cutters.co.uk/threa.../#post-3011914 - elevated pb 19, cu 8 and Fe 7 on just 2.2k miles, yet Millers state 'ok'! Photos show copper in many bearings and one bearing breaking up!

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These were the final clincher for me (I found the 1st few late on in my hunting). Oil analysis can miss failed bearings!

***Confirmed analysis missed bad bearings***

delirium330 - https://www.m3post.com/forums/showthread.php?t=1300528 - Cu/Pb at 1 & 2, yet 1 bearing to copper!! Oil life 3092 miles. Bearings changed just ~1500 miles after report. 62k miles

IIAp3x - https://www.m3post.com/forums/showpo...3&postcount=11 (no photos of engine, but states that it blew up 1k after report! Photo of report), Pb/Cu 12/2 ppm. His extensive thread - https://www.m3post.com/forums/showthread.php?t=1119912 55k miles.

MMachines - https://www.m3post.com/forums/showpo...postcount=2109 - shells 4-8U have partially worn through to copper, last oil report (at 84,079 miles shows Pb/Cu at 3/2 ppm), later oil report -

View post on imgur.com

note on his reports, 'mileage' switches from Kms to miles at 2017, 84.3k miles.

Davisca455 - https://www.m3post.com/forums/showth...2#post27215942 - multiple shells showing large amounts of copper, report at 63.9k miles, bearings changed at 65.3k miles

InnerBlueSkies - https://www.m3post.com/forums/showpo...postcount=2211 - multiple shells showing small patches of copper, report at 79.7k miles, pb 5, cu 2, bearings changed at 81.3k miles.

Assimilator1 (yep, me! 2/2021) - Bearing photos https://www.m3post.com/forums/showpo...postcount=2045, oil report pb 4, cu 3, (74.8k miles) https://www.m3post.com/forums/showpo...postcount=1050 - all upper shells showing copper, 2 showing blue streaks from getting hot! 75.4k miles

sv848evo - https://www.m3post.com/forums/showpo...&postcount=736 - unknown mileage on oil, but more than 2800 miles. 1 bearing mostly worn through to copper! And a few others just gone through to copper. Oil report, pb 7ppm, Cu 3ppm, bearings changed 1k miles later. 75k miles.
His photos :-




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So their you have it, whilst my data collection is relatively small (it still took months to find & collate!, & I will add to it, last list update 22/3/20), it does show that oil analysis won't necessarily pick up problems.

How/why? Mostly, & probably predominantly because the high wear rate occurred at some point before the oil report(s). The only way it can be reliable is if the reports are done from the very 1st oil change, from new onwards!
(I found 1 owner who nearly did this, & he posted the results here, can't remember his name [update], I believe it was someone in the 'Oil Analysis Reports' thread (starts in 2009! Which btw is a good read if you want to get an overview of many oil reports), I'll have to go through it to see who it was. Might have been MTROIS, op of the thread, multiple reports combined here.
For reference m6pwr posted What's in our Castrol 10w-60 TWS' & run in service oil analysed.

If you change your rod bearings (with lead/copper ones) & then oil test with every oil change, then yea you can keep a good eye on them, but it won't necessarily pick up other problems (e.g high main bearing wear, unless you changed them too of course).
Oh incidentally, Iam FODI (whose now posted below), said that it's possible for metal particles to be broken down into such small or big particles that it would be missed by regular oil analysis anyway. I haven't been able to look into this particularly, so I don't know how likely that is. I may look into that further, but as I've decided not to rely on oil reports anyway it has a low priority for me. And I'm going to change the rod bearings anyhow on mine.

Btw, my background to this is that I bought a 2008 M3 e92 in November as my weekend/fair weather/occasional track car (never thought I'd be able to own such an awesome car!).
I joined the forum just before getting it, so a few of you know me now, thanks for all the input & PMs guys! I had wanted to use the oil analysis to keep any eye on my car's rod bearings, as I didn't fancy doing more car work in my spare time , as I'm a full time car tech/mechanic. (25yrs, mostly worked for inde garages, did a couple of 1yr stints at Nissan & Peugeot, now working for a Suzuki dealer (6+ yrs), not that makes much odds to this thread though ).
I've owned BMWs since 2004, and of course I work on them (bar recalls & MoTs).

Further info.
My clean up and update of the blown engine list.
My categorisation of bearings in the rod bearing condition thread and other sources.
LCI bearing I partly rubbed down showing the copper they have, and that this one bearing had not worn through the babbitt layer. Thanks to Helmsman for the bearing .

[Helmsman]

Cheers mate, interesting compilation and "conclusion" (i'm aware data is limited but still).

"It does show that oil analysis won't necessarily pick up problems. How/why? Because the high wear rate occurred at some point before the oil report(s)."

To me another indication that most of the wear on fair/high milage shells we see that ran fine, probably are worn in its early life. Once shaved off they continue to do its job.
That said sure, still a good idea to replace them "early" to reduce risk.

[IamFODI]

Originally Posted by Assimilator1

how could metal being shed not be picked up??

...

...oil analysis won't necessarily pick up problems.
How/why? Because the high wear rate occurred at some point before the oil report(s).

...

Oh incidentally, I did hear from 1 guy (I forget who ), that it's possible for metal particles to be broken down into such small particles that it would be missed by regular oil analysis anyway.

FWIW, I addressed all of this and more here: https://www.m3post.com/forums/showpo...postcount=1261

[Assimilator1]

You're the guy I was thinking of , thanks for the link .
I'll tweak my conclusion.
But the main point of my thread was to show the data that oil analysis can miss bearing failure. Your post whilst interesting & useful (so I'll add it here), didn't show that.
Btw, would be useful to know what's your background to knowing this about oil analysis?

Which wear modes produce particles too big for ICP?

Helmsman
Thanks , and could well be, but without stacks of people showing oil reports from early on, we probably won't know for certain.
I'm thinking I should add the mileages to all the reports I've posted.......

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Incidentally, I'm surprised that I've only had 2 replies with over 130 views! lol.
I'm going to see if I can post the pics to my op with the case that demonstrated oil analysis can miss bearing problems.

[Assimilator1]

Post by IamFODI (same as linked by him above).

Originally Posted by IamFODI

Well... yes and no.

Like most oil analysis labs, Blackstone gets its wear metals counts from ICP spectroscopy, which only catches particles up to a certain size -- and not all mechanical wear chucks out particles in that size range. Some wear modes produce bigger particles, to which ICP spectroscopy is completely blind. Furthermore, ICP-detectable particles can come from chemical processes that have nothing to do with what most people would consider mechanical wear -- processes like acid attack from overextended oil change intervals, or highly active surface chemistry from aggressive anti-wear additives in the oil. So, if you see big numbers, it's difficult or impossible to say whether they're anything to worry about. And if you see low numbers, maybe everything's fine, or maybe there's a wear mode that ICP spectroscopy can't detect. You have no idea just from looking at the report.

S65s with the original BMW rod bearings are lucky in that they sometimes produce lead and copper particles in ICP-detectable sizes when their rod bearings wear abnormally, AND they don't seem to produce ICP-detectable lead or copper in significant quantities for any other reason (barring leaded fuel or new oil cooler hardware or something). So, if you see those high numbers from one of those engines, then yeah, it's probably rod bearings. But again, if you don't see those numbers, you have no idea.

We don't know how or to what extent the updated BMW rod bearings or any aftermarket rod bearings will show wear on ICP spectroscopy, if they even do at all. Aftermarket bearing manufacturers will say they went for leaded bearings to facilitate oil analysis, but there's been no rigorous testing of that idea and the data from the field is incomplete. What little evidence we have on the updated BMW bearings is not favorable, though we don't even know what we're looking for because we don't really know what they're made of.

ICP spectroscopy can be useful for tracking early-stage wear when you have a lot of background knowledge about the application in question. You have to know in advance whether and how any potential wear problems will show up on oil analysis, and you have to know about any possible sources of false-positives. Then you have to sample frequently enough to catch the wear while it's still in that early stage, before it starts producing particles too big for ICP spectroscopy to detect.

In other words, tracking wear with oil analysis requires a bunch of things that are difficult if not impossible for an end user, running oil with unknown chemistry, in a hand-built car engine with largely-unknown metallurgy, operated in the real world under uncontrolled and constantly varying conditions. And that's the main problem here.

It's generally assumed that frequent and regular sampling can reduce the futility of oil analysis in an application like this. That's why I'm doing it. But I'm sampling every 5k miles and using a slightly more extensive analysis package (Polaris Labs Advanced Engine Plus), and I'm not taking low numbers to mean a clean bill of health. I'm already planning to revisit my rod bearings within 60k-80k miles after the first change. What I'm looking for are signs that I might have to do them sooner, as well as signs of other kinds of trouble like fuel dilution and other contaminants -- which, by the way, is where oil analysis is truly useful in a car engine. Maybe that's another thread.

The set of oil analysis reports you had prior to changing your rod bearings wasn't so much a consistent history as a few snapshots over tens of thousands of miles. And again, that's in addition to the serious limitations of oil analysis for tracking wear.

Is what you did better than nothing? Absolutely.

Is it mysterious that oil analysis missed your rod bearing wear? Not in the least.

[IamFODI]

Originally Posted by Assimilator1

But the main point of my thread was to show the data that oil analysis can miss bearing failure. Your post whilst interesting & useful (so I'll add it here), didn't show that.

Absolutely. I was responding only to the points I quoted.

I agree that nothing makes the point better than evidence, and therefore what you've collected and presented here is vastly more important than the theory behind it.

Originally Posted by Assimilator1

Btw, would be useful to know what's your background to knowing this about oil analysis?

I'm not much more than a guy who listens to professionals in the field, honestly.

Originally Posted by Assimilator1

Which wear modes produce particles too big for ICP?

Don't think I could do much to improve on the answer I gave here: https://www.m3post.com/forums/showth...7#post25701187

[Assimilator1]

My memory sucks, so I appreciate the reminder .

[Assimilator1]

Added another case of ***Confirmed analysis missed bad bearings***.
Link to an oil report carried out just before the RBs change to follow [edit] now added.

[Assimilator1]

2 in a row! Added another case of analysis missed bad bearings.

[Assimilator1]

Added a couple of ambiguous cases from my data file to the 'no claim either way' section.
Added mileages to remainder of cases not previously noted.

Also I spotted an error by myself (& the owner) of the 'missed bearings' report for amrazM, aside from their 1st line, they had actually advised him to take further investigation due to the slightly elevated pb/cu levels that had occurred over just 500 miles!, and the visible metal he had reported seeing. I've now moved that case to the 'oil analysis reported bad bearings'.
Also added a new section 'Oil analysis advised caution & to recheck in near future', moved wfdecon88's case there (possibly others need to go there too).

38 reports in total
22 reports un-ambigouosly flagged bad bearings (~58%)
4 reports clearly missed bad bearings (10.5%)
The remainder weren't clear enough to come to a solid conclusion (e.g lacking info, bearings borderline, levels vs comments contradictory, too bigger a mileage gap between oil report & bearings removed etc)

[Assimilator1]

2 cases added, de jemster and Burns.

Burns was very lucky as one of the shells copper layer had started to break up!!
Not added to 'missed' section as the levels clearly show a problem, even if their summary says 'ok'!

[torrque]

Guys, the failure does not occur if the bearings get worn a bit, and copper shows... it's normal. The problem occurs when they "spin" , which happens when they wear so much at the top where the little notches are, that keep them into place... then they move and spin around the crank and cause a lot of debris to enter the engine and damage the crank also... wear at that middle point is normal.
Of course if other components pollute the oil and debris gets around between crank and bearing, it will cause failure also.

[Scharbag]

Originally Posted by torrque

Guys, the failure does not occur if the bearings get worn a bit, and copper shows... it's normal. The problem occurs when they "spin" , which happens when they wear so much at the top where the little notches are, that keep them into place... then they move and spin around the crank and cause a lot of debris to enter the engine and damage the crank also... wear at that middle point is normal.
Of course if other components pollute the oil and debris gets around between crank and bearing, it will cause failure also.

Please explain in detail how it is considered normal for hydrodynamic bearings to show copper. I am all ears...

Also, the notches? What are you blathering on about here? If you are referring to the bearing tang, then you may be interested to know that the tang does nothing other than help locate the bearings during installation...

Please, pretty please, do just a little bit of research before presenting your opinion.

[pbonsalb]

Yes, someone needs to learn about both bearing wear and bearing installation.

I am close to 50k miles on my 2nd set of bearings. I think next year I will drop the engine and do both main and rod bearings and then install a supercharger. The car will have 110-115k miles then. The supercharger will keep me entertained for a 2-3 more years until I can buy a 991.2 Turbo.

[Scharbag]

Originally Posted by pbonsalb

Yes, someone needs to learn about both bearing wear and bearing installation.

I am close to 50k miles on my 2nd set of bearings. I think next year I will drop the engine and do both main and rod bearings and then install a supercharger. The car will have 110-115k miles then. The supercharger will keep me entertained for a 2-3 more years until I can buy a 991.2 Turbo.

Damn I love a man with a plan!!!

Question is - when you buy a 991.2 Turbo, will you sell your M?

Cheers,

[pbonsalb]

I don’t know yet. I might keep it since it really is a good car. It would depend on how much I end up driving it. I don’t really want to have cars I don’t drive. I have an E36M3 that is turbocharged.

[Assimilator1]

Sounds good!
And I look forward to seeing the rod bearing photos (aftermarket right?)

Originally Posted by torrque

Guys, the failure does not occur if the bearings get worn a bit, and copper shows... it's normal. The problem occurs when they "spin" , which happens when they wear so much at the top where the little notches are, that keep them into place... then they move and spin around the crank and cause a lot of debris to enter the engine and damage the crank also... wear at that middle point is normal.
Of course if other components pollute the oil and debris gets around between crank and bearing, it will cause failure also.

Showing copper is definitely not normal (for most engines anyway!), the lead embedding layer is not supposed to wear out, unless perhaps the engine has done serious starship mileage! . Also the lead layer acts as a temporary lubricant (of sorts) on starting (and stopping) the engine when their is insufficient oil pressure. So if copper is exposed it will, at some point, pick up when even small debris enters the oil or when starting/stopping the engine. If it gets away with not seizing up the bearing (and then spinning) when running, it will break up and seize/spin that way instead!

If you look at my megapost at the rod bearing condition thread and scroll down to the bottom part titled 'Good condition non S65 bearings', 1 of the links shows a bearing after 154k miles with almost no visible wear, this is how they're supposed to be, oh btw it makes no difference that it's a lower revving lower hp engine, the principle's the same! It's a non contact bearing when the engine's running, or at least it's supposed to be! S65's with OEM shells don't seem to realise that .

As the others have said the notch only keeps the bearing in place for assembly, the clamping of the rod end by the bolts is what keeps it in place.

I've copied this from the rod bearing condition mega post I did their recently discussing all the photos there. At least check out the tech docs by the bearing manufacturers, or at least the ones by King.


The ones that are clear cut are the lead/copper bearings which are showing copper, this clearly shows that the soft babbitt layer has worn through. This layer allows particles to embed into the shell & thus prevent crank damage, as well protecting the crank when starting and stopping the engine, if it's worn ultra thin (e.g copper showing at the edges) or it's just plain gone then this protective layer is gone & the crank is imminently vulnerable to debris damage or pick up, & thus scoring &/or seizure under those conditions. If you don't believe that then read this literature by the bearing manufacturers:-

King bearings - engine bearing materials http://www.kingbearings.com/wp-conte...-materials.pdf
Engine bearings & how they work pdf http://www.kingbearings.com/wp-conte...-they-work.pdf
More info here at their tech page http://www.kingbearings.com/technical-info/

Mahl (Clevite) - https://www.mahle-aftermarket.com/me...l-brochure.pdf
Engine bearing failure analysis guide https://www.mahle-aftermarket.com/me...s-brochure.pdf

ACL - https://aclperformance.eu/products [limited info]

Glycol - http://www.wilmink.nl/Glyco/Glyco_la...informatie.pdf (Glyco aka Federal Mogul were bought out by Tenneco 10/18, pdf not available from their site currently).

[anerbe]

anerbe - https://www.m3post.com/forums/showpo...&postcount=967 - spun bearings, elevated pb on 2 reports! High copper on final one. Comments not shown for report prior to spun bearings. 54k miles.

To clarify, the report I got a few hundred miles before the spun bearings stated I have much more elevated levels of lead. Once the engine started making some ratcheting noise, I got another test that showed very high levels of copper.

The replacement engine had 25K miles (vehicle had 54K), I replaced with VAC extra clearance bearings before installation.

Here's the latest report attached from end of August - with an additional 47K miles.

Funny that they think Aluminum bearings are installed in the engine.

This is driving daily including the difficult Michigan weather, parked outside.

[Assimilator1]

Thanks for the update anerbe

[Davisca455]

Not an opinion, but an observation/question.
In an earlier post in this thread, it seemed like it was stated that the bearing tang was only for installation purposes?
Not sure if that is what was meant, so it generated the next question.
I get that they have to be installed correctly, and that tang to slot helps us do this, but when I looked at the rods, caps and bearing/tangs as an assembly, it looked to me that tangs serve more purpose than just installation of the bearing?
It looks like they are the only location feature to limit lateral movement along the axis of rotation, and the tang also seems to be the only feature that would prevent rotation of the two shells once the connecting rod/cap are assembled?
Or is there some other more subtle thing going on that I don't yet understand?

[Scharbag]

Originally Posted by Davisca455

Not an opinion, but an observation/question.
In an earlier post in this thread, it seemed like it was stated that the bearing tang was only for installation purposes?
Not sure if that is what was meant, so it generated the next question.
I get that they have to be installed correctly, and that tang to slot helps us do this, but when I looked at the rods, caps and bearing/tangs as an assembly, it looked to me that tangs serve more purpose than just installation of the bearing?
It looks like they are the only location feature to limit lateral movement along the axis of rotation, and the tang also seems to be the only feature that would prevent rotation of the two shells once the connecting rod/cap are assembled?
Or is there some other more subtle thing going on that I don't yet understand?

There are lots of tangless bearings out there. The tang does nothing but help installation.

Once the rod cap is tightened, the bearing is held in place by that force. As it has been said, 10 pounds of stuff in a 5 pound sack is an apt way to describe it.

Cheers,

[Davisca455]

Originally Posted by Scharbag

There are lots of tangless bearings out there. The tang does nothing but help installation.

Once the rod cap is tightened, the bearing is held in place by that force. As it has been said, 10 pounds of stuff in a 5 pound sack is an apt way to describe it.

Cheers,

Ahh, that makes sense, so the bearing shell assembly has a slight interference fit with the connecting rod assembly once everything is clamped up.