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12-05-2017, 02:56 PM | #243 | |
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From another thread:
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12-05-2017, 03:01 PM | #244 | ||
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12-06-2017, 07:53 AM | #245 |
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The pics of his damaged bearings are not the micro grooves that the Glyco catalog speaks of. I have not seen a set come through my shop with wear like that so I can't inspect or measure them to determine the cause, but I can confirm that the micro grooves in BMW bearings are not that large nor do they run perpendicular to the journal rotation. I think I have a set I can photo to show the micro grooves....
I might speculate that the appearance may be caused by inconsistent babbit or bonding layer thickness during manufacturing. I don't see how a 2" shaft could indent such small wear lines into a 2" journal. The load is too evenly dispersed on the surface when it makes contact. Edit: I don't have any Glycos. Didn't find much online to show either since they're too small to pick up in a regular photo. This photo from Taiho Bearings shows what the circumferential micro grooves look like. Last edited by deansbimmer; 12-06-2017 at 08:23 AM.. |
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12-06-2017, 08:17 AM | #246 | |
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We are assuming the bearings were good too, I wouldn't be surprised if those are high spots from the manufacturing process or something. |
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12-07-2017, 01:31 AM | #247 |
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Recently witnessing main bearing failures. What a way to end the year!
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12-07-2017, 01:54 AM | #248 |
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Be interesting to see if engines fitted with increased rod bearing clearance bearings show any indication of an increased main bearing failure rate.
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12-07-2017, 03:48 AM | #249 |
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Why would they? There is virtually no loss in oil pressure with the increased clearance bearings.
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12-07-2017, 07:28 AM | #250 |
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Even if that were true, which it isn't, it wouldn't matter because the main bearings are junk anyway
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12-07-2017, 11:15 AM | #251 | |
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Man you are like the plague... |
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12-07-2017, 06:44 PM | #253 |
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At least you are consistent...
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12-07-2017, 07:01 PM | #254 |
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Well, it would make sense to see increased main bearing failure rate on those particular engines...all engines that have catastrophic rod bearing failure have avoided the possibility of main bearing failure. So, if you prevent rod bearing failure then you are now allowing the possibility for that engine to have main bearing failure. Damn I can't believe I'm feeding SP's nonsense!!
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12-07-2017, 07:19 PM | #255 | |
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Ahhhh but suppose you swap the connecting rod AND main bearings as well.... Does the tree make a sound ? GM |
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12-07-2017, 09:25 PM | #256 | |
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12-07-2017, 09:26 PM | #257 |
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No. Making main bearings is much more complicated. With rod bearings, you only need to pay for one set of tooling. For main bearings, you need four. That would be about $100k investment for main bearings.
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12-08-2017, 06:58 AM | #258 |
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That's not so bad...I'm thinking group buy? We'd only need like what, at least 500 commitments? Maybe lets start a gofundme account??
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12-08-2017, 07:28 AM | #259 |
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There are about 60,000 motors. But probably only 10% of the owners agree their motors could have bearing issues and maybe 10% of that 10% might be proactive enough to do mains. The rest of the jobs will be by mechanics or salvagers after the fact, but I bet those people will be seeing more and more seized engines as these cars age and go through multiple owners with sometimes questionable maintenance and driving.
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12-08-2017, 11:53 PM | #260 | |
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So my bearing maintenance fund has just doubled to $6k.. |
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12-09-2017, 11:10 AM | #261 | |
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Or am I way off base here?
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12-10-2017, 08:15 AM | #262 | |
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12-10-2017, 07:41 PM | #263 | |
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Cheers,
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12-11-2017, 07:56 AM | #264 |
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The issue isn't the OEM bearing quality it's the clearances, correct. Although I'd rather have copper in my bearings if given a choice.
If you want to refresh and adjust clearances on the mains, depending on which bearing color/size they used originally you may just be able to go to the next larger bearing color and be OK. If not then yes you're cutting and refinishing the crank to whatever spec your builder specifies. On damaged journals, generally you polish/cut until the journal cleans up and then measure to see where you are. There may or may not be bearings available that would work with the new smaller journal size. Sometimes the journal scoring may be so bad that you have to weld up the journal and rebuild it. |
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