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Old 08-20-2009, 02:22 AM   #1
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Default If you know you spun a bearing clap your hands...Clap clap

Just about 350 miles in the new engine break-in and..

Im having my machinist inspect the m-tuned rod to see if its still usable.

Piston is trash and new one is on its way.

Head is also trash, no pics but the cam journals are completely shot with DEEP scratches all around, there goes $400 in head work down the drain.

Got a new head and had that worked on, just picked up from the machine shop today.
Sourced a perfect long nose crank and block for cheap($75).New ACL race bearings are here, full gasket kit and new rings are on there way. Re-using ARP hardware. Anything else?

bearing FAILURE pics VVV enjoy.

Good bearings on the left, Spun on the right






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Old 08-20-2009, 02:59 AM   #2
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Throw that rod away. Throw everything away, actually. I woudn't reuse a single part from that motor.

Buy new parts, pay someone who knows what they are doing to assemble it. I just did my 3rd track day on my shortblock and it runs perfectly. Minimal blowby, burns no oil at all.

Edit: "Good on the left, spun bearings on the right" Both of those bearings are fucked. The left side is fucked; the right side is fucked.
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Old 08-20-2009, 03:02 AM   #3
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Rod = fucked. Everything = fucked.

You so called good bearing on the left.... not so good.

Good job man.
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Old 08-20-2009, 03:03 AM   #4
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Sav, you got any kind of instant messenger?

PM me
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Old 08-20-2009, 03:08 AM   #5
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AIM is the same as my screen name. Let's chat about getting a decent motor into your car.
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Old 08-20-2009, 03:26 AM   #6
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****.
What was the root cause?
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Old 08-20-2009, 03:43 AM   #7
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dont know but somehow the bearing was starved of oil

New rods will have to be ordered..again

i haven't even paid off these rods yet through my credit card,****.
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Old 08-20-2009, 03:55 AM   #8
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i've gone WAY past my build budget so for rods im looking these. ETD is m-tuned right?

Mazda Miata 323 1.6 1.8 B BP H Beam Rod Rods:eBay Motors (item 190328220337 end time Aug-22-09 18:46:53 PDT)

They dont include the rod bolts but i still have them from the m-tuned rods
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Old 08-20-2009, 04:35 AM   #9
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plastigage = ftw?
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Old 08-20-2009, 04:43 AM   #10
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seems like some of the debre from the piston rings break in might have clogged the oil passages for the bearings?

sighhhhh
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Old 08-20-2009, 04:46 AM   #11
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?
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Old 08-20-2009, 05:05 AM   #12
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Quote:
Originally Posted by Savington View Post
?
indeed

i have no clue
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Old 08-20-2009, 11:07 AM   #13
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Not sure about that theory on the piston ring debris. It would have to make it through the oil filter first.

oil sprays on bottom of piston and picks up debris -> oil and debris drip into sump -> pump pulls from sump -> oil goes through filter -> oil goes to main bearing.
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Old 08-20-2009, 01:24 PM   #14
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Definitely some sort of oil starvation. That is scary. I am just now finishing my motor assembly. I did it my self and I've never done it before. I hope to god it doesn't end up like this. I think some root cause analysis is in order here.
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Old 08-20-2009, 01:44 PM   #15
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Quote:
Originally Posted by railz View Post
dont know but somehow the bearing was starved of oil

New rods will have to be ordered..again

i haven't even paid off these rods yet through my credit card,****.
smart
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Old 08-20-2009, 01:58 PM   #16
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Quote:
Originally Posted by wes65 View Post
Definitely some sort of oil starvation. That is scary. I am just now finishing my motor assembly. I did it my self and I've never done it before. I hope to god it doesn't end up like this. I think some root cause analysis is in order here.
If that is the case, based on my experience, check the pressure relief valve on the oil pump.
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Old 08-20-2009, 02:13 PM   #17
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Were any of your bearings on your mains on backward? That would cause starvation to a rod easily but not be noticed through oil pressure.

Well I guess your machine shop disassembled it so they wouldn't admitt a mistake they notice on disassembly anyway. The above is my best guess at the problem.
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Old 08-25-2009, 04:51 PM   #18
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(CLAP, CLAP)

I am still rebuilding mine. This has me freaked out that it's going to happen again during break-in.
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Old 08-25-2009, 05:12 PM   #19
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I spun a bearing in my 1875cc vw once. Forgot to put the dowel pin in the rear main journal. Ruined the case halves, and a 8 pin balanced stroker crank. All happened in under 5 miles. :( DOH!

Never did that again.

knock on wood I have yet to spin a bearing on a conventional bearing cap engine.
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Old 08-25-2009, 05:34 PM   #20
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perfect, 300bhp motor crew signing in. Wisest car money I've spent in a while.
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