Main Bearing trouble.

Old 04-25-2008, 10:56 PM
  #1  
Tod74
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Default Main Bearing trouble.

Well in previous threads about " crankshaft company" while others have bashed them I defended them...but now I am not so sure...I had my motor out this week to swap heads and decided to pull the pan and look at the bearings..VERY GLAD I DID. didn't look so good.I only made a few passes on it and it ALWAYS had good oil preasure..even while braking(I made it a point to look while braking,and I have a large line to gauge not the tiny one) The rod bearings looked ok but 2 of the mains( number 2 and number 4) looked like doo doo. Shiney on only one side and appeared to be flaking. Crank not hurt at all. Also the piston skirts were a little scratched up...not sure if it because the clearance is tight (I have no way to check that...no dial bores) or if it is just because the long stroke brings the piston so far down past the bottom...that's what I think it is.I put this turd together and I did take a sand roll to the sharp edges at the bottom of the bore..maybe not good enough. When I put it together the crank mic'ed right at the low end of standard which is what they told me it would check at when I bought it...again, I have micrometers but no dial bore so the only thing I can do is mic crank and check clearance with plastigauge( I know I know) ops: but that's all I have. Anyway it had about .0025 on the rods and .003 on mains best I could tell with plastigauge anyhow...When I ordered this short block it was suposed to be ready to assemble. Told me I would only need to file fit rings, wash it and put it together that all clearances would be checked...I still checked everything I am capable of.

SO I called Schmidt Automotive in Indianapolis as they have always done very good work and talked to them...I asked about just getting the crank checked every which way cause I have no clue why this thing chewed up the bearings so fast with good oil psi...and to me if it was an oil problem the rods would take a crap before the mains as they are oiled last..but anyway before I even told him which mains it was he said "Was it number 2 and number 4?" :shock: I said yeah..how did you know? He said if it is a balance problem that is where it would show up normally. so right now the crank and one rod,piston bearing etc is there being checked and rebalanced if needed. My luck is the worst ever.... I am not blaming crankshaft company just yet just have to wonder what could have caused this...I REALLY hope the thing isn't balanced correctly cause then I would know...if it turns out ok then I will be stumped. Any thoughts on what would kill the mains in only a few passes. No evidence of detonation on plugs or pistons. I will post pics tomorrow my camera is dead at the moment. Also gona tyake the whole darn thing to Schmidt Auto next week and have everything measured and checked to be safe..he saisd he would check bore size vs pistobn size for me to see why the piston skirts arev scuffed. And I cleaned the crap out of this thing before assembly...took out plugs and ran briushes throgh ouil galleys and hand washed three times after pre assembly.
OH yeah new Merlin III block, canton power pan and melling HV oil pump.( Tried a stock pump first but didn't have too good of oil preasure when hot so I switched it. Never ran it with the stock pump except in garage. Balancer was a brand new ATI super damper 7 " or whatever they are...actually a little bigger than 7" but not an 8". They told me they normally use an 8" balancer but since it is internally balanced I didn't think it mattered.
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Old 04-26-2008, 12:25 AM
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olds48
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Man,that sucks,bud.Hope it all works out okay,and don't cost too much$$$
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Old 04-26-2008, 12:35 AM
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Tod74
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Originally Posted by olds48
Man,that sucks,bud.Hope it all works out okay,and don't cost too much$$$
It shouldn't cost much I hope...but enough. it is 175 for the balance job( even if it isn't bad cause they still have to spin it to check) plus rings bearings and gaskets...crank wasn't hurt. My only worry is WHY it did it. If they don't find SOMETHING wrong then I will be scared to death every time I run it waiting for the big kablewy!!

The stupid thing is...I just bolted on the heads and adjusted the valves and put on the intake...THEN decided I better look at the bottom end...LOL there went about a hundred bucks worth of gaskets down the drain. ops: I am wondering if those Fel Pro head gaskets can still be used. They were torqued down but never ran...Anyone KNOW? I figure once torqued down they are done but not sure. they are 1017-1 with the steel wire ring.
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Old 04-26-2008, 05:15 AM
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ashtrak
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Man that really does suck. I think i would balance everything to make sure ( If that is problem ) and then be worry free :roll: At least you caught it before a major melt down because that would really SUCK. Best of luck to you take care.
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Old 04-26-2008, 07:33 AM
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signsbyesa
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hey tod, on horsepower tv, they have dynoed an engine, and reused
the gaskets so i think you would be ok with just torquing them down.
and just for the heck, what main bearings wear used on your motor?
when i wanted some good bearings i looked at what pat musi was
using and he uses a lunati crank with king bearings, so i went with
king bearings coated, if they can take the abuse of a bbc from
musi, they should last on a mild motor :wink:
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Old 04-26-2008, 07:55 AM
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suicidebomb
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Tod74, I've reused head gaskets that were torqued but never run, not saying I reccomend it, just that I got away with it. Also that was an 8/1 comp. motor, nowhere near what you're running. Sounds like our luck is about the same this year. Good luck, things are bound to get better!
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Old 04-26-2008, 09:34 AM
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billhendren
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A bearing that is shiney on one side only indicates that either the crank isn't the same size all the way across the journal or the main bearing bore is tapered. taper on the journal is common with those cranks.usually if its a balance problem the damage will be equal all across the bearing on both the top and bottom half.Bill
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Old 04-26-2008, 11:18 AM
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Tod74
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Originally Posted by billhendren
A bearing that is shiney on one side only indicates that either the crank isn't the same size all the way across the journal or the main bearing bore is tapered. taper on the journal is common with those cranks.usually if its a balance problem the damage will be equal all across the bearing on both the top and bottom half.Bill
journal taper was exactly what went through my head when I saw it...based on all the stuff I have heard online about this company...I told the crank guy that and asked him to check eeeeverything that could possibly be wrong. The bearings were those federal mogule/speedpro bearings that are brownish colored ch7200 or somethin' like that.(part num),

After the crank guy saw the bearings he said same thing about equal damage across but SINCE it was the 2 and 4 bearing he would still check it.
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Old 04-26-2008, 01:23 PM
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OK here are some pics ...these are number 2 and number 4...some of the crosswayscratches on the dark portion of bearing are from me having piled them into a wal mart bag all together and they banged against each other....the thrust bearing had one deep mark in it also ..very narrow showing a tiny bit of copper. sorry pics are so large..couldn't see the damage when resized.
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Old 04-26-2008, 01:24 PM
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