Generation III Internal Engine 1997-2006 LS1 | LS6
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Old 10-22-2009, 07:08 PM
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Default spun bearing

i have a lsx440 and it spun #2 crank bearing any ideas why
Old 10-22-2009, 07:29 PM
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Do you know what the bearing clearance started at you could check #'s 1&3 if they arnt to damaged they may have been to tight. how does the rest of the parts look?
Old 10-22-2009, 07:36 PM
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the motor has a 1000 miles the rest of the bearings were little scorched but not spun
Old 10-22-2009, 07:52 PM
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The caps may not have been properly torqued, wrong size bearings, or too much play in the crank will cause a bearing to spin. I have seen it a few times on motors remanned from Cummins.
Old 10-22-2009, 07:58 PM
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Scorched meaning they turned black from heat ?
Old 10-22-2009, 08:01 PM
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it back fired on the dyno pretty bad spraying nitrous could that caused it
Old 10-22-2009, 10:58 PM
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A nitrous back fire should be seen more so on your pistons and rod bearings but if it was hard enough it is possible put a slight bend in the crankshaft that would take out a bearing.
Old 10-23-2009, 08:24 AM
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it drove fine after that but i was getting more blow by
Old 10-23-2009, 08:35 AM
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How much oil clearance was on the mains. I have heard that some of the stroker cranks will flex on the 2 and 4 mains in high hp engines and sometimes require .0035"-.004"+ oil clearance.
Old 10-23-2009, 08:32 PM
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If your engine had an increase in blow by the damage was done then. When the crank has to work to overcome the pressure of a bearing trying to spin it increases the cylinder pressure on the rings that is where the extra blow by came from.
Old 10-25-2009, 06:55 PM
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thanks for the info




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