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Discussion Starter · #1 ·
Lack of lubrication? They were stock GM bearings in a marine application (NA stock powered).. all the same-

crank measures good with 1.3 thou undersize (possibly polished to achieve marine spec). Crank still good -

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Race it, Don't rice it!
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No, It's supposed to be that way.
Bearings are designed to be out of round up to .002-.003 at the parting line bigger. This does primarily two things, It helps get the oil wedge get going between the bearing and journal and prevents the edge of the bearing from scraping off the oil and ruining the oil wedge.
Performance bearing are typically made with a bigger parting line as you see here.
NOTE: Bearing installed in a rod or main cap torqued to spec are always measured 90' to the parting lines for true represention of the oil clearances while the journal is expected to be perfectly round.
 

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You are circulating a lot of dirt and the seams are typically wider than the bearing bore these are made by broaching the bearing bore not rotary boring that bore. Since the non wear is on both sides it can also indicate the shaft journals are too worn thus essentially undersizing the shaft and that’s presents too much clearance.

This is an engine needing a professional cleaning. The crank needs to be turned to a standard under size and the main caps need to professionally resized and new bearings honed to that to restore straight and centered.

Given the cost you might want to consider a reman short block.

Bogie
 

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Discussion Starter · #7 ·
I micd 5he journals they are all within half a tenth all round. Crank is straight too. Must be dirt, thus has been rebuilt and thy prob recirculated trash from the oil cooler..
 

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Discussion Starter · #10 ·
thanks- im wondering if one can open the cooler up - flush and reseal? I do have a holley race fuel pump i use to flush em - rotating in all directions for 5 minutes.. did the lines this way and they cleaned up very well but i hear ya-

thanks for the replies - i think thats what previous builder must have overlooked cos the motor wasnt worn at all..
 

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Race it, Don't rice it!
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If I have to reuse a cooler I hook it up my parts washer pump and let run for a while them follow up with water and compressed air. Those expanding type ear plugs work well as pigs with compressed air to help clean out hoses and lines after assembly or a spontaneous auto disassembly.
 
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