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Help with some main bearings questions

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Old 08-22-2012, 02:14 PM
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Default Help with some main bearings questions

2002 5.3L and I have a set of King OEM bearings part # MB5293SI std size. I measured them with a dial bore gauge and only have between .0005 - .0010 clearance on all my mains. So i'm thinking of getting .0010 undersized bearings or should I get a set of .002 undersize and mix/match to get the right size?
Old 08-22-2012, 07:08 PM
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Why not get a shop to polish the main surfaces to the proper clearance? Might get them to double check your clearances while you're at it...
Old 08-22-2012, 07:35 PM
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I was thinking about that except when I used the dial bore gauge it left some marks on my bearings. Bad enough I can feel it with my finger nail.
Old 08-22-2012, 08:44 PM
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You don't want to polish the crank to get your clearance, it will leave the journals egg shaped and tapered. They'll look pretty though.

If I were you, I'd keep the STD bearings and have the crank turned to get the clearance you want. That will ensure the journals are straight and round and it's cheaper than buying new main bearings. Also, if you're scoring the bearings with the fingers on the dial bore gauge, you may want to set it up with less preload.
Old 08-23-2012, 10:53 AM
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Thanks for the advice, i'm going down to my machine shop today to get this figured out.

Thanks!
Old 06-14-2013, 05:28 PM
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How did these bearings work out for you? I'm about to buy a set off ebay, pretty cheap. Summits description says they offer additional oil clearance, but you say they were tight? We're you using a new crank, or used oem?

I just need a std bearing...
Old 06-14-2013, 06:30 PM
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why not just buy the clevite standard main bearings or the felpro standard main bearings?

I use both on a regular basis... clearances usually fall .0015"-.0020" strait out of the box.
Old 06-14-2013, 09:30 PM
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Buying undersized bearings isn't going to give you more clearance - it gives you less. Undersize means the bearing shells themselves are thicker to compensate for situations where you have crank wear or are running a ground (undersized) crank. based on what you said your measurements were your crank is "oversized" for the standard clearance bearings and as KCS said you need to have your crank ground to increase that clearance.



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