broken piston skirt

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Mar 11, 2006 | 04:46 PM

77' f-100 ranger xlt

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broken piston skirt

alright now i have a major question here! i am in the middle of building my 400 and i rotate it over to put in the lifters and i hear the sound of metal on concrete. i look down and see what looks like a piece of my piston skirt and it was. now what would cause this. they are kb 177 bored .060 over has not been started hell i only have a short block right now. oh and i took the broken piston out and will post pictures if you all need to see what i am talking about.

Mar 11, 2006 | 06:18 PM

Torque1st

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The piston was probably dropped during assy. They are a hard aluminum that is fairly brittle.

Mar 11, 2006 | 07:19 PM

77' f-100 ranger xlt

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hmmm i assembeled it and i did not drop it, but maybe the machine shop did when they were balancing it all.

Mar 11, 2006 | 10:53 PM

grclark351

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From: chicago burbs

check for glue!

Mar 11, 2006 | 11:46 PM

Torque1st

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All it takes is one drop and a crack forms. The broken part can fall off any time. Inspect pistons very carefully! They can also be broken if cocked in the bore during assy.