Scoring Due to Foreign Matter or "Dirt"

Corrosion of the lead in copper-lead and lead-bronze alloys, and of lead base whitemetals, may be caused by acidic oil oxidation products formed in service, by ingress of water or coolant liquid into the lubricating oil, or by the decomposition of certain oil additives.

Removal of overlays by abrasive wear or scoring by dirt exposes the underlying lead in copper-lead or lead-bronze interlayer's to attack, while in severe cases the overlays may be corroded.

http://www.gbbearings.co.za/page29.html

The piston skirt is intact but the ring area might have scuffs and scoring to maybe half way down the piston, more so on the exhaust port side. Now if you see it as I do then read on, if I'm wrong then read the next answer.

https://answers.yahoo.com/question/index?qid=20130328163940A...


XJ40 • View topic - DIY alloy wheel refurbishment - Xj40.com
www.xj40.com/viewtopic.php?f=32&t=4810‎
Jul 15, 2012 - 10 posts - ‎9 authors
Dont use a wire attachment over the outer surfaces, it scores the alloy too deeply. i used an angle grinder very gently where the rim was ...

https://answers.yahoo.com/question/index?qid=20130328163940A...

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Note added at 1 hr (2014-02-04 20:21:55 GMT)
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Também pode ser "riscos", "entalhes".

http://www.wordreference.com/pten/sulco