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plating, anodizing, & finishing Q&As since 1989




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Repairing Pitted Engine Bore

2003

I have a combustion engine bore of 8 3/4" diameter with some pitting due to water condensation on the top section of the bore (horizontal engine), can the cast metal be replaced? (I want to avoid sleeving this large bore and stroke engine 8 3/4" x 15"

It will have mechanical loads applied, dragging from the Piston ring and thermal expansion as the cylinder temperature rises.

So I do not want the metal to fall off and jam the piston! It must also wear at the same rate as the parent metal so no high spots will appear.

When using the brush plating method can the area be cleaned, built up and rigid honed back to a acceptable working surface without having to do machine work?

Regards,
Alastair.

Alastair Geddes.
- Brisbane, Queensland, Australia

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2003

My answer is that I think this would prove doable, but only by someone very skilled and experienced in the art. I believe it would require welding, followed by grinding, followed by brush plating, followed by grinding. If you can have a skilled mold repairer look at it, s/he will be able to tell you if it can be done.

Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey

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2003

Brush plating can be used either with welding or without welding depending on the depth and extent of the surface corrosion. A repair shop in New Castle recently repaired a 300mm MTU Diesel bore by brush plating. The alternative was to ship the block to Germany for repair.

Michael Wisniewski
- Chatsworth, California, USA

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2003

If pits are within 0.010-0.015" it could be practical and economical to hone the cylinder oversize then brush nickel plate then hone. If corrosion is deeper the alternative points to thermospray then hone. Special gun for inside diameter would be required. In any case all sleeves must be treated equally for uniform performance. Probably you will find a chrome plating shop willing to quote but chrome is too hard and ring design would have to be revised. G. Marrufo-Mexico

Guillermo Marrufo
Monterrey, NL, Mexico