MAN 1550 Chrome Valve Cover Pitting

You can try polishing them with nevrdull which will take the green off and make them shiny. In the future you want to wipe them with nevrdull about monthly and wipe off (if you do it this often it takes a few minutes and not hours). Without seeing them it might be hard to determine. The pitting could be caused by poor metal underneath and a reaction between that and the chrome and replating them would cause the same results usually. Plating them will take about two weeks usually and do you want your boat un-usable for that period of time as well as the engine open. You may want to take one to a plater and see what their thoughts are and cost and compare to new......I'm not sure what Man valve covers go for, but it probably isn't cheap. Another option is to have the powder coated or painted white and do away with the chrome....

Octobriana

I have 820's and have one cover out of 20 that pitted - for the life of me I can't figure why, unless its just statistics.

Had the same. One went all funky and pitted. No idea why.

I've seen the same. I think it's a poor casting.....

Maybe I can shed some light on your plating issues. I have been in the electroplating, anodizing, electropolishing industry for over 34 years. Your valve cover application is best served by powder coating. You can get PC that mimics stainless steel, polished chrome, polished gold and/or any color of the rainbow.

Plating on the other hand is especially tough on castings of any kind. The quality of any plating job is about 90% dependent on pre-cleaning of the part and the smoothness of the substrate. Chrome plating is actually a 'flash' or very thin coating of chrome over nickel and/or copper/nickel and then chrome. The thickness of the copper/nickel coating and its integrity is more important than the chrome itself which is only there to prevent the nickel from tarnishing and provide a shiny appearance.

Chrome is a well known and documented carcinogen. It has been all but outlawed in the EU. It is declining in popularity here because of its rising costs that are mainly associated with EPA issues.

No, my company does not do chrome plating and never has. No, we don't do powder coating. The cost of entry to powder coating on a large scale is large and the ROI is inversely proportional. To summarize: Find a good shop that does multi colors and get your metal parts (or wood) powder coated. The cost will be much less than chrome and will last far longer in our harsh marine environment.

Check with these folks if you want to get them re-plated. Melimar Finishing

They do beautiful work and will give you very honest advice as to whether it's worth doing on not.