Powder coating is the way to go for sure. I decided to repaint my valve cover, and I did an immaculate job. Sandblasted the surface, prepped it with TSP, put 6 coats of primer and 3 coats of engine paint. I waited for the perfect ambient temperature and humidity.

One year later, it's starting to bubble up again. Aaaaargh! Wish I had powder coated it!

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-tp


1990 300SE "Corinne"- 145k daily driver - street modified differential - PARTING OUT OR SELLING SOON - PORTLAND OR. AREA - PM ME FOR DETAILS
1988 560SEL "Gunther"- 190K passes anything except a gas station
1997 S420 - 265k just bought it with a rebuilt trans. Lovely condition

I'm not so sure. A guy I know powder-coated his valve cover red and man it looks awesome. But two years later it is starting to flake off. I was going to powder-coat mine but the guy at the coating shop here said they have not had good luck getting powder coating to stick to valve covers - he said they start to flake off after a couple years. He said to use high-temperature paint. So I am going with the PJ1 high-temperature motorcycle exhaust flat black spray bomb paint. I live in a hot climate so I need all the heat transfer and cooling I can get. Flat black is the best radiant emitter there is. It would be better to use a catalyzed two-part paint but I am running low budget these days. If the PJ1 starts to flake off, I'll just repaint it.

FYI, only paint the outside... MB puts some kind of gold-colored coating on the inside of the cover and it was flaking off too to so I had it all sandblasted off.

Repainting is never a big deal, but stripping off the old paint and prepping the piece is a total nightmare. I had a friend with OCD help me out with it last time. She enjoyed the hours of tedious manual labor. I don't.


Too bad powder coating isn't working out..... I don't know what I am going to do next time around.....

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-tp


1990 300SE "Corinne"- 145k daily driver - street modified differential - PARTING OUT OR SELLING SOON - PORTLAND OR. AREA - PM ME FOR DETAILS
1988 560SEL "Gunther"- 190K passes anything except a gas station
1997 S420 - 265k just bought it with a rebuilt trans. Lovely condition

Your OCD enabled friend will LOVE the experience!

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'84 300SD sold
124.128

Problem is with M103 valve covers at least, is that they are cast aluminum and riddled with pits that then have to be filled and sanded. Polishing wouldn't work out too well. My M117 is another story, but the paint is fine after 22 years so go figure......

__________________
-tp


1990 300SE "Corinne"- 145k daily driver - street modified differential - PARTING OUT OR SELLING SOON - PORTLAND OR. AREA - PM ME FOR DETAILS
1988 560SEL "Gunther"- 190K passes anything except a gas station
1997 S420 - 265k just bought it with a rebuilt trans. Lovely condition

Right on. I had mine sandblasted (aluminum oxide) inside and out. Cost $40, and that very well-spent I might add. I first tried chemical stripper and it worked great on the flat surfaces but down inside the ignition valley it was a complete nightmare. What was I thinking?!?!? I futzed with it for awhile and then it was off to the sandblaster!

I think the cover (on the 104 at least) is either pot metal or magnesium. I don't think it's aluminum. You are right, the casting is rough and fairly pitted - would be tough to polish out and make it look nice.