Boeing 717

Can i have my valve covers sand blasted or is that a no no????

Thanks
JERRY

Geoffrey

Yes you can, both the aluminum or magnesium ones. If the mag ones are deteriorating, the blasting will most likely leave pitting and render the valve cover even more useless than it was.

chancecasey

Yeah the mags are usually in terrible shape at high mileage. Probably not the "best" thing to do, but I chipped/picked away the loose bits, then sanded them all down with sand paper to the point I was confident nothing would "flake off". Then I taped a large piece of sandpaper to a good flat bench top, and grabbed the cover and rubbed it around in circles to get the bottom edge nice and flat. Then make absolutely certain there is no grit left - clean them really well. Bolted them on with new gaskets and no leaks since.

People will also say this is a big no-no, but I also put a very small bead of high-temp RTV in the gasket groove, LET IT DRY COMPLETELY (24 hours), then put in the gasket and bolted it up. Yes, having RTV or anything else floating around in the engine would be bad - but if you let it cure completely BEFORE any oil or anything else wet touches it, it's pretty solid stuff and should not break loose or dissolve.

Let the flaming of my method begin...

chancecasey

P.S. - the reason for my RTV approach was because even though the "top" of the gasket channel was flat from my sanding, the bottom of the channel had high and low spots that of course cannot be made flat - at least - not in a way that's practical vs. buying new covers. It's the bottom of the channels that counts toward making a good seal.

Boeing 717

Thanks, so i will have it sandblasted or some time of media blasting. Is there any tricks to it such as covering the portion where the gasket goes and can they just blast away???

JERRY

chancecasey

I wouldn't mask any of it for blasting purposes.

MisterRisky

Sounds like a great approach to me! I like that your approach is pragmatic yet slightly untraditional.

Les Dawes

Hi, I did similar to Chance; I flatted the seating surface on a sheet of fine emery paper, then had mine BEAD BLASTED (it's gentler and peens the surface) after masking the mating area completely (my powdercoater uses a self adhesive very thin metal foil for masking, which is not affected by the paint curing heat). Upon return from the coaters I cleaned the masked off area before fitting. Not sure if my covers are aluminium or magnesium, I think aluminium as 1992 C4.
Regards, Les.

Ritter v4.0

Any issue with powder coating brand-spanking new aluminum covers?
Any special prep work advised?

Fred's 964

Jerry, I recently powder coated my magnesium valve covers. I cleaned them, stripped the paint with paint remover, blasted with medium aluminum oxide, cleaned again with brake cleaner, baked at 350 degrees for 15 minutes to outgas any contamination, then powder coated. There was some pitting in the magnesium, but the blasting didn't make it worse. The pitting was generally in the area of the plug wire holes so no oil comes in contact with it. I haven't put them on yet. I like Chance's suggestion about RTV in the grooves. Here are some pictures:




I am happy with the results. I've since done the fan and housing too.

Ritter v4.0

It seems like a 993 kind of thing to do <<ducking>> but I think before I install the new Hargett covers I'm going to powder coat them. Why not.

It'll be easier than after I install them.

parsecnc4

When did Porsche stop using the magnesium valve covers on 964?

Boeing 717

Holy cow fred those are nice.

JERRY

Fred's 964

Thanks Jerry. Everything is coming out great. Doing the 60K service at 55K miles and decided to drop the engine for some detailing. Replacing most gaskets, seals, hoses, etc. while it is out. The project keeps growing as I find things to do "while I'm in there".... I have the 993 Coupe to drive while I'm working on the 964, but I do miss the Cab with the cool weather.

Boeing 717

Yea Fred im finding things that need to be done to my engine since it has come out. Bad motor mount a few ragged hoses etc. but im amazed to find no oil leaks or any major problems. Good luck man....

JERRY