70' 911e engine rebuild, soda blast cases?

gspeedster57 · 02-28-2011, 08:26 AM

I am performing a concourse engine restoration/rebuild on my 70' original paint 48k mile 911e.

I have heard of baking soda blasting the cases for optimum finish, opposed to machine shop pressure cleaning solution.

Has anyone had any experience of baking soda blasting early 911 cases ?

Thanks

Tippy · 02-28-2011, 08:41 AM

I don't have first hand experience with soda blasting but I can attest to the niceness the cases shown here on Pelican.

I don't think any chemical cleaning can reproduce the results mechanical cleaning can due to the instant corrosion (spotting and darkening) chemicals/soaps and water do to magnesium and aluminum.

tom1394racing · 02-28-2011, 09:26 AM

For a concourse finish, have the case tumbled by Ollies.

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Flieger · Flieger's Garage

I have heard at least one expert recommend soda blasting the case, since it is so gentle and will not abrade the surface.

356RS · 356RS's Garage

Ceramic Porcelain Media is what's used in the tumbler that Ollie's has. It's the gentle rubbing of the media that produces a deburring effect on the case. IMHO soda blasting on a mag case would take a very long time, and I don't think it's a strong enough media to accomplish the same thing a tumbler provides.

Carrerax · 02-28-2011, 12:24 PM

I had mine tumbled with ceramic media and it turned out perfect. Ill look for pictures. Just remember that media will get everywhere and into everything. you or your engine builder must be very diligent to get it all out. I thought I had it all out and then my builder informed me otherwise. That said, glad I did it.

brads911sc · brads911sc's Garage

M Callas recommends against using any media on the case. He actually wont use it. wont be as pretty but also wont have to worry about missing any...

hbrand · hbrand's Garage

I have had a 911S case locally Soda Blasted and it came out great. Clean up with water and air.
Keeps all the edges sharp as they are, while tumbling will round up corners.

Thanks, Harold

Walt Fricke · 04-06-2011, 02:47 PM

I can confirm that soda blasting is gentle. I can hold the parts in my hand without gloves. Worked great on the hard to deal with grime on an aluminum 915 tranny case.

Didn't do as much on a mag tranny case. However, you don't really want to remove the surface oxide layer from these cases, as it is what protects it. So you can remove grime, but not necessarily get an even finish, much less a shiney one (which wouldn't last long anyway, due to oxidation).

For true concours, at least in some classes, you will be docked points if parts of your car are better looking than when the car rolled out of the factory!

Walt