Fine Polishing of Engine Fan

I had my 11-blade fan bead blasted, and then using my dremel, polished it out with an assembly of small wire brushes. I'm not very pleased with the finish, as it looks like it has a cheap coat of silver paint on it.

I've seen some fans that have been polished to a chrome-like shine, but I'm not sure how to proceed after the wire brushing.

Any input would be appreciated.....

Thanks!

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Michael
'78 911SC Euro

Your fan blade is made of magnesium and will tarnish rapidly. I don't think it will hold a fine luster for long.

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8 9 9 1 1, The last of the line.

You procede to polish with felt bobs and finer and finer compounds. You can go to diamond compounds with particle size in the microns. I personally can't stand doing stuff that tedious but our polishers at work do this for optic sufaces on molds. 89 is right your fan will oxidize again and need continuous attention. I would suggest chrome plating. You could step up and hard chrome. We use this for a high wear coating on molds where the surface finish needs to be perfect but is exposed to abrasive molding materials (plastics).
david 89 turbo cab


[This message has been edited by 5axis (edited 05-12-2001).]

It's a waste of time, as far as I'm concerned. I went through the whole exercise, posted queries just as you have, got answers all the way from "anodize it" to "anodizing it doesn't work," and went through a whole lot of tsuris to hand-polish mine at great effort. The first time around, I clear-coated my polish job with some super-coating and it went bad in a month, something to do with the stuff that inevitably remains in the considerable magnesium-alloy porosity. So I stripped off the coating and repolished everything with a buffing wheel and a lot of handwork, it gleamed like silver. Ran it 50 miles and it looks like an ordinary, untouched, unpolished fan. Bottom line, I think, is that the fan runs in a hostile enough area, at high enough rotational speeds, that polishing it is an exercise in frustration. Some people go to great expense to have the thing professionally painted, but as far as I know, even that stuff begins to strip off the ends of the blades fairly quickly. Maybe there are people out there who have discovered some super process that will paint or coat fanblades so they stay that way, but I suspect they are people who never turn the engine more than 2,000 Rs on the way to the concours. Look into the front of a 747/757/767 and tell me what the fanblades look like. Look into the engine compartment of a full-race Porsche and tell me what the fanblades look like. Gray, right? Go with flat gray and be happy.

Stephan

I too have been through this. I ended up painting my last fan (on a 2.4L) and my present (3.3T). I ran the 2.4L for several years and it stayed as nice as day one. Factory colors for the fan and shroud. Powdercoating also works very well. Did this to another, it also lasted the few years I had it. I have a picture of the 2.4L right before I sold the car. One of these days I'll get a scanner. That motor was really pretty.

can only speak for myself, but my powder coated fan still looks perfect after several years.
and I certainly exceed 2000 rpm. In fact, I redline the car several times each and every time I drive it. just can't resist!
jim

The fan is a tough one. You will have to repaint or recoat it every few years if you don't clean it often. The magnesium doesn't take well to polishing or coating. Count on maintaining the surface for a few years after you do it...

-Wayne

I am looking to get this kind of finish which is the clean, slightly bronzed type of finish. How do I get it and is it easily maintained? I hate the dirty grey finish of the standard 911 so another possibility would be chrome plating, any views on the pros and cons of this. Would painting the fan and housing silver help maintain the look better?



Found another photo that better shows what I mean. This type of finish is found only on 964 and later models. How is it done??




[This message has been edited by 930fan (edited 05-13-2001).]

[This message has been edited by 930fan (edited 05-13-2001).]

Here is a guide to a many metal finishing options and properties.
http://www.reliableplating.com/guide.htm
david 89 turbo cab

I was just wondering if there is a market out there for a carbon fiber fan; it would look so cool and be so light.

Originally posted by SeaDweller:
I had my 11-blade fan bead blasted, and then using my dremel, polished it out with an assembly of small wire brushes. I'm not very pleased with the finish, as it looks like it has a cheap coat of silver paint on it.

I've seen some fans that have been polished to a chrome-like shine, but I'm not sure how to proceed after the wire brushing.

Any input would be appreciated.....

Thanks!

Did mine by polishing and lacquering with a clear coat acrylic varnish - finish stayed good but the base material had colour variations in it which I didn't like. Tried red last weekend but is still not quite right. When I inspected fan prior to painting the previous finish was still good.



Sorry - first image was too big!!

Roy



[This message has been edited by Roy M (edited 05-15-2001).]

My idea of a "clean" fan was just an effort to clean all the burned on undercoating and crap that was glued to the finish. Now the fan is clean, not gleaming, but presentable. Before it was the first thing you saw and noticed. Use some stiff brass brushes and then move on.

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8 9 9 1 1, The last of the line.