Cleaned up fan and housing

[JackS]

Hello clean engine freaks. I thought I would pass along a tip that worked out well for me. I had to replace my fan blade and housing with used parts that were functional, but not very pretty. I keep a fairly detailed engine compartment, so this was a bit of an eye sore. I tried using Mothers mag wheel cleaner and fine steel wool and had very good results. It's a bit of work and if you wanted to take everything apart, you could be more thourough.
I spent about 2 hours carefully polishing out the oxidization. I ended up with a pretty clean looking fan and shroud. It makes a huge difference in the appearance of the engine, and it cost only a few dollars. My wife thinks I'm nuts!

[JonT]

where do you get "fine steel wool". I didn't know there were degrees of abrasiveness for steel wool. Thanks.

Also-post some pics if you can.

[Rot 911]

Originally posted by JonT
where do you get "fine steel wool". I didn't know there were degrees of abrasiveness for steel wool. Thanks.

Any good hardware store will have various grades of steel wool. I think the bags run in grades from O to OOOOO. The more "O"'s the finer the grade of steel wool.

[APKhaos]

Jack - this is just an observation, not citicism, OK?

Mag alloys are notorious for surface oxidization, which is what transforms beautifully polished fans back to their natural dull grey in a matter of weeks.

Treating Mag alloys with any iron-based materials [tools, steel wool, etc] actually makes things worse - the iron bonds with the alloy to form a really corrosive dissimilar metals mess.

Cleaning up fans & housings is best done with scotchbrite or other non-ferrous abrasives.

[Oldporsche]

BTW, Scotchbrite comes in different grades too!



Good luck,
David Duffield

[carnut169]

Yep- no steel wool. I would go back w/ some 1500 grit wet/ dry sandpaper and some metal polish.

[PDACPA]

Do you all take the fan out for these cleanings? I would love to clean mine up, but the removal seems to be a pain.

[JackS]

I didn't know that about the steel wool. Thanks for the criticism. No offence taken. I'll pick up some scotch brite and do it again!

[GSpreeman]

My fan is filthy and I would love to clean it but am also reluctant to pull it out. Can I clean/polish it without taking it out?

[GSpreeman]

While we're on the subject, the fan and housing shot in Wayne's book...can that be done with a can of spray paint or does it need to be done in a professional shop with a compressor, etc.?

[carnut169]

If I did not have a Cab & the support piece that goes across the back it would have been a snap to remove. You can clean it in place, but for a really good polished look it seems like it would be easier to pull it apart. That way you can also Powdercoat your shroud!

(Just another excuse to post these photos!)

[911X2C]

WOW!!! Carnut169, you have given me the motivation to get my fan and shroud detailed. Was the shroud the only item powder coated? What was used to the fan and what was used for the final finish? For the pulley hub, I assume you had that polished? Any details you can provide would be greatly appreciated!!

Thanks,

Lee

[autobonrun]

I polished mine a few months back and rebuilt the alternator. The alternator failed this week so I've got to pull it off. My polish job lasted about 3 months so I'll get another opportunity to do it again. It still looks bright but the shine diminished. I've seen a few posts above about using steel to polish the magnesium fan. Each has an opinion but I'm reposting the response from a magnesium manufacturer about how to polish/coat our fans. Goes against some opinions to use steel to polish magnesium. But diversity of opinion is what makes this board interesting. Some may remember it but with the new members every month, reposting won't hurt.

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MY ORIGINAL POST on Pelican:

I read all the posts on polishing vs painting engine fans and could not get a concensus on which way to go. So, I looked up a manufacturer of magnesium parts to get another opinion. I received some good feedback via email. I'm still in the middle of correspondence but here's the email data I have so far. Once I get the formulation and a firm path forward, I'll post again.


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RESPONSE FROM Magnesium Manfacturer's engineer to me.


The short answer to your inquiry is that there is nothing I know that will give you that “polished look” on magnesium for the long term. This is the same issue people have for polished magnesium wheels. If you “polish” magnesium and simply apply a clear coat, the clear coat will delaminate (turn milky) from the magnesium at sharp edges and stone damage sites in even quite mild (humid/wet) conditions. This is because of the following factors –

Polishing with certain abrasives can contaminate a magnesium surface with cathodic (iron containing) impurities. This has the effect of further increasing the corrosion rate of magnesium alloys and aggravates the situation. Safe polishing media for magnesium would be high purity aluminum oxide, silicon carbide, glass or diamond. Do not use emery powder. Never use a wire brush to “clean” magnesium components.

Magnesium is an alkali metal and requires a conversion coating to be applied before painting. The conversion coating will passivate the magnesium surface and improve paint adhesion. This will slow or prevent delamination of the paint under corrosive conditions. All the best conversion coatings for magnesium are colored and most contain chromates. The “best” available conversion coating that would maintain a “shiny” finish is known as the # 21 Chemical Treatment (If you send me a fax number I can copy you with the chemical formulation which does contain hexavalent chrome compounds).

Magnesium is an alkali metal and epoxy based paints are preferred. Epoxy based paints suffer from UV degradation so should not be used as a top coat. Its probable best to apply a clear epoxy primer followed by a clear polyurethane for the look you are after. Cellulose paints on magnesium behave poorly.
Don’t know if this will help you – why not chromate the fan assembly using one of the better chromate treatments, rinse, dry the chromate film between 110 to 120 C, then apply a silver base/clear coat system.