Cleaning Fan and Housing

[speedster911]

Need guidance from the experts. How do I clean this fan and housing?

I have tried diluted (3:1) simple green and tooth brush with no luck. Want it to look original so powder coating or painting is not an option I want to explore.


Thanks for your help!!

[Cooper911SC]

I restored mine a couple of years ago now. I had some help from a shop that had done some before.

I just wanted a stock/original type look on the Mag. Wasn't interested in paint/powder coat etc.

I disassembled mine including the center fan hub. Walnut blasted it and had to drum sand some gouges inside the housing.

I then dipped the fan and housing in muriatic acid to even out the look of the Mag. CAUTION!! This is dangerous and can ruin your parts or hurt you if you're not careful.
It's definitely a "foamy" science reaction when the Mag hits the acid.
Think baking soda and vinegar.

The "dip" takes about 3-5 seconds and the parts need a running water rinse immediately!

Following the acid the parts will be blackened.

I put them into a tumbler with 1" smooth ceramic chips and ran for around 2 hours.

Next the mag parts were sent and coated with a clear satin ceramic. I went this route as the coating is very thin and bonds well to the base metal.
Paints and powder coat can have adhesion problems and require machining the fan and/or housing to fit.

The pulley halves (along with other engine fasteners) were sent out for gold zinc plating in the meantime.

Once back, the center pulley was hand riveted back into the fan. (These only fit one way so no need to re balance)

Sorry, only have "after" pics on my iPhone.

[gomezoneill]

Take them to a machine shop have them bead blasted then apply clear coat. Will come out very nice.

[shadowjack1]

All of the above. You do have to remove them from the engine. While you are in there...........

[Flojo]

Originally Posted by shadowjack1

You do have to remove them from the engine.

yep. it's the only way, as I did encounter. tried to scrub it clean twice while installed. doesn't come out perfect.

further: do not make my mistake (as I did at my third attempt) to paint the rotor fully as the center part is the other half of the pulley. it must stay bare metal for the belt to align and run freely. the paint will prevent neat alignment and wear out badly... even maybe ruining the belt.

best is to drill out the pulley halve before refurbishment. at least, mask it before painting.


edit: the dirt in the air soaked in by the rotor is very abrasive in the long run. so even cleaned bare aluminium will wear again soon.
thus best would be to ceramic plate it by a pro.

[86 911 Targa]

^^^^^
Bead blast/paint.

Best,

Gerry

[turbobrat930]

I hope Cooper911sc does not mid me using his photo, but this is by far the EASIEST and SAFEST way to take the fan off of the alternator shaft WITHOUT damaging the fan.
Take a look at the photo. Take two holes directly apart from each other and thread those using a tap. ( IIRC, I used a 1/4" x20 tap) then, take a screw or bolt that is about 2" in length, and thread them into the holes. Taking turns threading each one a couple of turns at a time, the end of the bolt or screw will hit the alternator case and gently push the fan off of the shaft.

[IMG]IMG_12311496290321 by Brad, on Flickr[/IMG]

[mb911]

I sand blasted mine then drilled the rivets out and then replated the pulley and sprayed ceramic paint to match the mag best i could.. I think it looks great

[Flojo]

how did you re-rivet?
I got rivets but no tool.

[turbobrat930]

Originally Posted by Flojo

how did you re-rivet?
I got rivets but no tool.

The rivets you would need to reattach the hub to the fan would require a bucking bar and an air hammer to do it correctly. Look up Aviation rivets and bucking bars

[Ferrino]

or just use countersunk bolts and locking nuts.

[mb911]

Originally Posted by turbobrat930

The rivets you would need to reattach the hub to the fan would require a bucking bar and an air hammer to do it correctly. Look up Aviation rivets and bucking bars

Exactly.

[JohnJL]

Forget about getting it nice while installed. Take it out and do a proper job, from then on it will be so very easy to keep it clean.

You can indeed powdercoat both the fan and the housing and it comes out very nice and durable. The key, like most things, is preparation. I happen to have one on my bench now, this one started as a 1978 SC fan and housing. I did this all at home in a reasonably equipped garage.
- Soaked it in simple green and hot water and scrubbed, rinsed and dried.
- Blasted with fine glass bead
- Blasted with walnut to remove the glass residue and give a nice finish
- Washed
- Baked to 250f for an hour, cooled, and
- washed in simple green
- baked again to 250f for an hour, cooled and
- cleaned off with solvent
- powdercoated in red and black from a gun and media from summit racing
- baked to 400 for 8-10 minutes, cooled and
- 1000 grit sandpaper taped to the inside of the housing used to trim back the powdercoat
- voila

This one has ~5000 miles on it and looks great. I have another on a race car that has 50+ track days and 7 years on it and looks perfect. There are no chips or wear on any edges, except where the belt sits. No problems with the belt either, no slip just some hidden wear underneath the belt shoulders.






This one is from a 1976, prepared as above up until powdercoating, just then gently massaged with Gills' oil with a diaper once. That was 2 years ago. Still finishes up nice.

[Jack Stands]

Is it just me, but do red fans bring bad thoughts about M..........ster?

[Shaun @ Tru6]

Both of these customers wanted the same look as you, very nice original, no bling polishing and not perfect as you can achieve when using Cerakote. Getting the pitting out is about how far down the rabbit hole do you want to sand while preserving originality.

Shine on the first is from a coating of Gibbs.

Satin on the second, Mg fan and Al housing is a ceramic clear. Hub and pulley were originally done in clear zinc back in 65 but I use clear cadmium since zinc is blue these days.

Carrera














65

[Flojo]

Originally Posted by Flojo

...
further: do not make my mistake (as I did at my third attempt) to paint the rotor fully as the center part is the other half of the pulley. it must stay bare metal for the belt to align and run freely. the paint will prevent neat alignment and wear out badly... even maybe ruining the belt....

here you can perfectly see what I meant...:
further, eventually the paint will tear arount the rivets and the edge of the pulley-halve towards the rotor... guess why I know...

Originally Posted by JohnJL

[speedster911]

Thank you everyone for your input and guidance. Pissed at myself that it got this bad.

[JohnJL]

Originally Posted by Flojo

here you can perfectly see what I meant...:
further, eventually the paint will tear arount the rivets and the edge of the pulley-halve towards the rotor... guess why I know...

Its not paint, this is powdercoat and its heat-cycled at more than a few track days.

i have had no problems with belts, and I have the same finish on a 7-year-old track car with more than 50 track days on it with no problems.

What is it you meant?

[JohnJL]

Originally Posted by Jack Stands

Is it just me, but do red fans bring bad thoughts about M..........ster?

Yeah but I spent more hours making my fan look and function properly than motormeister ever did assembling an entire motor.

Also its a bit unfair to ruin having a red fan because some d*^@#%bags used to do it...kind of like how one guy can ruin the name Adolf for everyone for 100+ years...

[Gretz]

I don't see any mention of anyone using steel wool or fine grade sandpaper to clean and smooth the fan and housing. Are there issues with using this type of method? Possible damage to the magnesium? I've also seen mentions of using a scotch brite pad.

I'm not currently looking to paint my fan and housing, but I'd like to remove the 40 years of grime. Can I simply use a minorly abrasive method as mentioned and then coat it in Gibbs oil?