polishing fan

Some months ago, I carefully polished my entire fan, which rebuilding the engine, and coated it with some kind of supposedly bombproof POR15 transparent coating of the kind that one might use on polished alloy wheels. Put the fan in the attic--it looked great--and now that I've gotten it back down again, months later, the fan has turned a bit ugly. It's still polished and the coating is still perfectly intact, but underneath it there are tiny spiderwebs of what look like corrosion. I'm reasonably sure they're not actually corrosion, but some kind of reaction between the aluminum--not magnesium--and the coating seems to have taken place. Has anyone had success in polishing and protecting a fanwheel, and if so, how? Or is it something that simply needs polishing and constant repolishing?

Stephan Wilkinson

Stephan,

I think you will find that the fan is indeed Magnesium, and I found the same problem about 15 years ago after spraying mine with clear Laquer. Magnesium is legendary for difficulty in protecting from corrosion!

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Warren Hall
1973 911S Targa

If the fan is magnesium you'll have trouble keeping it looking good. As Warren mentioned, mag is very susceptible to corrosion. At work we use a zinc chromate coating to protect magnesium aerospace components. A very ugly green color....not to attractive for a Porsche...effective though. I’ve seen pictures of polished fan blades in Excellence. How do they do it? Are some fans aluminum and other mag?

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Bruce
1982 SC

[This message has been edited by BruceSwanson (edited 12-22-2000).]

In my bordom of last winter I took the time to polish my fan while it was in the engine. A couple of items I found: Use a very stiff stainless or brass brush to get the baked on crud off. Use Wenol or Wadding metal polish to get the oxidation off. It will look good for a few weeks but the spinning fan and air contact produces oxidation rapidly. I would suggest avoiding painting. I have seen several painted fans that the edges start to chip and wear. In the picture, the fan is clean, but has the matte oxidation. Overall, it looks much cleaner then before.

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

I polish my fan with Mother's Mag polishing every once in while.

Nick

I just attended a magnesium die casting technical meeting that dealt with corrosion.

Evidently one of the best ways to protect magnesium is to have it e-coated. This is the process recomended by large magnesium smelters like Norsk-Hydro in Europe. There is supposedly a fairly new "clear e-coat" which has been used in a number of magnesium automotive valve-cover applications, however I have not personally seen any of these in actual use. A local industrial plating company could provide more information on this process.

I find it is better to listen to the fan than look at it. Much less work.

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Robert Stoll
83 SC
83 944

Yes, and what a beautiful fan it is, too. I listen to it every day. I have some excellent CDs in my car too, but they don't sound as good as that fan.

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'83 SC

Hi All,
When I did the engine detailing on my car I thought about powder coating the fan, but I used to race a drag boat and I did everything on it with Hi- Temp paint.

I never had any problems with chipping or fading. If you do it right and bake the parts between coats you will get a beautiful finish that will last a long time.

I did this to my fan last year and I haven't had any problems with it and it has been auto crossed, on many long drives and ripping through the mountains here in So Cal - even with rain going in it didn't bother it. Here is a picture - you can see the whole process on my web site http://members.rennlist.com/5150targa
(hope this works!)



Tom Sharpes

Let's try this one.

DOH !

[This message has been edited by team5150 (edited 12-28-2000).]

[This message has been edited by team5150 (edited 12-28-2000).]

OK this is the one - I can feel it.

Has anyone seen one of these? I thought it interesting that Porsche polished the fan ring and fan wheel...

BTW, the above pictured engine is cleaner that my kitchen table at home!

"polished fan ring and fan wheel
air filter housing and intercooler frame painted red"


Vehicle Type 911 Turbo S - Lightweight
Model Year '93 (P)
Concerns Vehicle description - Porsche 911 Turbo S - Lightweight
Introduction The Porsche 911 Turbo S - Lightweight can not only be driven in normal road traffic but is also extremely well suited for sports activities. The handling and the performance of the vehicle are particularly impressive in competition use.
Designation Name 911 Turbo S - Lightweight
Vehicle Ident. No. from WPO ZZZ 96 Z PS 47 9001
Engine type M 30/69 SL
Transmission type G 50/52 - without double-mass flywheel (ZMS)
Body Two-seater coupe (without rear seats)



Comparisons in the following description refer to the standard models 911 Turbo models year '92/N and 911 Carrera RS (basic version).

--------------------------------------------------------------------------------
Engine
Engine type - M 30/69 SL
Displacement - 3299 cm3 (3.3 L)
Engine power - 280 kW (381 PS) at 6000 rpm
Scope of Modifications
camshafts
injection valves
no servo pump
no A/C compressor - possible with Z order 1555 (A/C system as special equipment)
single fan motor
polished fan ring and fan wheel
air filter housing and intercooler frame painted red
fan tensioner belt coated black

I found a picture of one of these engines...this is the factory finish






[This message has been edited by David Griswold (edited 12-30-2000).]