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Cooling fan refinish 3.2 Carrera Sport

jkeith

Well-known member
Joined
22 Jan 2010
Messages
643
I'm planning on improving the engine bay on my '86 3.2 carrera sport. I've seen another thread where the cooling fan was media blasted and then hand polished with steel wool then Mothers Mag polish.

Will this polished finish remain durable or will this require frequent hand polishing? I remember using Solvol Autosol but it needed additional polishing after a few weeks.

The car is Grand Prix white. I have considered red, black and silver finishes and would invite any views from anyone who has done this alteady.

Cheers, Keith
 
Keith, hi I'm sure this was covered in detail on impactbumpers.com when I used to have an air cooled 911. Your right having it polished is one way but high maintenance. I think the coating is like an anodised finish a lot of the guys had them painted up or just fitted new ones, but they are expensive if I recall
 
Thanks Geoff, I'll check it out on IB.

Cheers, Keith.
 
It looks like a ceramic spray paint (cerakote) is the favoured option from threads posted on pelican.

My prference now is to go with the fan painted silver (charcoal) and the housing painted silver (platinum).

I'm now exploring who might do this locally.

Cheers, Keith
 
Ok, having done as much research as I felt comfortable with, I came to the conclusion that my aspirations to get the finish close to the original factory finish was just not realistic.

This was more to do with the practicality and timescale to get the job done. I didn't want my car blocking the way at my local indy (D&G Porsche) who I trust implicitly with the work (I didn't have the time or inclination to tackle this as a diy project).

The cooling fan is made up of three component parts.
The fan housing is a magnesium alloy that was factory finished with cosmoline (a bronzish finish).
The fan impeller is an aluminium alloy, also cosmoline coated.
The centre plate of the impeller has an alloy rivited (6 off) fixing which, I think, is a titanium alloy.

Most owners simply powder coat the housing and the impeller with the centre plate intact during the powder coating process.

I was not happy to do this so had the six alloy rivets drilled out.

It seemed the option to carry out media blasting followed by ceramic pait spraying (as carried out on guns and rifles) was simply too complicated for my short time plan. Cerakote is used in the States but I couldn't find a local sprayer.

Much information came from owners in America (no suprise that gun sprayers are more numerous over there) and a chromate finish was the preferred option followed by a satin clear finish.

These are pictures of the before.

Cheers, Keith.
 

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So, having looked at the realistic options available, I decided to go for a cosmetic engine bay upgrade.

The car was due a main service and I decided to get some of the other engine components re-plated. The engine stayed in the car so it was very much a cosmetic exercise. Not to get the car to show standards, simply to get the engine bay up to the standard of the rest of the car.

I discovered the re-plating of the impeller centre plate was not possible as the alloy would not accept the anodising (didn't try sheridising). I hand polished this and decided to refit the centre plate with nuts and bolts rather than getting it re-rivitted.

The other two main components (the fan impeller and the housing) were powder coated after media blasting (with aluminium oxide). The fan housing was prepared using a phosphate finish (similar to chromate).

A further complication was the small tollerances between the three parts.
Powder coating is quite a crude process and the impeller fan blade tips needed to be ground off to prevent catching on the housing.
The centre plate is a very close fit and the masking of the centre section still left a tricky task of removing the very edge of the powder coating using a craft knife blade.

Then the tricky job of getting all of the newly plated parts back and assembled.

I leave you to make your own minds up but I'm very pleased with the results shown on the following pics.

Cheers, Keith.
 

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That looks really good Keith. Well cared for rather than overdone show and shine sparkle. The replated parts make so much difference. Matches the GT3.
 
Thanks John and Mark.

I was very happy with the overall improvement but the biggest difference was the impeller centre plate. Drilling the rivets out and polishing the centre plate creates a very nice focal point.

Cheers, Keith.
 
Well worth the effort, it looks factory and not too overdone, less is more !
:thumb:
 
Thanks Jim, this was something I have wanted to do for ages.

Pleased now that it is done and very happy with the improvement.

Now, what do I want to do with the seats?

Cheers, Keith.
 
:D
 

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