IrocMan

Hi Fred, that's a really beautiful engine you have !

cobalt

I cast AZ91C, AZ91E, AZ92, ZE41A & EZ33A, K1A (KIKI) and several others I can tell you that it is none of these alloys. I would assume it is AM60 since these are die cast parts but could be other die cast alloys too. The rare earths (zirconium based) alloys like ZE41A and EZ33A are radiographically more dense than the Aluminum based magnesium Alloys like AZ91 & AZ92.

Although the general rule is as described above and i would agree powder coating and polishing are not recommended. A proper chemical conversion should be used prior to painting usually one of several DOW treatments. These can be found per documents MIL-M-3171 superseded by AMS-M-3171 which is primarily the same document. A decent paint should work but for maximum longevity I recommend using one of the Acid etches prior to painting. If not just make sure the paint is durable and hard with proper coverage and curing time.

As far as powder coating temperatures it is usually not an issue. Powder coating requires temperatures below 400 degrees. Annealing a part occurs at around 500+ for more than an hour. Most alloys like AZ91 require a T6 solution and artificial age temperatures held constant at around 770 degrees for 16-24 hours followed by air quench and artificial age of 425 degrees for around 4 hours. If done properly you should see mechanical properties around 18-20KSI yield 38-40 KSI tensile and roughly 3-5% elongation although required numbers are lower. ZE41AT5 is an alloy ideally suited for wheels since it is strong with a higher Yield than the aluminum based alloys. Most of the F1 wheels are made of this alloy.

Fred's 964

Thanks Luc (IrocMan), I thoroughly enjoyed doing it all. I am still trying to explain to my wife why I need an oven in my workshop.

Jeff Curtis

FWIW - I had mine painted soon after purchasing the car about 7 years ago...just now started showing some bubbles where the fan blades meet the center section...going to bead-blast and repaint Grand Prix White as before!

The fan looked great for MANY MANY years and yes, had a few chips in it but that's going to be with any type of coating I would imagine, although powder coating would be more durable.

cobalt

How many miles and time spent outdoors would be a better way of judging how well it stood up to the elements. I did the fan on my 79 SC and it lasted 79k miles and 10 years without issues and then I sold the car. I acid pickled the part first and it is probably still good today.

Also another concern is once it shows bubbling the corrosion underneath might be more extensive than you realize.

jimq

Hey Fred long time no see! That white car of mine behind your yellow one is having fan issues. I may give you a call in the next week or so for some guideance on how to get it off and replace the bearings on the altenator or fan itself depending which is bad.

Fred's 964

OK Jim, I'll be glad to help. I'll bring over the 993, I have the LPMM's on and it sounds nice. Or I'll bring the 964 so your's will have a twin to park next to..... If you need tools, you could bring it over to my shop. Something tells me you may have enough tools to do the job already. Either way, we could powdercoat a few parts while we are in there just for kicks.

jimq

Sounds great Fred! We need to have another wrenching party only this time with my car My fan has a chip out of it from hitting the surround so I am afraid I need to replace it also. I dont have a puller to get the fan off so if you have one of those that would be great.
I do need to adjust the valves. Hmmmmmmm
Hoes Donna doing?

Fred's 964

Jim, Donna's doing well, thanks. Her hair is growing back and she is regaining her strength. She is running 10 miles tomorrow morning. I'll ride the bike with her while she runs.
If your fan is chipped, I would recommend replacing it. We'll pull it and inspect it. I'm off next Friday, do you want to look at it then? I'll bring some tools and come over. Let me know.