Caramic vs Powder vs epoxy paint for engine aluminum

[gliding_serpent]

I have been researching this topic and was looking at pros and cons. Here are a few threads:

To Powder Coat or Ceramic Coat, that is the question?

Powder Coating In this thread the OP answers a lot of powder-coating questions.

My goal is to paint some or all of the below parts (At least upper valve covers, fan and shroud, fuel rails, plenums). I would be looking for a natural aluminum/silver (not gunmetal, not chrome). I might go Speed yellow or similar for the fan. So far all parts have been dipped at the machine shop to lift the major grime.


So here are my options:

1. Bead blast: cheapest (~150$ by the machine shop). Would look great at first, but would eventually corrode again. This might lead to obsessive polishing.

2. epoxy paint (crinkle paint or other): I have a local body shop that could do this for me at low cost. Pro's seem to be ease of re-application in case there are chips down the road. Down side is durability. Not sure I would want to clearcoat on top of this as it is known to discolor and flake.

3. Powder coat: Getting more expensive as specialized, but I was quoted 460$ by a local powder coater who works mostly with bike components. Downside is difficulty to touch up any future damage to the powdercoat, and difficulty removing. Touch up should not be a huge issue if the color I choose is a metal color anyway. Heat can warp mating surfaces, requiring leveling. Not sure if this significantly effects heat transfer.

4. Ceramic coating: Same quoted price as above. Similar to powder above, but less color options. I would not do for the magnesium fan housing as my local ceramic coater uses high heat curing ceramic. Warping may still be an issue. Some advise against for valve and timing chain covers as it can lessen heat dissipation (good for headers, bad for engine parts).

Edit 5. Leave it alone!: A car is original only once. Clean it up, get rid of the oil and grime, maybe scotchbright things up. Advantages are cost and originality. No metal lost to media blasting.

Reminders to keep powder coat and ceramic out of mating surfaces, internal engine surfaces, and screw holes (can effect torque specs).


I am looking for experiences/additional pros/cons of each, and I am wondering what is the best media prep for the final 3 options.

thanks for any help

[jkuntze]

i have not done my 911 have done some parts on my 356 and e type did myself with eastwood kit very easy dont know about heat transfer

[hcoles]

my 2 cents - be very careful the type of blasting used, it can be almost impossible to clean good enough afterwords for surfaces exposed inside the engine.
I would not coat parts other than the fan and maybe the fan housing. There are a number of threads around here re. coating the fan. I had my fan and housing coated with urethane clear about 8 years ago, looks good at this point.
I doubt the heat dissipation will be significantly affected. There are times you want heat kept in - e.g. during warm up.

[gliding_serpent]

Originally Posted by hcoles

my 2 cents - be very careful the type of blasting used, it can be almost impossible to clean good enough afterwords for surfaces exposed inside the engine.
I would not coat parts other than the fan and maybe the fan housing. There are a number of threads around here re. coating the fan. I had my fan and housing coated with urethane clear about 8 years ago, looks good at this point.
I doubt the heat dissipation will be significantly affected. There are times you want heat kept in - e.g. during warm up.

The main reason I began researching this topic was related to media. This is one area where I have found little good info. Can you advise media types and abrasive levels advised? Like most painting success seems to be in the prep. I fully realize that blaster pressure and distance from the object also effects things, so it is not so black and white.

This is my poor-man's summary of media (there are far more options), in order of least to most invasive: (note there are grades of each)

- walnut
- soda
- plastic beads
- glass beads
- silica sand/crushed glass
- aluminum oxide

The rougher the tooth you create the better the mating surface for paint, but the more surface material it removes, and the more likely it will retain media in the surface which can contaminate your paint (requiring things like pre-curing to burn off excess media).

The guy that is offering to power/ceramic coat my parts said he uses sand/crushed glass grit blasting (sounds great for the steel he normally works with) but when I began to ask pointed questions about media, especially related to cast magnesium, he got quite short with me, which made me nervous.

[McLovin]

None of the above.

[gliding_serpent]

None of the above.

?? (Lengthened as a one character reply was said to be too short)

[Neel]

"he got quite short with me, which made me nervous."
Whatever you decide, this guy is not the one to do it... Anytime someone makes you feel that way, move on.. My $.02.........

[McLovin]

I wouldn't do any of it. I'd just clean the parts. If you are interested in the resale value of your car, that's what you would do, too.

[McLovin]

Painting natural finish Porsche engine parts is cheesy. IMO.

[gliding_serpent]

Painting natural finish Porsche engine parts is cheesy. IMO.

I generally agree with you (still deciding on the fan). Thus my thought of using metal colors. Natural look, but easier to clean/no polishing hassle.

That being said, it took 30 years to get my engine to look like it does now, so a clean and polish should be fine for some time.

Resale does not matter to me, but originality does, so point well taken on options that involve harsh media blasting. No returning from that option...

[McLovin]

The problem is "natural color" paint doesn't look any anything like the original natural finish. Its like a bad toupee or an Astroturf lawn.

[gliding_serpent]

Hey, many folks like their astroturf bright red or yellow. ;-)

I have also seen some incredible looking metal powdercoating on this forum... But i am leaning your way...

[Trackrash]

I too, am going through this decision processes.

As far as blasting goes. It depends. The problem with glass beads is when the beads get old and fractured they leave a rough surface.

I was hoping to get a new and clean look to my valve covers, with some shine. I was envisioning a finish something like what is on the lip of the original Fuchs. A clear coat with a semi-polished look.

I ended up polishing my valve covers, since I was never happy with how "clean" I could get them. I think I got them too shiny.

I'm thinking I'm going to leave them for now and see how they "age". My hope is they will stay clean since they are aluminum rather than the old mag type.

[Trackrash]

Some good info here. Metal Preservatives Testing on Polished Cooling Fan

[Racerbvd]

Originally Posted by gliding_serpent

Hey, many folks like their astroturf bright red or yellow. ;-)

I have also seen some incredible looking metal powdercoating on this forum... But i am leaning your way...

[gliding_serpent]

Thanks. Great thread. I found that last year, but lost it. Such experimentation is valuable. I started trying to polish my fan. My current leaning to a natural finish is probably due to forgetting how much work that involves. 17 hours for his fan!!!

Some good info here. Metal Preservatives Testing on Polished Cooling Fan

[tirwin]

You can see what I did here:
Zen and the Art of Porsche Repair Maintenance

Fan was previously done before the engine drop and discussed here:

Mark Motshagen is a real craftsman.

[bike2ride95]

Leave it the way the factory intended it to be.

[Trackrash]

Originally Posted by bike2ride95

Leave it the way the factory intended it to be.

That's my dream. To have the '78 SC motor I'm restoring look like new.

AND STAY THAT WAY.

I just spent four hours cleaning my valve covers. I tried every chemical and tool I could think of and still they are dull gray. I am not going to bead blast them. I am open to other ideas.

Has anyone tried those vibrator polishers like they use for jewelry?

[gliding_serpent]

Bike, I don't think porsche was thinking what it would look like in 30 years. Some of mine is pretty gruesome. Trick is to do things well.