Engine Detailing

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Nov 27, 2017
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Massachusetts
No idea where to post this. I figured this might be the best place to post it. Sorry if it's out of place.

I just purchased some high-performance cylinder heads that I overpaid for (but that's a different story). They're aluminum and they just look so pretty right now when they're new. Has anyone had experience with painting aluminum heads? I have seen that VHT, Rust-oleum, and a few others offer high heat engine enamel paints. It is brand new, as in never installed. I've seen that they offer some high temp clear coat paints as well. I was wondering if a cleaning and spray of two or three passes of clear coat would preserve the look. I don't want to primer and paint the heads as I haven't seen a paint that closely mimics the look of new aluminum. Rust-oleum and VHT have engine enamel paints in an aluminum finish. They look nice, but......not quite as nice as new, bare, and polished aluminum.

Aluminum heads don't rust and don't corrode or age that much. However, it still does oxidize, dull, and generally lose its shine as time goes on. I just kind of want them to stay looking close to they way they look now for as long as possible.

My dirty engine block is a different story. I'm going to really have to clean that thing over and over. And clean it over and over some more. Then I'm going to have to apply a few layers of primer, followed by a few layers of paint, and finally followed by some clear coat.
 
If its covered in a greasy mess, what's underneath that grease will look good after it has been cleaned. Like stated, I wouldn't paint anything.
 
You wouldn't be the first person to paint AL heads.

I would use POR15 engine enamel if it was me and they had the color i wanted.

Help us out here, is the engine out of the car? Are you rebuilding the engine? Is the car a hot rod or a restoration or just a driver?
 
Aluminum heads can be painted if prepped correctly and the correct primer, paint, and sealer is used. There are many production vehicles with painted heads and blocks. Aluminum heads do look nice in their nature state on street rods etc. Unless you are going the sleeper route. You may want to consider your compression ratio if this is just a cylinder head swap and using the same pistons. I’m sure I’ll see some differing opinions but more compression is needed to make the same power with aluminum heads vs cast iron heads.
 
Just about any automotive (exterior) paint will hold up to the heat just fine. Don't use rattle cans if you want a great paint job that holds up. In fact, you can choose a metallic silver that looks quite like aluminum and will remain awesome looking for years.

You can treat aluminum with clear alodine/alodyne/bonderite (chromic acid treatment) for corrosion inhibition. It won't preserve that utterly brilliant freshly machined aluminum shine (pure aluminum is what mirrors often use) , but it will slow down the oxidation, and leave a very nice look.


 
You wouldn't be the first person to paint AL heads.

I would use POR15 engine enamel if it was me and they had the color i wanted.

Help us out here, is the engine out of the car? Are you rebuilding the engine? Is the car a hot rod or a restoration or just a driver?
Yeah. I've seen POR15 and I like it. However, I don't like it quite as much as the bare polished aluminum on the heads right now. I've seen rustoleum and POR15 have clear coat for engine enamel. No idea if this is feasible or a good idea.

It's a hot rod is the best way some would put it. I'd call it a mid-life crisis/ project car that got away from me. I am planning on rebuilding the block to all new forged internals even though it definitely doesn't need rebuilding. However, I'm just pushing too much power for the stock rods and a little too much boost for the compression ratio on the pistons.

The block isn't out of the car yet, but the new heads are as I haven't swapped them out yet. I have a built rear end, a built 6 speed manual transmission, a mildly reinforced chassis, and an expensive suspension setup. The engine's bottom end is the only thing left. I really need to stop after the engine. A fool and his money..............
 
Aluminum heads can be painted if prepped correctly and the correct primer, paint, and sealer is used. There are many production vehicles with painted heads and blocks. Aluminum heads do look nice in their nature state on street rods etc. Unless you are going the sleeper route. You may want to consider your compression ratio if this is just a cylinder head swap and using the same pistons. I’m sure I’ll see some differing opinions but more compression is needed to make the same power with aluminum heads vs cast iron heads.
Thanks. It's an aluminum head for an aluminum head swap, so I'm not changing material, just better flowing heads. The new heads will knock the compression ratio down (slightly bigger combustion chamber) to 9.85:1 vs the 10.195 they are now, BUT this is a forced induction setup. Playing around with the idea of octane booster/meth injection/race gas setup......I've decided I just want pump gas. Fill it up and step on it.
 
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Just about any automotive (exterior) paint will hold up to the heat just fine. Don't use rattle cans if you want a great paint job that holds up. In fact, you can choose a metallic silver that looks quite like aluminum and will remain awesome looking for years.

You can treat aluminum with clear alodine/alodyne/bonderite (chromic acid treatment) for corrosion inhibition. It won't preserve that utterly brilliant freshly machined aluminum shine (pure aluminum is what mirrors often use) , but it will slow down the oxidation, and leave a very nice look.


Thanks so much. I'm going to read into these options. As you said, I definitely expect it to "dull," for a lack of a better word, over the years. But I want to kind of slow it down so to speak.
 
Aluminum heads can be painted if prepped correctly and the correct primer, paint, and sealer is used. There are many production vehicles with painted heads and blocks. Aluminum heads do look nice in their nature state on street rods etc. Unless you are going the sleeper route. You may want to consider your compression ratio if this is just a cylinder head swap and using the same pistons. I’m sure I’ll see some differing opinions but more compression is needed to make the same power with aluminum heads vs cast iron heads.
Oddly enough, this is also a pontiac I'm working on.
 

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Years ago when I was young I rebuilt a few engines - when they were much simpler and made from cast iron, and they came back from the machine shop freshly cleaned and bored I would paint them with rattle can engine enamel. It all held up quite well, and I believe they make clear engine enamel.

Not sure why everyone is saying not to paint them. Is there something about aluminum that you shouldn't paint them?
 
I quit detailing engines after burning out coils and sensors. Newer vehicles have too much to go wrong. Maybe blow it off with air but that's it
I do not either, but when you've got stuff out of the engine bay.....opportunity just presents itself. I usually don't care at all.
 
Years ago when I was young I rebuilt a few engines - when they were much simpler and made from cast iron, and they came back from the machine shop freshly cleaned and bored I would paint them with rattle can engine enamel. It all held up quite well, and I believe they make clear engine enamel.

Not sure why everyone is saying not to paint them. Is there something about aluminum that you shouldn't paint them?
You can paint them. I've seen it plenty of times. If you keep the paint out of places it shouldn't be, you'll be fine. For example, I'd buy a cheap header gasket and put it on the head to not paint any surface mating areas. I'm sure it may be paranoid but better safe than sorry.
 
Thanks. It's an aluminum head for an aluminum head swap, so I'm not changing material, just better flowing heads. The new heads will knock the compression ratio down (slightly bigger combustion chamber) to 9.85:1 vs the 10.195 they are now, BUT this is a forced induction setup. Playing around with the idea of octane booster/meth injection/race gas setup......I've decided I just want pump gas. Fill it up and step on it.
Not enough of a drop to cause a loss in power. A better flowing head will definitely increase power and allow for more power adders if that’s the direction you go. Keep us posted. Nice Poneyac by the way.
 
Not enough of a drop to cause a loss in power. A better flowing head will definitely increase power and allow for more power adders if that’s the direction you go. Keep us posted. Nice Poneyac by the way.
Thanks man. I appreciate it. As you're probably not surprised, I'm way over budget. I'm at 530whp at the moment. What pontiac do you have?
 
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