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Ways to clean cast iron intake for paint?

Evan Frucht

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What do you guys do ?

I have a dirty old intake with layers of old paint falling off and it's leaking oil. It's an original cast iron poly 318 4 barrel intake.

Want to remove it and paint it and then install so it won't leak oil anymore

I was gonna pull it off, apply a heavy duty paint stripper such as that aircraft stuff, scrub it down and then wash off. Then scrub it with dish soap or degreaser and hose it off, dry it, then paint it with some 2k urethane.

But is there a better way to clean it?

Any advice?
 
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How are you going to get the oil off? That is first before paint stripper. I’d take it someplace with a parts washer and it will remove both oil and paint at once.

Hot tank, or a wash cabinet with alkaline soap and hot water, it works wonders.
 
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How are you going to get the oil off? That is first before paint stripper. I’d take it someplace with a parts washer and it will remove both oil and paint at once.
Forgot to mention I plan wipe it down with a degreaser before the stripper. But the stripper is nasty stuff I think it would eat through oil anyway.

Pretty sure the laws in California make it expensive or illegal to get stuff hot tanked now
 
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Blast cabinet. Done!
 
Blast cabinet. Done!
I have a sandblaster but no blasting cabinet. I was worried about blasting because it's an intake and I don't want any blast media to get stuck inside and then destroy my engine.

How would you prevent that ?
 
Blow it out when your done.
 
Short of throwing in my blast cabinet, or before I had one, paint remover, brushes, scrapers, elbow grease finished up with brake cleaner.
 
Sandblast it. If you have sand left inside by the time you paint it and reinstall it you really did something wrong.
Ha! It's true but I'm kind of a worrier. I'd worry dust left over from blasting might be lodged deep inside or something to that affect.

If I had a proper blast cabinet with better media it might make more sense.

I do my own blasting of small parts with a cheapo gun and use dried and sifted play sand, which has really fine dust like particles, that's what worries me.
 
How you going to clean the carbon out of the heat cross over? Hot tank is the only way I know of. ..................MO
 
How you going to clean the carbon out of the heat cross over? Hot tank is the only way I know of. ..................MO
I guess I'm sort of assuming the inside of it is fine, and don't plan to clean the heat crossovers, unless I really should or need too? The car runs fine, it just is pouring oil put out the rear intake oil gasket. Also it looks like ****!
 
Throw it in the oven for a few days at 425. Grease, old pant, rust and carbon all gone.
 
Degrease it then power wash it, if it's legal to do so. Sorry, I'm not aware of what Ca will permit you to do.
 
1. Soak in Acetone
2. Wait for wife to go on errands
3. Place in dishwasher on high heat/heavy load
4. One more Acetone wipe
5. Bake in oven at 425 overnight

Quick Method:
1. Place in oven and turn on "auto clean"


trust me
 
Degrease it then power wash it, if it's legal to do so. Sorry, I'm not aware of what Ca will permit you to do.
Ha! They permit power washing.

In California we have emmission laws now. Processes which release fumes that damage the ozone are under fire. We have to use low VOC auto paint formulations. Chrome plating shops are getting shut down or heavily regulated and can't do the good type of chrome anymore... etc.

I've been told it's hard to get stuff hot tanked now because of that.
 
I’d just scrape all the loose paint, maybe hit it with a drill powered wire brush, then rub it down with some phosphoric acid based paint stripper. Phosphoric acid is the active ingredient in most biodegradable paint strippers, degreasers like simple green, as well as many anti-rust goops, so just do it in one step.

May take a couple of rounds, so I just wipe as much as I can to save it, then rinse, wire brush, repeat. After the first round to get rid of the old nasty stuff, I soak the second round over night and cover it with something to keep it from drying out.

The acid won’t hurt the iron. If you use muriatic, it’ll go faster but also attack the iron.

Also, keep it somewhere warm, it’ll go faster.
 
Engine shop could dip/boil it clean like they do engine blocks and tins.
Blasting it with sand or glass beads would leave a cleaner surface.
Not sure if the Poly intake has the tin oil shield under it like the LA small blocks. I think you would have to remove that to get all the blast material out?
Maybe you can seal it off with duct tape before blasting to keep the sand out?
 
You could always tape over ports and then blast if your worried about sand getting stuck inside.
 
Easy Off oven cleaner and a scrub brush..

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I've probably cleaned 15 intakes. I do it today the same way I did it 45 years ago. Elbow grease with an assortment of things to scrap with and detailing brushes, carb cleaner, hot water and Dawn dish soap.

I would never, ever let my intake anywhere near sand, or a sand blaster.
 
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