Manifold Clean Up Suggestions

[keithb7]

Hey folks my engine rebuild is progressing along. Internals are done. I am pretty-ing things up now as I move to the bolt on items.  
 

The manifolds, I want to clean them up and paint them. I have full access to industrial media blasting equipment . Yet I am cautious about glass-beading anything on an engine. 1 tiny piece of glass bead can do a lot of damage if it gets left behind.  Somehow finding its way into a cylinder or an oil pump. 
 

I am interested in learning what you did to clean up both intake and exhaust manifolds. I was thinking degrease the  intake. Wire brush the rough stuff off . Maybe a little sandpaper. Mask off the ports and spray paint it. 
 

Exhaust manifold, I’d like it black with high temp paint I think. It has lots of dry flaky rust on the surfaces. Sand blast would likely work great. But…

 

Tips appreciated. Thx.  Keith

 

 

 

 

[RobertKB]

Take them to an engine rebuilder and have them tanked. Maybe magna-fluxed while you’re at it. In my experience it doesn’t matter what you paint the exhaust manifold with, it will sooner or later burn off. Intake manifold holds onto paint way longer. I did my intake silver and exhaust black.  Just a personal preference. 
 

Your engine is looking great by-the-way!

[Loren]

I would use sand blasting.

The engine rebuilders use steel grit.

You are absolutely right about Glass Beads any moisture or oil and they will be in there forever!

One shop I worked at had a blaster with walnut shells that worked very well.

 

[Bryan]

I don't see how glass beading could hurt anything on the exhaust.  Engine is blowing out thru it, not sucking in. You'd only need to be careful that nothing was in the immediate exhaust port areas. Imagine you would have anything else like the draft tube hole and oil pump/fuel pump hole closed before you put on the exhaust manifold so nothing falls in. Wouldn't use beads on the intake. Kind of up in the air..if you use another method on the intake probably wouldn't cost much more to have the exhaust done...don't know the prices.

[DJK]

In regards to the exhaust manifold, make sure the mounting surface is true, had to have mine trued up on a large belt sander.

[Adam H P15 D30]

@keithb7Send them out for ceramic coating, it will look like new for years.

Enjoying your videos on YouTube!

[1949 p17]

one cup of citric acid to one gallon water. soak for a week. it will be completely rust free. we clean all the vintage parts this way. you can coat the cleaned metal parts with boiled linseed oil for a protective coating if you aren't going to paint the item.

[Racer-X-]

If you must media blast the intake manifolds, consider blasting with walnut shells media.  On the odd chance anything does get left behind, it's organic and it burns.  It's also not overly abrasive. That's actually what is often used on modern "direct injection" engines to clean intake valve deposits.

 

The citric acid solution also works well and will resolve most rust issues and dissolve some grease/dirt buildup.

 

Exhaust manifolds or headers that I really care a lot about go to JetHot for coatings.  That comes after thorough sandblasting, and they really still don't like dealing with old/used parts.  That stuff keeps heat in the pipe (they do the inside and the outside) and prevents a lot of thermal issues.  Of course, mostly, I deal with modded higher performance engines, so headers burning up ignition wires and other heat issues around the exhaust are a bigger issue for most of my projects.

 

For street stuff that isn't worth the round trip shipping to JetHot, I use VHT "Flame Proof" exhaust paint on the outside.   Sometimes I'll get the aerosol spray coating from Eastwood.  They sell the stuff in a kit with a "special" hose and nozzle for coating the inside of pipes.  See https://www.eastwood.com/eastwood-hi-temp-internal-exhaust-coating-w-nozzle.html for information and pricing. As long as the pipes are freshly sand blasted, I haven't had issues with the stuff flaking off in any short number of years. 

[Dartgame]

Hot tank first to get grease, carbon, and oil paint etc off. Next you can try muriatic acid - chemically known as hydrochloric acid (HCL), fast acting, depending on how rusty, it will take probably only a few hours. Inspect your parts once or twice an hour, flush with water each time and you may want to wire brush to get chunks off. Soak in acid until the rust is gone and flush with clean water. Immediately immerse them in caustic water (drano or lye dissolved in water) to neutralize the acid and to prevent flash rust, and then flush with water again. Dry them with compressed air, heat them with a propane torch to get all water out, and coat them immediately with the paint of your choice. A light coat of oil WD40 etc inside will keep them from rusting again until engine runs. Save the acid it stays strong and effective for a long time. I use 5 gallon buckets to store it. A large plastic flat pan is suitable to soak parts. BE CAREFUL. HCL and drano/lye are very destructive to concrete and you. USE heavy rubber gloves and eye protection. Never add water to HCL or other strong acid, instead add the acid to water. Spattering can occur from the heat of solution if water is added to acid, acid added to water allows the heat to dissipate immediately.

[Sniper]

1 hour ago, Dartgame said:

Hot tank first to get grease, carbon, and oil paint etc off. Next you can try muriatic acid - chemically known as hydrochloric acid (HCL), fast acting, depending on how rusty, it will take probably only a few hours. Inspect your parts once or twice an hour, flush with water each time and you may want to wire brush to get chunks off. Soak in acid until the rust is gone and flush with clean water. Immediately immerse them in caustic water (drano or lye dissolved in water) to neutralize the acid and to prevent flash rust, and then flush with water again. Dry them with compressed air, heat them with a propane torch to get all water out, and coat them immediately with the paint of your choice. A light coat of oil WD40 etc inside will keep them from rusting again until engine runs. Save the acid it stays strong and effective for a long time. I use 5 gallon buckets to store it. A large plastic flat pan is suitable to soak parts. BE CAREFUL. HCL and drano/lye are very destructive to concrete and you. USE heavy rubber gloves and eye protection. Never add water to HCL or other strong acid, instead add the acid to water. Spattering can occur from the heat of solution if water is added to acid, acid added to water allows the heat to dissipate immediately.

 

Then how do you dispose of it?  Don't be pouring it down the terlet unless you want a real surprise.  Water and muriatic acid are exothermic, which means it makes heat when mixed and it will foam and the fumes are nasty.  I'd rather do the molasses thing to remove rust

 

 

 

[kencombs]

Acid disposal.  First add a base to water.   Baking soda will work.  High school chemistry chapter acids vases and salts.  Mix the first two at the right ratios and you get a neutral ph liquid and a salt.  Just be really careful with mixing.  What to what and speed matter.  Not getting any deeper as one should do their own research, not listen to an internet dummy like me.  . 

[kencombs]

More on acid.   Best not to use really strong ones at home.   Citric or vinegar work just as well with none of the danger. 

[OUTFXD]

If you do anything short of a full clean metal prep (Sandblasting or chem-dipping) Be sure to Use a rust converting Primer. I prefer Rustoleum Rusty Metal Primer. It will kill whatever rust you miss and prevent future rust growth.  It will "Dry to the touch" in 15 minutes.  I suggest spraying a coat in the evening and let it sit overnight before going to finish coat (Gotta Get them Paint solvents out).

Edited December 1, 2021 by OUTFXD

[kencombs]

16 minutes ago, OUTFXD said:

If you do anything short of a full clean metal prep (Sandblasting or chem-dipping) Be sure to Use a rust converting Primer. I prefer Rustoleum Rusty Metal Primer. It will kill whatever rust you miss and prevent future rust growth.  It will "Dry to the touch" in 15 minutes.  I suggest spraying a coat in the evening and let it sit overnight before going to finish coat (Gotta Get them Paint solvents out).

Ospho is my go to on any metal with rust.  After dip, blast pr sanding.  Followed by an appropriate primer for the paint. 

[1936Forepoint]

You could also take them and get them shot peened.  No issues for contamination.

[Matt Wilson]

I talked with a hot rod engine builder a couple of years ago, and he said he likes to do soda blasting.  I think it's baking soda that's wetted and run through a sand blast nozzle or gun.  He says it does a good job of getting rid of rust but the soda dissolves in water so that it doesn't leave any solid chunks like you'd get with sand blasting, bead basting, etc.  He said he's seen examples of people who cleaned parts with those solid blast media, and in some parts, like oil pans with baffles, you'll never get all the grit out, and that's a real risk for causing damage to the engine.  I might feel similarly concerned over intake manifolds too.

[Dartgame]

No offense intended. I am a degreed chemist. Use HCL carefully and it works great. If you are unsure, do not use it. 

[Sniper]

I worked in semicondutor R&D for years, nasty chemical disposal I am familiar with.  I just prefer not to have it around in an unsafe setting and a tub of HCL in my garage is one of those settings. 

 

My parts washer is full of Simple Green, it works slower than old school parts washer solvent, but it works and it is so much safer.  We all make out own choices, as long as it's an informed one I have no issue.

[Loren]

In another lifetime ago I was in the Turbocharger business.

We had a manual from AiResearch that explained the different methods of how to clean exhaust housings, bearing housings and turbine wheels.

Since we did huge amounts of parts and were spending a lot of capital on the labor intensive job of cabinet blasting with aluminum oxide grit, new ideas were most welcome. I was tasked with writing a report evaluating what we could do.

As I read through their suggestion for a sodium bath, I came to the conclusion they were putting us on.

The beginning of the article sounded like a reasonable recipe but then it kept getting more and more ridiculous. What they were talking about was a bath of molten sodium metal. I remember high school chem class and the demonstrations with sodium metal. To do that kind of work would require a huge industrial infrastructure with incredible safety requirements that even an OEM like AiResearch would have struggle with. I really didn't want to present my report because management was convinced that AiResearch knew what they were talking about. If I told them AR was pulling our leg they wouldn't have it. Finally I just said that the method suggested required too large of a capital investment for the volume we were doing and that cabinet blasting was still more cost effective.

Happily they accepted my eval and we moved on.

[Dartgame]

Not to mention that sodium metal will react and explode into flames when dropped into water. VERY dangerous.

[keithb7]

Thanks for all your suggestions folks. I considered them all. 
 

I washed both manifolds in an industrial hot de-greaser. I diligently hand sanded the intake manifold with emery cloth. I cleaned it and washed it again. Sanded some. Then more. Then washed it again.  Then painted it to match the block with high heat paint. 
 

I did decide to media blast the exhaust manifold. I washed it again for considerable time. Blew it out. I painted it black with high heat paint.  
 

Reassembly is in progress now. Thermal exhaust valve is all fixed too and working well. 
 

Edited December 13, 2021 by keithb7

[keithb7]

[Bryan]

1 hour ago, keithb7 said:

Thanks for all your suggestions folks. I considered them all. 
 

I washed both manifolds in an industrial hot de-greaser. I diligently hand sanded the intake manifold with emery cloth. I cleaned it and washed it again. Sanded some. Then more. Then washed it again.  Then painted it to match the block with high heat paint. 
 

I did decide to media blast the exhaust manifold. I washed it again for considerable time. Blew it out. I painted it black with high heat paint.  
 

Reassembly is in progress now. Thermal exhaust valve is all fixed too and working well. 
 

Good you didn't crack the exhaust manifold. Looks good.

[RobertKB]

Manifolds look really good!!

 

How soon before you fire the rebuilt motor for the first time?

[keithb7]

7 hours ago, RobertKB said:

How soon before you fire the rebuilt motor for the first time?

 

Robert I have some time to go  yet I think. I've only been working on the engine on the weekends lately. Work really cuts into the hobby. Lol.

I do have some time off work between Christmas and New Years. Hoping to make some good progress then.

I still have some some nit-picky things to do. Oil filter housing and new lines. New Vacuum advance line. Install fuel pump and heat shield. Carb and heat shield. 
 

Next big steps are hoisting the engine off of the stand so I can get the flywheel, bell housing and starter bolted up. Then I suppose it's time to drop it into the engine bay.  I am considering bolting up the transmission too. Maybe lift them both in together? I've not doe this before. The radiator and nose cone are off. I think there should be ample room?

Edited December 13, 2021 by keithb7