Cleaning cast aluminum tips?

[gnoplos]

Hi everyone just wondering if anyone has any good tips on cleaning cast aluminum parts like the picture below (I realize it’s not technically a roadster engine by birth, but it will be by transplant!)

Not sure if a chemical would work or some abrasive method. I’m trying to use the least intrusive method as this is a freshly built engine.

Also on this topic does anyone have any suggestions on what or if I should paint this engine?? Going into a silver roadster with red interior.

[Nissanman]

I used a grit blasting cabinet with #80 carborundum media.
My A/C is only capable of 100psi but that was adequate to clean all the alloy to a smooth grey finish.
It is not that severe as it sounds and you can mask areas from the media with ordinary masking tape.
I do suggest that all parts are thoroughly de-greased prior to media blasting, no matter what it is or who does it.
I'm not into polishing but I'm sure the surface was smooth enough to do that.

[gnoplos]

Now I have done that method for cast aluminum parts and it did make it look very clean. Problem was, obviously something had to be done to keep it clean, as anything that touched it would leave a mark. I tried to clear coat it and it turned almost a battleship grey. Is that the same finish you had?

[Nissanman]

No, I just left the parts natural after the media blasting.
Don't have an issue with marks.

[eye]

Find someone that does "Vapor blasting" and have them spray it with conditioner when finished. Looks better than new and lasts almost forever. Totally non abrasive.

[eye]

Here is a before and after

[CSP311]

Yep, vapour or aqua blasting is the way to go on alu. parts. I even have my steel parts done, a whole lot less abrasive than sand blasting. Ideal for the natural steel finish for yellow zinc plating. The place I use, puts an inhibitor in, so the steel doesn't rust.

A few bits from my website, scroll down a little on this page;

https://csp311.net/blog/page-6-%e3%83%9 ... e3%82%b86/

[gnoplos]

Wow vapor blasting seems like a really good option if I had known about before I assembled everything! But I think I'll start with the etching cleaner and see how that goes.

[greydog]

I've had good luck with a stiff nylon brush and Simple Green to get the grease off, then Eagle etching wheel cleaner but I have had trouble keeping the engine looking good as the miles roll on.
I tried several paints and have pretty much settled on Duplicolor High Temp Aluminum engine paint. Once I have everything clean (including the etching cleaner) a coat or two leaves everthing looking new and is much easier to keep clean.
Dan

[justinmc89]

Some info I saved awhile back from a motorcycle guy..... and the photos I saved of his process.

"I decided at this point that I might as well remove all the rags for a good bath and that I should probably spray out the cases in case I got swarf in there. Brake cleaner got the bulk off and loose and that was followed by degreaser and... I just know that this seems wrong, a power washer with hot water.

I looked at it this way - water won't hurt anything in the engine. I've drowned bikes and flushed them and they come out okay. It's the water in the oil that's the killer. So I'll get the water out after.

I've cleaned a lot of old BMW's and at this point I have my "system" that works for me. Degrease, scrub with an stainless brush, degrease again and then rinse. After that, when it's all clean, I spray it down with mag wheel cleaner. It's an acid that etches the aluminum and I only spray it on the block when it's wet. I've tried when the block is dry and it's very splotchy but a soaking wet block seems to spread the acid evenly.

Leave it on for a few minutes and then rinse it off. If you want to brighten it up some more give it another spray down on the wet block, let it sit and rinse well. It even got all the rust off the flywheel. I sprayed all the galleys and nooks and crannies and wondered all the time if I'd regret this.

After I rinse the mag cleaner off and the block is clean I spray the whole thing down with WD40. This keeps the aluminum from oxidizing and getting white. Having owned the trailer for a few years I'm starting to convert over to LP3 which does a real good job as well."

[JT68]

Yes, next to vaporhoning, a very effective technique.

[notoptoy]

Carburetor cleaner worked a charm for me, I used the spray stuff, followed by pressure cleaning. Comes out looking like new. I used this on my Transmission - though I did this OUT of the car.

[gnoplos]

I've had good luck with a stiff nylon brush and Simple Green to get the grease off, then Eagle etching wheel cleaner but I have had trouble keeping the engine looking good as the miles roll on.
I tried several paints and have pretty much settled on Duplicolor High Temp Aluminum engine paint. Once I have everything clean (including the etching cleaner) a coat or two leaves everthing looking new and is much easier to keep clean.
Dan

Thanks I’ll try that paint out once I figure out if I wanna add any color or just clear coat!

[gnoplos]

So here’s where I’m at after a degrease scrub, brake clean rinse, etching mag cleaner soak and scrub (x2) and rinse. It looks worlds better but there’s still some nasty bits of corrosiony looking spots. I’ll try one long soak with the mag but I may have to hit it with a wire wheel. I’ll start in an inconspicuous spot to make sure it doesn’t mark up the finish too bad

[C.Costine]

So here’s where I’m at after a degrease scrub, brake clean rinse, etching mag cleaner soak and scrub (x2) and rinse. It looks worlds better but there’s still some nasty bits of corrosiony looking spots. I’ll try one long soak with the mag but I may have to hit it with a wire wheel. I’ll start in an inconspicuous spot to make sure it doesn’t mark up the finish too bad

gnoplos, note that justinmc89 stated that he used a stainless brush. That is because a regular steel bristled brush or wire wheel can leave a little steel on the surface which can then rust later on.