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Finish On An Aluminum Engine: What Do You Guys Do?

2K views 14 replies 8 participants last post by  4 Jaw Chuck 
#1 ·
I'd like to know what you guys do to the surface of an aluminum block/heads...polish, sand blast, paint? I know what I'd LIKE to do on mine, but not how. What I'd LIKE to do is have it natural, but I know natural is subject to stains, corrosion, discoloring, etc. If I could get it all cleaned up, and one consistant finish, I could seal it with some sort of clear, so it wouldn't stain corrode, etc. Question is, HOW to get it to a nice, as cast finish, and then WHAT to seal it with. Would walnut blasting do the trick...and give it that nice, smooth, sheen? Sandblasting leaves a rough, porous finish...not looking for that type surface... :confused:
 
#3 ·
Whenever I do aluminum or stainless, I just polish it up til I can shave in it and then seal it with a heavy clear coat. It makes it real easy to clean later as grease and dirt just slide of the clear. A few wipes and it looks new again. I would never hide it with normal paints, let the polished surface shine!
 
#4 ·
If ya just want to get any current gunk off of it and clean it to a "before installation" look, try some aluminum wheel cleaner. I've just cleaned up a crusty, oily, dirty aluminum intake and it looks like it just came out of the box instead of being on an engine for the past several years. To help the cleaning action, I utilized some brass and nylon brushes to really scrub the hard-to-reach areas.

- Mike
 
#5 ·
Aluminum

You can go to any Big Truck Wash, and they deal with aluminum and stainless, all the time with the truckers.
They can presure wash the gunk away, then sray on BRIGHTENER, which is a mild acid, and it brings the alum back to a nice bright condition.
IF you decided to go the polishing route, you could clear it all, but they also mak a citrus based wash that they use on the polished wheels of the trucks...cleans em well and does NOT ruin the shine.
Also most Truck Stops have guys that work the paring lots, and the Truck Washes have guys that all they do all day is polish alum, and stainless.
$5 a wheel and they are BIG wheels. $20 for a 120 gal side tank....beer is extra though.
 
#6 ·
I re-build aluminum Ford " Teksid" Blocks all the time. While I have seen so polished, and yes they look nice, I also believe they usually cost around $3,000.00. I like to get my blocks as clean as I can, I start with the usual de-greasers like Gunk and hot water, this softens or removes most build up. After that I break out the pressure washer and blast away, till i have everything off that's coming off. Most engines look good at this stage, but some don't. Sometimes aluminum gets stained, and looks dirty when it's not, for those times I get out the sand-blaster and using glass beads, I go over the block, either entirely of just the trouble spots, and this does a great job, it removes the built-up areas, and evens out the casting surface. Honestly, I usually blast them regardless of how clean I get them in other stages. Sand-Blasting, just does to nice a job, to limit it's use. I can remove casting scale that should have been removed at the factory, and I can even the whole surface color, so it appears to be a new block. once the block is clean, and all the machine work is completed, I use a cast aluminum paint (spray) and call it a day. If you want a really nice show engine, then you would have to even up all the outside surfaces, which would require a liberal use of surfacer/primer, and sanding between groups of coats. Some areas might even need some filler to smooth out. Lastly, I would then coat the block in a nice glossy color of choice, followed by a couple coats of clear. Good luck
 
#7 · (Edited)
Before you polish a block consider what the headders heat will do to any coating you put on them. header heat does a real job on clear coat...

I have seen this company completely "jewel" a block with CNC high speed cutters, while lightening, never seen anything nicer...or brighter..

http://lsmeng.com/Block-Lightening.html

On my Keith Black blocks we just pressure wash, soak tank, pressure varsol spray, and then real hot water wash, to keep them clean. My headders get real hot...
 
#8 ·
Powder coating will stand up to all but direct contact w/ headers. My exhaust system on my Willys is powder coated from the header flange on back. My intake manifold is powder coated and after 5 years looks like new, even @ the hottest exhaust X-over area. Anywhere you powder coat an engine block will be way cooler than it would take to damage the coating. I powder coat all my engines and polished aluminum tranny cases and have never had a discoloration problem.
 
#9 · (Edited)
Willys what brand blocks do you powder coat? Are they aluminum, cast or billet?

Once I get a KB alum cast block prepped for assembly it usually has a cost of 6800-7K, (with finish work and do dads done) and I do not trust the powder coaters masking abilities to not screw anything up...I would never touch the finish on a billet block.
 
#10 ·
OHD said:
Willys what brand blocks do you powder coat? Are they aluminum, cast or billet?

Once I get a KB alum cast block prepped for assembly it usually has a cost of 6800-7K, (with finish work and do dads done) and I do not trust the powder coaters masking abilities to not screw anything up...I would never touch the finish on a billet block.
I don't do anything as exotic as that. Old junk yard iron hemis, straight 6s, that kind of stuff. The steps I take are; Get the iron stripped & hot tanked and crack checked; if it is restorable, take it to the powder coater and have it coated; Finally take it back to the machine shop and have all the machine work done. This way it doesn't matter if they don't tape it off very well, the machine work will clean up any over spray on critical areas. Anyway, powder coat comes off really easily w/ good paint remover so it isn't the end of the world if they goof up a bit.

For my trannys, I polish the cases then take it to my coaters for a clear powder coat. Haven't had any problems with the result.
 
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