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I'm rebuilding 351w not realizing pistions were aluminum I dropped them in ZEP Industrial Cleaner soaking them turned them black. What can I do now to clean them. I tried wire brushing one and now worried I damaged pistons. I have glass bead but read that will damage piston. Now I don't know what to do thinking of buying new pistons. I have a press but from reading the proper way to install is with heat. Also saw that how far you push new pin in is critical so how do I know how far to push pin or will the piston manufactor have specs?
 

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pistons

If they are a set of cast rebuilder pistons i think at this point i would get another set. Not sure it's worth a chance on destroying a good short block for a $100 set of pistons.

The pressed rods can be done at home with a oxy/acc torch, but i would very strongy recommend taking them to a shop and having them done. If you get one stuck during the installation it's a real pain in the keester...


Keith
 

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In my autoshop class, I was tought how to press the pins on an old set of pistions, but when it came to changing the pistions on my '67 200 6cyl ( Hotrodded turbo engine ).. I sent them to Napa, and I think ran like $50
 

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About ten years ago I had a spray washer in the shop that would go nuts a couple of times a year. Everything aluminum would come out BLACK. Aside from the obvious color change, the parts were all ok. I just cleaned/wiped the pistons down and never had a problem with them.

Glass bead will not hurt pistons. Just avoid (tape off) the ring lands.

As for pressing pins. Don't, if you have no experience doing it.
 

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k-star said:
Interesting....Did you ever find out what was causing the jet washer to do that??


Keith
I use Alumasafe powder from Chem tech in my soak tank (hot tank), and although it is safe on aluminum, and does a fair job, it almost always stains them to some extent. I've noticed the more porous, rough castings are always pretty dark, but the machined surfaces are much less so. So I've taken to painting aluminum when I can get away with it!
 

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Aluminum is a very reactive metal that can be attacked by a lot of solvents, like chlorinated and others. Sometimes it is just a patina (like the green on a copper roof) that you are seeing, alkalines make for black crud, or smut. Some chemicals destroy the aluminum quite quickly, so not knowing the chemical reaction there it's hard to say. Like said, new pistons would be your safest route. Just sayin'...

BTW got a data sheet ref number for your cleaner?


Not that it has anything to do with your post, but cool.
Reaction of Aluminum with Bromine
 
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