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I'm looking at some used piston heads, flattop with 4 winks. They say that there a couple of small nicks on the top and the piston heads were bead blasted. Is this okay?
The small nicks should be okay but I'd be concerned with the bead blasting and what material was used to blast them. I'd also be concerned about the pin and skirt wear and tear. I don't understand why guys bead blast these things??? To make them look pretty?? In some cases it ruins a perfectly good set of slugs as blasting can remove piston material leaving them useless. Are these forged or cast pistons? Forged can take a little more abuse than cast but really depends on the media used to blast them with. Are they cheap?? Are they on eBay? G.
you should never bead blast a piston never it leaves pits where carbon starts to form and the material can scratch the walls just buy new ones pistons should only be cleaned in a parts washer and a soft bristle brush
This is exactly what was told to me about these piston heads. ""They are out of a 1970 390. The pistons are stamped 360 4V. I assume that they are cast, but not sure. I have the casting number from the actual pistons.....C8AE6110A.....As far as the blasting....it was silica beads. They should not cause any damage to the material. Any divits from the blasting would be minor compared the nicks that are already there.""
Can nicks be buffed out?
You dont want 'em. Even if you do buff out the divit's, you also increase the deck clearance and lower compression. You also weaken the piston. He (the seller) cheaped out, or was just an wuss, it should take no more than a some break cleaner and a brush to clean piston tops.
Where are you finding all this junk, debestuss? First the fubar'd rods, now this.
Yup, Ebay. Don't critisize, sometimes you can find some pretty good stuff at yard sales. There's always the possibility of finding something cheap that the owner has no idea of what they are getting rid of. Besides, I'm active duty military, not alot of money floating around at my house. If anybody feels they need to contribute to Wally's expensive hobby, feel free.
NOTE: I don't bid on anything until I clear it through FTE.
Last edited by debestuss; Nov 21, 2004 at 09:32 AM.
Okay, I'll be honest, I'm still thinking about getting these pistons. Here's why. I've done some asking around. The pistons weren't bead blasted, they were sandblasted with silica (sand). The rods were taken off, the guy had enough foresight to protect the wristpins. Now, I agree with Rusty, you shouldn't have to do more than brake cleaner and wire brush but that doesn't change the fact that he cleaned them up in hopes of selling them. I don't think there could be very much damage to a metal piston using sand. I can't just let go of this thing because I could save almost $400. Yes, bead blasting is a bad thing for pistons and rods but not sandblasting. Talk to me Kurt.
Last edited by debestuss; Nov 21, 2004 at 08:53 PM.
You are kidding, right? People went to beads because sand was so destructive! And pistons are not steel - they are aluminum.
Wow, I had no idea that the lines would be do definative. I didn't say steel, I said metal. I have a friend that built drag racers, he's 65 years old now. I asked him the exact thing that I've asked you all and he say's there's not problem with silica beadblasting piston heads. He couldn't understand what the problem was. Hmmmm. Somebody tell me what silica is, exactly. I wish I had some experience to pull from. I'm still listening guys. Keep talking.
Last edited by debestuss; Nov 21, 2004 at 10:05 PM.
Silica = dirt. Main component of sand. I think pure sand is pure silica. Normal sand that we think of, like beach sand, is mixed with organic substances which makes it yellow. To my knowledge anyway.
As was said, these pistons hosed. It's simply people trying to get rid of their junk on ebay.
I'd advise you to go down to Napa and price out a set of Silvolite 1131h pistons. They're hypereutectic and of the right compression height. Very nice units, and should work well. If you want to spend even less, have 'em price the 1131 pistons, which are the same as the 1131h's but are just plain cast. Better yet, have 'em price both. I think you'll be surprised. To get the best price, slip the guy a $5 under the table and tell him to run you through an account.
You dont want used pistons. You dont know how many miles they were used, whether or not the engine was overheated, what shape the ring lands are in, how wore the skirts are, how wore the pin bores are, etc. Not to mention, then you have to find wrist pins and retainers.
Okay. Thanks guys. I haven't put anything used on my build yet so why start now. I didn't stop to think of why they were replaced to start with. I'm not very sponteanious (hard word) and this time it paid off.