replace piston?

[Logan]

Ok, I'm rebuilding a big block and in the process of removing one of the pistons I dropped the darn thing on the concrete floor of my shop. There is no visable damage. What should I do? Would it help to magnaflux check it or what? Should I just continue with the rebuild or should the piston be replaced.
No, I was not going to bore the block' if I can help it. After seeing the condition of the bores I was planning to change the rings and use the OME pistons. Thanking you in advance for you advice, Logan.

[sanders440]

Logan, Do you happen to know if it fell on the crown or skirt? Are these cast or forged pistons? Some are more brittle than others. If it fell on the crown and there is no visible signs of damage, chances are its ok. If it fell on the skirt, have it magna-fluxed. It may not hurt to have it done anyways, no matter which way it landed. When in doubt....have it checked out!

[Larry S.]

Last I heard, it was real hard to magnaflux aluminum pistons. Aluminum is a non-ferrous metal, meaning magnets have no effect on it.

[Logan]

Thanks,Sanders440, Thats what I thought, just wanted to be sure. Hey Larry s. when did they start putting aluminum pistons in 1971 FORD 429 anyway? Yea I know, MOPAR! I drive a V8 Dakota, but I'm Trying to finish up a Galixie 500 project I started a while back. My next project is a Challenger. Thanks anyway Larry S.

Hey Sanders440, Thanks again... Logan

[Larry S.]

Logan, when did they quit putting aluminum pistons in Fords? Go to a machine shop and ask to have that piston magnafluxed and see what kind of response you get!

[Mopar400hp360]

I don't know the extent of the damage but I can tell you this much - pistons are cheap - I'd rather replace a piston than have the block bored due to a bad piston.

[Logan]

Ok, Larry, I'm STUPID!!! The darn things are aluminum...I never would have known it if you had'nt said something, you know the bad thing is that right after I responded to your reply, I went and checked it out...boy, talk about eating my words...Thanks for that eye-opener...Now back to work, Mopar400hp360 said replace the piston, Should I go ahead and replace all of them, or just the one?

[Larry S.]

Hey Logan, you aren't stupid. You drive a Mopar don't you? That puts you up at least ten points higher in IQ than the guys driving those other cars. We all have brain farts once in a while (boy have I had my share!) The main thing is that we all help each other out here and have fun while we do it!

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1970 392 Hemi Cuda

[Larry S.]

Oops, forgot to address your question about the piston. (There's one of those brain farts now!)If the rest of the pistons are good, I would take that one to a good machine shop and get it checked. A friend of mine used to run a machine shop, and he showed me how they check aluminum for cracks. They use some type of dye I believe. I wasn't paying too much attention when he was explaining it,but do remember him saying that it was pretty good at showing up any problems. I'm sure that one of the other guys here could explain it better than I have. If you are really worried about it and want total peace of mind, replace the one piston, and have all the pistons weighed and balanced.

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1970 392 Hemi Cuda

[DartJustin]

How many miles are on the block? If you're going to the trouble to rebuild it and you're already down that far, you should bore it. Why not? It'll last a lot longer, or do you WANT to tear it down again when the rings don't seat properly or you're not getting the right compression. ...but then again, how many miles are on it?...how much of a ridge do you have?...are the cylinders out of round?...just food for thought...

[Christopher]

The piston is probably OK.You have to remember that once inside the engine,a piston is under a bunch more stress than being dropped on a concrete floor.

[Logan]

Justin, I'm unsure of the miles on the motor. When I found it it was already out of the car. The man who runs the junk yard I bought it the engine from said the motor was low miles and still ran very well. At first I thought YEA RIGHT! but after I started to tear it down I started to wonder if he was'nt right all along. Anyway I figured I've got it on a stand and I'm in no big hurry, so I'll go ahead and strip it, clean it up, paint it and plastigage the mains. There almost no ridge at all, I can feel it with my finger nail but just barely. The bores look good, no scoring or anything. I'd like to put her back togeather and sell her so I can start on a challenger I've got my eye on.
By the way, Thanks to everyone for all the advice...Logan.

[340king]

Logan, one of the most vulnerable areas of the piston is the skirt. I would have all the skirts checked for collapse, especially the one you dropped. I would also check the side gap of the rings in the piston grooves, use new rings to check. If both of these check out, reuse the pistons, sell the engine and rock on in that Challenger!