Ring lands broken

[cheyenne264]

I have a 85 K10 w/ a 350. It was bored .30 over and the crank was .10 under when I got it. I had a horrible knocking sound from the lower end from the #4 cylinder. Replaced the #4 rod bearing and the lower end noise went away. I then had a (knocking) type noise coming from more of the top end. I pulled the engine and removed the heads and all 8 pistons are shot to sh*#. All the top ring lands are missing sections out of them. I don't know what happened, I don't abuse the truck by any means. My question is are the heads ok. They seem to look fine, no apparent damage. I don't know where all the metal from the pistons went because it's not in the oil pan or any where else for that matter. Should I send the heads out to a machine shop and get them checked or just rebuild them with new valve seals and and maybe a valve job. I'll try to post some pictures of the pistons and heads tomorrow.

Thanks,
Will

[GreaseDog]

Have them checked and gone through while they're off. Have the block checked out too. No sense in half assing it now.

[Doober]

If ring gaps aren't checked and are too tight, this can happen. The ends will butt when the engine heats up and wedge against the walls, ring lands, etc. and break them. Like GD said though, have everything checked to see if anything else is wrong.

[Chevy53]

id deffinitly check the heads out too see if you got any bent valves as well sometimes you cant see the bends with springs on and the valves in the head

[cheyenne264]

I ran the casting number today and it turns out that the engine is from a 69-79 car or pickup. Only the bank 2 side is messed up. Bank 1 pistons are fine but all the rod bearing are worn down to the copper and like I said there is no obvious damage to the engine or heads. It used a little oil before and ran a little rough at idle but I just thought it was due to the carb since carburetors are all new to me. I just don't understand how all that damage could be done but no metal or damage to the engine.

[Doober]

Sounds like an error in assembly. I still think the rings were gapped too tight. My 383 was the same way, I'm glad I checked all that stuff.

[Geoffreye]

If you look at the bottom of the following website you will see quite a detailed animation of this 'action'.