I'm trying to learn something here. Scroll down about half way and look at the pics of the rust in the cylinders. Notice it's on the top? I have a guy trying to tell me that this is from condensation of a motor that has been wrapped up in a tarp and from the repeated warming and cooling in a humid climate. The motor is not his though. I think he is full of crap but I might be wrong. I think it's from the motor being stored upside down with heads on and water got into the cylinders. That's the only way I can see it rusting on JUST the top and no where else. Look at this link about half way down and tell me what you think. Can just condensation cause this where it's at? If I'm wrong.....please tell me nicely!!!! lol


http://67-72chevytrucks.com/vboard/s...d.php?t=350816

I'm thinking it just sat for a really long time with the valve(s) open to the atmosphere and the piston sitting below the rust-line.

A car stored with the Exhaust Pipes on the engine can really rusts the cylinders were the exhaust valves are open. Condensation in the pipes raise and collect in the cylinders. That's why it's best to stuff a rag in the Tail Pipes, pull the plugs, spray Rust Check into the cylinders and turn the engine over occasionally.

I'm going with condensation as well.

He's not pulling your leg I rebuilt a small V8 about 10 years ago that had the exact same rust and marks. The tarp thing really does not matter all that much, the V8 I rebuilt was sitting in an engine bay of a jeep in a shed for about 12 years. The rust on the walls typically will show from where the crud collects and up the the outer portion of the cylinder walls down to the pistons will look some what cleaner because there would most likely have been a bunch of crud in there kinda looks like mud from water and other chemicals and rusty flakes piling up. Once the rings seize to the cylinder walls the cylinders work like a bowl and hold everything above them. It may or may not be savagable depending on how long its been sitting. The V8 I rebuilt needed to be bored and a new crank, I also did a small outboard with the same problem that we got away with homing and new bearing/rings etc.

Dub,
That is not from water. If it had been upside down with water in it, the cylinder walls would have been pitted pretty badly. I have a couple of blocks that we bored and never finish honed a few years ago. They are sitting in my other unit next door to the shop and a couple of them are starting to get some surface rust on them exactly like that. The difference is that unit is only barely heated in the winter and no AC in the summer. I have some blocks and cranks that have been sitting in our main shop for 5 years and they look like new. Difference is heat and ac ... keep the shop at 75 degrees year round.

The damage in your case is definitely condensation.

I have already thanked him for teaching me something I didn't know. Will make me more cautious when I'm rat-holen my next motor. It's a great group of guys on that forum. They know 67-72 trucks like you all know Camaros! I like them too cuz they dig my little pro-streeter that's in my signature. ;o)

Pssst......notice though when I wanted to get an absolute correct answer I posted it here!!!!!! Yeah baby. Me trust yous lots!

Dub,
The key is in the temperature changes. A basement or heated & air conditioned shop is best.