Rusty Bore

[Billydelrio]

I sent a weathered 360 block to the machine shop to be bored. It cleaned up fine at .030, but after it sat for a day, rust stains started to appear in the cylinder walls only where the rust was before the cylinders were bored. I plan to put the torque plate on, hone it, and use it anyway as it checks to be a good block. Is this a common occurrence?

Billy

[shannon]

Same thing happened to a 340 with me. Fresh bore and hone. Even with wd 40 in the bores and wraped in plastic bags I still saw a little rust (more like spots where the cylinder is a darker color). Now the cylinders are full of axle greese (bare block, no pistons). Been that way for 3 months now with no signs of rust.

[racer_amx]

I have had engines do that within just a couple hours of sitting, it is fine as long as you dont leave it their long enough for the rust to start eating into the cylinder walls again. I agree with shannon just put some grease on it if your gonna let it sit a while and it should be fine

[Karl43]

My buddy and I went in halves on a 75 Valiant with a "blown motor". The owner broke a timing chain and replaced it. He did not realize that he bent two valves with it. He had one head off and the cylinders accumulated some rust (the car was stored outside and he did not cover the cylinders). Took it home and cleaned off the rust with a fine wire wheel and then vacuumed the cylinders out real good. The engine runs fine. It is better to take the rust off instead of let it get into the rings. Take your time to get as much rust off out of the cylinders before you assemble.