I have this motor, a remanufactured Autozone 455. Rebuilt about 18 months ago. I bought a 72 lark that caught on fire for parts and the engine. Well I turned the motor over before I bough it but I must not have turned it a whole 360degrees as when I was attempting to put a fuel pump on it, it would only turn about 3/4 of a revolution and then bound up. Luckily it was still on my engine stand... So my buddy Jim (James_P) came over and we dropped the pan, nothing wrong, next came the manifold and then popped the heads and we found 2 cylinders where coated in a rust substance, I am guessing from the fire extinguisher. I took some rust remover, cleaned up the rust, then honed out the damaged areas. I am now able to turn the motor over freely. But, I am concerned because there are still some small ridges from the rust lines and some pits as well. What should, can I do with this thing? Also, the pistons are stamped 040 so I am assuming it was bored 40thousands. Can this motor be bored out to .060 or is there not enough difference in bore sizes to clean the cylinder walls? attached a couple photos thanks
#8 Cylinder this the worst one, it is pitted and some ridges. they are not deep but you can feel then with you finger
You have to be careful cause if you overbore .060 you might not get all the pits and scaring out of the cylinders. Being everything else is in good shape I would take everything out and replace the block and bored the new block .040 over to match the pistons. Plus, if you bore it out to .060 you'll still need to replace the pistons which would be as much as replacing the block, so you might as well be better safe than sorry.
where you see the rust in the cylinders is from the intake valves being left open. happened to me on a pontiac 400 years ago. always shut all the valves for storage. good luck .
its hard to tell how deep te pits are from the pictures. as a general rule of thumb, if you can feel the pits with your fingers, you have problems. They could clean up with a quick hone, but you would have to measure the pistons, and teh cylinder. to much hone would reslut in a nice piston slap. if they won't clean with a hone, you could bore to .050, or .060. you could always sleeve those 2 cylinders and keep your .040 slugs. Joe
thanks to all! thanks everyone for the suggestions. I now have many choices to investigate. Either way I guess it looks like I am talking machine work and new pistons or new block and old pistons. I guess I need to figure out which is worth it or if either or maybe buy a complete motor from one of our many favorite builders:grin:
