I just pulled my engine out of my car and im about to start tearing it down this weekend and see how the bottom end is after i believe i spun a bearing. i noticed however my pistons have a good amount of carbon on them and theres a good layer of carbon around the combustion chamber. i hear people using scotchbrite to clean them but i hear mixed reviews of it working fine or being to much and potentially scratching the cylinder walls. whats the best way to clean the walls off as well as pistons? on a side note, when i reassemble the engine would it be alright to use my pistons as is or would i need new rings, wrist pins and or have them professionally restored for reuse?

 

You're already planning to take the crank to your local machine shop to inspect it, right? Have the shop jet wash and inspect the block and pistons as well while they're at it. They will tell you if your block needs a bore and/or if your pistons need replacing.

 

If you have a ridge of carbon buildup at the top of the piston cylinder, this is cleaned with a cylinder ridge reamer. It’s basically a round thingy with some cutting blades around the perimeter. You stick it in the cylinder, adjust it for snugness and start turning. Some skill is required. Can this tool be rented? Used to back in the day.

For cleaning the cylinder walls after the ridge has been scraped off use a cylinder hone. Some have three long blades of fine grit material spring loaded to grip the walls. Newer (and my preference) are ones that look like they have marble sized grit ***** sticking out all over. These are not adjustable and must be purchased according to the cylinder I.D. Which ever, use plenty of oil and go up and down to form a nice cross hatch pattern.

You could clean up the cylinders before you go the machine shop. If you have a set of inside bore gauges and a micrometer you can insect the cylinders for possible out of roundness or tolerance issues. Likely you don’t have these tools. So, like Dax says, if (when) you go to the machine shop they will check and measure everything for you. If you are on a budget you might get away with new rings, a turned crank and bearings. If the cylinders are seriously out of round or worn they can be bored slightly oversize and, if the pistons are OK, you can install piston rings that are slightly larger in diameter. There are lots of options. If you look up, you should see the sign on the machine shop wall that says “Speed costs money. How fast do you want to go?”

jvf

 

forgot to mention-the ridge reamer is turned with a wrench or preferably, a ratchet wrench and socket. cyl hone is turned with your favorite drill at a reasonable (not too fast) speed.