Block cleaning

[dwg86]

Just passing some info...When I tore down the 4.0 getting ready to go to the machine shop, I noticed the inside of the block was painted black. Pretty cool, I thought, coming out of the factory like that. I got my block back from the machine shop yesterday. It looked all clean and pretty. When I got home and started inspecting it, I noticed that the black paint on the inside of the engine was gone. I don't know how they clean the blocks but I found a few spots where a little bit of the paint was still there. It was burnt and flaking off. Not a real big deal, as a wire brush on a drill quickly removed it, and I always wash an engine with soap and water and blow dry with compressed air before I start build up.

[Alex22]

The best way to clean the bores just before assembly is with lacquer thinner. If you're not going to assemble it right away, WD40 the cylinders.

I don't think my 4.0 had paint on the inside of the block. (came out of a 98 grand cherokee.)