So, I got my block back from the machinist..when I painted it, I masked of everything important except for overlooking the holes for the lifters. Overspray got in there. So, I was wondering if anyone had any labor saving tips or tricks besides using my finger and some fine sand paper to get it out. Anyway, this motion would appreciate any words of abuse that could save me some time. Thanks play hard, drive fast
If paint is there it will be everywhere where it shouldn't be. Last thing you want is minute particles becoming loose and finding their way or being being washed down into the oil pan or being trapped in suspension in the oil as it goes through the engine. Will the oil filter trap these particles before any damage, will a wet clean do the job sufficiently, I've no idea. You want the inside of your engine to be squeaky clean before it's all buttoned up and put in the car. As suggested I would use paint thinners on a clean t-shirt and wipe up the bores to remove the over spray and everywhere else before washing things down for peace of mind. Rotate the rag from dirty to clean to ensure that you get as much off as you possibly can. If assembled I'm sure others more experienced than me will chime in with recommendations and/or other solutions. Definitely no sand paper as the dust will become airborne and go into other areas, oil galleries etc. Last thing you want is anything abrasive or sludge getting between the moving parts, cylinder walls or bearing shells. What engine is it, a SBC? I purchased a Moroso SS screen (280 microns) that goes on top of oil filter and another that is epoxied into lifter valley to ensure everything stays nice and clean and if there is any mechanical failure it'll be captured and prevented from contaminating the oil and hopefully prevent it from causing any further damage. It may be overkill but cheap insurance IMHO.
I have read that you want to wash the block in soap and water before assembly. So I see no harm in using some paint thinner first to remove the overspray. And while you do want a clean engine and parts for the assembly process, I see no need to worry about a few small specs of paint that might be left behind. How much cast iron, steel, and bearing material will be in the oil during break in?
Hope you did not But, It sounds like you painted the inside of engine, NOT a good idea IMO. I bought into that BS in HOT Rod magazine back in the early 70's and followed their procedure exactly as printed, was the only engine failure I had back then, was building 4 cylinder Chevy 2 midget engine for my Dad's Midget racer and luckily a yellow came out and I noticed oil pressure was way down, shut it off, bearings gone, rods starting to turn blue, would have been pieces in a few more laps. The paint clogged oil pump screen and some through pump, a mess, but could have been much worse, had it back together for next weekend. I was buying parts from SESCO racing engines and went to work for him to pay off a SESCO racing engine I purchased from him, learned many skills that served me well throughout my years in my racing hobby. So...... my point is, everything you read or hear is not always the gospel, Good Luck with your build.
I'd talk to the machine shop and see if their cleaning process will remove paint. If it's a jet wash machine, with fresh soap solution, it probably will. But expect it to take some effort to make sure all the paint is gone from inside the engine, before you assemble it. Painting an engine is best done after the engine is completely assembled.
I paint them after assembly too. On my 355 it has aluminum heads so I masked off everything internally. Lacquer thinner and a soft rag will take paint off, even cheese cloth.
Ive used a fiberglass rod about 1/8" diameter ( tent pole or driveway reflector) run a slit up the pole with a razor knife. Shove a piece of cloth in the slit and chuck it up in a drill. Cut the cloth length so it will go into the bore, when you spin with the drill it expands, dip in your choice of solvent. I generally use this to polish bores with an abrasive, but it should work fine with just cloth.
Heres one set up with emory cloth that i use to clean inside tubes. Home depot sells driveway reflectors for a few bucks that have a 3' fiberglass rod. Denim or a similar heavy cloth dipped im solvent should clean up the lifter bores very quickly