Lifter valley paint

[Barry_R]

I don't like paint inside the engine.
I don't like paint inside the engine.....

[speed220mph]

As Barry says, don't paint. For one thing, it doesn't help the flow of oil to the pan. Secondly, it was mainly for sealing debris that should've been cleaned out in the first place such as casting sand and plain old dirt from inside the block. My experience is not to add anything such as paint that get loose and contaminate the oil or worse, block an oil gallery. So do it right the first time and remove any flash and, if you have a lot of time, smooth the lifter area with a die grinder fitted with a burr or an abrasive stone, then clean the heck out of the block afterwards.

I cover block preparation and all other aspects of engine building in my newly published book, The Racing Engine Builder's Handbook. I show how race blocks are prepared for NASCAR Cup, Busch, late model, Dash, boat or whatever racing. Bottom line is cleanliness, it's the key. If it doesn't make horsepower, leave or get it out. The biggest problem with many engine builders is they do excessive "romancing" of the parts. Painting the interior of a block falls under this category. Save the paint for the exterior of the engine, but wash it down with brake cleaner first.

[Woodz428]

I would have to agree about not painting. I haven't used it on an automotive engine for some period. I don't think it will help oil flow any better than deburring and polishing in the same area. That's what I have done for quite a while. I have always been worried about the possibility of paint flaking off and destroying an expensive piece. Although, I have never seen any indication of that, it is always a possible. Since most blocks have casting "slag" that is left, by removing that and a little time with a sanding drum accomplishes that same without an potential side effects. I wouldn't have used it on the Harley if I wasn't trying to stop seepage through the early castings.

[Carnut427]

My Genesis block came painted with glyptol. I had to have the engine decked to get the quench I wanted, and the machine shop ran the block through their pressure washer afterwards. Some of the paint flaked off from that, telling me it wasn't a good idea. I used paint stripper and a wire brush (in a drill) to remove the rest of it, and obviously cleaned the block extremely well afterwards. Don't paint it. It's just a possible failure point.
My 2 cents,

Dan