i was thinking about rebuilding my own rotary instead of having someone else do it and i was wondering if painting it would make it heat up more or not. if i can paint it without it making much of a difference...what kinda of prep work should i do to it before painting (scruffing it, primer, ect?). also...what kind of paints should i use.

 

Go with powdercoat. Way more durable, the heat difference is negligible.

 

the only way paint affects an engine is if it sits in direct sunlight, such as driving around with your hood off, which is white trashy anyways... dark flat colors soak up heat and hold them in more than brighter colors, if you keep it out of the sun then it doesn't matter what color you use.

we are talking minimal temp changes due to color anyways, engines run at 200 degrees F at the block to 800+ degrees F at the exhaust.

 

I painted mine here are some pics. But i would suggest powdercoating it the paint chips easy. and does not look as nice.

 

For some reson i could not edit the above post. here fixed them

 

i prefer to sandblast aluminum parts, it looks the same as your pics above, i painted my engine black, powdercoating and even high temp engine paint will discolor over time so i choose dark colors that will not fade over time.

 

Got my paint at walmart. Ford blue. Still looks good after one year. Just prep the surface properly and it will last longer.

 

Got my paint at walmart. Ford blue. Still looks good after one year. Just prep the surface properly and it will last longer. I only painted the plates. The aluminum was just cleaned good and scotch brite pad used on it.