How to paint engine bay?

No black unless rest of car is black. Got it? (JK. It's your car.)

I shot under hood and trunk area of Demon with single stage body color clear coat. I took most of engine compartment to bare metal to prime. Foil on brake lines and the stuff you won't be able to get out of the way is a great idea. I taped and wished I had thougt/heard about using foil.

I kept a little color and catalyst off to the side when I need touch up. The mixture will pass through a Pre-Val spayer (Home Depot or Lowe's paint dept.) if you have a new propellant can. It's faily thick and will begin to sputter as charge runs low. This makes the Pre-Val only good for touch up.
To actually paint the entire compartment, a rental spray rig works well. Get plenty of stuff to blow the gun clear of paint, otherwise you'll be paying for a rebuild.