Muscle & Steel: Custom Chest Tattoo Design

Create a tattoo for a man's chest featuring two cylinder heads (motorcycle engine like a Harley Davidson). The cylinder heads should be partially in cross-section to reveal the pistons, piston rods, valves, and cams. Additionally, part of the engine with the crankshaft should also be in cross-section. You might add a spark or flames to one cylinder (simulating the explosion phase) and perhaps the exhaust phase to the other. Try to prepare the background for potential extension of the tattoo.