You Know You're an Engine Builder if.......
 

You've corrected the clothes dryer vent hose for flow restrictions.

You know the volume displacement of your coffee can.

You mix fuel and have plotted an advance curve for the lawn mower.

Youv'e stuck a loose piece of wall paper back with Gaskacinch.

You mic'd your business card.

You used Loctite on your cabinet knobs.

Your rubber entry mat is on your workbench.

I think those would be signs that you have totally lost it and need to take the P-car for a drive.