[patrickt]

If the car runs well, the pipes heat up evenly, and you even watch the valve train with the covers off and every valve goes up and down cleanly, then I would try and locate the tick using a mechanic's stethoscope. An engine tick coming out of a Surface is a little tricky to identify. The fact that your engine runs well is a good sign. A stethoscope will help you spot the location of the noise, if it's mechanical (it could even be something like a mechanical fuel pump misbehaving).