In grad school I made one out of a peanut butter jar with two rubber hoses. I put a 12v Harbor Freight air compressor into the end of one, and theend of the other one attached to the manifold with duct tape. Inside the jar, I shoved a cigarette into the hose with the end in the manifold. Lighting the cigarette, closing the jar and turning on the compressor was enough to fill the entire engine with smoke. It cost like $4 for the smokes, and the rest I scrounged. Easy and cheap.

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Garage:

2017 Chevy Colorado Diesel (nanny state emissions)
2005 Volvo S40 T5 AWD, 77k
1987 Mercedes-Benz 300D turbodiesel, 4 sp auto, 156k - 28.7 mpg
1996 Tracker 4x4, 2 door, 16v, 3 sp auto. 113k - 28.6 mpg

WARNING: this post may contain dangerous free thinking.