It was winter 1996. The outside temperature was hovering at a balmy 10F; the shop doors were closed. A nasty old propane-fired heater kept me toasty warm, its vent plumbed through a cut-out coffee can into an old cast-iron chimney spouting 40 ft over the 100-year-old residential garage. Years ago there was a coal stoker connected to that chimney. Today, the decrepit heater nearly explodes every time the propane burner lights off-small gas leak at the thermal coupling, I guess.
The venerable old BMW 2800 sedan sitting in the center of the garage sputtered, then roared to life after a decade-long dormancy. The once-mighty M30 engine belched a noxious mixture of oil, rust, hydrocarbons and soot from the ancient ANSA free-flow exhaust system. Bits clanged underneath, and the dry-rotted Bosch copper-core ignition wires set off a light show like a Blue Oyster Cult concert in the cob-web infested engine compartment. My friend Jeff pulled his Camel Lights sweatshirt up over his nose and reacted in the colorful local Northeastern Pennsylvania vernacular: "You dumbass! Open up da goddamn door before you 'fixate da boatovus!"
I didn't think the old Bimmer was going to start, even with a borrowed battery and its fuel line stuck in a can of fresh Sunoco 94. Amazing what a little shot of ether will do. Ha!
But seriously, asphyxiation is no joke. Carbon monoxide (CO), a colorless, odorless component of exhaust gas, can be quite deadly. CO levels from exhaust fumes in a closed garage can reach unhealthy levels in minutes; deadly levels in a few more. It is one thing when you've got a rusty old Bimmer depositing stuff on your floor that looks like it came from someone after a bad night of Double Whoppers and cheese fries-anyone knows you need ventilation then. There was nothing colorless or odorless about what came out of that 2800. But even a warm engine in good condition needs exhaust ventilation if it's run indoors. Jeff was right, and it took me awhile-and a new garage, with a new heater-but I did him one better with this cool Exhaust Away garage door exhaust ventilation kit from Eastwood Company for $60.
The kit contains a big rubber hose that looks like the arms of the robot on "Lost in Space." It has a handy integral hook so you can hang the hose on the wall when it's not in use. The hose simple connects to the tailpipe at one end and an exhaust port leading through the garage door on the other end. The exhaust port has a little flappy door. The hose sticks through it, venting the fumes outside. Eastwood has a dual-exhaust version of the same kit for a hundred bucks.
Installation is simple. You need to cut a hole in your garage door in order to fit the exhaust port. The job calls for a hole about 3.75 in. Unfortunately, hole saws are commonly sold only in 1/4-in.-size increments. This is probably why the installation instructions advise using the exhaust port flange as a template to scribe a line on the door and cutting it out with a jigsaw. I don't know about you, but I really don't like jigsaws. I don't know why. I used a 4-in. hole saw, which left a gap that was amply covered by the flange on the exhaust port. I finished the job by painting the exhaust port white to match the painted aluminum garage door.
Now I need another old Bimmer to resurrect.