by Rob Tourand
I took a blower and its mounting bracket out of a another late model bus (a '73 maybe, looked like mine (two outlets)). I then figured out where under the front floorpan I needed to mount the blower. If you're in the bus, it's on the passenger side floor pan, to the right of the emergency brake lever. If you are lying on your back under the bus looking up, these are my measurements:
To splice into the duct, I used a saber saw and cut the tube, leaving about 3" hanging down on the front tube (closest to the front of the bus), and about 5" on the tube that comes from the back. Before I mounted the blower, I capped the right side blower outlet closest to the passenger frame rail. I used a 2" PVC cap from the plumbing store and glued/duct taped it on.
Once the blower was mounted, I used some flexible aluminium tubing to connect the blower to the system. I connected the rear heater tube to the blower air inlet (the squirrel cage) with 3" tubing, a hose clamp, and duct taped it. This way, the blower is sucking the hot air from the back blower and increasing the velocity (volume) of the air entering the bus. The left blower outlet is connected to the front tube the same way (hose clamps and duct tape).
As for the wiring, I ran a wire (12 G - I think), from the back blower power feed (red/black?) to the same spot on the front blower. That way, when the back blower comes on, the front one comes on, too. (I spliced an in-line fuse in this circuit to protect the front blower). Now if you want, you can run the power feed to the front blower through a 3-way switch so you can control the speed of the front blower. Make sure the switch is a heavy duty sort or your switch will melt. The other wire from the blower (brown) is the ground and I just mounted it to the frame with a screw.
I have had this set-up for more than three years with no
problems (well maybe one - sometimes too much heat!!!!)