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914World.com _ 914World Garage _ Heater blower motor

Posted by: zonedoubt Jan 12 2005, 11:54 AM

The heater blower motor in my '74 is toast. I bench tested the motor w/ 12VDC and confirmed that the supply circuit is working OK. It's probably the original motor and finally kicked the bucket from constant heat exposure in the engine bay.

The type of motor that is in there is the single output tube with a Y-adapter. Two hoses come off the Y and go to the two J-tubes on either side of the engine bay. I know that on most 74's, the motor has one output and that the passenger side J-tube is usually capped. This car was probably set up to output more heat to deal with the cold Canadian climate.

My question is whether the motor from the earlier 2-output fan blowers can be easily removed and fitted to the housing on the later style blowers? Alternatively, are there any other motors (Porsche or VW) that will fit?

Or...does anyone have a good condition working motor they want to sell? It could be the single output type since I could simply swap the motor the Y-adapter.

Posted by: Root_Werks Jan 12 2005, 11:59 AM

Some motors will interchange with some housings. The show stopper will be plastic or metal housings. Motors from plastic housings mount just a little different than the ones from the metal housings. Nope, you can't just swap the fans around and drill holes to make it work either. The fans on both types mount differently. So if you can find a good used fan with the same type housing (plastic or metal, 911 or 914 or VW doesn't matter), then you can swap out the motor. IPB Image Done it tons of times.

Oh yeah, if you can find the motors that are bigger, usually the 911 motors, grab those. Better motor.

Posted by: DJsRepS Jan 13 2005, 07:42 AM

Is that the blower in the motor bay? Can you get the front blower out with out removing the gas tank ?? Mine wont work.

Posted by: Root_Werks Jan 13 2005, 07:48 AM

Yep, I was referring to the blower motor in the engine bay. The fresh air fan I think, mind you think can be removed with the gas tank in the car. But don't quote me on that one. Been too long. IPB Image

Posted by: michel richard Jan 13 2005, 09:00 AM

I have a couple of those motors in Montreal. I would sell one real cheap. Please email michrich@videotron.ca if you're interested.

Michel Richard

Posted by: Gint Jan 13 2005, 10:28 AM

Here's a write up I did a few years back (my first 914). It may gice you an idea of some of the variables you'll have to deal with.

I attempted to rebuild a heater blower motor without much success. Mechanically it was shot. You can see in the pictures that the choke coil from the power lead to the brush kept de-soldering itself when the windings smack the magnets due to the shoddy bushing in the bottom of the housing. Notice the grooves in the magnets. Replaced it with a motor from a 73 single blower unit. The mounting flange of the motor was too large to fit in the 74 double outlet housing. With a die grinder I removed approximately .050 all around the mounting hole in the housing. Sandblasted the mounting clamp. Works like a champ if not a tad weak. The motor is a smaller unit, but it beats freezing.
IPB Image

http://members.rennlist.com/gman/porsche/74_914_heater_motor