C3 High Performance HVAC Blower Motor

[Mark E.]

The 53 year old blower motor in my '70 works but runs slow. I've cleaned the circuit connectors and grounds already.

I plan to get a new replacement to see if this helps, but does someone offer a "high-performance" bolt-in motor that runs at higher speeds?

I know these tend to be a bit puny even when new, and I know about the C4 blower motor mod that requires a spacer.

Thanks folks.

[Mike T.]

Re: C3 High Performance HVAC Blower Motor

Mark - Are you still getting all '3' speeds out of your blower motor and all speeds seem a bit slow?
I'm not aware of any high performance type of blower motor being available.
In the last couple years I've replaced the blower motors in both of my Bigblocks, a 66 and 65. One of the
RockAuto replacement motors is Four Seasons #35587 and hard to beat for under $30. They fit fine but
they do have that large hole in the side of the motor casing, that I believe was used in C3's that had a rubber
conduit to push cooling air back into the motor casing. Since midyears didn't use that configuration, I just plugged
the hole with a rubber plug that had a small hole in the center. DSCN6245.jpgDSCN6246.jpg

[Mark E.]

Re: C3 High Performance HVAC Blower Motor

Thanks Mike. Yes, the original motor works on all speeds. High speed is pitiful... equivalent to level 3 out of 10 with the blower in my '93.

I ordered a new blower, so we'll see if that makes a difference. Plan B is installing a C4 blower.

[Mike T.]

Re: C3 High Performance HVAC Blower Motor

Mark - when I got my 66 L72 Roadster, summer of 2021, I was checking the blower motor and heard all '3' speeds on it but the airflow was almost nonexistent. I did eventually replace the blower motor but that first test had me baffled because the motor sounded like it was pushing some air but nothing coming out. Pulled the resistor on the backside of the plenum and it looked good, as expected, but when I went to reinstall it, I felt something sticking out the small rectangular resistor hole. Check out the pic which explained where most of the firewall insulation had gone to.
The rodents had created this big 'Mouse-House' inside the plenum. Took me 3/4s of an hour to tweez out the pieces. And, of course, I didn't realize the heater core was shot otherwise I would have done all that work at one time.IMG_8255.jpg

[Mark E.]

Re: C3 High Performance HVAC Blower Motor

Mike- This is a good reminder to check for debris in the plenum and ducts.

I replaced the AC evaporator, so all spaces and ducts are clean and sealed. I can hear the blower running... it doesn't run very fast.