At 01:59 PM 4/29/03 +0000, Phil Bates <jello@ida.net> wrote:
>.... The question I have is this, can I do the same for an MGA fan. Mine
>is not putting out air very well since I changed polarity, and a fan
>upgrade is probably worth the effort. .... I know the box is a little
>different, is it reasonable to do this conversion to an A heater??
>....
> >..... you can upgrade the heater core, the blower motor, and the
> squirrel cage fan. See here: http://chicagolandmgclub.com/photos/b_heater
> > Beware that the larger fan has to be placed inside the box and attached
>to the motor shaft before the box is closed. ....
I'm only about 98% certain, but I think the answer is yes. The MGA and MGB
heaters are quite similar above the heater shelf, except the motor mounts
on the opposite side, so it has to turn in the opposite direction (more
like the MGA Twin Cam heater which is a mirror image of the standatd MGA unit).
The MGA and MGB can use the same part number for the heater core, so I
presume the boxes are the same depth, and the MGA unit would accept the
same oversize fan as the MGB, except the fan needs the opposite sloping
blades to rotate the other direction.
The motors are all physically interchangeable, with differences in
rotation, internal windings, and shorter length of the later MGB
motor. The (original) MGA heater motor is series wound and will run the
same direction even if you change the power input polarity. The only way
to reverse the (original) MGA motor is to open the case and switch the
wires to reverse polarity of the field coils. Later MGB motors are shunt
wound motors and will run the other direction if you just swap the input
power wires. Some replacement motors for the MGA may do the same
thing. If you run the fan with the wrong direction of rotation it will
only move about half as musc air. So if you think you lost some air flow
when changing polarity, maybe try swapping the fan power wires to see if it
helps.
So I think the MGB uprated heater core and motor and fan will all fit the
MGA heater box, and the motor can be made to run in the appropriate
direction. That just leaves you trying to find the opposite rotation fan
for the MGA, and I suspect that may be available from the same source as
the other upgrade parts. Doesn't hurt to ask.
If anyone has done this, or will do this to an MGA, please let me know how
it comes out, as I would like to add it to the tech section of my web
site. Of course I'm not frivolous enough to do it myself, as it doesn't
make the car go any faster, and I have a good coat suitable for winter driving.
Barney Gaylord
1958 MGA with an attitude
http://MGAguru.com
/// or try http://www.team.net/cgi-bin/majorcool
/// Archives at http://www.team.net/archive
|