The Stovebolt Site Forums The Shop Area The Electrical Bay 1946 Chevy 1/2Ton - 12v Heater Motor

I'll be converting from 6v to 12v. I searched some old threads, but does anyone have an updated 12v heater motor that is plugged and play? My 6v motor has a 1/4" shaft. I also have the defrost motor on top. Is that the same motor?

John, I had a nice 3 speed motor that would have probably fit right in there for you. I tried for over a year to give it away for the cost of postage and finally somebody took it. Many 12v motors from hang-down units, aftermarket units, etc might fit. I'd suggest removing your motor, measuring everything and looking on the large internet auction site. I would suggest a step-down converter (12v to 6v) however the amperage might be the stumbling block. Those 6v motors took between 5 amps and 10 amps and if there was extra drag from old/deteriorated bushings might take over that. A 12v to 6v step-down with 15 amp ability and a proper heat sink will cost you the same $30 a Chinese made 12v fan motor might cost...and you'll still have an old motor.

Thanks Jon. I was wondering about using a 6v with a voltage reducer since I'm converting to 12v. I can find 6v motors with a 1/4" shaft which would fit my fan. The 12v motors look to have 5/16" shaft, so that would mean drilling out the hole in the fan and I guess that would work. Most motors say "some modification may be necessary" - not sure how much though.

Almost all 12v motors will have a 5/16" shaft but that's an easy fix (as you said...drill it out by 1/16"). There are some inexpensive 12v heater fan motors that might work. Example: https://tinyurl.com/2u9tx2ck And a common speed controller like this one would be handy (you may not want the motor running at high speed all the time): https://tinyurl.com/mwc3evh6

Hope this is helpful, John.

There is one other option, John. A computer fan like the one shown in the link here might work: https://www.amazon.com/Nidec-dell-B35502-35-120x38mm-CN-0Y4574/dp/B00B87CTDA

It is a 12v DC motor, it puts out a fair amount of air and it only uses about a third of an amp at full speed. You would just remove your fan and the motor and attach this on top of the heater core. The key is would you have enough room to fit in 1.5" (that being its depth)?

Somewhere in the attic I have one of these I'd be happy to send for the cost of postage and I may also have one that might be a bit thinner...can't remember that for certain but I did save some of these from a thermoelectric project I did about 20 years ago.

This is the route I may take. Not running a voltage reducer to 6v motor seems like a good idea to me.

I agree. You want a nice predictable heater and not Mount Vesuvius.

Update: Well, I ordered a 12v fan motor awhile ago and I'm starting to put the heater unit back together. My original 6v motors have a case diameter of about 2.5". The new 12v motor is a fat 3" and does not fit inside the round heater core. So now I'm searching for a 12v motor that is 2.75" in diameter or less. Or, I'm thinking about using my old 6v motor with a voltage reducer. I'd rather find a 12v motor. I need two - one for the main fan and one for the defrost fan on top. The search goes on.

John - I did a little searching through Stovebolt and found this very on-topic discussion started by Bolter Grigg 10 years back.

It seems he found a suitable plug and play 12v motor for his heater from NAPA under the number 655-1022. I checked current NAPA offerings and think this
NAPA # BK 6551022 is the present day equivalent and seems like you can even order it for home delivery.

Might be just what the Dr ordered???

Edit: On second look, perhaps not. Grigg said the original dimensions fit inside his round heater core, but the NAPA site lists this ones overall case dimensions as 3".

Jim Carter lists one for round heater core, 12v replacement for 6v heater. Says it's a smaller diameter than the original 6v motor.

EL116 $62.95

Here's the link for the Jim Carter offering EL116.

I called Jim Carter today and they told me the EL116 had a 3" diameter. Anyway, I went out to the garage to get some pictures. My old 6v motor sits in the heater core and has some air space around it. I then placed the new 12v motor so you could see how tight it is and does not fit... but wait. It started going in if I giggled it (to be clear I'm talking about the motor going into the heater core!) I can get it maybe 90% in and maybe I can sand the inside of the heater core and the outside of the motor. My question is: Should there be some space to help keep the motor cool? Should it be touching the heater core? I have a brand new core, but sadly it does not fit inside my existing heater box/case.

Just looked at the picture with the new 12v motor and I'm not sure if the wires will be in the way if I try to push it down all the way.

Here's a picture of my original heater core and 6v motor. It does look like there is some space around it.

Here is the new and old heater core side by side and the new core installed. Maybe these pictures will help. Maybe not.

What's the size difference of your new core compared to the old one?

In your last picture, is the housing surrounding the core the part that your new core won't fit into?

Yes. My new core looks like your first picture. It has the three threaded rods. My '46 setup only has two that are lined up and down. I'm betting the new one is for '47-'54? I'm going to look at it tomorrow to see if there is a way to make it fit my '46 housing. That would make things easier with the 12v motor.

Otto - Your recirculating heater and core are different than Johns earlier style heater. Apples and oranges here, so they aren't the same to begin with and his core clearly has a smaller diameter motor recess.

John - I think you will be fine on the contact between the motor case and the core honestly. It's not like it's going to act like a huge heat sink for the core or anything and since it designed to be in an enclosed case, it's meant to be able to handle the heat IMHO. If the motor wasn't up to handling the heat, it would have been designed with air flow openings for and aft on the case to allow for cooling air flow.

Just searching the internet this morning and have a question: When looking for a heater motor I had assumed most were the same as in spinning clockwise. I see some motors that are labeled counterclockwise (CCW). Does anyone know which direction for my '46 heater motor? Is it clockwise?

The direction of rotation should make absolutely no difference. The heater won't know the difference your electrical system won't know the difference. The fan blades can also be installed in either direction to either push or pull air.

John - I can't be 100% sure, but in searching through Chevy and GM related Master Parts resources, it appears the original motor is listed as "counterclockwise". At one point in the mid to late 50's GM listed a common 6 volt replacement motor for the early Deluxe heaters like yours as GM #5047733. It replaced about 2 dozen like type 6v heater and defroster motors for Chevy's and other GM brands.

The 1957 Chevy parts book indicate a replacement for the original heater motor for Deluxe heaters from 1935-47 being listed as GM# 5047532. That's one of the many numbers the GM# 5047733 is listed as a replacement for.

I know it doesn't help a bunch with trying to find a 12v motor to fit that space, but wonder if acquiring one of a few NOS 6v motors I found currently listed on line for sale, if one of those motors could be used with a variable voltage controller like the one posted in this Electrical Bay thread???

Thanks Dan! I'm actually thinking about staying with a 6v heater and just adding a voltage reducer. I'll take look at these 6v motors. Thanks for taking time to research this for me.