6V heater systems, increased CFM air flow?

[m-mman]

6 volt heater blower motors. I have several and whether low speed or "high" they dont move much air. Is there anything that can be done to move more air?

Yes, I live in the 21st century and have become used to turning on HVACs in newer cars and having a mini windstorm come out of vents.

Is the gentle blow all these old heaters ever did? 

 

I have cleaned and checked the electrical (grounds, other connections and opened up the motors for cleaning and evaluation, etc.) I have even tested with direct connections to the battery.

The motors all 'work' but the airflow is just "Eh". . . 

 

Has anyone ever experimented with higher speed motors? (greater RPM) 

Bigger or different fans?  I changed the squirrel cage in my 69 Ford truck (original = 4 inches, replacement = 8 inches) used the original motor and it made a big difference in CFM that was very noticeable. 

[trini]

I am not going to answer your question directly . My past experience may lead to something to think about. I had 68 4 door Biscane  with a 327 engine. That heater was always cold  even with a 180 thermostat. The fan shroud was missing. After installing a shroud the heat inside was just great. May not apply to your case.  

[Akstraw]

6 hours ago, trini said:

I am not going to answer your question directly . My past experience may lead to something to think about. I had 68 4 door Biscane  with a 327 engine. That heater was always cold  even with a 180 thermostat. The fan shroud was missing. After installing a shroud the heat inside was just great. May not apply to your case.  

Good idea to consider whether something other than the fan speed is really the issue.  Easy to measure the temp of the heater core with one of those point-and-shoot laser temperature guns.

 

[Ben Bruce aka First Born]

1 hour ago, Akstraw said:

Good idea to consider whether something other than the fan speed is really the issue.  Easy to measure the temp of the heater core with one of those point-and-shoot laser temperature guns.

 

 

What he said.   Many (most?) old car heater cores are plugged with lint, etc.

 

  Ben

[kgreen]

When new, the amount of heat dissipated by your heater is based on entering water temperature, flow rate of the water, surface area of the heat exchanger, entering air temperature and the amount of air passing over the coils.  Changing one or more of these will affect the amount of heat inside your car.  When the system is old, many other factors come into play that restrict or alter the same functions described above, including things like Ben said above.  Changing fan speed is a start, but you have other options to improve your heater's performance.  You did hit on one other really important factor.  Todays expectations for comfort greatly exceed those from years gone by.

[bryankazmer]

not sure if the housing would permit it, but changing the pitch angle of the HVAC fan (NOT the engine cooling fan) will change airflow

[Rusty_OToole]

Years ago I overhauled the heater on a 59 Ford. Took the blower out, cleaned and lubricated the motor, and cleaned and painted the squirrel cage fan. The fins of the fan were filled level with dust and dirt. It took some soaking and careful scraping and scrubbing to get every bit of dirt out, but necessary to get ALL of it so it did not throw the blower out of balance.

The difference in air flow was unbelievable. It felt like it was blowing 5 times as much air. All I did was clean it carefully lube the bearings with white lithium grease and give it two thin even coats of spray bomb paint. While I was at it I made sure all the ducts and hoses were fitted correctly. The difference was like night and day, the heater and defroster worked like new. O ya I also blew out the heater core with compressed air and vacuumed out any dirt and dust from the ducts.

If I was doing it today I would oil the motor bearings with synthetic motor oil. For an even better job, replace the bearings with oilite bearings soaked in synthetic oil.

Edited September 16, 2021 by Rusty_OToole (see edit history)

[trini]

Removing the heater core and boiling it out will help. Heater motors bearings are usually bronze , oilite. Had to be soaked in oil for a long time ,maybe 24 hours. The oil do dry out over a period of time. I think Rusty-Otoole said it right. use synthetic oil and soak the bearing. Starters and generators uses those bushings at the brush ends also.

[m-mman]

The accessory Lion heater in the 1929 Cadillac has a 4 blade fan and despite repairs and restoration, moves very little air.  Not the biggest problem as there is currently no water hooked up to it.

Getting other stuff on the car fixed first, and its not the kind of car that I am going to take out on a cold dark winter's evening. 

 

I might remove it entirely, but then there are the holes in the firewall . . . . 

 

. 

 

Edited September 17, 2021 by m-mman (see edit history)

[m-mman]

The Weathermaster in the 1942 Hudson has a squirrel cage blower and on high I could feel nothing. There is little information in the owner's manual about how it works. 

 

Eventually I found a small line in the shop manual. It says that "heater' air flow comes from opening the cowl vent which provides "clean filtered air to the heater" 

 

However when the fan is turned to High, air is blown out the ports on the side which have tubes that lead to the defrosters.

 

I am new to Hudsons and will have to open up the heater to trace the airflow, but it seems strange that there isnt a knob or something that can deliver a high volume blow to your feet. 

[JFranklin]

People just were not so demanding back when life was simple. I do see ducting to the passangers feet. The heater in my 1936 Chevy just blows into the passanger compartment at the passenger seat.

[39BuickEight]

My restored 6v heater blows pretty good in my car.  Certainly not like anything new, but I was pleased to see what it could do for a little thing.  I have no idea how it would compare to another one that may not be restored or working optimally..

[Bloo]

Check the voltage at the fan, as well as the charging voltage of the car.

 

 

[plymouthcranbrook]

My 52 Plymouth is six volt and the heater and defroster fans move relatively slowly but warm up the car in moderately cold air tems.(40's- and above.) Like some others I cleaned things up and made sure there were no obstructions and am satisfied as I do rarely drive it when it's colds outside.

[keithb7]

My '38 Chrysler 6V has a cab heater. Built in Canada, an option. Due to amp draw, the fan output is lower at idle. As I speed up, the generator puts out more amps. Then the fan speeds up and I get very good heat. Grounds, switch and wire contacts need to be clean and tight of course. I think in my 6V '38 Plymouth I worked up to  about a 7-10 amp fuse inline, to keep it running.

[Larry Schramm]

20 hours ago, JFranklin said:

People just were not so demanding back when life was simple. I do see ducting to the passangers feet. The heater in my 1936 Chevy just blows into the passanger compartment at the passenger seat.

 

Keeps the wife warm

[Str8-8-Dave]

So there are a couple of things that hold back airflow in these old heaters.  Fan design, I.E. airplane propeller is very inefficient compared to a squirrel cage blower wheel installed in a blower scroll with a properly designed cutoff, inlet ring and upstream inlet duct, fan location downstream of the restriction of the heater core's airside passages (blowers do much better with downstream restrictions to airflow than upstream restrictions to airflow), 6 volt low current wound field motor VS 12 volt high current (up to 30 amp) permanent magnet motor.  A lot of the old tech design is driven by lack of package space in the heater box and the cars electrical system's limitation on available power.   I spent many days in the Ford HVAC lab working to develop A/C airhandling systems that would produce 250 SCFM airflow in Max A/C recirc mode at less than 30 amp current draw.  By the time you arranged ductwork to properly distribute airflow equally to panel registers with some floor bleed a system that put out 225 SCFM in Max A/C recirc was considered exceptional.