1960 heater

[Joe Maulsby]

I decided to take the heater motor off last night to figure out what type of motor was installed. The label says "Made in Canada" and has a PF-??? part number. Two wires extend out of the inboard side; one black, one orange. Another label describes how to determine the motor rotation direction by the way the wires are hooked up. I assume this is not the original motor?
Questions:
1)The motor case has an open, 1-inch diameter hole on the opposite side of the wires. Is there suppose to be something plugging up the hole or is it for cooling purposes?
2) How was the original motor grounded? The ST-12 and AIM just shows one brown wire coming out of the motor.
3) What is the purpose of the coiled up capillary tube? The ST-12 shows it on the outside of the motor housing, but mine is connected to a small bracket mounted in front of the heater core. Is this the correct location for the cap tube on a 1960 heater?
4) What type of nut is required to hold the squirrel cage on? A "cap nut"? Mine did not have a nut on it. Not sure how it stayed on the shaft.

[Jim T.]

Re: 1960 heater

The hole in your motor you mentioned indicates your motor has been replaced. The one in my 70 with factory air has a hole in it where a rubber tube supplys cooled air from the air conditioner. When I replaced it with one from GM I believe it did have a Made In Canada sticker on it. It has a nut and I believe a washer that is used to secure the squirrel cage to the shaft. My squirrel cage is plastic and only fits on the shaft one way with the flat on the shaft and the squirrel cage molded to fit. Evidentily the interferrance fit of your squirrel cage has retained it on the shaft.

[Roy Braatz]

Re: 1960 heater

The original motor has no hole
One brown wire only- hot to heater switch
ground wire from dash area to the heater housing under dash
Motor runs clock wise
lock nut

[Dennis A.]

Re: 1960 heater

Joe,

The motor you have is not original. common replacement motors have the orange & black wires. Original motors have the brown wire, ground to the dash, and are hard to find. The nut, is a "Pushnut Fastener" ( make sure you have the cage turning the right direction before you install this fastener)

[John H.]

Re: 1960 heater

Joe -

The capillary tube was supposed to sense the temperature of air leaving the heater core and "automatically" adjust the water valve to maintain a constant temperature based on the position of the temperature control cable; very few of them ever worked, and the replacement water valves don't have this feature (I think the same guy that designed this also designed the "Godzilla Spring" on the clutch linkage, and later went to work for Malcolm Bricklin ).

[Joe Maulsby]

Re: 1960 heater

I would like to make replacement motor wiring situation closer to the original. Is there any reason why I can't cut the black wire off that extends out next to the orange wire and run a black ground wire from under one of the windshield t-bolts to one of the screws that holds the fan motor mount plate to the steel fan box?

I almost pulled the motor halves apart last night to see how difficult it would be to replace the orange wire with a more appropriate brown wire. It that as simple as it seems? Before I do this, is there a secret to putting it back together so the brushes don't get in the way?

[Michael Jones]

Re: 1960 heater

Joe:

You should be able to run a wire from the fan motor mount plate wire to any point that is connected to the car's ground assuming the fan motor mount plate is connected to the internal ground of the motor. This would be, for example, the same point that the existing black wire ties to inside the motor.

I haven't been inside the '60 repro heater motor but there's no conceptual reason why you can't replace the orange wire with a brown one. At worse you would have to make a splice that doesn't get in the way of any moving parts. You may luck out and find the orange wire tied to a terminal.

HTH

Michael

[John M.]

Re: 1960 heater

Joe,
As others have said, That motor is clearly not an original motor. The original motor is grounded to the case and only uses one wire. The correct grounding path for a 60 car would be through the Temp control cable to the clock plate in the console which is grounded to the harness. That is the only grounding path to the motor as it did not have a dedicated grounding wire like eariler model cars. This path works well as long as you keep the water valve bracket in contact with the fan housing. I put the gasket on the wrong side of the bracket by mistake ind insulated the valve from the housing that was why I was cussing when you saw me in Waco, because I took 20 points for a non-operating heater!
I am not sure, but I belive that the motor was not Corvette specific and was used on a lot of cars. Ifyou are going to show the car, then the ground wire would stand out like a sore thumb on a 58-62 to a judge.The one with the hole is from an later model where air was ducted from the box to flow over the motor windings.

The capillary tube is not installed on all the repro water valves sold today, but you can put your old capillary tube on the new valve to make it appear correct. The concept was that once you set the temp by the cable pressure on the valve, any change in temp would open or close the valve to mantain the same temp. It was probably one of the first attempts at a thermostatic climate control system! It was a grand idea for it's time and it worked pretty well until the charge leaked out of the sensing tube. There is no downside to keeping it, and it may even still work! If you are ever planning on showing the car then it is a real plus.

Regards, John McGraw

[John M.]

PS

By the way, I would seriously doubt that the T bolts of the windshield frame are a grounding path! You would want to check this with a meter, but the only grounded parts that I am aware of are the clock plate, instrument cluster and Radio case and the radio case is not grounded unless the ground wire is running from the radio support to the valve covers.

[Joe Maulsby]

Re: 1960 heater

John, thanks again for sharing good info. I thought maybe I could ground the motor to the case and do away with the separate ground wire, but once I took the motor apart, the ground wire connects to one of the brushes, so I can't ground the motor to itself. The magnets are not insulated from the motor housing so grounding through the case would cause a short, wouldn't it? Looks like I am stuck with a ground wire; unless someone knows a trick to ground it some other way.

I can get rid of the orange wire lead sticking out of the housing by splicing a brown wire inside the motor housing and bringing it out the side. Maybe that is a lot of trouble for nothing if I can't get change the ground wire situation anyway.

[Al C.]

Re: 1960 heater

Joe,
Use an ohmmeter to determine if the case currently connects to any of the wires or the brushes. I don't think that anything else (magnets) should matter, unless insulation is damaged on the motor coils with resultant short to case - thats what you will test for.
If the above check shows no continuity, then you are go to internally connect (if there is room) the non-hot brush wire to the case, and use an external ground via the case mounting, if that's the correct configuration.
Regards,
... Al 'a58 #378 245hp