TR6 TR6 Heater Fan question

[bcbennett]

Hello all,

My heater core gets hot when I pull open the valve, but when I pull the switch for the fan, my fuse blows. I assume that my fan is locked up since my car was in storage for ten years.

So, do you replace the whole unit to get a new fan, or can you just repair or replace the fan motor?

Happy Holidays,

CB

 

[Brosky]

When that happened to me, I found that my heater motor was seized. This was after checking the switch and wiring leading to the heater motor. I did replace the motor at time of the transmission removal, because everything was out of the way.

This is a "how-to" on a case that I bought from ebay and rebuilt, "just in case". I do not have the pics on the case removal. Sorry....

Oh, be VERY careful on the fan removal from the motor shaft. I soaked mine for a week with rust busters to try to get it loose so it wouldn't crack as they are usually very hard to get.

https://www.74tr6.com/heater.htm

 

[TR3driver]

Hmm, so the TR6 heater motor IS at least somewhat different from the TR4. The leads are attached differently, and of course the TR4 doesn't have the resistor for low speed. I'll bet the TR6 motor is designed to turn faster when supplied with a full 12v, too.

Thanks for the article, Paul.

BTW, it shouldn't be too difficult to fabricate a replacement for the resistor, if necessary. Just need someone to measure the resistance (preferably when operating) of the original.

 

[jjbunn]

Hmm, so the TR6 heater motor IS at least somewhat different from the TR4. The leads are attached differently, and of course the TR4 doesn't have the resistor for low speed. I'll bet the TR6 motor is designed to turn faster when supplied with a full 12v, too.

Thanks for the article, Paul.

BTW, it shouldn't be too difficult to fabricate a replacement for the resistor, if necessary. Just need someone to measure the resistance (preferably when operating) of the original.

Hi Randall: what makes you comment that the TR6 motor is different from the TR4? (The Moss part #s are the same I think.)

Why would you expect the resistance of the heater resistor to change when it is passing current? I have mine out on the becnh: it measures 2.5 Ohms cold. Looks like a 20W type.

 

[TR3driver]

Hi Randall: what makes you comment that the TR6 motor is different from the TR4? (The Moss part #s are the same I think.)

Just the things I mentioned above, not really any hard evidence. But just because a replacement meets both needs doesn't mean the originals were identical. I think the TR4 motor would work in the TR6 application anyway, though it might not blow as much air.
<div class="ubbcode-block"><div class="ubbcode-header">Quote:]Why would you expect the resistance of the heater resistor to change when it is passing current?[/QUOTE]Most resistors change value when they get hot, some more than others. With no experience with the TR6 setup, I have no idea if the resistance change is enough to be significant or not.<div class="ubbcode-block"><div class="ubbcode-header">Quote:] I have mine out on the becnh: it measures 2.5 Ohms cold. Looks like a 20W type.[/QUOTE]That should be easy enough then ... Digikey has a 25W vitreous enamel resistor in either 2.0 or 3.0 ohms for under $4. Or if you really want to be exact, they have a 3.0 ohm adjustable for about $6 (which you could tap at 2.5 ohms).

 

[jjbunn]

Hi Randall: what makes you comment that the TR6 motor is different from the TR4? (The Moss part #s are the same I think.)

Just the things I mentioned above, not really any hard evidence. But just because a replacement meets both needs doesn't mean the originals were identical. I think the TR4 motor would work in the TR6 application anyway, though it might not blow as much air.
<div class="ubbcode-block"><div class="ubbcode-header">Quote:]Why would you expect the resistance of the heater resistor to change when it is passing current?

Most resistors change value when they get hot, some more than others. With no experience with the TR6 setup, I have no idea if the resistance change is enough to be significant or not.<div class="ubbcode-block"><div class="ubbcode-header">Quote:] I have mine out on the becnh: it measures 2.5 Ohms cold. Looks like a 20W type.[/QUOTE]That should be easy enough then ... Digikey has a 25W vitreous enamel resistor in either 2.0 or 3.0 ohms for under $4. Or if you really want to be exact, they have a 3.0 ohm adjustable for about $6 (which you could tap at 2.5 ohms). [/QUOTE]

You could even put the pot in the console, and have a fully variable heater fan speed control /bcforum/images/%%GRAEMLIN_URL%%/smile.gif

 

[Andrew Mace]

You could even put the pot in the console, and have a fully variable heater fan speed control /bcforum/images/%%GRAEMLIN_URL%%/smile.gif

...which, as I recall, is what the later TR3s had, in the form of a rheostat blower switch. Not that it made a tremendous difference, but.... /bcforum/images/%%GRAEMLIN_URL%%/smile.gif

 

[TR3driver]

which, as I recall, is what the later TR3s had, in the form of a rheostat blower switch. Not that it made a tremendous difference, but.... /bcforum/images/%%GRAEMLIN_URL%%/smile.gif

AFAIK, all TR2-3B had the rheostat when fitted with the optional heater.

But it really only had 3 settings :

Not enough,
Less than that,
None at all.

 

[Andrew Mace]

AFAIK, all TR2-3B had the rheostat when fitted with the optional heater.

Right; I was thinking of the instrument lighting switch. My bad!

But it really only had 3 settings :

Not enough,
Less than that,
None at all.

Yeah, but it was almost infinitely variable between "not enough" and "less than that"! /bcforum/images/%%GRAEMLIN_URL%%/grin.gif

 

[TR674]

CB
I had the same problem. I found that the fan shaft had rusted to the shaft bushings. A lot of WD40 and some extra persuasion got it loose. After a clean up and check it works as new now. I suspect that your fan shaft is ceased too.
Unfortunately, to get to the fan requires complete heater box removal. Good luck!!
Regards
Craig