temp sender

[twostickmutt]

I've been thinking of putting a 6 volt cooling fan from speedway in the '39. The car is still 6 volt positive ground. I can't seem to find a coolant sender for 6 volt to go to the relay to start the fan. I was told their 12 volt sensor/sender wont work with 6 volt. Question is could I use a sender from 1940 up to the early fifties when they were still 6 volt to use to go to the relay to kick the fan on. Thanks

[JSeery]

Originally Posted by twostickmutt

Question is could I use a sender from 1940 up to the early fifties when they were still 6 volt to use to go to the relay to kick the fan on. Thanks

Wouldn't think so, it would work completely different than a fan sensor. The original sensor is a pulse device that controls the current flow to heater coils to bend bi-metal components. You are wanting basically an on/off switch to trigger the fan relay. The two-terminal driver side sensor does that, but at a point near the boiling point.

[twostickmutt]

Originally Posted by JSeery

Wouldn't think so, it would work completely different than a fan sensor. The original sensor is a pulse device that controls the current flow to heater coils to bend bi-metal components. You are wanting basically an on/off switch to trigger the fan relay. The two-terminal driver side sensor does that, but at a point near the boiling point.

ok jerry thanks for the quick reply.

[JSeery]

They claim this is a 6v compatible controller, but I can't find it in the spec's.
http://www.maradynehp.com/mfa120.html

[cederholm]

Someone has to make a 6v themo-activated switch. I'd do a search on ebay - and not just the car section. Thinking electronic/scientific.

~ Carl

[TJ]

Sponsored Links (Register now to hide all advertisements)

Maybe I missed something, but the temp sensors I'm familiar go to ground when they hit a certain temperature from the motor. The ground triggers the relay to engage and start the fan. It's the engine temperature that causes the internal part of the sensor to go to ground, not whether it is 6 or 12 volts.

[JSeery]

Another link: https://www.amazon.com/Maradyne-MFA1...VS8PMXDKF7EGEF

[supereal]

The temp sender is just a switch. The relay activated by the switch would be voltage sensitive. We installed such a system for customer using a 6 volt starter solenoid for the relay. Electric fans usually require high current, particularly in a 6 volt application. In a 12 volt system, the amperage draw is reduced by half. We generally discourage electric fans in six volt vehicles because the charging system is inadequate.

[JSeery]

Originally Posted by TJ

Maybe I missed something, but the temp sensors I'm familiar go to ground when they hit a certain temperature from the motor. The ground triggers the relay to engage and start the fan. It's the engine temperature that causes the internal part of the sensor to go to ground, not whether it is 6 or 12 volts.

Believe TJ is correct and if polarity is not an issue (and I would guess it is not).

[twostickmutt]

Originally Posted by supereal

The temp sender is just a switch. The relay activated by the switch would be voltage sensitive. We installed such a system for customer using a 6 volt starter solenoid for the relay. Electric fans usually require high current, particularly in a 6 volt application. In a 12 volt system, the amperage draw is reduced by half. We generally discourage electric fans in six volt vehicles because the charging system is inadequate.

it's advertised as drawing 8 to 10 amps. I have a alternator (30 amp ) and was hoping that's plenty. stock 6 volt bulbs and no radio or heater.

[twostickmutt]

thanks everyone for your help !

[twostickmutt]

Originally Posted by TJ

Maybe I missed something, but the temp sensors I'm familiar go to ground when they hit a certain temperature from the motor. The ground triggers the relay to engage and start the fan. It's the engine temperature that causes the internal part of the sensor to go to ground, not whether it is 6 or 12 volts.

which sender would you use TJ. I'll need something that will break ground after it cools down 20 or whatever degrees to shut the fan back down.

[Flathead Fever]

Originally Posted by twostickmutt

I've been thinking of putting a 6 volt cooling fan from speedway in the '39. The car is still 6 volt positive ground. I can't seem to find a coolant sender for 6 volt to go to the relay to start the fan. I was told their 12 volt sensor/sender wont work with 6 volt. Question is could I use a sender from 1940 up to the early fifties when they were still 6 volt to use to go to the relay to kick the fan on. Thanks

What about a 6V DC to 12V DC converter rated at 10A to control the 12V temperature sending unit. Then have the 12V sending unit activate a 12V starter relay but run the 6V across the contacts in the relay.

Wire in an override switch incase something fails so you can bypass the electronics and send 6V directly to the fan.

There are the adjustable sensors with a capillary tube that slips into the radiator hose. I had one on a '66 Mini Cooper S that worked real well.

Summit has this one. There are kits where the capillary tube slides\ under the hose and inside the upper tank. I though they would leak but the one I had was fine. There also kits where the capillary tube goes between the fins in the radiator core. I think you use one of these kits powered by a 6V to 12V converter. You can hook it up negative ground just by running the circuit's own separate positive and negatives wires from the battery.

https://www.summitracing.com/parts/prf-30104/overview/

[Red98]

No starter solenoid. Neither a starter solenoid nor a horn relay is rated for continuous duty which a cooling fan control demands. Instead a simple Tyson/Bosch 40A 6v relay is adequate and inexpensive. A well chosen temperature switch is totally voltage independent.

There are too many questions here which really need a local speed shop professional to advise you on. Personally, I'm leery about any cooling fan on 6v. I just went through a lengthy search for a 16" 12v puller all of which draw about 20 amps. Limiting to a 6v puller to 20 amps mean a 10" fan which is marginal singular cooling fan.

In your case, to accomplish better cooling, I'd strongly advise fashioning a shroud around your belt driven fan which doesn't require any electric components yet will give about the same cooling enhancement.

[Flathead Fever]

You are correct about the starter relay not being meant for continuous use but in this case its only going to carry 10-20 amps instead of 300+A. Unless the coil pull-in windings are not made for continuous use? That could be an issue. Many of the fleet vehicles I worked on had aftermarket second batteries added before they were delivered to us. To charge both batteries some of the vehicles had an expensive battery isolator and some just had a continuous duty solenoid that looked just like a single wire Ford starter solenoid but these was made for continuous use.

Summit has this single terminal grounding switch that could control the ground to a 6V relay.

https://www.summitracing.com/parts/s...SABEgJgG_D_BwE

[Red98]

Most temp controls I've seen have on/off temps of 195°F on, 175°F off, but they are available all over the place. That good looking switch shown is 185°F on, 175°F off. Being that close means it could cycle too quickly. I suggest getting several opinions before spending $40 twice.