If you want to run an automatic electric fan with a flathead, you will need a temp switch screwed into the head to tell the relay to kick the fan on at about 185 degrees. Walker Radiator Works quoted me $58.00 for the switch which comes with a weird type of connector. Here's the Borg Warner part number for one with the right threads, temp, and a spade style terminal for $18.99. TFS664. This temp switch originally came on '72-'76 Saab and '71 Volvo. You can get the relay kit from Speedway for $9.99. I hooked up this combo the other day and it works like a champ. pigpen
BTTT--this little goody was on page 99 already since it doesn't need reply, but lots of folks need it.
Buicks38. You are most welcome. I tried the system out on a local run this Saturday in a line of 200 cars going from one side of town to the other. Traffic, signals, near rear-enders, all that stuff. The flathead did not overheat at all, even with a relatively small radiator. I was almost amazed. I even got to be the camera car (open '27 roadster) for the local TV news guy. It was a very good day. Regards, pigpen Gettin' the same kicks since '46!
Are the threads on that Volvo unit metric? Rich, I can't find my Almondale yearbook, you'll have to tell me who won Miss Littlerock.
There is also a neat setup from Saab that has a threaded housing that fits in-line on the upper radiator hose.It fits Model 99 and 900 series Saabs late 70's and early 80's.The good part is that Saab uses two of these switches set to come on at different temps.This is for a/c equipped cars that utilize dual electric fans.One comes on at 95 degrees C and the other at 110 degrees C. I used one in a 302 powered Pinto wagon I built years ago and the housing fit the upper radiator hose perfectly. Don't have a part # but I'm sure a Saab dealer could order one.
Phil. I don't think the threads are metric; they fit the flathead too well and don't leak. They seem to be just regular pipe threads. pigpen Do the name Charlene Brumbach ring a familiar tone? That's right, my old 7th-8th...... grade girlfriend. I wonder what she looks like now? Hmmm
That sounds great. It would free up one of the ports for a heater hose assuming you want to run a heater. An enterprising hot rodder could probably make a rig like that. A Saab dealer in Wichita Falls, TX? Surely you jest! If they don't make pickups that can carry an entire Meth lab in the back, forget it! pigpen
I've also been thinking about wiring a manual switch into such a system downstream of the temperature sender. That way, it'll still work automatically, but you can turn the fan on at any time. Run it off an always-hot fuse (headlights, for instance), and you can even run the fan when the car is off. d
I did just that; hooked the switch accross the normally open contacts of the relay which are already on a live fuse. If the sender or relay fail, you have a backup. I've been thinking of adding a second electric fuel pump with a manual switch for the same reason. Redundancy, just like an aircraft. pigpen
My fan sender is from an early Voyager van. Turns on at about 180. Comes with two terminals which connect at temp. I wired one to ground and used the other to ground the relay switch. I put a light on it so I can tell when the fan comes on.
I learned something new about the temp sensor switch today. The fan has been coming on after the motor was shut down due to the heat buildup in the head. Rather distracting. Tonight, I moved the sensor from the port in the head to the port in the right hand waterpump which is considerably lower and cooler (theoretically) when the engine is shut down. Now the system works like it should and the on/off temp is about the same. Aren't thermodynamics fun! pigpen
Looking through the newest Speedway catalog, I find that they now have the sensor, or one just like it for $15.95 plus shipping. Here's the pic's of the sensor and the relay kit. pigpen
Good evening. If an electric fan is being used with the flathead (8BA), can one of the sensors in the head be the electric fan temperature sensor wired to the two prong sensor in the other head or do they both need to be OG sensors? If anyone knows of a thread mentioning this please kindly share. I cannot seem to get a straight answer and because of this I want to just try it out and see if it works so that I may share if someone else has always pondered this question/setup. Also, I am currently using a 180 degree probe in the left upper corner of my radiator (I don’t feel this is reliable) and it seems to not activate the fan at the stated temperature, reason for my thinking. It seems to be kicking on at about 220ish degrees. Still using original temperature gauge. Any assistance to this question is appreciated. All in all I’d like to use the original setup/look with the exception of replacing the single prong OG sensor with the fan on/off temperature sensor if possible and have it still operate for the head/system as intended and as the OG would have. Otherwise, I’ll look at other possible alternatives. Thank you kindly in advance. **Pictures are of electric fan probe and current OG head temperature sensors.
It'll work. The two heads have different temps but close enough for that fan sensor. I stuck mine in the bottom of the radiator and I have had no issues for several years. I have two temp gauges in the dash and they read 15 - 20 degrees different side to side (who knows if the gauges are actually correct). I have tested them with an IR and they are close to accurate. Hope it helps.
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