The Ford Barn

Merc Cruzer · 08-28-2018, 07:29 AM

Quote:

Originally Posted by tubman

My '51 also reads about 3/4 when it's at 180. I think that is the way they were originally set up. I would hesitate to try to change the gauge to work differently that it was originally designed.

Also, I have heard nothing but bad things about the reproduction temprature senders. If they work at all, it's only for a very short time. Better to try to find an NOS or good used original unit. I was able to repair a non-functional original unit by disassembling it and cleaning and filing the points. There is an adjustment screw inside the sending unit as well; if you want to try to adjust it, you sould begin there.

The reality of the system is that you are only measuring the temperature of the right head. With the two separate gauges you can see the temperature of each side. When you say you disassembled the sending unit, which one are you referring to, the one with two screws (in the left head - this is supposed to be a pass through unit) or the one with a single screw (in the right head - this is the one that the gauge reflects the temperature ). What was the process for disassembly?

tubman · 08-28-2018, 09:04 AM

I concentrated on the single pole sensor as that is the key to the system. See post #10 in this thread : https://www.fordbarn.com/forum/showt...ghlight=sender. it also has photos of a disassembled sensor.

I believe the repair of the two pole sensor would be a simple task of cleaning the points (unless the bi-metallic strip was fractured).

rotorwrench · 08-28-2018, 10:58 AM

The flathead cooling system is an odd duck when you compare it to anything modern. There is no temperature reading for any scale on the indicator. A person has no idea what the actual temperature in Fahrenheit or Celcius. All there is is a scale from cold to hot.

Back in the day, folks were so used to overheating in hot climates that they would carry water bags on the front of the car. Many of the early depression era cars had no indicator at all. When the coolant started to boil, it came a blowing out the cap and overflow so it was apparent. At least with an indicator, a person could see that it was getting somewhere close to boiling if it was pegged on H. The two sides are separate but only to a point. When the steam boils up it could come from either side but it still all comes out the same place. If one side overheats, it's going to overheat the coolant for other side as well.

Monitoring actual coolant temp may give a person an idea which side overheats first but that doesn't help much when you are on the side of the road. I've had them heat up on me clear up the the H going up a steep grade only to have it drop back down again when going down the other side. How fast it comes down will tell you which side was getting hot. If it comes down slow, it's the right side. If it drops real quick, it's the left side.

Best I can advise is to shut it off when it starts to blow steam and let it cool down. If it does this once, you know it's either too hot outside with too much load or the engine cooling system has a problem. Find out what the problem is before operating the car further or the cracks will show up in the valve pockets pretty quick if it doesn't already have one. Continue to operate it while it over heats and I can guarantee it will crack the block.

08-28-2018, 09:04 AM	#22
tubman Senior Member Join Date: Dec 2013 Location: Minnesota, Florida Keys Posts: 10,319	Re: Temp senders on my '51 8CM I concentrated on the single pole sensor as that is the key to the system. See post #10 in this thread : https://www.fordbarn.com/forum/showt...ghlight=sender. it also has photos of a disassembled sensor. I believe the repair of the two pole sensor would be a simple task of cleaning the points (unless the bi-metallic strip was fractured).

08-28-2018, 10:58 AM	#23
rotorwrench Senior Member Join Date: Jun 2010 Location: San Antonio, Texas Posts: 16,436	Re: Temp senders on my '51 8CM The flathead cooling system is an odd duck when you compare it to anything modern. There is no temperature reading for any scale on the indicator. A person has no idea what the actual temperature in Fahrenheit or Celcius. All there is is a scale from cold to hot. Back in the day, folks were so used to overheating in hot climates that they would carry water bags on the front of the car. Many of the early depression era cars had no indicator at all. When the coolant started to boil, it came a blowing out the cap and overflow so it was apparent. At least with an indicator, a person could see that it was getting somewhere close to boiling if it was pegged on H. The two sides are separate but only to a point. When the steam boils up it could come from either side but it still all comes out the same place. If one side overheats, it's going to overheat the coolant for other side as well. Monitoring actual coolant temp may give a person an idea which side overheats first but that doesn't help much when you are on the side of the road. I've had them heat up on me clear up the the H going up a steep grade only to have it drop back down again when going down the other side. How fast it comes down will tell you which side was getting hot. If it comes down slow, it's the right side. If it drops real quick, it's the left side. Best I can advise is to shut it off when it starts to blow steam and let it cool down. If it does this once, you know it's either too hot outside with too much load or the engine cooling system has a problem. Find out what the problem is before operating the car further or the cracks will show up in the valve pockets pretty quick if it doesn't already have one. Continue to operate it while it over heats and I can guarantee it will crack the block.