head temp guages

B

bk53

Senior Member
Hi,
I'm thinking of putting L and R temperature guages in my 53 f100 at least while i get to know this motor.
I don't know much about the circuit. Does anyone have any recommendations on compatible guages? Does it matter that this is 6v +g?

Thanks,

Bill
 
my 52 has one on each side, drivers side is single post and pass side is two post for wires to dash gauge, Im not certain how the combo works but it seems accurate. all is 6v and looks original. Ken
 
The original gauge reads the average temperarure in the engine. Both sides of the block are seperate water systems connected only in the radiator. If one side gets hot it is going to the raise the mixed coolant of both sides. Get a laser pointed thermometer and check the temperatures on the goose necks or on the head outlets just below the hoses. This is the only coolant temperature you have to be concerned with. Once you get those readings you can tell on the gauge where the real temperature is. I just bought one on eBay last night for $39.00 including shipping. They have some in the $10.00 range but I think Raytec is a little better. I have 3 of them in Florida but need one up here in Pa. It's less bother to order a new one than have one of those shipped. This is a tool everyone with an old Ford should have. G.M.
 
"Once you get those readings you can tell on the gauge where the real temperature is".
good idea. thanks, I'll start with one of those.

Bill
 
Ken Arms said:
my 52 has one on each side, drivers side is single post and pass side is two post for wires to dash gauge, Im not certain how the combo works. Ken
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Here's how the combo works: Current comes from the ignition switch then first goes through the temperature gauge then through the left sender which is just an on/off circuit breaker switch that opens at high temperature breaking the electrical circuit to the gauge and sending it to maximum. After going through the left sender it goes to the right sender to ground to complete the circuit. The right sender is the only one that measures temperature and it is just measuring the right side temperature which is best since the right side runs hotter than the left side. So, the two senders do not "average" the temperature of both sides of the engine and send it to the gauge. The right one measures variable temperature and the left one is just a "circuit breaker" for extreme temperature in that side.
 
In my opinion, it is the water temperature at it's hottest point that is more critical than the actual engine block or head temperatures since the water is much more sensitive to extreme temperatures, i.e. it will boil out long before the block or heads will melt down. That's why the temperature gauge senders are immersed in the coolant and are measuring its temperature accurately, not the temperature of the metal of the block or heads. Measuring the temperature of the heads is not measuring the temperature of the water in the heads since the water goes into the bottom of the block cool and gains heat as it goes through the heads but never quite reaches the temperature of the heads before it exits and goes to the radiator where it is cooled again. This can be demonstrated by measuring the temperature of the head coolant outlets and comparing them to the temperature of the top of the radiator. So, the more accurate reading of the temperature of the water at its hottest point coming out of the heads is the top of the radiator near where the water goes into it. The coolant loses virtually no heat from the time it leaves the heads and travels through the hoses before entering the top of the radiator. The thin metal at the top of the radiator is a much better thermal conductor than the head outlet and should be exactly the same temperature as the water inside. (I have tested it with a thermometer in the water compared to the surface of the radiator and it is the same.) So, that's where I measure my water temperature for an accurate reading of that more critical water temperature, not anywhere on the block or heads or hoses.
 
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mechanical guages, do you want to rebuild the motor at today's cost, be safe a small price to pay... I got 2 new senders, NOS temp guage, and still was reading hot?
check the radiator with thermometer 180dg on the button. So went mechanical, peace of mind.
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Peewee - I just installed a newly rebuilt 8ba in my '46 tudor. I used the stock, single contact sending unit in the driver's side head and put a mechanical gauge in the passenger's side head. By so doing, my original dash gauge works and I can compare the "new" engine readings to the "old" engine readings. Also, the mechanical gauge gives me the temp of the right head which seems to be slightly higher than the left head, based on engine test stand results. Just another way to do it. FWIW
 
thanks guys, Thanks Old Henry, I didn't realize the temp senders were immersed in water. I saw em poked in the heads and put two and two together and got 47. I appreciate the school in flathead temp guages everyone. also Old Henry, enjoy following your travels

Bill
 
bk53 the temperatures where I told you are accurite. These temperature are within a few degrees of the coolant. Try the laser gun and you will see how they work I have conducted hundreds of test over 12 or 15 years developeing cooling components and I can tell you I got good accurite readings. I have found a few guns that gave incorrect readings and returned them. You can test them at home or in the store. Lets say the thermostat in the store is set at 76 degrees, the counter tops and other materials should read about 76. Point at these items if purchased at a store to check it before buying. A friend bought one at Sears and I used it and said this is way off which it was. He took it back, showed the sales person and they tested another one that verified it was off. Also when taking temperatures say in 5 minute time spaceings you need to hold the gun the same distance from the work, at the same angle and hit the laser dot close to the same spot every time or they can very a few degrees. Try and borrow one from a friend to try it. G.M.
 
I've seen numerous references and my own 8BA reflects the same, where the right (pax) side of the engine runs about 5 to 10 degrees hotter than the other. Not sure why, but this might be useful info for someone that wants to run only one gauge. That is, I would want to know the hotter of the two.
 
36tbird said:
I've seen numerous references and my own 8BA reflects the same, where the right (pax) side of the engine runs about 5 to 10 degrees hotter than the other. Not sure why, but this might be useful info for someone that wants to run only one gauge. That is, I would want to know the hotter of the two.
Click to expand...

That's why the stock variable temperature sender is in the right head - to measure the hotter of the two.
 
Would two stock 1-wire sending units work ok if they were wired thru a toggle switch so each side could be selected by flipping the switch? i would think so. just curious....jack
 
Henry/Kokomo, I along with my two mechanical guages I did keep the single pole thermo sensors on left side so that the stock guage would still work. It does read better. So, the left head has the stock sensor and the mechanical sensor, I used both ports.
 
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