I am working on a 72 Pantera with a 230 degree gauge. It is my understanding that an in line resistor to the gauge. However, I forget what the value should be.
So ...... what size resistor should I use?
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Bob,
You shouldn't need a resistor with the 230* gauge. I would recommend that you add a separate ground wire from the temp gauge to a good ground point. This will eliminate fluctuating gauge readings that are caused by the original wiring's daisy chain configuration.
If you need to replace the temp sender, the Echlin TS6628 from NAPA should be a good match for your gauge.
John
You shouldn't need a resistor with the 230* gauge. I would recommend that you add a separate ground wire from the temp gauge to a good ground point. This will eliminate fluctuating gauge readings that are caused by the original wiring's daisy chain configuration.
If you need to replace the temp sender, the Echlin TS6628 from NAPA should be a good match for your gauge.
John
I am having "Da ja Vu" all over again, Indy Dave is providing you with lots of info, but the bottom line is the gauge does not require a resistor, a 1972 Torino is the same sender. The only way to get good and accurate readings on the original gauges is to replace them! Auto Meter can make a almost identical looking gauge set for your car for about 1000.00 . On the root question,"what is" the best way never to overheat? My personal recommendation is to instal a oil cooler, they are inexpensive and it eliminates the problem. That is assuming you have a adequate rdiator.www.autometer.com
quote:Originally posted by snaponbob:
I am working on a 72 Pantera with a 230 degree gauge. It is my understanding that an in line resistor to the gauge. However, I forget what the value should be.
So ...... what size resistor should I use?
If you wanted to have a very accurate coolant temp gauge but also wanted it to look OEM, you could always have a gauge shop replace the workings of your original gauge with VDO workings. Then use the VDO sending unit. I say "VDO" because that seems to be the preferred manufacturer of most gauge shops.
That being said, if you use the correct sending unit, the OEM gauge is reasonably accurate in the part of the range where you need it to be.
That being said, if you use the correct sending unit, the OEM gauge is reasonably accurate in the part of the range where you need it to be.
quote:Originally posted by David_Nunn:
If you wanted to have a very accurate coolant temp gauge but also wanted it to look OEM, you could always have a gauge shop replace the workings of your original gauge with VDO workings. ..
The VDO Vision Chrome series is almost a dead ringer for Veglia, except for the orange needles.
Everything was original. I say "was" because I have upgraded the cooling system. I am reading temperatures 20-30 degrees below the gauge reading at the coolant tank. It is my understanding that Ford provided 260 degree gauges (via a TSB) that read correctly with the original sending unit.
quote:I am reading temperatures 20-30 degrees below the gauge reading at the coolant tank.
Temp readings at the cooling tank are irrelevant. The temp sender should be mounted in the engine block, just above the water pump. See the last picture on this page: http://www.banzairunnerpantera...dates_thermostat.htm
Take a temp reading with an IR Temp gun there and compare to your gauge readings. Then make sure you have the correct temp sender for the 230 gauge.
Bob, when Ford was trying to reconcile the Italian Veglia gauge to the U.S-made sender, they used two different value resistors; first in '72, a 5 ohm 1/2 watt resistor (Tech Service Bulletin 2 article 13), then replaced in mid-'73 by a 10 ohm 1/2 watt resistor (Tech Service Bulletin 8 article 61), in-line between the sender & gauge. My "OEM" resistor was twisted into the gauge wire, under black tape- not even soldered.
The most direct fix is to actually calibrate the gauge to the car, but for safety's sake, first unscrew a 1/4" pipe plug right under the thermostat housing, horizontally in the block. Unscrew the temp sender in the tank. Interchange the two using a little pipe tape to seal. Note- too much pipe tape on the sender will electrically unground it and you'll get no or erratic readings. The stock wire to the sender in the tank will bend back & reach the sender mounted in the block. This position gives a more stable, accurate engine temp reading.
To calibrate, use an IR heat-gun on the block right near the sender and a 0-20 ohm variable resistor in the gauge line. Adjust the variable resistor so the gauge on the dash reads what the IR gun says is the block/water temp. When I did this many years ago, the 230F gauge needed an 8 ohm resistor in our '72 while the 260F gauge needed none. Never checked but I suspect the late 260F gauge has a resistor built in.
The most direct fix is to actually calibrate the gauge to the car, but for safety's sake, first unscrew a 1/4" pipe plug right under the thermostat housing, horizontally in the block. Unscrew the temp sender in the tank. Interchange the two using a little pipe tape to seal. Note- too much pipe tape on the sender will electrically unground it and you'll get no or erratic readings. The stock wire to the sender in the tank will bend back & reach the sender mounted in the block. This position gives a more stable, accurate engine temp reading.
To calibrate, use an IR heat-gun on the block right near the sender and a 0-20 ohm variable resistor in the gauge line. Adjust the variable resistor so the gauge on the dash reads what the IR gun says is the block/water temp. When I did this many years ago, the 230F gauge needed an 8 ohm resistor in our '72 while the 260F gauge needed none. Never checked but I suspect the late 260F gauge has a resistor built in.
A LOT of good input, and I appreciate it. Given the owner's desire to stay as stone stock as possible, Bosswrench's suggesting will be tried first. As for the cooling system, all the hoses and pipes have been replaced as has the radiator (to a deeper unit) with higher capacity fans and blades.
I absolutely know the gauge is way off. It hit 230 yesterday with one fan on, and given that there is only 100% water in the system that did not boil out, the error is at least 15-20 degrees (and I understand the effect of a 13psi tank cap). Also, I have checked (with an IR heat gun) all over/around the block and cooling system and have not seen ANY temps near what the gauge is showing.
I have a set of TSBs, so I will refer to them as well. JB1490, thanks for the part number. When I move the sensor, I'll install one of those.
I absolutely know the gauge is way off. It hit 230 yesterday with one fan on, and given that there is only 100% water in the system that did not boil out, the error is at least 15-20 degrees (and I understand the effect of a 13psi tank cap). Also, I have checked (with an IR heat gun) all over/around the block and cooling system and have not seen ANY temps near what the gauge is showing.
I have a set of TSBs, so I will refer to them as well. JB1490, thanks for the part number. When I move the sensor, I'll install one of those.
If you want to take the time to "dial it in", install a variable resistor first, 0-50 ohms or 0-100 ohms, bring it up to temp, use the IR gun and adjust the variable resistor (potentiometer) to get the right reading. Measure the setting with an ohm meter and install the right resistance value/values to match. I had to put two in parallel to get the right value.
quote:100% water in the system
Do the 50/50 instead, it not only reduces risk of freezing which may not be relevant to you, it also reduces the deterioration of alu components like perhaps your radiator. Not a good place to save money.
quote:first unscrew a 1/4" pipe plug right under the thermostat housing, horizontally in the block. Unscrew the temp sender in the tank. Interchange the two
Fully agree. And think everybody does. But why did the factory go to the expense of having a boss in the tank when there was room for the sender in the block? Does anybody know? It was an extra cost to Signor DeTomaso, so it must have been done for a reason, right?
quote:Fully agree. And think everybody does. But why did the factory go to the expense of having a boss in the tank when there was room for the sender in the block? Does anybody know? It was an extra cost to Signor DeTomaso, so it must have been done for a reason, right?
To be honest, I think this item is something we all talk about but makes very little difference, if at all.
We are measuring water temperature, not block temperature. I doubt the water has cooled much from the trip from the block to the swirl tank. I hear it is more accurate in the block but what does that mean? One degree better???
I had a water temp gauge in the block and one in the coolant tube right before it went into the radiator for cooling. The two gauges were ALWAYS within 5 degrees of each other...
As to location of the sensor, I read a VERY small different with an IR.
As for the coolant, I will be putting in 50/50. Had 100% H2O to test for leaks in the cooling system as it was 100% replaced.
Continued appreciation for all the input.
As for the coolant, I will be putting in 50/50. Had 100% H2O to test for leaks in the cooling system as it was 100% replaced.
Continued appreciation for all the input.
So, installed new sender at the proper spot on the block and added a 10 ohm resistor. Might be about 5 deg LOW instead of 20-25 degrees HIGH. Check THAT off the list!! Thanks for the help folks.