At its current stage of equipment, my outfit runs 100º over the ambient temperature - decreasing down to the thermostat opening temp of 185º. This is a result of a series of tests where I either did a "burn down test" at idle in the driveway - or drove the car and jumped out with the infrared thermometer. All of these readings were taken at the thermostat housing - just to be sure they were relevant to each other. Like clockwork - on a day where its 106º or 107º in Tucson - the infrared shows +100º. The 200º+ numbers don't seem to have had any ill effects - other than trying to cook the carb or firewall. I'd like to have a bit more than marginal tolerance - but its going to take a better radiator than the shorty T-bird stocker and probably a more efficient water pump to feed it.

Make sure your radiator has decent fluid in it - and use anti-freeze "coolant". Where pure water will boil at 212º (at sea level) - Ethylene-Glycol 50/50 mix will run the boiling temp up to 223º in an unpressurized system. You get about an additional 2.5º per PSI from the radiator cap - so a 6 pound cap is worth another 15º. The combination of the two will make the system "safe" (from boil over) to 238º. The worst ambient I've seen around here is 126º on the 101 freeway in Phoenix - so it was getting close for sure.


 
 Steve Metzger       Tucson, Arizona

Thank you! I'm happy to know that now. : )

Most dont seem to get the mesage that 200dgs is not hot,with even a 6 pound cap watter wont boil. hot water is more  eficent  in rejecting heat it the rad. like several posts if your rad is not boiling  over you are not in cricis. I have 2 water temp gauges 1 atback of head 1 at therm end of int. ther is alwayes a differenc of 10 to 15,as the heads create most of the heat, so with the inacurat factory guages 
sender at coolest part of the head, the temp at therm is quite diferent .guage should be at the therm end of intake giveing the temp of both heads and if you have 200dgs ther you are perfect. just my take on it all. 

Been looking for a 6 Volt Voltmeter also. Not found One anywhere. Buy the best Gauges You can afford. Electrical Type are easier to install but I think the mechanical Ones are more Accurate. Like anything else You get what You pay for quality and accuracy wise.

  

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Looks like progress on you meter issues for Oil pressure and temperature. As for Voltage versus Amps, I believe most newer instrument packs have Voltage meters that are for 12 Volt cars and do not read lower than 8 Volts. The older under dash units usually had a oil pressure gauge and an Ammeter gauge for 30 Amps. I am not sure of any supplier that has a 6V Voltage meter to fit these panels. Maybe someone on this board can knows - Bob

AKA   Bob-93021

Well that puts me at ease some then thank you very much!

Can any of you suggest some good models of instruments to use? I'd like to, as well, use one of those Temp/Amp/Oil Pressure clusters. My main issue is finding one where the Amp meter will read lower then 8 (I still have the original 6 volt system).

I have a quality Aftermarket  Mechanical Temp. Gauge under the Dash along with Oil Pressure, Voltmeter, and a Vacuum Gauge(Mileage Minder). I drilled and tapped Intake Manifold  behind the Thermostat Housing to get a very accurate Temp reading of Coolant leaving the Rad. The Factory Temp Sender is in the Head at rear of Engine. Is that One reading High or Low compared to the placement of mine?

  

190/200 degrees is nothing to worry about if it is stable at that temperature.

A colder thermostat is not generally a good idea.  It will have little, if any effect on the temperature because it controls the minimum operating temperature, not the maximum.  If you have some problem causing it to overheat and it is not actually the thermostat causing the problem, then it is still going to overheat.  A colder thermostat will reduce efficiency and increase wear.- not by an alarming amount, probably not even significant enough to be a concern for the typical collector vehicle, but increased wear nonetheless.

I use an aftermarket gauge mostly because the factory one never worked in my ownership and the wiring under my dash is a mess.  The thing I do like about a gauge that actually indicates the temperature is in the event that something does happen which results in the engine running hotter than normal.I can use the gauge to determine if I can make it home or need to call a tow truck.


Lawrenceville, GA

I put an aftermarket gauge in my 1955 tbird long enough to establish exactly what temp it was running at when fully warmed up which was 170 degrees. The factory gauge was indicating at the top of the white zone at 170 degrees. Seeing the gauge up so high was upsetting so I removed the factory gauge and very gently bent the needle towards the cold range . At 170 degrees the factory gauge now points right in the middle of the white zone .
Guess that was a "calibration" that I performed.

Hey sorry for the delay,

Thanks to tall of you for your advice, it really is helpful and put me at ease some.
I've actually tried that temperature gun trick last year on the car, but that was before I put a colder thermostat in. but I think I remember the engine being around 190/200 degrees.

So do most of you guys use aftermarket gauges?