Okay I put the DeWitts in, A Stewarts stage II pump and 160 T-stat all great for summer driving, the problem is in cold weather it never even gets to 160. I've already ordered a 180 Robert-Shaw t-stat to replace the 160 currently installed. Does anyone else have a similar problem? If so what have you done to get your operating temperatures up? A piece of cardboard blocking part of the radiator possibly?? I'm sure some will find this amusing as most of us are looking for ways to cool our midyears not increase the temp.... Dave..

 

I run a 180 stat and it takes a good while to get the temp up in the car. It should help you but it may not get really warm. Mine only gets to around 160 with the 180 stat.... but I'm running a Vintage A/C unit and I may have a valve that isn't opening all the way. Give it a go and see what happens

 

When I was driving mine back and forth to work in the winter (4 mi. one way) I would cover the bottom 1/3 of the radiator with cardboard. Helped quite a bit on those single digit days.
Aways ran a 180 t'stat.

 

Leave the 180* Robertshaw in it all year 'round - the thermostat has nothing to do with controlling abnormally-high operating temperature; it only controls MINIMUM operating temperature, like now in cold weather when you want the heater to work.

 

Thanks John, I was just under the school of thought to keep temps down by having the 160 in there during the summer. The theory as it was explained to me was that if you start at a lower operating temperature that once say you get stuck in traffic you will have a little bit more of a buffer. This being said that if you had a 180 in there and heated up to 220 with a 160 in the same situation you would possibly be at 200. I know that the tstat will not limit the high end of the temp but does this make any sense? Is there any reason not to think this would be a good train of thought?

 

If you have a 180* in it and it heats up to 220* in traffic, then replace it with a 160*, it will still heat up to 220* in traffic, assuming the same conditions; when the thermostat is open, it's open. The only time a lower thermostat rating will help is if your cooling system is capable of bringing the operating temperature down to or below the thermostat's rating in hot weather, and that's not usually the case. The only things that determine operating temperature (at or above the thermostat rating) are the radiator's heat rejection capability and the airflow through it, assuming your ignition timing and vacuum advance are working as designed.

Even if you have enough cooling capacity to bring normal operating temperature down to 160*in hot weather, that's not hot enough; it won't let the oil get hot enough to boil off the blow-by contaminants and condensed moisture in the oil, and the rate of bore wear at 160* is over twice the measured wear rate at 180*. The engine was designed to operate at 180*-200*, and that's where it will last longest and wear the least.

 

John it looks like I will leave the 180 tstat in once I get it and just sit the 160 on the shelf. Thanks for the info on oil temperature. Dave..

 

John - I have to disagree with your mention that once a stat is open it is open. I just went through a problem with another car which had the temp spiking high then going down, then up again, etc. I replaced it with a NOS (old type) stat that originally came in the car. The one that was in it was a new NAPA (made who knows where). Once replaced it now runs fine and at the correct temp. Stats can malfunction both ways, either not open at all (the most common), or can begin to close and restrict at a much higher temp than it is rate for.

 

If the thermostat is closed, the flow path to the radiator is blocked, so coolant pump output is recirculated back through the engine via one or more "bypass circuits" - internal water pump bypass, heater core circuit, and (if equipped) the external bypass, which are present on SHP/FI SBs through about 1965, but IIRC the external bypass on L-79 was eliminated beginning in '66.

Nominal thermostat opening temps have a plus or minus tolerance of two or three degrees, and the "opening temperature" is the nominal temperature that the stat just cracks open, so there is still considerable restriction in the radiator circuit, and a good deal of coolant will continue to flow through the bypass circuits.

If engine temperature rises above the initial opening point, the thermostat will continue to open reducing the restriction in the flow path to the radiator, and since the coolant will follow the path of least resistance, more coolant will flow to the radiator and less through the bypass circuits as the thermostat continues to open, reducing the radiator path restriction.

The thermostat will not be full open until about 30 degrees above the initial opening temperature, so a 180 degree stat just begins to open at about 180 and will not be full open until about 210. So the "normal" operating range would be considered to be about 180-210. If the temp goes above 210 it usually means cooling capacity is limited by either the radiator or air flow through the radiator.

The two conditions that will usually result in the highest operating temperatures are extended idling in hot weather or very high speed driving in hot weather, however, if the cooling system is to OE spec and in good operating condition, the coolant should not rise more than 30 degrees above the thermostat opening temperature, except for very extreme conditons or if there is a problem with the cooling system such as a deposit buildup in the radiator, or a malfunctioning fan clutch.

Duke

 

I have an interesting engine-temperature related issue.... I have a Fastburn 385 crate motor in a 66 with a BeCool radiator and electric fan. The engine has a 180 degree stat and the BeCool controller for the electric fan turns the fan on at 195 and turns it off at 175. The issue is, once the fan turns on, it will never turn off! The engine generates enough heat in puttering around town in Northern California to trip the 195 degree mark--this turns on the fan. The combination of the fan and the BeCool radiator is fantastic--you can see the temp gauge moving as heat is pulled out of the system. BUT--once the engine is cooled to 180, the stat is closed, thus the engine (which is where the temp sender is located) can never get down to 175 for the fan to turn off! The stat then controls the temp from that point on, and the radiator (with the fan whirring away) is more than adequate to extract any additional heat generated.

I've found a source for 170 degree stats, which seems like the best compromise (since BeCool doesn't offer a higher ranged sensor). Does this seem like the best avenue to pursue? Thank you.

 

That's why I recommend the Robertshaw "balanced-flow" thermostat, #330-180 (also marketed by Mr. Gasket under their name); its calibration is much more accurate than generic store-brand thermostats, it responds much quicker to temperature variations which eliminates the "spike" syndrome, and if it fails, it fails open.

 

Sounds like at least someone is still making decent ones. The old Harrison I put in my other car was a real work of art and quality