intermitten overheating

No t/stat originally, but many have added them.
I have, as engine tends to run better at the governed temp and it slows the water passing thru so you don't puke it out. JMO, others will chime in on their pros/cons of running a t/stat I'm sure.
Paul in CT
 
kartek said:
Am I to understand that these engines do not use a thermostat? So far my research suggests no....Thanks
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Reliable thermostats didn't exist until a few years after the model A production ended. Many of us have added one to our cars for the same reasons that the rest of the world now uses them in all new cars. Restoration purists demure. All of the model A parts houses sell one with a handy collar attached for clamping inside the upper radiator hose. Also, a modified water outlet with a thermostat housing built into it is available, for more money.

Steve
 
1931 flamingo said:
No t/stat originally, but many have added them.
I have, as engine tends to run better at the governed temp and it slows the water passing thru so you don't puke it out. JMO, others will chime in on their pros/cons of running a t/stat I'm sure.
Paul in CT
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Interesting.... How/where is it installed? Is there a special housing that needs to purchased along with it? I'm assuming it would install at the top of the head at the water outlet? Thanks for any details!
 
kartek said:
Interesting.... How/where is it installed? Is there a special housing that needs to purchased along with it? I'm assuming it would install at the top of the head at the water outlet? Thanks for any details!
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On my Model A I installed a common 180* thermost and held it in place using a 3" piece of tight fitting rubber hose inside the upper radiator hose. On a friend's car I went to Menards and bought a plastic pipe fitting with barbs on one side, then cut off the threaded part and pushed the barbbed side down against the thermostat. Be sure to push the barbs down from the top, so they tend to lock as it's pushed toward the radiator. Also be sure to have the wax pellet of the thermostat facing down, towards the engine. You want the thermostat as close to the engine as it will go. I also drilled two 1/8" holes in the thermostat to allow some coolant flow, to be sure the wax could sense the hot flow when it should.

BTW, no third hose clamp is needed to hole the inner hose, or the barbbed fitting in place, so the top hose will still look stock even with the thermostat.
 
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Here's the combination housing/outlet you can buy--kind of goofy looking but very well made:

IMGP0386-1-1.jpg


Here's the collared thermostat that Snyders and others sell. You can see the extra by-pass holes that have been drilled, as Tom mentioned. The collar keeps the stat square in the hose and provides something a hose clamp can grip to hold it in place. Theoretically, as Tom said, you want it as close to the motor as possible, but a lot of folks let it "float" in the hose, to avoid the unsightly third hose clamp. The stat then works its way up to the top of the hose, where is still seems to work ok.

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Yes, Model A's does well with a thermostat. Just buy the 160 degree one with the sleeve made on it from any Model A supplier, rub a little grease on it, slide it in the UPPER end of the hose, (NOT ***-backwards) clamp the hose, and you're done! I DID NOT drill any holes in it, and on initial cold fire up, I was surprised that it had a fair amount of flow, I guess it had an engineered leakage to prevent an air trap under the thermostat. Some have a small "dingle" valve to prevent air locks. I don't remember if mine had a "dingle" valve. Maybe I'm the "DINGLE?" Bill W.
 
Any car that was designed to use a thermostat will have some bypass provision allowing coolant to circulate around in the head before it opens to the radiator. The idea is to get even heating-up and avoid hot spots or even localized vaporization. Circulation through a hot water heater core could serve the same function.

Drilling the holes in the thermostat accomplishes this function, as well as assuring that the wax pellet gets a good sampling of the coolant temp in head, and allowing easy relief of any air bubbles that might get into the system. Unfortunately, of course, it partly defeats the thermostat function by slowing down warmup. A while ago, someone posted a modification to the model A block that creates a true recirculation loop; clearly, the best way to go but probably too extreme a mod for most of us.

Over the years, I've used thermostats with zero, 1, or 2 holes drilled. But, they all were manufactured with at least a tiny little relief hole in the flange that probably would have sufficed to pass an air bubble. All seemed to work ok, but that could be a VERY motor-dependent result. The Vintage Precision housing in my first picture above has two little bypass relief holes cupped out at the edge of the flange.

Steve
 
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In my epic quest to find my source of overheating it is safe to say I tried everything to solve the problem. Changed the radiator twice, 160 and 180 thermostat, flushed the motor with muratic acid and finally bought a new 3 core radiator from Gary Bergbauer.

Guess which one worked? Thermostat in my car did get it up to running temp faster but didin't solve any overheating issue. Just gave me something to watch as the temp gauge would get up to 180 and then fall as the tstat opened up and then worked its way back up to 190+ temps. My problem was that my car had a 2 core radiator and was not enough for these Oklahoma temps to keep it cool.
 
steve s said:
Sorry to be picky, but two things: First, specific heat refers to "per gram", so to compare effectiveness on a per volume basis (i.e., the way radiators are filled) densities need to be taken into account. At normal operating temperature (~160 F), the specific heat capacity of 50/50 antifreeze is about 85% of that of water. But, it is also about 7% more dense than water at the same temperature. So, the heat capacity of 50/50 antifreeze would be about 8% less than an equal volume of water. So, my second picky is whether or not 8% difference qualifies as "much more".

On the other hand, in water's favor, its thermal conductivity--the rate at which heat can move through it--is nearly twice that of 50/50 antifreeze.

On the third hand, antifreeze's higher boiling point reduces the risk of localized vaporization at hot spots or when the going gets rough, at which point both heat capacity and thermal conductivity really do become much less.

Steve
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So you proved to everyone I am an ignorant jerk. Hope you are happy!
 
The holes in the thermostat is to keep the water pump from cavitating. If there is no flow the pump will heat the water and turn it to steam. This will ruin the pump. Some modern engines have a heater hose size by pass around the thermostat.
 
Louis said:
No Paul....You just did it yourself, But, youll probley feel better after a good night's rest :rolleyes:.


Steve,
Thank's for the helpfull info. I found it very interesting ;).
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Louis,
I admit I am an ignorant jerk. Steve just confirmed it. I was just trying to help. I took chemistry 35 years ago. It was presumptive of me to base my response to a request for advice on concepts I learned so long ago. It was ignorant of me to consider an 8% difference in heat capacity between water and antifreeze as significant or "much more." Since Steve states that water's thermal conductivity--the rate at which heat can move through it--is nearly twice that of a 50/50 antifreeze mix, I was stupid to suggest that someone might try swapping their 50/50 mix for pure water as an experiment. In my defense, I did state in my post that the likelihood of success was slim. The remainder of my post was full of foolish suggestions I am embarrassed to recount here. Steve apologized at the start of his post for being "picky." I should be fine with the fact that when I respond to a request for advice on this forum, my response will be thoroughly scrutinized, criticized and picked apart.

Sincerely,
An ignorant jerk immature enough to be offended by "picky" posters!
 
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He makes the most accurate and best radiator cores. Do a Google search for Berg's radiator and you might find the information. He's in Illinois.
 
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