Should you run a car without a thermostat?

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Back to the real issue........ If you are getting detonation at 180 degrees (normal operation temperature), you need to find the real cause.

Forget about this thermostat thing.

What's your compression?
 
67Dart273 said:
You still have not explained "how you change" this path


I don't want to argue, I'm asking for REAL proof. I'm asking for an engineering reference (you SAID you are an engineer) to back up your claim THAT HAVING OR NOT HAVING A THERMOSTAT CHANGES THE PATH OF THE WATER FLOW IN AN ENGINE
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I don't believe he said it changes the path of water flow. By having the restriction from the thermostat, along with the pressure in the system, water is forced into all areas of the cooling jackets.
Remove that restriction and the water goes from the water pump up through the heads and out the top radiator hose. Yes, it will travel to other areas of the engine but it is not forced through. Thus, it will remain in the rear of the engine longer than in the front, leading to higher temperatures.
Besides, if thermostats weren't necessary, I doubt Ma Mopar would have put them in the engines.
And, other one tidbit to remember, thermostats do not control the maximum engine temperature but merely the minimum temperature.
 
If your gonna run without a thermostat you need to either put in a big washer to restrict flow or "gut" the thermostat by removing the spring and guts and put the gutted thermostat back in to restrict flow. The water can't cool your motor very well if it moves too fast through the system. All of my Destruction Derby cars get this treatment, as a failed thermostat will stop flow completely.
 
About your thermostat, RUN ONE.

About your timing, I have a strong running 340 that likes 14 initial and 34 advance which is normal but I also run the vacume advance with no pinging EVER on 91 octane. I have never been able to run this much timing on a stock cam low compession motor without it at least running rough if not pinging at times. You need a cam with decent overlap and good quench to run a ton of timing. On stock motors I run 8-10 initial and no more than 36 total with no vacume advance and they run smooth and don't ping on 87 octane.

Hope this helps:)
 
Thanks for all the input.I ran the car for 4 hours today with no pinging whats so ever.Ran at 170 degrees all day.So do i leave the vacuum advance hose off and leave the carb port pluged?Or do i just get the distrubator curbbed and put lighter springs on the weights.Will i loose much bottom end with the setup i have now.I put one of those new aluminum 600 holleys on it.They are 5 lbs lighter than the origanals.Runs real good right out of the box.Thanks
 
Dart GT, if you disconnect the vacuum advance and the car stops pinging, then you will need to run without vacuum advance.

I've got several buddies that are unable to hook up their vacuum advance for the same reason. Most just install a re-curve kit to eliminate the vacuum requirements altogether(mechanical advance) and, once reinstalled, just run your rpms up to about 3000 for a few seconds and set your total timing. Usually somewhere around 28-34 degrees.

Southernman
 
67Dart273,

I'm only going to respond to you one time here, and it's mainly because of your request for the "obvious" (i.e. any backyarder should be able to understand this - but you're one of those argumentative types that would rather hurl invectives than to check it out for yourself).

Do this for me:

On a small block mopar, look at your intake manifold, specifically where the thermostat resides. If you look closely, you'll also note that the upper radiator hose is attached to the top (discharge) side of the intake manifold. This is where hot water is returned to the radiator for cooling based on thermostatic value. Now suppose for a moment that hole was completely blocked off...

Now you tell me, where does the water go when you block this passage ?

Do the same on a big block water pump housing, which is where the thermostat is located. It's the same scenario.

I've got a 16 yr old nephew that fully understands this concept, but you want...engineering diagrams...?

What exactly do you do for a living...?

Southernman
 
Thanks Southernman for your help.Ill order the lighter springs for the weights and curb the carb.Good luck with 67dart273.lol Later David
 
David, I'm glad to hear you've got your pinging and overheating problem solved.

I'm glad to help in any way I can.

Southernman
 
Unless I missed it, nobody ever asked if he was runnin the vacuum can off manifold vacuum. That would explain the spark knock.
 
Yep.. won't help running without a stat. The motor needs an even temp. The stat helps warm it up by restricting flow. and at the same time keeps it in the radiator to cool the fluids..
 
?? What is your total adv on the timing and when is it in full adv?? I run mine at 32-34 total at crusing rpms.. 2800 - 3000 rpm
 
I know I can't run one in my set up. When I first bought the car I pulled out the restrictor and put in a T stat. Every time I ran the car and shut it down the upper radiator hose would collapse. Found out the hard way that with the electric pump there is no recirc line so when the T stat is closed it dead heads. I run my car on the street to local cruise ins and such with a restrictor and don't have any issues with it. The highest temp I've seen was around 190 or so on a hot day with prolonged driving.
 
Nice write up. Heres my opinion. Since the thermostat is at the end of the system where the water exits the engine, whether the flow is blocked or not the fluid path remains constant. If the thermostat were inside the block mid system it may have the ability to alter fluid path. Fluid path is controlled by fixed water paths in the block and head, not by toggling back pressure on the water exit.



67Dart273 said:
Sorry, nope. Doesn't do it for me. NO WHERE have I ever read that a thermostat somehow magically causes water flow to divert to the rear of an engine and back.


What I'm asking for here is a quote from a recognized text, or other authoritative source.

Sometime ago I found myself here:

http://www.stewartcomponents.com/Tech_Tips.htm

They don't seem to agree with you
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These guys seem to think:

http://www.arrowheadradiator.com/14...apability_in_high-performance_automobiles.htm

[FONT=arial,arial,helvetica]The heat load to the cooling system is related to the flow through the radiator and the temperature drop through the radiator by the following expression:[/FONT]
[FONT=arial,arial,helvetica]Q = M * cp *dT[/FONT]
[FONT=arial,arial,helvetica]Where Q is the heat load BTU/min., M is the mass flow rate of the coolant in BTU per pound per degree F, dT is the temperature drop through the radiator in degrees F[/FONT]

[FONT=arial,arial,helvetica]Looking at the previous expression, we can see that slowing the coolant down is the wrong way to go[/FONT]

[FONT=arial,arial,helvetica]What would happen if we increase the coolant flow?[/FONT].....................


........................[FONT=arial,arial,helvetica]will result in better heat transfer performance. There are some cautions to be observed in increasing coolant flow rate, however. Going too far may result in aeration and foaming of the coolant, possible damage to the radiator by overpressure, cavitation of the pump, due to excessive pressure drop through the radiator, and erosion of the radiator tubes.[/FONT]
=============================================

Nowhere in these discussions does anyone say anything about a restriction being necessary to promote circulation in the engine block and heads.
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Mopar to ya said:
Absolutely not. You need to fix the actual problem. With no thermostat, the coolant flows with restraint and doesn't stay in the radiator long enough to cool properly. It can actually run hotter w/o a t-stat under certain condition.
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That is a myth, I get by each summer with no thermostat, engine runs 10--15 degrees cooler. The 180 will be going back in soon but come next May, off with the thermstat once again. Engine warms up quick in summer heat and hold 170 to 180 while driving, perfect for my set up
 
340_833 dart said:
Besides, if thermostats weren't necessary, I doubt Ma Mopar would have put them in the engines.
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They are necessary in cool-cold weather. As for the manufacture advice, of course they will say you need to buy their parts, even in the summer run our Thermostat and if it runs hot well we sell new fans and radiators also. They are not going to offer a free fix tip
 
I'll probably regret this, but here goes.

Thermostats do not alter the path of water flow inside the engine. They simply add the radiator into the circulation loop. While the pressure in the cooling system may drop slightly IMMEDIATELY after the T-stat opens, the pressure will be equalized very rapidly by the pump because the cooling system is a closed system. The water pump provides the same pressure at a given RPM regardless of whether the radiator is in the system or not. If the pressure (RPM) remains constant, the velocity changes only based on the size of the passageways in the engine. The passageways in the engine do not "see" the passageways in the radiator, and are unaffected by adding it into the system. The flow velocity at a given location will only change with the rpm's of the engine, as the pump's output pressure will change with RPM.

Furthermore, thermostats do not "cycle". They open at a set temperature, and remain open until the temperature cools below that setting.

So, lets say its 105* outside. Your car warms up fast, and your T-stat opens at 180* (just one example, I know they come in other temperatures). But its damn hot, so your car's temperature goes up to 195* and stays there. The T-stat remains open. It doesn't have a timer, it's set up strictly on temperature. Since the water temperature never cools below 180*, the T-stat doesn't close. So, now you're running around with the T-stat open. Based on Southernman's theory of water flow, at least as I understand it, water would not reach the back of my engine under these conditions.

But, that's obviously false. Why? because if that were the case, everytime my water temperature went above 180* and stayed there, I'd cook the rear cylinders of my block. Since my car routinely runs above 180*, sometimes for hours and hours on end without pause, there's no possible way its being starved of water flow.
 
You may also want to try 93 octance fuel which you can get anywhere. The gas is really poor that we get now days also a ethanol neutralizer doesnt hurt it will help your fuel pump on hot restarts.
 
72bluNblu said:
I'll probably regret this, but here goes.

Thermostats do not alter the path of water flow inside the engine. They simply add the radiator into the circulation loop. While the pressure in the cooling system may drop slightly IMMEDIATELY after the T-stat opens, the pressure will be equalized very rapidly by the pump because the cooling system is a closed system. The water pump provides the same pressure at a given RPM regardless of whether the radiator is in the system or not. If the pressure (RPM) remains constant, the velocity changes only based on the size of the passageways in the engine. The passageways in the engine do not "see" the passageways in the radiator, and are unaffected by adding it into the system. The flow velocity at a given location will only change with the rpm's of the engine, as the pump's output pressure will change with RPM.

Furthermore, thermostats do not "cycle". They open at a set temperature, and remain open until the temperature cools below that setting.

So, lets say its 105* outside. Your car warms up fast, and your T-stat opens at 180* (just one example, I know they come in other temperatures). But its damn hot, so your car's temperature goes up to 195* and stays there. The T-stat remains open. It doesn't have a timer, it's set up strictly on temperature. Since the water temperature never cools below 180*, the T-stat doesn't close. So, now you're running around with the T-stat open. Based on Southernman's theory of water flow, at least as I understand it, water would not reach the back of my engine under these conditions.

But, that's obviously false. Why? because if that were the case, everytime my water temperature went above 180* and stayed there, I'd cook the rear cylinders of my block. Since my car routinely runs above 180*, sometimes for hours and hours on end without pause, there's no possible way its being starved of water flow.
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I'm gonna have to have Southerman's back on this somewhat because an open T-stat is still acting as a restrict-or plate.
Sounds like the problem has been solved anyway though But.....
Here's what I always did: Back off the timing little by little by ear until the pinging stopped. I never had to mess with the T-stat other than if it stuck. I'm no expert but it always worked great for me.:hello2:
 
Originally Posted by 72bluNblu

"They open at a set temperature, and remain open until the temperature cools below that setting."





What you have described Sir, is a cycle.

:tongue7:

I am just messing around.


You are differentiating between cycling every few minutes (or seconds?) and cycling based on system temp in a high heat environment which may require the entire duration of the drive to achieve a cycle. Both scenarios are possible depending on the conditions.

My 62 fairlane 260 would cycle open - closed every 3 or so minutes on a brisk Ozark mountain morning, in the fall.

.
 
I do know my engine cools off better with no thermostat, even tried those "high flow" ones.

Once the weather outside is cool, like today high 60, the engine needs a thermostat or it take 10 mins to reach 150, and likely stay under 165, that is too cool
 
Rice Nuker said:
Originally Posted by 72bluNblu
"They open at a set temperature, and remain open until the temperature cools below that setting."

What you have described Sir, is a cycle.
:tongue7:
I am just messing around.

You are differentiating between cycling every few minutes (or seconds?) and cycling based on system temp in a high heat environment which may require the entire duration of the drive to achieve a cycle. Both scenarios are possible depending on the conditions.

My 62 fairlane 260 would cycle open - closed every 3 or so minutes on a brisk Ozark mountain morning, in the fall.
.
Click to expand...

Yes true, you have me there. :eek:ops:

But that's a technicality in my definition, the point is that the thermostat does not open and close on any set amount of time. It is controlled strictly by the coolant temperature, which means it can stay open for long periods of time.

As you pointed out, the open part of the cycle can last minutes, hours, maybe even seconds. But, if the open part of the cycle lasts for hours (say, the time it takes to burn through a full tank of gas), the cooling system would fail and the engine would overheat if coolant did not reach the back of the engine. That is not a technicality.
 
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