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What degree thermostat to use and what Radiator?

1

1965GTFB

Member
67 289, 4v, shorty headders, T5, AC, PS, Flow Kooler water pump, car will be daily driver.
Checked the original shop manual. Lists the following:
Low Temp - opens 155-162 full open 184-186
High Temp - opens 188-195 full open 210-210
Is Low Temp for folks in the hot climates and High Temp for the great white north?

I'm in Nor Cal thinking and thinking going 180 degree stat and using a Robert Shaw stat.

Still deciding on what to use for a radiator. I have a couple of original 21" wide 2 rows and a 21" wide 4 row. If I used on of those I will get them rodded out, cleaned etc. Would like to use a 24" wide since the opening is that big. Was there a 24" for a small block in 67?
Thinking of staying with a brass radiator, one place you read brass cools better, another place aluminum is better??????? I like the idea that a brass unit can be repaired and cleaned down the road.

Thoughts and experiences.
 
Mines not running yet but I went a similar route. '67 289 stroked to 333. I like the original look so I bought a 3 core 24" wide for the '68 289/302 with AC (I am going to add AC also). I didn't like the top strap on the '68 (TMK the '67 289 was not offered with 24" radiator). I removed those side cover pieces and bolted it in down the sides with a 2 pieces of aluminum flat stock painted black. I also was going to have to repaint the top of the tank (scratched/chipped paint new from NPD) but like the look of raw metals so I wirebrushed it down to the brass and clear coated it. Bought a factory shroud for the '68 24" off a forum member (one of the forums) and installed 6 blade with Thermo clutch.

I'll have to check but I think I went with the 195* EMP Stewart T stat, want it to be in optimal operating temp range and that's close to what they use originally.
I also have an alum. waterpump (high flow?).

Again, I can't say how well this will work untile the motor is broken in but it's all an improvement over stock to me.
Jon

IMG_1293.jpg
 
I'm running a 160* T-stat in my .040 over 302, with a fan shroud and a 3 row core on my stock 20" rad. It liked the Bay Area just fine, but up here in Sacto it struggles when the temps hit the 95+ levels. It really didn't, and doesn't, like heavy traffic, crowded drive-thru lines or parades. I went with the 160 T-stat because a cooler engine produces more h.p. and, with the more aggressive cam and greater ignition advance (14* initial) I figured it needed an offset. When I had the engine rebuilt, the machine shop wanted to see my installation before they would warranty the short block. They expressed their dislike for the 20" Ford radiator until I told them it was actually a 3 row, and they didn't like the flex fan that I had on it. They asked me to swap back to the stock 4 blade fan, which I dutifully did, but now, as I'm looking for cooling solutions for toasty Lincoln, CA, I am beginning to question why they said that. Anyone have any idea?

Jonk67, I like your setup. If I wasn't a slave to keeping the engine bay visually period correct I'd have gone to the 24" radiator too, or an aftermarket aluminum radiator. These Mustangs have such puny cooling systems from the factory. The 20" radiator is marginal for driving and is relatively useless in stop-and-go traffic. Ford could have spent a little more on this stuff to insure adequate cooling.
 
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RagTop said:
I'm running a 160* T-stat in my .040 over 302, with a fan shroud and a 3 row core on my stock 20" rad. It liked the Bay Area just fine, but up here in Sacto it struggles when the temps hit the 95+ levels. It really didn't, and doesn't, like heavy traffic, crowded drive-thru lines or parades. I went with the 160 T-stat because a cooler engine produces more h.p. and, with the more aggressive cam and greater ignition advance (14* initial) I figured it needed an offset.
Click to expand...
A 160 can actually help an engine run hotter in the right circumstances. It can allow coolant to flow too early and too fast not allowing the radiator to do its thing. Not saying that is the case in your example but it has been known to happen. Most guys run a 180 in a SBF.

Aluminum radiators will absolutely cool better than brass. Simple matter of metalurgy, construction and heat dissipation. A well designed 2 row will out cool a three row, all other things equal. There is more surface area in a two row to dissipate the heat.

I have recommended these to everyone that asks and a lot of the guys here now run them. To my knowledge they all have done very well with them. This link is to one for a 65/66 but they make models for other years as well.

http://www.ebay.com/itm/321406397775?_trksid=p2055119.m1438.l2649&ssPageName=STRK:MEBIDX:IT
 
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So cars with 180* T-stats run cooler than ones with 160* units and cars with two row radiator cores run cooler than those with three row cores. Ok then.
 
RagTop said:
So cars with 180* T-stats run cooler than ones with 160* units and cars with two row radiator cores run cooler than those with three row cores. Ok then.
Click to expand...


I can tell you the two 1" row aluminum radiator mentioned by Terry above runs cooler in my 65 than the four 1/2" row aluminum radiator it replaced. I hardly even need a fan!
 
RagTop said:
So cars with 180* T-stats run cooler than ones with 160* units and cars with two row radiator cores run cooler than those with three row cores. Ok then.
Click to expand...
You can either be grateful for the responses people give trying to help and try to understand, in this case, the physics of their answers or you can be an ass and make that kind of comment. Choice is yours. You might want to try and learn something, however. I'd be happy to walk you through the reason both of my thoughts are correct if you are willing to listen to PROVEN and factual science. Or keep driving your overheating car until it suffers damage. I won't even bother telling you why a flex fan is crap compared to the stocker though, you are obviously too smart for that.:rolleyes:
 
kb3 said:
I can tell you the two 1" row aluminum radiator mentioned by Terry above runs cooler in my 65 than the four 1/2" row aluminum radiator it replaced. I hardly even need a fan!
Click to expand...
How can that be, Ken? Four is more than two. ;) Must be those damn laws of physics again.

OK, now I'm being the ass. I'll stop. Seriously, if you want some help (Ragtop) understanding it I am willing.
 
One more thing to point out. You stated earlier that a cooler engine produces more power. That is not necessarily true. A cooler fuel charge is what I believe you mean. Being cooler it is also therefore denser supplying a larger amount of "fuel" in the same space. That is why a car runs faster on those cool summer nights. You get more "bang" in each intake cycle drawn into each cylinder.

A colder running engine can actually create problems and cause a loss of power. You can get less efficient fuel burn in the combustion chambers for one thing. It can lead to higher carbon build-up and oil sludge in the engine.

That's why most SBF run a 180* thermostat.

Don't believe me? Research it. Here's a discussion by some guys who get it.

http://www.jalopyjournal.com/forum/threads/any-reason-to-not-use-a-160-thermostat.128850/
 
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Horseplay said:
You can either be grateful for the responses people give trying to help and try to understand, in this case, the physics of their answers or you can be an ass and make that kind of comment. Choice is yours. You might want to try and learn something, however. I'd be happy to walk you through the reason both of my thoughts are correct if you are willing to listen to PROVEN and factual science. Or keep driving your overheating car until it suffers damage. I won't even bother telling you why a flex fan is crap compared to the stocker though, you are obviously too smart for that.:rolleyes:
Click to expand...
Forgive me for not having fallen to my knees in gratitude for your pearls of wisdom imparted to me out of your unselfish desire to teach the ignorant and unwashed. I'm not the one who is an ass here, pal. My question was basically asking you how you arrived at the conclusion that a 160* thermostat makes an engine run hotter than a 180* thermostat. You responded not with an explanation, but with a personal slur. I usually find that personal attacks and name calling is safety sought by people who are on less than solid ground. Your are offended that I might question your opinion, huh? So tell me what your basis of opinion is beyond the "PROVEN and factual science" that you refer to.? I don't see anything in your posts that ventures beyond your opinion and some pontifical woof and blab. Have a nice day.
 
My question was basically asking you how you arrived at the conclusion that a 160* thermostat makes an engine run hotter than a 180* thermostat.


Easy answer is a cooler thermostat does not give the coolant in the radiator enough time to cool down before moving back into the engine and heating up again .

Mike
 
RagTop said:
My question was basically asking you how you arrived at the conclusion that a 160* thermostat makes an engine run hotter than a 180* thermostat. You responded not with an explanation, but with a personal slur. I usually find that personal attacks and name calling is safety sought by people who are on less than solid ground. Your are offended that I might question your opinion, huh? So tell me what your basis of opinion is beyond the "PROVEN and factual science" that you refer to.? I don't see anything in your posts that ventures beyond your opinion and some pontifical woof and blab. Have a nice day.
Click to expand...

You didn't "ask a question" you made a snide remark implying my initial response was BS. I wasn't looking for you to kiss my ass and offer me gifts for my advice. I just thought someone asking for help/advice might be, I don't know...receptive to it. Also, I didn't give you my opinions. I gave you facts and a source to support it.

Did you bother to go the the radiator link I provided? In it they do an excellent job of explaining why a well designed two row aluminum radiator far out performs older style multi-row brass units. That's not my "opinion". That is science and engineering coming together to make something we use better. KB3 then came along to share his "actual" experience with that exact radiator which gave you a real life example.

I tried in a very short post to give you the very basic reason a 160* can be a problem. Mike (c6fastback) just came along and posted the same thing. Thermostats are not absolute devices. The temperature rating on them indicates when they will reach their maximum open state. They begin and slowly continue to open at much lower temperatures. They act as restriction in the primary water passageway. The sole purpose is to limit/reduce coolant flow rate to allow adequate time in the radiator for the heat to transfer out of the coolant. If the water flows through too quickly the radiator, regardless of design, simply cannot withdraw enough heat.

And yes, too cool a running engine can create all kinds of problems. Engines are designed to operate under a specific level of thermal expansion. When an engine is built we all know about the importance of a bazillon clearance tolerances. Why do you think they exist? As the various metal components heat up they expand and for lack of a better way to put it, close up those gaps. Production (and street performance) engines are built with much looser tolerances than racing engines. Engine builders will tell you that a street engine shouldn't run a 160* stat but nothing lower than a 180*. But don't take my word for it. Ask around.

A cold running engine will also not burn the fuel charge nearly as effectively. Your gas mileage will really suffer. More importantly, the POWER will drop. To argue the cooler temp allows one to up the timing, etc. is negated as all you are really doing is MAYBE re-couping some of the power lost to inefficient burn.
 
Jonk67 said:
Mines not running yet but I went a similar route. '67 289 stroked to 333. I like the original look so I bought a 3 core 24" wide for the '68 289/302 with AC (I am going to add AC also). I didn't like the top strap on the '68 (TMK the '67 289 was not offered with 24" radiator). I removed those side cover pieces and bolted it in down the sides with a 2 pieces of aluminum flat stock painted black. I also was going to have to repaint the top of the tank (scratched/chipped paint new from NPD) but like the look of raw metals so I wirebrushed it down to the brass and clear coated it. Bought a factory shroud for the '68 24" off a forum member (one of the forums) and installed 6 blade with Thermo clutch.

I'll have to check but I think I went with the 195* EMP Stewart T stat, want it to be in optimal operating temp range and that's close to what they use originally.
I also have an alum. waterpump (high flow?).

Again, I can't say how well this will work untile the motor is broken in but it's all an improvement over stock to me.
Jon

IMG_1293.jpg
Click to expand...
Is that a 6 or 7 blade fan? I like the idea of how you mounted the 24", I'll probable do the same.
 
Mine's a 6 blade, 7 would be too much horsepower:D. The side mounts were easy to make, picked up some alumimun flat stock, cut them to a large 'C' shape, drilled some holes and mounted it with flat top carriage bolts I found at Lowe's 4"? X ?" long, looks like I used 28" long total.
IMG_0370.jpg

One side trimmed one side being marked
IMG_0363.jpg

After trimming, used carriage bolts to mount to opening, radiator holes drilled towards fender
IMG_0368.jpg

Used these flat head carriage bolts to mount rad to adapter. Drilled holes then used square file to make tight fit that wouldn't spin, flat head goes against rad opening, bolt heads point towards engine. I think I cut them shorter once mounted, I don't like extra threads showing.
IMG_1287-1.jpg
 
I'm running a Robert Shaw 180 T Stat along with a two 1" row Northern brand aluminum 24" radiator using homemade brackets similar to what Jon is doing. 10,000 miles later with zero heating issues.

To the OP, be sure to do a stovetop test of the stat before you install it.
 
Horseplay said:
You didn't "ask a question" you made a snide remark implying my initial response was BS. I wasn't looking for you to kiss my ass and offer me gifts for my advice. I just thought someone asking for help/advice might be, I don't know...receptive to it. Also, I didn't give you my opinions. I gave you facts and a source to support it.

Did you bother to go the the radiator link I provided? In it they do an excellent job of explaining why a well designed two row aluminum radiator far out performs older style multi-row brass units. That's not my "opinion". That is science and engineering coming together to make something we use better. KB3 then came along to share his "actual" experience with that exact radiator which gave you a real life example.

I tried in a very short post to give you the very basic reason a 160* can be a problem. Mike (c6fastback) just came along and posted the same thing. Thermostats are not absolute devices. The temperature rating on them indicates when they will reach their maximum open state. They begin and slowly continue to open at much lower temperatures. They act as restriction in the primary water passageway. The sole purpose is to limit/reduce coolant flow rate to allow adequate time in the radiator for the heat to transfer out of the coolant. If the water flows through too quickly the radiator, regardless of design, simply cannot withdraw enough heat.

And yes, too cool a running engine can create all kinds of problems. Engines are designed to operate under a specific level of thermal expansion. When an engine is built we all know about the importance of a bazillon clearance tolerances. Why do you think they exist? As the various metal components heat up they expand and for lack of a better way to put it, close up those gaps. Production (and street performance) engines are built with much looser tolerances than racing engines. Engine builders will tell you that a street engine shouldn't run a 160* stat but nothing lower than a 180*. But don't take my word for it. Ask around.

A cold running engine will also not burn the fuel charge nearly as effectively. Your gas mileage will really suffer. More importantly, the POWER will drop. To argue the cooler temp allows one to up the timing, etc. is negated as all you are really doing is MAYBE re-couping some of the power lost to inefficient burn.
Click to expand...

Terry:

I followed the link to HAMB and read the posts there. Like here, lots of anecdotal experiences and opinions, but I couldn't find the "science" you reference. Not saying you are wrong or Ken is right, rather, there appears to be more than one "right" answer when it comes to to the question: "What works for my application?"
One additional question I have is: if a 160 degree thermostat has no useful purpose in our vintage engines, why do the thermostat manufacturers make them?

For reference, I run a 195 degree thermostat in my big block using a 4 core conventional radiator (Modine 379-4) with a stock 18.25" clutch fan and shroud, Edelbrock water pump, and a 50/50 mixture of antifreeze/distilled water. For the most part my engine runs "cool" most of the year, even with the A/C running, but when the ambient temp hits 100 degrees, it gets damn hot even when traveling at freeway speeds, sometimes to the point where the under-hood temps are high enough to boil the fuel in the float bowls. I concluded that the ethanol in the gas boils at a lower temp than conventional gas but the "science" here would dictate that the ethanol has no effect on fuel percolation. Despite this science, I'm a skeptic based upon my experience.

Regards, Jeff
 
Jeff,

The science I allude to is that covered in the radiator bit I posted. Simple math of surface area combined with what is known about how heat is removed from, in this case, the coolant.

Here is a good read on the subject of thermostats and engine cooling. It answers a lot including why there are even 160 thermostats around. Sorry I grabbed this one from a GM guy.:(

http://www.gmc4x4.com/topic/280-tech-tips-thermostat-theories-and-cooling-system-explained/

There is a TON of stuff out there if one wants to research it. You can find discussions on virtually every forum from one like ours to engine builders to racers, etc. If you can take all the detailed technical jargon and physics talk there is stuff out there in engineering type areas as well. Bottom line though is pretty simple. Engines like those in our cars require a higher (north of 180 degrees) operating temperature to run more efficiently, reduce wear and even to make more power.

The biggest problem I think people have in understanding all of this is that they simply do not comprehend how each component fits into the larger pie or even how each one actually works. Many do not even understand how a thermostat works let alone how that action relates to the cooling action and efficiency of the system. And here's the thing. This discussion was started about a SBF in a mustang. Yes, there may be nuances to everyone's cars but if it is in a mustang engine bay and it is some version of a SBF applications are, for this discussion, pretty much the same. Nothing is a one size fits all but in this case it is a 95/100 type deal.

I offered my original advice to a poster who was currently running a 160 degree thermostat and was having overheating issues on hotter days and when, essentially, stuck in slow moving traffic. His symptoms are classic examples of inadequate cooling capacity in the radiator, poor fan performance and, knowing the thermostat used, poor coolant flow control. The engineers at Ford didn't put a 160 thermostat in a production SBF. That alone should tell us something.

On top of all that, I have my own personal experiences in both building engines and my mustangs. I never asked anyone to take my word as gospel. I just share my experience and knowledge as learned as I go.
 
c6fastback said:
My question was basically asking you how you arrived at the conclusion that a 160* thermostat makes an engine run hotter than a 180* thermostat.


Easy answer is a cooler thermostat does not give the coolant in the radiator enough time to cool down before moving back into the engine and heating up again .

Mike
Click to expand...

That makes no sense.
 
buckeyedemon said:
That makes no sense.
Click to expand...
It does to a degree. Yeah, intentional pun.

First you have to understand that a thermostat does not "set the temperature of an engine". It merely is a device which opens and closes to allow the coolant to pass between engine and radiator. The degree value assigned to a thermostat indicates when it will reach its fully open state. If one were to utilize a 160* unit in a car with a poorly performing radiator it is possible that maximum coolant flow happens so early that the restriction caused by a closed or partially open thermostat never occurs allowing the flow to be limited and the coolant to gain enough time in the radiator to allow the heat to be removed. What you end up with is a flow rate and volume so great that the radiator cannot perform the job of cooling. That's why sitting in traffic it can overheat.

Have you ever had an overheating issue with a newer car and found that by turning on the heater the engine temp went down? Why do you think that happened? By switching on the heater you allowed the engine to pump some of the coolant flow in through the heater set-up (fan blowing through heater core...think mini-radiator.., cooling effect), removing it from the source of heat generation (the engine) and giving it a bit of time to cool off. That can't happen in a radiator if the flow is happening too quickly. It goes in and out and right back into the source of the heat before it can be cooled. This trick will work for a very short period of time until that new loop also builds up heat and the benefit is lost.

Bottom line in this whole discussion is this. One needs to have a radiator with the capacity to reduce the operating temperature of the engine to a safe level. Ideally, you want to run north of 185* and, likely for most applications, less than 200*. This would give you your safest operating temp for the engine and also keep it in the range in which it can run most efficiently while producing peak power. The best combination of parts available today to get you this result is a 180* thermostat and a quality modern 2 x 1" row aluminum radiator. Aluminum wins out over brass due to strength (tube design) and heat transference capabilities*.

*brass is great for shedding heat but when used in radiators the parts are soldered together and the solder inhibits the natural ability of brass to the point that aluminum can outperform it.
 
Horseplay said:
It does to a degree. Yeah, intentional pun.

First you have to understand that a thermostat does not "set the temperature of an engine". It merely is a device which opens and closes to allow the coolant to pass between engine and radiator. The degree value assigned to a thermostat indicates when it will reach its fully open state. If one were to utilize a 160* unit in a car with a poorly performing radiator it is possible that maximum coolant flow happens so early that the restriction caused by a closed or partially open thermostat never occurs allowing the flow to be limited and the coolant to gain enough time in the radiator to allow the heat to be removed. What you end up with is a flow rate and volume so great that the radiator cannot perform the job of cooling. That's why sitting in traffic it can overheat.

Have you ever had an overheating issue with a newer car and found that by turning on the heater the engine temp went down? Why do you think that happened? By switching on the heater you allowed the engine to pump some of the coolant flow in through the heater set-up (fan blowing through heater core...think mini-radiator.., cooling effect), removing it from the source of heat generation (the engine) and giving it a bit of time to cool off. That can't happen in a radiator if the flow is happening too quickly. It goes in and out and right back into the source of the heat before it can be cooled. This trick will work for a very short period of time until that new loop also builds up heat and the benefit is lost.
Click to expand...

I understand that a thermostat does not set temperature. It merely controls the minimum steady state operating temperature (assuming the heat generated is higher than that dissipated by air cooling prior to opening).

Saying that a 160 thermostat will lead to higher temperatures than a 180 is non-sense.

The quality/design of the radiator, shrouding, external temperature, amount of heat generated by the engine determines what the maximum steady state temperature will be.

Talking about coolant flow through a radiator (including the heater core, which is the same as a radiator) being to fast and not cooling is pure non-sense. If this was the case, then regardless to what temperature themostat was used, the result would be thermal runaway (almost like positive feedback).

Fast flow through a radiator also means fast flow through the engine. Therefore on a per cycle basis, the temperature change in the radiator will be less as compared to when the rate is slower and the temperature change while the coolant is in the engine will also be less on a per cycle basis. However, with a faster rate, there will be more cycles through the system for a given amount of time. The end result is that the total time spent in the radiator will be the same regardless of the rate (this is all assuming the thermostat is open).

To summarize, faster flow results in less of a temperature delta in the system (i.e. 120 degrees when the coolant enters the engine block with a slower rate versus 150 degrees when the coolant enters the engine block with the faster rate. the maximum temperature as measured at the exit of the block will be the same).
 
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