To Stat or Not To Stat? That is the question.

[Old Henry]

To try to answer this question I devised a controlled scientific experiment taking two drives over the same course attempting to duplicate everything about each drive except one was without thermostats and the other was with Stant 14157 thermostats installed. (More about them here: https://www.fordbarn.com/forum/showthread.php?t=113366)

4.8 miles from my house is the beginning of Squaw Peak Road that rises 1,779 feet in 4.1 miles (8% grade) to Squaw Peak Overlook. (Put that in Google Earth to see it.) It is the only road in Utah that I've ever overheated on, although it was only once. Last Saturday, the 3rd, I drove from my house to Squaw Peak Road then up the road to the overlook recording elevation and temperatures every mile along the way going up and coming back. I could only go 20-25 mph in second gear going up the climb. When I got back I intended to install two Stant thermostats and do it all again that day but when I opened one of the boxes it had some other thermostat in it. So, I had to take that one back to O'Reilly and order another that didn't come in until last night. So, had to take the second ride with the thermostats in today. Everything about the drive was identical to the one Saturday except the outside temperature. On Saturday it was 90° and today it was 84°. I don't know how much difference that 6° makes to my conclusions. I let you decide for yourself.

The data for the two drives is in the attached PDF file if you want to open it and study it. Here is the data in graphic form (done by VeryTangled subsequent to initial report):



Before reporting what I learned new let me review facts that I think are not largely disputed.

1. Engines run better, more efficiently, and last longer if they are kept above a minimum operating temperature. The moisture and other contaminants in the crankcase evaporate instead of condensing, mixing with the oil, and contaminating it. For my 59A in my 47 Ford specifies a 160° thermostat which would seem to indicate that is the minimum recommended operating temperature.

2. On the other hand, if an engine gets too hot the water boils out and if it's not cooled quickly it can be damaged by the heat.

3. Thermostats are ideal for getting an engine warmed up to operating temperature quickly and keeping it from dropping below that. However, the thermostats currently being sold to replace the Ford butterfly valve thermostats are much lower volume and, in some instances, including if there are any other problems with the cooling system, they may restrict coolant flow enough to cause or contribute toward overheating. See more discussion about that here: https://www.fordbarn.com/forum/showthread.php?t=112889

So, with greater concern about overheating than underheating, many remove the thermostats and run the engine without them. I have done that, not being sure whether it made any difference or not. But, for me, I can't do that all year round cause it gets real cold where I live in the winter and I've got to get the engine warmed up to get heat out of the heater. Plus, after a long descent down a mountain my engine gets too cold and starts running rough.

So, although I had no doubt that there were benefits to thermostats at lower temperatures, I needed to know if they really did cause or contribute to overheating. That's why I did this procedure. To find out.

Here's what I learned.

1. It was no surprise that the engine warmed up to proper operating temperature much faster with the thermostats in than with them out, in fact twice as fast - 3 minutes with stats compared to 6 minutes without.

2. I was a little surprised that coming down the 8% grade for 4.1 miles that the thermostats actually kept the engine at operating temperature and prevented it from getting down to 130° that it did without them.

3. The best news of all was that the maximum temperature that the engine reached at the top of the climb was within 1-2 degrees whether or not I had thermostats installed. I must add that such was with the Stant thermostats that have 25% greater flow than the ones generally being sold for the 59A engines. I don't know whether the results would be the same for them and don't need to know since I will only be using the Stant stats from now on.

So, in my humble but studied opinion, there is no reason to run a flathead without thermostats if you use the Stant stats.*

Here's a picture I took up at Squaw Peak Overlook when I got up there looking down to where I live.



* The one exception would be if you use Skip's pumps that are not recommended for use with thermostats. They are designed to move more volume provided there are no restrictions - kind of like a fan vs. a compressor. For full discussion of difference go here: https://www.fordbarn.com/forum/showthread.php?t=106054

[Ross6860]

Just my opinion, but you want to run thermostats.

Below 160 you will actually start to wash the oil off the cylinder walls, and since your fuel doesn't vaporize completely you loose performance and fuel efficiency (well, such that a flathead is fuel efficient to begin with)

You will also contaminate your lube oil.

Besides, thermal cycling isn't too good for anything.

Your engine will be happier and live longer running >160, but not overheating. Most oils today are OK well into the lower 200 degree range. 215-220 is fine.

Are you running 50/50 glycol? Pressurized or open system?

See my other post today about specific heat and water vs 50/50. You will get better cooling with pure water and an additive package to protect from corrosion.

[Bluebell]

Henry.I do have two questions:
Is this a pressure systsem? (it appears to me it is)
and if so, What pressure is it?

Now you should give us your conclusion.
What can we learn from your results?.
I have my view, but you made the effort and spent your money. What have you deduced from your tests?

[Old Henry]

Originally Posted by Ross6860

Are you running 50/50 glycol? Pressurized or open system?

Usually I run 2 gallons of propylene glycol but right now I just have soft water and two bottles of Hy-per Lube Super Coolant. 4# radiator cap.

[Old Henry]

Originally Posted by Bluebell

Henry.I do have two questions:
Is this a pressure systsem? (it appears to me it is)
and if so, What pressure is it?

Now you should give us your conclusion.
What can we learn from your results?.
I have my view, but you made the effort and spent your money. What have you deduced from your tests?

Standard 4# radiator cap.

Read the end of my report. Conclusion is: There are very important reasons to run thermostats and no reasons not to if you use a high flow stat that approaches the flow Ford's original had.

[Bluebell]

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Originally Posted by Old Henry

Standard 4# radiator cap.

Read the end of my report. Conclusion is: There are very important reasons to run thermostats and no reasons not to if you use a high flow stat that approaches the flow Ford's original had.

Henry, I support your conclusions.

Very interesting that she was hotter without the stats while climbing, than with them.
What does that tell us about flow?

[4t8v8]

Been running my 8BA with 160 deg. therms and no pressure for 63 years now. Have the factory shroud on the radiator. It has never overheated in it's life and the heater can get the cab too hot on the coldest days. I pull the bottom rubber seal off the cap and leave the top one so the recovery system will work properly. 50/50 antifreeze mix with a couple of cans of rust preventative. Been listening to the stat argument many years. Guess I will keep on keeping on as I do believe the old gal is going to outlive me.

[Brian]

Basically, if thermostats were unneccessary, ALL auto manufacturers would not fit them!
On the contrary, ALL auto manufacturers supply their products with thermostats, draw your own conclusions.

[flatford8]

After all these runs down an eight percent grade I think I'd worry more about my brakes!!!!! Thanks for your time and effort. Mark

[Talkwrench]

Great testing..
Not to Hijack but as people are looking I just ordered the Bob Drake water pumps for mine, Are they similar to Skips? I cant remember seeing anything about removing thermostats?

[Old Henry]

Originally Posted by Bluebell

Henry, I support your conclusions.

Very interesting that she was hotter without the stats while climbing, than with them.
What does that tell us about flow?

I'm not so sure it tells as much about flow as it does about the day I climbed without the stats it was 6° hotter than today when I climbed with the stats. That may have made a difference. I don't know.

What was remarkable to me was that even though the engine was about 5-6 degrees hotter climbing without the stats it actually leveled off at the same temperature that it did with the stats.

[Old Henry]

Originally Posted by flatford8

After all these runs down an eight percent grade I think I'd worry more about my brakes!!!!! Thanks for your time and effort. Mark

Rarely ever touch the bakes on descent. Came down in second gear the same as I went up and at the same speed - 20-25 mph. Only tapped the brakes on the hairpin switchbacks.

[Old Henry]

Originally Posted by Talkwrench

Great testing..
Not to Hijack but as people are looking I just ordered the Bob Drake water pumps for mine, Are they similar to Skips? I cant remember seeing anything about removing thermostats?

I will tell you what my understanding is about Skip's pumps compared to others. Someone probably knows more and may contribute.

The design of Skip's impeller is what is known as a mixed-flow design that can move more volume with less pressure than the other pumps that are centrifugal design that create more pressure to push through restrictions. It's a bit of an anomaly in my opinion for some to taught Skip's pumps as high volume when they are only such if you remove the thermostats which, if you do, makes any pump high volume. Since it is so important to have thermostats keeping the engine above minimum operating temperature both in hot and cold weather it doesn't make any sense to me to sacrifice the benefit of thermostats just to get more flow from a pump that is no higher volume with thermostats than any other pump.

Hope that makes sense. Much more discussion on the difference between Skip's pumps and others here: https://www.fordbarn.com/forum/showthread.php?t=106054

[Bluebell]

What was remarkable to me was that even though the engine was about 5-6 degrees hotter climbing without the stats it actually leveled off at the same temperature that it did with the stats.[/QUOTE]
Henry, That's because the stats don't do the cooling, That is down to the transfer of heat energy from the block to the air, the rate of transfer, being the governing factor.

[FlatheadTed]

Did a run on a cool day sun in my 34 with shroud , took about 5 miles to get up to 180 ,yet in my modern car 1/4 mile its up to Temp ,so I will trying the stats back in.

[Dave D]

I find it hard to believe people still have to think about this question. Here is my take, name ONE automobile manufacturer in the world that doesn't run a thermostat.

Or are they all wrong?

[chuck stevens]

HENRY>>> your flathead will run better- last longer if it runs up around 190 deg. By running without the thermostats the temp goes up and down with the terrain.

[Cecil/WV]

I have 3 sets of Skip's pumps, 2 on 8BA's and 1 on a 59AB and I am not aware of any instructions telling me not to run stats, just be sure they don't restrict the normal flow,ie, Robertshaw 330 or similar.

[woodypecker]

Henry thanks for the test information.

[37 Coupe]

I run Skip pumps on my 59AB and do not use thermostats, I usually am only running in the summer. I am sure that either Skip,instructions or GM stated to not use thermostats,but I am probably wrong. I probably welcomed the advice not to use thermostats because of past problems with them. My problems have been with NOS Genuine Ford thermostats that tested fine failing shut and causing overheating and other problems like ruining a brand new set of Edelbrock heads,this years ago on an 8RT engine. Still I agree that Ford engineers knew what they were doing and a steady heat range is best overall for the engines efficiency and durabilty. Some say this brand or that brand restricts and I assume they are referring to new,possibly China made ones. What about the NOS boxed ones that show up at swap meets ,auctions ,Ebay,if they were good enough then why not now? I doubt Ford NOS ones were actually Ford built,probably sourced from one of the many suppliers and Ford boxed. I am always looking for 11A-prefix thermostats,to test .Ebay has one on now,11A-8575-C but the "C" means it is for a non pressure cap and I am using a 4lb cap.The one I am looking for is "B", stated for use with pressure. Anyone know if a specific supplier made these thermostats?