NAPA and Stant stats for 59A

[Old Henry]

Just read an old post on the H.A.M.B. that said a NAPA THM 111 and Stant 14157 thermostats work in the 59A engines. The pictures look a little higher volume than what C&G, Mac's and others sell. Anyone have any experience with them?

[51 MERC-CT]

No experience but sure looks like it's worth a shot.
Surprised to see that a 90's vintage Subaru used a stat that's only 170 deg.

[G.M.]

I have experience with Napa 111 stats and wrote several posts years ago that they don't work in hot weather even with 6 or 8 holes drilled in the flanges. They even made Mr. cool my 39 P/U that won't get over 180 on a 100 degree day run at 200 going down the road. The only modern stats for 32 to 48 Fords that work in hot weather are from Bob Shewman [email protected]. G.M.

[Old Henry]

Originally Posted by G.M.

The only modern stats for 32 to 48 Fords that work in hot weather are from Bob Shewman [email protected]. G.M.

Yes, I would expect they would work well in hot weather since they're riddled with holes to increase the flow when opened or closed but how about cold weather, like 0°? Have they been tested at that temperature to see if they will warm a 0° engine up to operating temperature? As you know, thermostats have nothing to do with cooling the engine, only with warming it up. So, how do they do warming up a 0° engine compared to a thermostat that actually shuts off the water flow completely?

[Automotive Stud]

I have the 111's in my 59a. I might have even been the one on the hamb to post about it. I can tell you after being on the road for 4-5 years now I haven't had any problems. If anything it still runs a little cooler than I'd like in colder weather, but it's great in the summer. Never got above 180 driving in the 95+ degree heat a few weeks ago.

[Old Henry]

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Went down to O'Reilly's and compared the 111's to what is now being sold for the 59A. (NAPA didn't have one in stock) Looks like the 111 is a higher volume to me. What do you think?

Current replacement on the left. Stant 14157, aka NAPA THM 111, aka O'Reilly's some other number on the right.





The 48 mm on the Stant is equal to 1 7/8" - exactly the outside diameter of my head neck. The rubber gasket can be removed but may not be a bad idea for keeping the stat from "floating" up as they tend to do. AND, the BIG BONUS (for those who really care) - look where it's made!!

[51 MERC-CT]

As stated in other post, stick em' in a pan of boiling water and compare them when the valves are open.

[Old Henry]

Originally Posted by 51 MERC-CT

As stated in other post, stick em' in a pan of boiling water and compare them when the valves are open.

As stated in other post, will do, IF I buy them. I didn't have my camp stove to perform the test on O'Reilly's counter where the pictures were taken. I did measure the openings and the Stant opening was larger than the other so should be higher volume.

[G.M.]

Henry I have a deal for you. I know you don't want to spend money for stats that work but are willing to blow money on Napa 111 stats. Save you money, give me your mailing address and I will send you FREE 2 Napa 111 170 degree stats with 8 holes in the flanges.
You deserve to have them for all your research in this area. G.M.

[Old Henry]

G.M. I appreciate your offer and your concern but I don't think you understand my unique need in the way of a thermostat. I don't just drive my car on the beach in balmy weather like those in your part of the country do. I drive my car all year 'round at all elevations from 262 feet below sea level at the bottom of Death Valley to 14,256 feet at the top of Mt. Evans and from 0° in the middle of the winter here in Utah to 100+ degrees in the middle of the summer here, and that is while climbing mountains. I'm quite sure that a thermostat riddled with holes would be fine for the hot temperatures you drive in but I'm looking seriously for a thermostat that will work at all of the temperatures, all of the seasons, and all of the elevations that I drive year 'round without having to ever change them or remove them for any drastic change of circumstances. That's why I'm trying so hard to find a high volume "real" thermostat that will totally close off all flow at 0° to get me some quick heat in the dead of winter as well as have higher than stock flow in the heat of the summer climbing the highest mountains. Price is not an issue. When I find what I'm looking for I won't care what it costs. Overheating in the summer and freezing in the winter are worth any price to avoid.

So, thanks but no thanks on the "holey" stats offer.

[Old Henry]

Bought the Stant stat today and heated it up with the current replacement and here's what I learned.

Looking up through open stats.



Looking down through open stats in the water.


Just the appearance should convince of the higher flow of the Stant stat. If not, here's the data: The diameter of the opening above the valve for the water to pass through (the sharp metal edge) is 25 mm for the brass and 28 mm for the Stant. That alone is a 25% increase in space for the water to go through. The diameter of the valve plates is 27.5 mm for the brass one and 29 mm for the Stant. But, once that valve is out of the way that difference doesn't matter so much. The difference that really matters in the 25% larger opening of the Stant stat. Then you have the issue of the space above the valve seats that the water must pass through. That's where the biggest difference is as you can see in the pictures. Just eyeballing it I don't think the total area of the openings above the valve seat on the brass one is even equal to the area of the valve seat. So, the real restriction in the brass one is those openings that are so small. Whereas, as can be seen in these and the previous photos, there really isn't any restriction above the valve seat in the Stant stat. Those openings are clearly bigger than the area of the valve seat.

So, my analysis suggests that the Stant stat has at least 25% higher flow than the standard brass ones now being sold for the 59A engines and likely even higher. To increase the volume of the brass stat to that of the Stant one you'd have to drill thirteen 1/8" holes in the space between the valve plate and the inside of the head neck, if you could fit them in there. But then, of course, you'd have a defective and pretty much worthless thermostat. And, the Stant stats are 30% cheaper than the brass ones - $7.00 from most suppliers compared to $10.00 for the brass one.

[51 MERC-CT]

The 12% sounds good but if you calculate the area of the openings you will find it to be more in the 25% range not counting the severe restriction on the brass one, then it looks more like 35-40% if not more.

[Old Henry]

Originally Posted by 51 MERC-CT

The 12% sounds good but if you calculate the area of the openings you will find it to be more in the 25% range not counting the severe restriction on the brass one, then it looks more like 35-40% if not more.

My calculations were as follows:

For the Brass stat: 12.5 mm radius X pi (3.14) = 39.25 sq mm

For the Stant: 14 mm radius X pi = 43.96 sq mm

The difference in area is 4.71 sq mm

That difference of 4.71 sq mm is a 12% increase over the Brass stat's area.

Did I miss something to get to your 25%?

[51 MERC-CT]

Originally Posted by Old Henry

My calculations were as follows:

For the Brass stat: 12.5 mm radius X pi (3.14) = 39.25 sq mm

For the Stant: 14 mm radius X pi = 43.96 sq mm

The difference in area is 4.71 sq mm

That difference of 4.71 sq mm is a 12% increase over the Brass stat's area.

Did I miss something to get to your 25%?

Area= Pi X R squared

[Old Henry]

Originally Posted by 51 MERC-CT

Area= Pi X R squared

Ah . . .

I wondered why the difference in area was the same as the difference in diameter. I knew I was missing something. I just redid my calculations and they came out right at 25.44% increase in area of the Stant over the Brass stat. All the better. I've revised my original report.

[Talkwrench]

Good work.. So the Stant no. Is 14157 when ordering. What is it 160, 170,180?
Might try getting some through rockauto...

[johnny]

To GM, A stat does two things 1 it opens at a pre set temperature 2 it then allows the liquid to flow through a given opening. If the opening is larger in B ,than in ,A and if it opens when it should ,how can it be no good .Also the maker of stat A does not have 160. which is much better for general use,especially for the flat heads that have the fan on the end of the crank. The 180 was used for winter in cold climates . I think you might be wrong on this one Johnny.

[Old Henry]

Originally Posted by Talkwrench

Good work.. So the Stant no. Is 14157 when ordering. What is it 160, 170,180?
Might try getting some through rockauto...

Yes. Google Stant 14157 and you'll find oodles of sources.
The stat is only made 170°.

[flatjack9]

A 160 deg stat is not better than a 180 deg stat. Just the opposite.

[Old Henry]

Originally Posted by flatjack9

A 160 deg stat is not better than a 180 deg stat. Just the opposite.

In the owner's manual for my 47 it says to use a 160° thermostat. That's why I've always used that one and avoided going to the 180° one. I won't mind the 170° Stant one though.