Road Test of Stant vs. Shewman Thermostats

[Old Henry]

I wasn't really interested enough in such a comparison to do it but have received several repeated PM requests to repeat the test I did last year comparing no thermostats to Stant thermostats (here: https://www.fordbarn.com/forum/showthread.php?t=113979) but this time comparing Stant thermostats to Shewman's "High Flow" thermostats. So, I did it exactly the same way I did it last year but on two consecutive days rather than a few days between. The ambient temperature on the first day when the Stant was tested was 92° and on the second when Shewman's was tested 90°. The details of the test are otherwise described in last year's thread referenced above. The data from the test is in the attached PDF file. Hopefully VeryTangled will graph them again for us like he did last year.

The data confirms what I predicted about Shewman's stats last year here: https://www.fordbarn.com/forum/showthread.php?t=112889 Post # 85. Because Shewman's stats do not completely shut off the water flow when closed the engine takes much longer to warm up to proper operating temperature (3 miles/7 minutes longer) and that operating temperature is not maintained (it drops 40° below the stat setting) when going down a long descent with no throttle. (Many have not even been able to get their engines up to operating temperature in the winter with Shewman's stats. See here: https://www.fordbarn.com/forum/showthread.php?t=121447) Then, on the other end, because Shewman't stats have a much lower flow than the Stants when fully open (33% less) they allow the engine temperature to raise much higher faster than the Stants, up to 10° higher. That is enough difference to boil or not boil over (and was for me). One other big difference - the Stant stats are $18.00 a pair compared to Shewman's at $50.00 per pair. I'll be putting the Stants back in.

NOTE: THIS TEST WAS ONLY OF SHEWMAN'S STATS FOR THE 59A ENGINE NOT THE ONES FOR THE 8BA.

Here is the graph of the data later created by VeryTangled with his graph of the elevations he made last year added by me and the numbers re-aligned by 51 MERC-CT to read a little easier.

[Ross F-1]

Nothing like real data, thanks! I've had no issues with the Stants.

[34PKUP]

Originally Posted by Ross F-1

Nothing like real data, thanks! I've had no issues with the Stants.

"THIS TEST WAS ONLY OF SHEWMAN'S STATS FOR THE 59A ENGINE NOT THE ONES FOR THE 8BA"
Really?

[Old Henry]

Originally Posted by 34PKUP

"THIS TEST WAS ONLY OF SHEWMAN'S STATS FOR THE 59A ENGINE NOT THE ONES FOR THE 8BA"
Really?

Really. Although they both start with the same stat, they are modified very differently for the two different applications. What Shewman has done is taken the Robertshaw 330 stats, that are perfect for the 8ba engine, and drilled holes in them for that engine which is most likely going to make it run cold in the winter and adds nothing for the summer since, once the stats open in an 8ba, the water flow is unlimited by the stat. Then, for the 59A, since the stats mount differently than for the 8ba, he trimmed off the stat flange, after drilling the holes in it, and brazed a tube onto it to hold it in the upper radiator hose just where it goes into the radiator. That's the real rub since the cup that moves out of the way of the water flow in the 8ba just stays in the way in the hose of the 59a. Two very different applications for which Shewman tried to make one thermostat work.

So, for allowing the highest water flow at high temperatures in the 59a, Shewman's stats can't be beat. For fast warm up, particularly in cold weather, the stock Robertshaw (without the holes drilled in it) would be better. For 59a, Shewman's stats have no advantages, only disadvantages.

[Old Henry]

Later today did a 150 mile round trip to Mirror Lake climbing up over 10,000 feet. On the way down the Shewman stats let the engine get clear down to 120° for the 30 miles coming down the mountain, 60° below their rating of 180°, the temperature that they opened when tested before installing them. So, the holes drilled in them really do defeat the purpose of a thermostat.

[JM 35 Sedan]

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Sorry....but with all the previous posts on the mechanical and electrical issues with this test vehicle and some of the "fixes" that were made, plus the previous negitive posts that were made by this same person about Skip Haney's and Bob Shewman's products, I would not rely 100% on these test results. Of course this is just my opinion

[JWL]

Well, as they say in the movie "Used Cars"---this "blows the hell out of those high prices".

[V8COOPMAN]

Originally Posted by JM 35 Sedan

Sorry....but with all the previous posts on the mechanical issues with this test vehicle and some of the "fixes" that were made, plus the previous negitive posts that were made by this same person about Skip Haney's and Bob Shewman's products, I would not rely 100% on these test results.

Thank you, thank you, thank you!

Could not have said it any better. DD

[VeryTangled]

Chart

[Old Henry]

Originally Posted by JM 35 Sedan

Sorry....but with all the previous posts on the mechanical issues with this test vehicle and some of the "fixes" that were made, plus the previous negitive posts that were made by this same person about Skip Haney's and Bob Shewman's products, I would not rely 100% on these test results.

. . . not to mention the very few actual miles the person drives his vehicle.

It's pretty easy to criticize without any contradictory data or even personal experience. Not very persuasive though.

If you don't have any way to refute the message all you're left with is to kill the messenger.

It doesn't take a rocket scientist to do exactly the same thing twice, changing only one thing, record the data and report it. Interpretation of the data may vary but the data itself are facts that can't be disputed.

[Old Henry]

Thanks to VeryTangled for graphing the test results for us. I added his graph of the elevations he made for the identical test last year and the numbers were re-aligned by 51 MERC-CT to read a little easier.

[gearhead1952]

The graph does not look right to me as the bigger numbers should be on top all the way along.

[Old Henry]

Originally Posted by gearhead1952

The graph does not look right to me as the bigger numbers should be on top all the way along.

[Numbers rearranged by 51MERC-CT] The numbers for the Stant are above its line and the ones for Shewman's below. So, when Shewman's line goes above the Stant line the numbers look upside down but are still in the same orientation to their line as for the entire graph.

[bobH]

Old engineer's 'creed'... If you have something that is working well, and you try to make it better, if you screw with it long enough, eventually you will f**k it up.

I ran this same test several years ago, on another engine (the other brand, sbc350). It's a vehicle/engine that has always had overheating problems during the 40+ years that I've owned it. I got exactly the same results. Stock stat went back in.

[VeryTangled]

Hi Everyone, gearhead1952, I agree. [edit: Oops I see Prof. Henry beat me to the comments.]

The numbers below the data point are for the Yellow/Shewman's stats. Numbers for the Magenta/Stant are above the data point.

Because the lines cross in a couple of places, the numbers where they cross look weird. A good example is the last two points. The yellow is 189 and the magenta is 182.

[51 MERC-CT]

Originally Posted by VeryTangled

Hi Everyone, gearhead1952, I agree. [edit: Oops I see Prof. Henry beat me to the comments.]

The numbers below the data point are for the Yellow/Shewman's stats. Numbers for the Magenta/Stant are above the data point.

Because the lines cross in a couple of places, the numbers where they cross look weird. A good example is the last two points. The yellow is 189 and the magenta is 182.

Is this a little better?

[gearhead1952]

Originally Posted by VeryTangled

Hi Everyone, gearhead1952, I agree. [edit: Oops I see Prof. Henry beat me to the comments.]

The numbers below the data point are for the Yellow/Shewman's stats. Numbers for the Magenta/Stant are above the data point.

Because the lines cross in a couple of places, the numbers where they cross look weird. A good example is the last two points. The yellow is 189 and the magenta is 182.

Gotcha, thanks for the clarification.

[FlatheadTed]

The statement . So, the holes drilled in them really do defeat the purpose of a thermostat I go along with .The idea of a thermostat is it opens and shuts to maintain and maximise working tempt ,From my experience you only need to drill one hole in it to screw up its function ,Ted

Originally Posted by Old Henry

Later today did a 150 mile round trip to Mirror Lake climbing up over 10,000 feet. On the way down the Shewman stats let the engine get clear down to 120° for the 30 miles coming down the mountain, 60° below their rating of 180°, the temperature that they opened when tested before installing them. So, the holes drilled in them really do defeat the purpose of a thermostat.

[Mart]

The results look pretty convincing to me, I use stock type 'stats in mine, with a very small hole drilled to allow filling and air purge.

When I say stock they are the common type found on UK Minis and the like from the sixties.

Mart.

[flatjack9]

Common sense prevails here.