Shewman's High Flow Thermostats

[Old Henry]

I've still got a little heat problem and was considering installing Bob Shewman's "high flow" thermostats. He sent me some photos



but they really didn't show very well how they worked so I just called and talked to him about them so that I could understand what makes them higher flow than the standard stock syle thermostats now available for our flatheads. I thought maybe it had a butterfly valve that folded up and moved clear out of the path of the water to increase the flow or something else more "magical". What he told me was that he bought 400 military surplus 180° thermostats that work the same as the standard ones with a valve surface that opens and closes by a spring heating up and cooling the same as the others. He soldered a bushing around the tubular stat to make it fit tight in the flathead upper hose and drilled holes through the control valve to let more water through. That's it. So, it looks like to me that his "high flow" stats are nothing more than standard thermostats with a bunch of holes drilled through the control surface to increase the flow. Of course, that increases the flow both when the stat is open and when it is closed, which, in the winter may not let the engine warm up to temperature at all. All things considered, for $50.00 per pair, looks like I could drill holes in the stats I've already got and get the same benefit/detriment. Not condemning, just informing.

Note. This is for the 32-48 stats. The ones he sells for 49-53 are different. I did not discuss those with him.

[ford38v8]

Henry, Why not leave out your thermostats altogether and use a radiator cover till the engine warms up in the morning?

Or... you could install a pair of big brass gate valves with shiny red handles!

[Old Henry]

Originally Posted by ford38v8

Henry, Why not leave out your thermostats altogether and use a radiator cover till the engine warms up in the morning?

I've tried that. I'm not vigilant enough to watch the temperature gauge to know when to stop and take the cardboard out so I end up overheating in the winter. As I've said in response to this same suggestion before, the way I drive climbing up the steep side of a mountain and then down the other steep side, I'd have to be vigilamt enough to remember to stop and take the cardboard out at the bottom of the mountain and then stop again and put it back in at the top not to mention all of the shorter but still lengthy ups and downs on both sides. I don't like to see my temperature gauge go from 200 to 100 in a matter of minutes - can't be good for the engine I wouldn't think. So, I opted for Henry's idea - thermostats. Crazy idea I know but there you have it.

The manual valves would be even more work than the cardboard.

[52merc]

well you wont stop the temp going from 200 to 100 when you have been climbing working the engine then coming down the mountain the air will cool the radiator down you are fighting a losing battle against science

[Old Henry]

I actually tested it and that is not correct. The thermostat does, in fact, keep the engine from cooling down below the thermostat setting.

[russcc]

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Drilling relief holes in t-states is an old time solution that helps them open sooner, and at the same time flow more.

[51 MERC-CT]

It may be possible to modify the later high flow thermostat to fit inside the 59AB hose.

[Bill S]

I was driving around today out side temp got up the 75 and the Ford temp was a little under 1/2 way. No problem over heating.

[jdl]

Robertshaw # 330 is for the 49-53 Fords and others, I have been running the same pair of original Robertshaw t-stats for many years.

I don't know if there is a number for the earlier V/8's


link below could be a repop of the originals? (19.99 ea.)

http://www.flowkoolerwaterpumps.com/...c22/index.html

[flatjack9]

A little grinding on the OD of those thermostats and they fill fit the early engine just fine.

[L78CHEVELLE]

Many years ago I purchased some thermostats for the 48 back flathead engines that have a dial to set the opening temperature at 140 up to 190. With my '40 I set the dial on the thermostats at 140 year around. In KY my car runs 160 in the winter time and 160 to 180 in the summer. No holes drilled or changes to the original design. They fit in the heads and I think the brand name is Doyle. Maybe wrong about the name since I put them in about 2 years ago. The 140 gives a very good range and will not let the engine drop below 140 at any time after the engine warms up above the 140 mark. I have Carpenter new design water pumps on this particular '40 I'm referring to.

[41ford1]

Originally Posted by ford38v8

Henry, Why not leave out your thermostats altogether and use a radiator cover till the engine warms up in the morning?

Or... you could install a pair of big brass gate valves with shiny red handles!

Originally Posted by Old Henry

I've tried that. I'm not vigilant enough to watch the temperature gauge to know when to stop and take the cardboard out so I end up overheating in the winter. As I've said in response to this same suggestion before, the way I drive climbing up the steep side of a mountain and then down the other steep side, I'd have to be vigilamt enough to remember to stop and take the cardboard out at the bottom of the mountain and then stop again and put it back in at the top not to mention all of the shorter but still lengthy ups and downs on both sides. I don't like to see my temperature gauge go from 200 to 100 in a matter of minutes - can't be good for the engine I wouldn't think. So, I opted for Henry's idea - thermostats. Crazy idea I know but there you have it.

The manual valves would be even more work than the cardboard.

Back about 1960 a neighbor had a '57 brand X that he brought down from Canada. A heavy material roller shade was fitted to the front of the radiator. A system of pulleys allowed the pull cord to be run in to the passenger compartment. This arrangement allowed full control of the air flow through the radiator by the driver. Sort of like a manual version of the radiator dampers on diesels.

[mike42]

Where do you drill relief holes ?

Thx.....Mike

[ken ct]

Originally Posted by L78CHEVELLE

Many years ago I purchased some thermostats for the 48 back flathead engines that have a dial to set the opening temperature at 140 up to 190. With my '40 I set the dial on the thermostats at 140 year around. In KY my car runs 160 in the winter time and 160 to 180 in the summer. No holes drilled or changes to the original design. They fit in the heads and I think the brand name is Doyle. Maybe wrong about the name since I put them in about 2 years ago. The 140 gives a very good range and will not let the engine drop below 140 at any time after the engine warms up above the 140 mark. I have Carpenter new design water pumps on this particular '40 I'm referring to.

L78,the brand you are thinking of is "DOLE" / they made many Therm back in the day. ken ct.

[oldskool]

I have a pair of mr gasket thermostats that fit in 49-53 housings,they are made for racing ,160 or 180 looks like bobs to me

[Terry,OH]

I could not get my 35 engine over 140 without stats, I now have Roberts and run 180-190 driving very hot days. The only problem I encountered was a small bit of overflow when the stats opened due to surge of coolant to the tank. Took coolant level down a bit and no more overflow. I do not run a pressure cap and the overflow tube is not blocked. I'm happy.

[G.M.]

Terry you need Skips 3 lb pressure valve on the bottom of the over flow tube. Running with a low water levels decreases the amount of coolant in the system causing higher operating temperature. It is a 22 quart system not 17. G.M.

[Old Henry]

Originally Posted by 51 MERC-CT

It may be possible to modify the later high flow thermostat to fit inside the 59AB hose.

I like your thinking. If I do anything different that's probably what I'll do.

[donald1950]

on my 59 motor in my 41 PU, i took prestone 180 degree super stats, ground the outside down a litttle so they were slightly larger than the outlet of the head and so when i pushed the hose down over the stat and outlet neck on the head and clamped the hose, the stat never moved and i was able to use modern stats. they had enough flow that i only had it heat up at idle with low airflow through the radiator..... don

[john in illinois]

Thermostats for model A's are made with modern thermostats ground down as pictured above. They have an 1 3/4 " thin tube tig welded to the rim to stabilize the unit in the hose. Don't know if this would flow enough for a V8.



John

[51 MERC-CT]

Originally Posted by john in illinois

Thermostats for model A's are made with modern thermostats ground down as pictured above. They have an 1 3/4 " thin tube tig welded to the rim to stabilize the unit in the hose. Don't know if this would flow enough for a V8.John

Seriously doubt that these would be sufficient.
There is a considerable difference between a standard stat and a high flow stat.

[FlatheadTed]

I made these up and ran these in a flathead, in the summer I took them out as my radiator is marginal .With the shroud I now run or a better Radiator I think they would work fine .One hole is enough ,more holes than that I would think it would defeat the purpose of a thermostat.

[Old Henry]

51 MERC-CT, Don't know how you figured the inside diameter of the Robert Shaw 330 that would be left after trimming off what could be trimmed but what do you figure it for the 370 high flow? Could it be made to fit my 59A?

[jdl]

Pictures are of a original Stant 330 from the 1960's just adding to the info:

[jdl]

Outside dia of rim 2.125.. inside dia of stat 1.567

[Old Henry]

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I think I see now how this type of thermostat works and why it probably would not work in my 59A. This style is made for the bottom to sit in a large space with the water surrounding it rather than in the neck of the 59A head where the water has to pass by the "cup" on the bottom. It works great for the first environment because when the cup is lowered the water flows unobstructed over it and through the stat. But, in the neck of the 59A head the cup would be obstructing the flow of water unless it extended down into the more open area below the neck. If the cup sat in and then lowered into the narrow neck it would be blocking the flow of water that would have to pass around it on the sides in the narrow space between the cup and the sides of the neck.

Darn, I thought I had something there that would be an improvement for my 59A. I guess that's why that style of stat is not sold for the 59A heads.

[51 MERC-CT]

Originally Posted by Old Henry

I think I see now how this type of thermostat works and why it probably would not work in my 59A. This style is made for the bottom to sit in a large space with the water surrounding it rather than in the neck of the 59A head where the water has to pass by the "cup" on the bottom. It works great for the first environment because when the cup is lowered the water flows unobstructed over it and through the stat. But, in the neck of the 59A head the cup would be obstructing the flow of water unless it extended down into the more open area below the neck. If the cup sat in and then lowered into the narrow neck it would be blocking the flow of water that would have to pass around it on the sides in the narrow space between the cup and the sides of the neck.

Darn, I thought I had something there that would be an improvement for my 59A. I guess that's why that style of stat is not sold for the 59A heads.

And still here's another thought

[Bluebell]

So how do you get it in and out?
Good thread!

[51 MERC-CT]

Originally Posted by Bluebell

So how do you get it in and out?
Good thread!

Split with two flanges (left off for clarity) Have to leave something for the imagination which seems to be harder and harder to find.

[ford38v8]

Bluebell, you soak it in vinegar first, then it should suck right in there like a raw egg.

[Old Henry]

So, here's the rub:

The inside diameter of the 59A radiator hose neck is 1.5+"



The outside diameter of the cup on the smaller 330 Robert Shaw stat is 1.567"



Probably would not even fit inside of the neck. Even if it did, the problem is that the water must flow around the cup of the thermostat and over the top edge of it before it can go through the opening. Although there appears to be some possible passages in the bottom of the cup they would not be sufficient. So, no Robert Shaw stat will work in the 59A. Darn.

[flatmotor40]

Will not work on Offy heads inside dia of heads has to be ground out.Have to use standard thermostats and grind od to fit under hose

[Old Henry]

From another related thread:

Went down to O'Reilly's and compared the NAPA 111 thermostats 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]

Put em' in a pan of boiling water and compare them with the valves open.

[Old Henry]

Originally Posted by 51 MERC-CT

Put em' in a pan of boiling water and compare them with the valves open.

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.

[Old Henry]

Just in case anyone thinks I'm getting a bit fanatical and obsessed with finding the right thermostat (as I think G.M. just suggested in a related thread) here is my response in that thread to his offer to send me some free NAPA 111 stats with 8 holes drilled in them.

"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."

[G.M.]

Henry you are not going to find any modern stats that fit in the top of the heads in the water outlets that don't greatly reduce the flow and cause hot problems in hot weather. To get the full flow the stats need to be mounted in the hoses on 32 to 48 years. There are two problems one is securing the stats in place and the stat clearing the ID of the hose. With hose mounted stats they are away from the hot water in the engine with water backed up in the hose behind the stats. To make the in hose stats operate faster on warm up a small amount of water is bled through the stats. To prevent problems with the stats moving in the hose Bob's stats are located in the top of the hoses and sit against the brass radiator inlet tubes staying in place. I have 4 sets in various Fords and they work perfect in all temperatures from 50 to 95 degrees. A lot of others use Bob's stats and have worked for them also in colder weather than I drive in. As far as distance traveled I have put 115.000 miles on my 39 convertible on a lot of trips driven at 65 MPH for 2 10 hour days. Plus other old Fords I put a lot a lot of miles on. 39 P/U from Florida to Nova Scotia and back plus used it as a daily driver for a few years. Get a set of Bob's stats and if they don't work send them back. G.M.

[Joe AZ]

Just another thought on this..........when I was young, growing up in Minneapolis, it was common for us to exchange thermostats between hot and cold weather. Henry.....maybe there's not a perfect answer for "year round" use. Maybe you need to consider switching stats for the season.......JMO
Joe

[Old Henry]

Joe, you might be right. I actually tried that for a couple of years - took the stats out in the summer and back in in the winter but I got tired of it and my engine doesn't run well if it isn't kept at normal operating temperature in the summer. So, I continue my quest for the ideal solution which is not Shewman's concoction. With all that I've read about overheating problems I have a suspicion that my engine block may well have some casting sand in it blocking some passages and that may be why I have a little more trouble keeping it cool than others do. If that is the case there may not be a "stat for all seasons" that will work for me. Time will tell. I continue my quest. Thanks for your response.

[dude]

I could be wrong,but the idea behind drilling holes in the stat is to allow the air to burped out when filling the radiator. It really has nothing to do with the performance of the stat.
The newer stats (because of their size) don't allow you to drill holes around the outside.

[Old Henry]

If you look at the picture of the thermostat currently being sold for the 59A engine (post # 33) you'll see what's called a "jiggle plug" that falls down to let the air through when filling the engine



then lifts up to block that little hole when the engine is running.



The Stant stat next to it, which is for a 1990 Subaru Justy among other modern cars, doesn't have that and would probably need a little hole to let the air through when filling. I believe that the holes drilled in these thermostats to increase flow are drilled all around that same surface that the jiggle plug is in. There is no where else to drill them. But, the mere fact that whoever designed and built this thermostat went to the effort to create a way to plug that one little hole when not needed for filling shows how important it is for the stat to close off entirely to work properly and how adding holes defeats the purpose of the thermostat.

G.M. and Bob Shewman swear that drilling a bunch of holes in thermostats lets more water through and makes them better for hot weather. That's probably true but it defeats the purpose of the thermostat in cold weather or a long descent from a high mountain in hot weather.

[flatjack9]

Keep up the quest Old Henry. I'm pulling for you. Drilling holes all around the thermostat to make it high flow is a joke.

[Old Henry]

Originally Posted by flatjack9

Keep up the quest Old Henry. I'm pulling for you. Drilling holes all around the thermostat to make it high flow is a joke.

And that from a guy with a mechanical engineering degree that worked for 9 years designing and testing gasoline engines. Got to carry some weight.

Thanks.

[Old Henry]

Here's what all modern thermostats are competing against - Ford's original design.



These are NOS Ford stats for my 47 that a very kind barner has offered to sell to me. Just compare them with the modern stats and you'll see the real advantages of them. They have a butterfly valve that swivels clear out of the way of water flow. And, look at the size of that hole once it's opened up! Way bigger than any modern stats. And, the mechanism that opens it is small and much less intrusive into the water flow than modern stats. This is what I've been looking for and believe that, if they still work (I'll test before installing), they will work better than any modern substitutes for those reasons.

[VeryTangled]

Wow that is GOLD.

Having a good time following this thread and learning a lot.

Prof. Henry, is there any chance you can post more photos when you get them? I'd be especially interested in seeing one in the open position.

I'd also be interested in their opening temperature, and their closing temperature. It seems you will be interested in them closing correctly as the fluid cools on descent, preventing the temperature from dropping into an abnormally cool operating range, after being open during ascent. As I read it this is one of the areas you're looking for to get good performance.

-VT/JeffH

[Old Henry]

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I will give a full report with pictures upon receipt of them.

[ken ct]

Hope they work.If they do you better put that Barner on your yearly Christmas List.He has some generosity in droves. Good luck. ken ct.

[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.

You're correct. I fixed my error in my post.

Thanks

[Bluebell]

So having come this far, Just how much flow is required, and why do much bigger engines (of much higher hp output) function well with half as many thermostats? (I know about the ex. ports)
How many gallons per minute will flow through the standard stat, fully opened? and how many gallons per minute are required to meet the needs to sufficiently cooling the FHV8?

[Talkwrench]

Bluebell I was thinking the same thing...

[Old Henry]

Originally Posted by Bluebell

So having come this far, Just how much flow is required, and why do much bigger engines (of much higher hp output) function well with half as many thermostats? (I know about the ex. ports)
How many gallons per minute will flow through the standard stat, fully opened? and how many gallons per minute are required to meet the needs to sufficiently cooling the FHV8?

I don't know all the answers but I'll take a stab at a couple.

The only reason the flathead has two stats is because it has two water outlets, one for each side of the engine. Modern engines of any size do not have two separate sides like the flathead as far as I know. I suppose if you connected the two water outlets together with a pipe that size and had an even bigger hose to the radiator you could get by with one stat going from the T into the single hose.

As far as actual flow needed to adequately cool a flathead, I wouldn't think there is one number. It depends on how hot the fire is in the engine. Very little flow is sufficient at slow speeds on even ground but a much larger higher flow is needed going at high speed up a hill. Anything less than ideal conditions of the engine block and/or radiator is going to require even more flow to make up.

My 2¢

[Bluebell]

As JWL elluded to previously. The stat effectively stops or limits the water flow through the radiator until the stat begins to open (say 180F) it is fully open at say(200F)
These stats shown so far are all wax type stats. The wax expands to open them and contracts to close them. This is an action governed by the laws of physics.
They are reliable. If your engine is fitted with them with no extra holes drilled in them, they will not begin to open until the water on the wax pellet side of the stat reaches the designed temp. Your engine CAN run colder under extreme external conditions, but for most of you in the lower states your minimum operating temp is governed by the opening temp of those stats. This is good.
At the other end of the spectrum, conditions COULD be such that there is not enough differential between ambient temp and boiling point. I don't know how close these two temps can be, but it's going to be pretty hot.
In these circumstances your stat is going to be wide open, and I doubt that flow though the stat is going to be the limiting factor.
The point really is that most (I said most) people will have other issues with there vehicles, be it a dirty cooling system, loose belts, timing, (who always has their engine perfectly timed?) brakes dragging, fuel mixture,under inflation(tyres) and possibly a whole bunch of other things including up specing.
All of these things have to be 100% right, before we blame the thermostats.

Is Bob S. a member and can he give us a run down on any research he might have done?
Does anyone have any flow specs?

[Old Henry]

Originally Posted by Bluebell

Is Bob S. a member and can he give us a run down on any research he might have done?
Does anyone have any flow specs?

Bob Shewman is not a member as far as I know, at least I've never seen him ever comment on here about his stats, only G.M. He does have an email address: [email protected] and does answer his phone or return calls, at least he did mine and answered all of my questions. Apparently G.M. had something to do with development of Shewman's thermostats and may chime in here with any test results he did. Knowing now how Shewman's stats are made, the test I'd be interested in is how long it takes to get up to operating temperature with his stats at 0° and how low his stats let the engine temperature go on a long descent down a mountain. That's where I have my real doubts about them.

[Old Henry]

Originally Posted by Bluebell

The point really is that most (I said most) people will have other issues with there vehicles, be it a dirty cooling system, loose belts, timing, (who always has their engine perfectly timed?) brakes dragging, fuel mixture,under inflation(tyres) and possibly a whole bunch of other things including up specing.
All of these things have to be 100% right, before we blame the thermostats.

I totally agree with you. Even taking out stats is not going to fix a serious problem somewhere else. But, a good high flow thermostat might make up for some other weaknesses in the system to a certain extent. That's the only reason I've spent so much effort studying them.

[Bluebell]

Henry, I wouldnt publish his number in this public place.

I agree with your line of thought. I have enjoyed your postings. the photos make a big difference.

[Old Henry]

Originally Posted by Bluebell

Henry, I wouldnt publish his number in this public place.

Fine. I took it out.

[G.M.]

Originally Posted by Old Henry

Bob Shewman is not a member as far as I know, at least I've never seen him ever comment on here about his stats, only G.M. He does have an email address: [email protected] and does answer his phone or return calls, at least he did mine and answered all of my questions. Apparently G.M. had something to do with development of Shewman's thermostats and may chime in here with any test results he did. Knowing now how Shewman's stats are made, the test I'd be interested in is how long it takes to get up to operating temperature with his stats at 0° and how low his stats let the engine temperature go on a long descent down a mountain. That's where I have my real doubts about them.

I did extensive testing on gadgiteers stats in 40 to 100 degree temperatures and have been using them over 2 years. I'm talking about every day for 3 or 4 months with the same 20 mile drive to lunch, engine sitting for 30 or 40 minutes take temp, starting and return back to the shop. I don't just drive around the block and start talking how great something works, I test it for months before I mention it. I have at times posted things I was testing with the new gas problems. I jump out every time as soon as I stop and take measurements on the heads at the water outlets 1/2" below the top hoses. This is the output of both sides of the engine which are separate cooling systems not connected in the engine. The water in the top radiator tank is a mixture of both sides of the engine this temperature is a mixture of both sides and will not tell you if one side of the engine gets hot. EVERY time I took temperatures both sides of the engine were within 2 degrees of each other on 3 different engines and I still check once in a while. One real benchmark in testing for cooling or heating in this case is my 39 P/U Mr Coool that has Skips pumps, anti freeze, Purple Ice, a 6 bladed industrial fan, 4 lb pressure cap, water filled up to the neck of the filler opening and a shroud. This engine sat at a fast idle in 100 degrees at a EFV8 national show for over 2 hours and never got to 180 and when raced slightly the temperature came down a few degrees. With Napa 111 stats and 8 holes in each flange on a 90 degree day this same truck ran at 195 driving due to a restriction of water flow from the restrictive openings in the 111 stats. These are the same stats that I ran across the other day that I offered to you which the offer is still open. I have a collection of old and new stats I purchased over the years trying to find stats that worked. My posts are based on actual tests and the results not on what I think should or will happen. I found out years ago these WAGS (wild ass guess's) on what I thought would work didn't always work. I made a lot of impellers for Skips pumps testing each on a water pump test machine and in 5 minutes find a weeks work was a waste of time. As soon as I put the turbine impeller on the machine in 5 minutes I saw it pumped almost double the water than any pump we ever tested. Even without two pumps to test on an engine I had patterns made and castings were ordered. Skip worked for me on my collection of old Fords for over 20 years and I gave him the coils, pumps and pressure valves as his own project I have no financial interest. The same with Bob Shewman he ran the machine shop in my manufacturing business until we both retired. I developed the flex hose, vented carb spacer and the thermostats for Bob and did all the testing and worked out production problems with him. I have no financial interest in Bob's business either. Both Bob and Skip are quality oriented and every part is tested before shipping. Skip tests every pump, coil and distributor and Bob hot water tests every thermostat to make sure they open in the proper range before shipping. Both stand behind their products and have repaired any problems no matter how long the part was in service at no charge. I do know in 40 to 50 degree weather the engines come up to 180 in 4 or 5 miles with no pre warm up. What they do at zero I don't know. Like I said before get a set of Bob's stats and if they don't work return them for a full refund. G.M.

[Old Henry]

Originally Posted by Bluebell

I have enjoyed your postings. the photos make a big difference.

Pictures save a lot of words (such as in post # 59). It would be interesting to see such close-up detailed shots of Shewman's stats to see what they're really like. I can only imagine.

[VeryTangled]

Hi Everyone,

I found a "how it's made" type video on thermostats on Youtube. I learned some about the wax and how the melting wax causes the opening and how the spring causes the closing.

https://www.youtube.com/watch?v=xVPtIi6sVYg

-VT/JeffH

[Old Henry]

Originally Posted by VeryTangled

Hi Everyone,

I found a "how it's made" type video on thermostats on Youtube. I learned some about the wax and how the melting wax causes the opening and how the spring causes the closing.

https://www.youtube.com/watch?v=xVPtIi6sVYg

-VT/JeffH

Very good. I was wondering how they could sell what seems to be a complicated piece of machinery for $10.00. Cheap labor (machines).

That is also how Ford made the original thermostat for the 59A pressurized cooling system. (Pictures in Post # 44) However, Ford also made one differently for the non-pressurized systems - the 11A-8575-C. It used something else in the bellows that built up pressure under heat to open the valve and counted on a fixed pressure from the outside of the bellows to expand against, which it would not have had with a pressurized system.



Just out of interest, here are a couple more vintage stats.

The Dole adjustable stat that uses a bimetal strip to open and close.


And Fulton stats that work on the same principle as Ford's for non-pressurized systems:


(Pictures courtesy of my barn friend that sold me his NOS 78-8575-C's. Hope he doesn't mind.)

[peewee2you]

Okay here it goes, and I know I am going to ruffle a few feathers with this post, but I feel that it is worthy enough to say it, in hopefully helping a fellow barner before he's encounters what I did. This is just my experience and have not heard of anyone else having this problem so, maybe just me... but I am ept enough, not an expert to feel that there was no way possible this was going to work for my application which was from a stone stock standpoint. Shewman's thermostat's there is a photo on here and it's the stat on the right that I used, for 47 Ford 59AB block, I think and believe a stock radiator and aftermarket repro hoses w/ford script? Got the stat's and heated them up actually opened around 185 to 190, but I was okay with that.

My problem came where these stat's fit in the upper portion of the hose near the radiator and they slide inside the hose, no easy task even with dawn soap, didn't want to use anything and hammer on them to drive them in, now either my radiator necks were longer than should be, but I think not, I had to drive the stat so far in that it reached the curvature of the hose neck, which seemed odd, just so I could get the rest of the hose on the radiator neck far enough to sinch up the clamp.
I was uncomfortable with this because of the way the thermostat's open the bottom half of the stat pulls down or let say the inner portion of the stat, and I can see inside the hose to know if it was working or would not work because it was at the curve of the hose? The other side my passenger side, I couldn't get the thermostat ever in far enough to even get it on the neck of the radiator far enough to tighten a clamp? I work a day and a half spent money on various pieces' to use trying to drive them into the hose far enough to get on to the neck so I could try them out. Sorry but after 1.5 days frustration, anger, cussing, I decided anything that I had to work that hard at isn't going to happen, so yes I removed them...now that was another ordeal, because afterr I got them in there, I rinsed them out with a hose to get all the dawn soap out, so now you have a thermostat stuck way in a hose with friction binding of the brass, and rubber hose and trying to figure out how can I remove them now without damage... crap I was pissed. Now, all that being said I returned them and will never try that again with those stat's with my application. I am thinking also that everyone uses different types of hoses like those flex hoses, I can't imagine how it would work in those, but seems some of you have used them I got them installed on your car, how I don't know, like I said maybe it's me, and that's okay...hoping better luck for you if that's the route you decide to take...I have used Shewmans other products with good success...just not those.

[peewee2you]

in one section of my post I said I can see inside, and I meant that I couldn't see inside.

[Old Henry]

Originally Posted by peewee2you

in one section of my post I said I can see inside, and I meant that I couldn't see inside.

You can edit your posts to fix that kind of stuff. I do it incessantly. Just click on the edit button of the post you want to fix.

Thanks for telling your story. It needed to be told. There are some definite myths on this forum that need busted and the truth is what busts them.

Do you still have Shewman's stats that you could get some close-up macro pictures of like I've posted to show us and measure them to give us some dimensions?

[ken ct]

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Originally Posted by Old Henry

Very good. I was wondering how they could sell what seems to be a complicated piece of machinery for $10.00. Cheap labor (machines).

That is also how Ford made the original thermostat for the 59A pressurized cooling system. (Pictures in Post # 44) However, Ford also made one differently for the non-pressurized systems - the 11A-8575-C. It used something else in the bellows that built up pressure under heat to open the valve and counted on a fixed pressure from the outside of the bellows to expand against, which it would not have had with a pressurized system.



Just out of interest, here are a couple more vintage stats.

The Dole adjustable stat that uses a bimetal strip to open and close.


And Fulton stats that work on the same principle as Ford's for non-pressurized systems:


(Pictures courtesy of my barn friend that sold me his NOS 78-8575-C's. Hope he doesn't mind.)

I have a pr of 175 like in that last pic you show in my 36 and have another spare pr. And a pr of the ones with the big coiled flat spring near the bottom. ken ct.

[Bluebell]

Old Henry, those first ones in post #62 are bellows type stats.
If I recall they are alcohol filled.(I cant remember for sure)
Anyhow this might be of interest;
The wax stats normally fail in the open position, (a good thing) and the bellows type usually fail in the closed position (bad)
I dont think anyone is making the bellows type commercially anymore.

[Old Henry]

Originally Posted by Bluebell

The wax stats normally fail in the open position, (a good thing) and the bellows type usually fail in the closed position (bad)

I've heard that but can't figure out how the wax ones can fail in the open position when they have that spring holding them shut. What would make the wax expand against the spring when it fails?

Curious.

[Bluebell]

I have never cut one of the pellets open, but I think the wax just leaks to the other side of a piston. Anyhow, I have removed a few over the years and that is how I found them. Stuck open.

[Old Henry]

Maybe it has something to do with the metals that they mix in with the wax that swell up when the wax is gone. Interesting.

[peewee2you]

Old Henry thanks for the editing tip, I must have missed that. I do not have them, I returned them. the pic on post #1 that you showed the picture of it was the one on the right, as I did not take any photo's of them. If I remember from the topside look like most of your standard type stat's. The bottom cylindrical half pulls downward allowing a nice 360 opening for the water to flow thru, I don't doubt that if you can get them properly installed they would work very well as stated.

[Old Henry]

Originally Posted by Old Henry

Here's what all modern thermostats are competing against - Ford's original design.



These are NOS Ford stats for my 47 that a very kind barner has offered to sell to me. Just compare them with the modern stats and you'll see the real advantages of them. They have a butterfly valve that swivels clear out of the way of water flow. And, look at the size of that hole once it's opened up! Way bigger than any modern stats. And, the mechanism that opens it is small and much less intrusive into the water flow than modern stats. This is what I've been looking for and believe that, if they still work (I'll test before installing), they will work better than any modern substitutes for those reasons.

Received these NOS stats from a barn friend. They work fine opening at their 180° specs.

The butterfly valve closed.


Fully open.


The spring that pulls it shut rather then pushing it like modern stats.


This Ford NOS stat has an opening of 29 mm compared to the modern replacement of 25 or even the Stant of 28. That's 7% higher volume than the Stant and 34% higher than the current replacements. Too bad no one makes 'em like this any more.

[Old Henry]

Just in case anyone wants to get the Stant stat for their engine here is some information about that. It is a Stant 14157 available on line many places including Amazon here: http://www.amazon.com/dp/B000C822YC or at NAPA part number THM 111, or at O'Reilly that sells the same stat as a Murray 4157, O'Reilly part number 2962.

[gearhead1952]

Great info Old Henry. Any thoughts for those of us running 49-53 engines? I found this on the napa website. It shows what they call a regular stat THM 70 and a premium stat THM 530060 both are 160 degree units. The premium stat looks in the pic to be less restrictive than the regular and very similar to the THM 111.

[flatjack9]

Go with 180's.

[Cecil/WV]

330-160 for an 8BA

[51 MERC-CT]

Originally Posted by gearhead1952

Great info Old Henry. Any thoughts for those of us running 49-53 engines? I found this on the napa website. It shows what they call a regular stat THM 70 and a premium stat THM 530060 both are 160 degree units. The premium stat looks in the pic to be less restrictive than the regular and very similar to the THM 111.

This is the one you want--
http://www.summitracing.com/parts/bra-330-160/overview/

[G.M.]

Originally Posted by 51 MERC-CT

This is the one you want--
http://www.summitracing.com/parts/bra-330-160/overview/

Robertshaw made the original 330-160, 170, 180 stats. They were sold to Cooper Tire and Cooper sold out to a company that from what I understand
is having them made in Mexico. The materials have been changed and I have had reports of quality problems. Bob Shewman has a supply of the original
330-180 Robertshaw stats made for military truck applications. These were manufactured under government inspections and tests and are made of ALL heavy duty copper and brass with no substitute materials like the new copies being made now. These are what he modifies for the old Fords and retests every unit before shipping. These are the best stats available for the 1932 to 53 Fords as they are high quality and have the least restriction of other modern stats. I have tested them in a number of old Fords in temperatures over 95 degrees and the engines all run at 178 to 182 on both sides. G.M.

[gearhead1952]

In looking at the pics of these high flow stats they look like they have large openings on the top but the bottom looks very restrictive am I missing something?

[flatjack9]

No.

[gearhead1952]

Originally Posted by flatjack9

No.

The napa premium 180 stat THM 530080 at $9 each has moved to the top of my list.

[Old Henry]

Originally Posted by gearhead1952

In looking at the pics of these high flow stats they look like they have large openings on the top but the bottom looks very restrictive am I missing something?

Yes. The Robert Shaw 330 stats work very differently than the stats for pre-49's. What you see that seems quite restrictive on the bottom is a cup that contains the wax pellet that opens the stat. The stat is opened by moving the cup down and away for the top flange so that the coolant then flows all around the cup and up through the large opening in the flange. None of the flow goes through the cup. It moves totally out of the way. But, this kind of stat will not work in hoses or in the head necks of the pre-49 engines because the cup then blocks the flow. But in later engines, the cup sits down in the block rather in a tube so that when it moves down the coolant can flow all around it and up through the larger opening. See discussion, pictures and diagrams beginning with post # 23 on this thread.

[51 MERC-CT]

Originally Posted by gearhead1952

The napa premium 180 stat THM 530080 at $9 each has moved to the top of my list.

You are missing something. The Napa stat looks like a standard stat and probably flows 25 to 45% less than the Robertshaw. stat.

[gearhead1952]

Gotcha. Thanks for the clarification. None of the places I went to described how the high flow units worked. Ok they are back to the top of my list.

[Old Henry]

Originally Posted by 51 MERC-CT

It may be possible to modify the later high flow thermostat to fit inside the 59AB hose.

That's what Shewman has done.
Just received a pair of Shewman's stats from another barner who decided not to use them and sent them to me so that I could get some macro photos and measurements to see how they compare with the Stant/NAPA stats that I've reported on.

Shewman's "high flow" thermostats are a Robert Shaw 330-FHT 180° thermostat (says it right on the side) from which the flange has been cut off and a brass tube brazed in it's place.



In this photo you can see the brazing of the tube where the flange was. You can also see the three holes drilled in the side of the middle bracket that, as best I could measure down in there, are about 6 mm. When the thermostat is totally closed water continues to flow through those three holes that are a total of 84 sq.mm. through the three larger holes seen in the bottom of the cup.



When the thermostat is fully open the bottom cup just moves down opening up a gap between it and the tube.





If that cup were moving into a wide open space full of water as the Robert Shaw stat is designed to do in an 8ba engine it would work fantastic. Unfortunately, with Shewman's stat installed inside of the hose, that big cup is still in the way of the flow that must go around that cup and through a 2.5 mm gap between that cup and the inside of the hose. The area of that gap is 317 sq.mm. In addition to that space are the three holes drilled into the inside bracket totalling 84 sq.mm. So, the total area for water to flow through Shewman's stat is 401 sq.mm whereas the Stant stat has 615 sq.mm. - more than 50% greater flow space/area than Shewman's. Plus, the Stant stat shuts totally off to allow full heat up in the winter whereas Shewman's stat leaves itself open to allow 20% of its total flow even when it's totally closed. Plus, the Stant stats are $18.00 a pair compared to Shewman's at $50.00 per pair. As from the start - not condemning, just informing.

Just thought someone might like to know.

[oldford2]

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Professor,
Why can't you let go on subjects covered ad nauseam.
" Ad nauseam is a Latin term for something unpleasurable that has continued "to [the point of] nausea".[1][2] For example, the sentence, "This topic has been discussed ad nauseam," signifies that the topic in question has been discussed extensively, and that those involved in the discussion have grown tired of it."


" Just received a pair of Shewman's stats from another barner who realized they were not the high flow represented so that I could get some macro photos and measurements to see how they compare with the Stant/NAPA stats that I've reported on.

Shewman's "high flow" thermostats are nothing more than a Robert Shaw 330-FHT 180° thermostat (says it right on the side) from which Shewman has removed the flange and brazed a brass tube in it's place."
So you have great pictures and measurements but have you tested them?? Stick to your great travel pictures and stories. When you have tested them report back. Then we can move on to vapor lock.
John

[G.M.]

John, Henry has been on a mission to put a hurt on Bob's stats for months. These are the original Robertshaw 330-180 stats all heavy brass and copper not the Mexican copies as shown on other posts with the light colored tops.. These are the highest flow stats I have seen that fits in the hoses of 32 to 48 Fords. I have 3 or 4 sets and a lot of friends bought and tried them before Bob started selling them all with good reports. My cars all run between 178 and 182 on 90 to 95 days. I did extensive testing on the Napa 111 stats a number of years ago and even put them in my 39 P/U which will run at a fast idle for 2 hours and never get to 180 with no stats on 100 degree day was running up near 200 on a 90 degree day with the Napa 111's with 6 or eight hole drilled in the flange to try to get more flow. G.M.

[Old Henry]

Originally Posted by oldford2

Professor,
Why can't you let go on subjects covered ad nauseam.

Because many people want to know and are not quite as "queezy" as you are as indicated in the previous acclamations of the info presented and inquiries for further information in this thread:

Originally Posted by Bluebell

Good thread!

Originally Posted by flatjack9

Keep up the quest Old Henry. I'm pulling for you. Drilling holes all around the thermostat to make it high flow is a joke.

Originally Posted by VeryTangled

Wow that is GOLD.

Having a good time following this thread and learning a lot.

Prof. Henry, is there any chance you can post more photos when you get them? I'd be especially interested in seeing one in the open position.

I'd also be interested in their opening temperature, and their closing temperature. It seems you will be interested in them closing correctly as the fluid cools on descent, preventing the temperature from dropping into an abnormally cool operating range, after being open during ascent. As I read it this is one of the areas you're looking for to get good performance.

-VT/JeffH

Originally Posted by Old Henry

Pictures save a lot of words (such as in post # 59). It would be interesting to see such close-up detailed shots of Shewman's stats to see what they're really like.

Originally Posted by gearhead1952

Great info Old Henry.

Originally Posted by gearhead1952

In looking at the pics of these high flow stats they look like they have large openings on the top but the bottom looks very restrictive am I missing something?

Originally Posted by gearhead1952

Gotcha. Thanks for the clarification. None of the places I went to described how the high flow units worked.

Without actual comparative flow tests, which no one has done, flow can only be predicted by the size of the passages that the flow goes through. My measurements of Shewman's and Stant stats are the first I have ever seen and give a more accurate prediction of flow than someone's testimonial that they have used them and they seem to work fine.

Like I said at the end of my last report - someone might like to know. If you don't want to know, ignore it, but don't criticize when you have no actual empirical data to contradict my measurements and conclusions. Until someone actually does comparative flow tests, my data stands as the best indicator of flow so far.

I have no "mission to put a hurt Bob's stats." In fact, if you read my first post, I was actually considering buying them to use. I just wanted to know the truth about them compared to other stats before I did. Now I know. Maybe someone else would also like to know. If they do, now they can. If they don't, I don't know why they would even open up this thread.

As for your nausea - take two Alka-Seltzer and call me in the morning.

[Roger/Sacramento]

I am all about learning how stuff works.......keep up the discussion until the answers appear. Doesn't make me sick.

[HotRodmicky]

So , where can i buy 49-53 robert shaw 330 180degrees Thermostats?

[51 MERC-CT]

Originally Posted by HotRodmicky

So , where can i buy 49-53 robert shaw 330 180degrees Thermostats?

Summit Racing

[51 MERC-CT]

Keep the info coming.
In regards to the 3 bypass holes, this is a stat. made by Robertshaw, modified and sold by EMT/Stewart.
It has the 3 bypass holes, which may or may not contribute to cooling but probably allow (because of flow) the sensor to see hot water sooner and open valve sooner in the cycle.

[G.M.]

Originally Posted by HotRodmicky

So , where can i buy 49-53 robert shaw 330 180degrees Thermostats?

Bob Shewman 1-610-933-6637 [email protected] Has the original NOS Robertshaw 360-180 all heavy brass and copper stats. These were built to military specs for trucks. He has them for the 49 to 53 Fords and modifies them to mount in the hoses of 32 to 48 fords. He also tests every stat before shipping to see that it operates in the 180 range. I use them and my engines stay between 178 and 182. G.M.

[Old Henry]

Next time we get a 90° day here (may not be until next summer) I may install Shewman's stats and do the Squaw Peak Road run (4 miles of 10% grade) to see how they compare to the Stants that I tested on the same road and temperature this summer and let you know.

[gearhead1952]

Originally Posted by oldford2

Professor,
Why can't you let go on subjects covered ad nauseam.
" Ad nauseam is a Latin term for something unpleasurable that has continued "to [the point of] nausea".[1][2] For example, the sentence, "This topic has been discussed ad nauseam," signifies that the topic in question has been discussed extensively, and that those involved in the discussion have grown tired of it."


" Just received a pair of Shewman's stats from another barner who realized they were not the high flow represented so that I could get some macro photos and measurements to see how they compare with the Stant/NAPA stats that I've reported on.

Shewman's "high flow" thermostats are nothing more than a Robert Shaw 330-FHT 180° thermostat (says it right on the side) from which Shewman has removed the flange and brazed a brass tube in it's place."
So you have great pictures and measurements but have you tested them?? Stick to your great travel pictures and stories. When you have tested them report back. Then we can move on to vapor lock.
John

I welcome any and all info. Keep it coming Henry. I bought a pair of Shewman's stats for my 8ba project.

Oldford did you know you don't have to read every thread and every post? Your post was unnecessary.

[Old Henry]

Originally Posted by gearhead1952

I welcome any and all info. Keep it coming Henry. I bought a pair of Shewman's stats for my 8ba project.

Good move. Should work great in the 8ba. That's the environment they were designed for.

[Old Henry]

In response to oldford2's repeated request for real life evidence of the problem with Shewman's thermostats I offer the following thread that just concluded with Shewman sending replacement thermostats for the 59A engine without the extra holes drilled in it so the engine would warm up in the winter which it wasn't doing with the holes drilled in it. There were several having that problem. It remains to be seen how they'll work in the summer without the extra holes. Here's the thread for anyone interested: https://www.fordbarn.com/forum/showthread.php?t=121447

[mark180]

Old Henry,

Thanks for all your work on this subject. My '37 runs cool in the winter (about 130° when the heater is on). I went to replace the thermostats with higher temp ones, only to discover I was running with no thermostats. That would explain why I was running cool.. I got some 180° stats from Speedway, and after running for a bit, the car would overheat, but after it cooled a bit, the stats would work fine. I'm looking for new stats now, and your research has been a HUGE help.

Mark

[gmc1941]

Thanks Henry (consumers that report to the flock are an asset) this is why we have the Ford Barn HELP IS ALWAYS ON THE WAY

[Kahuna]

I realize this is an old thread, But I've been using the Subaru Thermostats all summer and they work and regulate real well.

[Old Henry]

Wow, 11,430 views of a thread rated only two stars!

[Old Henry]

For any that missed the sequel where Shewman's went head to head on the road with the Stants here it is: https://www.fordbarn.com/forum/showthread.php?t=143576