To thermostat or not??

[plyfor]

After searching around the net, on the VFF and publications I found that adding a stat to the model A gets mixed reviews. One negative comment appears to be lack of cooling to rear cylinders, and one positive comment is faster warm up. Another negative is possible pump cavitation without drilling the extra holes. With cooler weather, our rebuilt engine doesn't seem to want to run above 140 with no stat. We removed the prior owner's working stat that had 3 1/8" holes drilled when installing new radiator, etc., so overheating isn't an issue. In hot weather, we never got above 165 or so. Our in -cabin mech.gauge is relatively accurate connected at the upper gooseneck.
I'm sort of at the point where it may be prudent to just leave the system as designed. This subject has probably been beaten to submission, but perhaps a refresher would be helpful..

[dmdeaton]

I am running one and getting ready to move it. Currently it is between the upper hose sections. I am replacing it with a Precision upper gooseneck and new hoses.

[1931 Flamingo]

Why does installing a t/stat prevent cooling to the rear cylinders??
Paul in CT

[Mitch]

Here is an informational thermostat thread from the tech area

https://www.vintagefordforum.com/forum/model-a/technical-reference/20821-thermostat-information

IMO if you're running 140 i would put one in. You risk oil contamination and sludging up the motor.

[Dennis]

I am going to run a thermostat in the winter with a hole drilled. In the summer I'll run without. I also have a stainless, I made myself because the brass screen failed, gano type screen in my upper hose that stays in always.

[tbirdtbird]

I don't want to restrict water flow to the rear cylinders, there is hardly any there to begin with. I would rather restrict air flow to the rad.
I cut a piece of cardboard, painted it black, and run it in front of the rad in the short winter that we have. In the summer no cardboard needed, and with the overhaul, cleaned block, and re-cored rad we never see over 180, even on 100° days.

I'm with Mitch on the effects of low water temp

[George Miller]

Maybe some one could make a adjustable shutter that looked good. Our Essex has one. There is a rod inside the car to work it.

[BNCHIEF]

Old mack trucks had them and they were temp controlled.

[carolinamudwalker]

Dave, you forgot to mention that the cardboard is not seen because it is hidden by the stone guard.

[tbirdtbird]

Bob, you are correct

[BILL WILLIAMSON]

Put in a THERMOSTAT---That's a NO BRAINER! POOR Old Horse A car without a THERMOSTAT is like a HOT WATER Heater, without a PILOT LIGHT

[CarlLaFong]

Why does anyone want to heat hot water??? ;)

[George Miller]

I think the thermostat needs to be as close to head as you can get it. It also needs a couple of extra holes drilled in it. I had good luck with one in my Sport coupe, never added water. and after 28,000 miles still ran well. But I no longer have that car. But I do have one in my pickup we will see how that works out.

[Mitch]

George said it not me... About the holes I holy agree tho

K-dddad wont> HEHE :rolling

[George Miller]

Mitch I have been in trouble before, I can be bull headed. So no problem i can take it.

[Mitch]

I have the stock set up so i use 3 holes in mine

[BILL WILLIAMSON]

I shoved a Suppliers' Sleeved, 160 Degree thermostat into the UPPER end of Minervas' upper hose & it worked flawlessly for over 11,000 Miles. Heat & Hot Water goes UP, enough said?
AND, why do some drill HOLES & screw up a perfectly designed thermostat? Why not just stuff a CHORE-GIRL Scouring Pad in the hose & filter the RUST FLAKES at the same time???
WHY do I read ALL this discussion, OVER & OVER?---I can't put that HORSE in this comment section (SORRY)
Dad Blearyeyed

[Dennis]

Bill , you can put it there... even the dog

[Tom Wesenberg]

I run a 180 stat with a couple 1/8" holes so the hot coolant circulates past the wax pellet in the thermostat. I also run a bypass hose, which will be my water heater later, so the coolant circulates through the block until the stat opens and sends it through the radiator. This works great.

Bypass Hose Model A.jpg

[George Miller]

That is a good idea, that should help the back cylinders.

[AL in NY]

I did the some thing using the VP thermostat housing. I routed a 3/8" SS line from the VF housing to the rear of the engine block. Keeps the rear cylinders from getting too hot.

[CarlG]

filedata/fetch?id=43036&d=1554119645&type=thumb RE: Post #6 (I still haven't figured out how to post pictures in a comment)

Although I have one of these, I have never installed it. The one I have is new in the box, but is missing the control cable. One of the other guys in our club has one that he uses all the time.

[BILL WILLIAMSON]

WHY do some think the rear cylinders can STARVE for water? We should put in 6 Goggle Eyed Minnows & have them report back:rolling
Chuck has a semi-floating, plastic FISH, in his Sediment Bowl, he said it was a BOTTOM FEEDER & ate the RUST FLAKES:rolling "Maybe" he'd loan us his Fish???
Dad

[tbirdtbird]

because they do
look at the water pathway and what the water pump does to every drop of water that enters the block from the return line

[Dennis]

I run a 180 stat with a couple 1/8" holes so the hot coolant circulates past the wax pellet in the thermostat. I also run a bypass hose, which will be my water heater later, so the coolant circulates through the block until the stat opens and sends it through the radiator. This works great.

Bypass Hose Model A.jpg

Similar to what I have. There is an orifice in my filter housing that's made just for coolant as well the filter. And it sends warm water back to the engine. I found the inlet housing on ebay awhile back. Haven't seen another like it. Couldn't live without it.

[CarlG]

Don't think I've ever seen a coolant filter like that before.

[Dennis]

Got em both from amazon. When I was working on heavy equipment we had a lot of coolant filters to maintain. Keeps the coolant nice and clean. You can also get the filters that have additive in them but I don't think you need to go that far with a Model A. I would have preferred a much smaller element and housing but I just didn't see them out there. I made a template if anybody wants to make their own.

[Ray Horton]

I have run my Model A's for 55 years without a thermostat. I keep all my cars stock, except a "performance" cam in the coupe and modern valves in the pickup, neither of which affects the cooling. My position is and always has been, keep 'em stock. Henry had the best engineers available at the time, and they designed the Model A accordingly, and we have them today because they did them right. It would be arrogant and presumptuous of me to think I know better or could improve on their work.
Besides that, if they're stock I know what I'm dealing with.

[BILL WILLIAMSON]

I "think" Henry didn't do thermostats, earlier, cause you couldn't trust the crappy thermostats, made "BACK THEN!
Dad Opionated

[Guest]

Running the Precision outlet with 160 stat. All this other stuff drilling holes taking in and out is a bunch of bunk! Modern Stats have a bypass system so water does circulate at a slow rate until the stat opens. My truck warms up to op temp quickly stays within range and the plus was it slows the flow slightly with my new water pump so it does not over run the overflow in the radiator. Ran for 2 full seasons on tours up to 6000 ft and have NEVER lost a drop of water or ran higher than 180 degrees. No holes needed in the fins of the pump either!

Some have installed their temp gauge sensor in the lower radiator hose. This is a bad idea... it belongs up at the water outlet on the block. Remember temps will be lower at the outflow of the radiator. What that means if there is an overheat problem the temp gauge will be the last one to know it. Just my 1.5 cents worth

[DaWizard]

Hey Dave, Welcome to the VFF!!

[Mitch]

Running the Precision outlet with 160 stat. All this other stuff drilling holes taking in and out is a bunch of bunk! Modern Stats have a bypass system so water does circulate at a slow rate until the stat opens. My truck warms up to op temp quickly stays within range and the plus was it slows the flow slightly with my new water pump so it does not over run the overflow in the radiator. Ran for 2 full seasons on tours up to 6000 ft and have NEVER lost a drop of water or ran higher than 180 degrees. No holes needed in the fins of the pump either!

Some have installed their temp gauge sensor in the lower radiator hose. This is a bad idea... it belongs up at the water outlet on the block. Remember temps will be lower at the outflow of the radiator. What that means if there is an overheat problem the temp gauge will be the last one to know it. Just my 1.5 cents worth

Welcome to the VFF!
Where is the bypass in the stats that the vendors sell for the upper hose? Is there a bypass in the design of the stock Model A cooling system?

[plyfor]

One of my mechanic buddies says the oil can get 15-20 deg. hotter than the coolant, and with modern oils, the oil doesn't crud up as with former formulations.Higher deg. stats are used to help control emissions. Just another point of view. Our engine hasn't seen freeway speeds yet due to breakin so high speed checks haven't been performed.
Also, attached is a dwg. from Victor Page's book showing the cooling system. Is the pump circulating water a propos to Mitch's question ?

[BNCHIEF]

He is exactly right.

[BILL WILLIAMSON]

IF there were a BIG water circulation problem in #3 & #4, Folks would be fitting those two pistons with .008" clearance!

[tbirdtbird]

we already fit those 2 pistons .001 over the front two because of this very issue...we fit 1 and 2 at .0035 and 3 and 4 at .0045

people who are having trouble with this need only borrow an IR temp gun and shoot the cyl wall temps which Henry conveniently made available to us on the driver's side and compare the readings you get...you may just be amazed at the differences you find.

Also, the water jacket does not extend all the down the cylinder wall, further reducing cooling effect front and back.

Lastly, any non-pressurized system of the past will have micro-boiling right at the cyl walls and thus not allow full contact of the water with the cast iron, which is why they eventually went to pressurized systems across the board.

From

http://www.hotrod.com/articles/understanding-the-cooling-system-cool-under-pressure/

"Pressure in a cooling system is vital for keeping water in contact with the metal surfaces of the cylinder heads and block. Pressure keeps the air compressed and maintains the water-to-metal contact that is vital to prevent localized boiling or steam pockets in the combustion chamber areas of the cylinder heads. When a situation occurs that causes temperatures to rise such as lean fuel mixture, too much ignition advance, or a clogged radiator, the air in the water will expand and form small steam pockets. This will start in the combustion chamber area (hottest spot) and the steam pocket will be attached to the metal surface. These spots get very hot and since it’s in the combustion chamber area, it will create a detonation problem. This is why engines lose power when overheating occurs. Once steam starts in the cooling system, the problem will magnify and continue to get worse."

[Bikerider58]

So, is Micro-boiling another reason why we should use antifreeze?

[DaWizard]

You know, I have put a LOT of thought into this and my common sense has brought me to the conclusion that I don't want to hold the water in the engine any longer than it takes to absorb the heat generated by the engine running. Now, all my life, or at least for the last 60 years or so, Model A's were known to run hotter than necessary or recommended by new car standards, which is not to say that the new car standards apply to the Model A, but were used to compare to the Model A.

Model As are not new cars, nor can they be compared to the closed pressurized new car systems, but everyone still uses the new car standards as a bench mark for the Model A. Now, granted I can't get inside the heads of those engineers that developed the Model A engine and cooling system, but I can use the same common sense that one would hope was used back when this was developed.

Ask yourself this, "why is the lower radiator opening smaller than the inlet?" To me this says that the water needed to be slowed down before exiting the radiator to allow the cooling of that fluid. Since I have two(2) separate and apart temperature sensors, one located at the upper neck and one located at the lower inlet pipe, I have seen for myself that my radiator does in fact reduce the temperature of the coolant by at least 20º between leaving the engine and reentering the engine, which tells me the radiator seems to be doing it's job.

Because I know the Model A tends to run hotter than new car standards, I feel that if the coolant isn't boiling out of the cooling system, it should be good to go, so what I did to help my engine run at it's happy temperature, I placed a 1¾" flat washer with the inside diameter of 1" in the exit of the lower radiator hose to give the coolant a little longer to remain in the radiator, which seems to work really well in maintaining the temperature in the engine in the 170º to 190º range at the exit of the coolant and the inlet coolant temperature into the engine in the 150º to 170º range and this has made me tickled pinkish because in my lifetime of owning and working on Model As I have never been able to do this to any of them.

Needless to say, I am not a fan of holding the water in the engine any longer than necessary, therefore I will never place a restriction, thermostat, in the exit of the engine with or without the bypass holes, as I feel there is no need to hold the coolant in the engine to allow it to warm up. If you need to get the engine temperature up quickly, start it and let it idle for a bit, it isn't a speed racer, so letting it idle an extra minute or three won't hurt a thing, it may actually help prolong the life of the engine by not immediately getting it on the highway and reving it up to speed.

My opinion and 2¢ worth on the subject!

[Mitch]

The climate of where one lives needs to be taken into account. If i lived in FL or a dessert i wouldn't run one

[George Miller]

In NC I have went both ways, it seems to be ok either way. The 28 sport coupe ran a stat for 26,000 miles it worked fine. It did have a sleeve and valve seat in number 3 because it was cracked when I got the car. I also fixed the crack that ran from the seat to the cylinder. The radiator was plugged, probably why it cracked.

[Tom Wesenberg]

Drilling holes in the thermostat is to allow the hot coolant to flow past the wax pellet so it will open when the coolant is up to temp.
Installing a stat gets the engine up to temp quicker, thus less condensation, and the engine runs more efficiently at higher temps.
A hotter engine boils of the condensation better, and that's why they are controlled by a thermostat to run 180 to 200 degrees.

As far as hose size, my 1950 Studebaker is just the opposite of the Model A. It has a 245.6 cu in engine, but only a 1 1/4" top hose, and a 1 3/4" lower hose.

I think the Model A pumps more volume than it needs to, so a thermostat helps there also by slowing the flow some.

[BNCHIEF]

Holding the water helps it to absorb heat I run a 180 stat and I also have water bypassing at all times all of this makes the heater I put in very efficient my cars runs at 180 neccessary for proper combustion everything is clean and new radiator. I also use a coolant filter as dennis posted.

[Dennis]

Still waiting for it to get cold enough to warrant putting a thermostat in. High today 76* Sunday 84*

[Mitch]

Here is a thermostat that has a bleed hole and a bypass valve. When both are closed the coolant moves through the bleed valve. Then on semi warm up, the lower bypass valve will open so the coolant is able to circulate without going through the radiator. Once the operating temp of the stat is reached the coolant will then flow through to the radiator. I’m about to put this in a newer Mazda..
The stock Model A has no way to bypass the coolant, so therefore needs a standard old school stat. The 3 little holes we drill are performing the same function as a modern day stat, less the bypass valve. Many of the stats from our suppliers already have two holes drilled into it and we place them in the upper hose. Many of us wish to keep the stock look as they were produced from the factory. Always make sure that a hole is at the 12:00 position

[CarlG]

Then there are those of us that aren't overly concerned about "looks", but rather functionality. Vince once commented to me that the only stock looking thing under my hood was the data plate, and he wasn't even sure about that!

[BNCHIEF]

Carl did you whip your hanky out and polish the data plate?

[Mitch]

AL in NY commented
Yesterday, 06:00 PM
I did the some thing using the VP thermostat housing. I routed a 3/8" SS line from the VF housing to the rear of the engine block. Keeps the rear cylinders from getting too hot.

Hey Al
Does it look like post #60 in this thread? See you have been here for a while now, you just didn't know it
https://www.vintagefordforum.com/for...at-information
That's a very nice clean job