What Temperature?

[WHN]

My advice is to skip installing any Thermostat. At some point down the road, it is going to fail, ...and the stress/damage that it will potentially cause you is not worth any benefit you might have felt. If you want to quickly warm the engine, then just after starting only slightly advance the Spark Lever during initial warm-up. The retarded ignition timing will allow the temps to rise quickly. Allow the engine to operate at a fast idle with the ignition timing retarded and you will see the coolant boil in just a few moments. That likely out-performs what any Thermostat can do.

More owners should take this advise!

Enjoy

 

[Kurt in NJ]

After a long parade on 4th of july 90 degrees plus with near full retarded spark ai idle walking speed.
160 degree thermostat.
The #4 cylinder runs the same temperature or lower than #2
The addition of the thermostat increased fuel mileage by 3 mpg.
The difference is in the thermostat, it is a bi metal thermostat with a large flapper door valve . I haven’t found another one even though I look where i found it every year— although I have found many other things — it was in the trash at Hershey.
When fully opened the opening is probably twice the flow of modern thermostat.
A lot of the early thermostats were made that way before pressurized cooling systems.

 

[katy]

Kurt in NJ, Got a picture? Does it look this? Or?

 

[alexiskai]

Kurt in NJ, Got a picture? Does it look this? Or?

That's a Robertshaw thermostat. They use wax as the controller, albeit with metallic paste mixed into it.

Robertshaw thermostats are not good choices for Model A because they have that large cup around the bottom. The action of the thermostat upon opening is to lower the cup, creating a gap between the cup and flange through which coolant flows. In OEM applications, there's a large space around the cup, so it doesn't obstruct flow when the piston opens. But in Model A, the cup almost entirely blocks the hose or water outlet at all times, even when open. Coolant has to flow around the sides. So it really restricts throughput of the system, which is not good when the engine is really throwing off a lot of heat.

Original Ford thermostats from the '40s used a sealed bellows as a piston. Inside the bellows was a fluid that would transition to gas as it heated, expanding the bellows and opening the valve.

Kurt may be referring to a Dole thermostat. These were made with long bimetallic coils that expanded to open a valve. I don't know much about these but adding more types of metal to the coolant environment seems risky to me.

 

[Jim/GA]

Everyone who makes Model A thermostats drills bypass holes in the flange. This is a solved problem.

IF that was enough to get uniform block warm up, a couple of holes added to a thermostat flange, Detroit would have adopted that approach instead of engineering in a bypass. That would have saved them a lot of expense and complexity. I am sure they tried it and then moved on.

Having the holes is better than no holes, because they get some hot coolant up to the sensing element in the thermostat to get it to open, but not really enough to provide uniform warm up of the engine block. Once the thermostat has opened and settled down, it does not matter, it's only about warm up.

A bypass is better. Easy to install. Or leave the thermostat out.
.

 

[nkaminar]

My bypass is the heater for the passenger compartment that uses the coolant. In summer I close it off with a valve and depend on the enlarged hole in the flange. That works well for me. Without the enlargement I had the problem that Jim described above.

 

[philosofriend]

My A has a water temperature gauge. When I installed a 180 thermostat the temperature readings would keep shooting up and down. iI other words the thermostat kept cycling open and shut. When I switched to an 160 degree thermostat the temperature gauge worked just like I expected: a fairly quick warm up followed by a steady reading.

I appreciate what folks have said about not needing a thermostat at all, but I drive sometimes when it is 25 degrees (Fahrenheit) outside so I'll keep the thermostat.

 

[alexiskai]

IF that was enough to get uniform block warm up, a couple of holes added to a thermostat flange, Detroit would have adopted that approach instead of engineering in a bypass. That would have saved them a lot of expense and complexity. I am sure they tried it and then moved on.

Having the holes is better than no holes, because they get some hot coolant up to the sensing element in the thermostat to get it to open, but not really enough to provide uniform warm up of the engine block. Once the thermostat has opened and settled down, it does not matter, it's only about warm up.

A bypass is better. Easy to install. Or leave the thermostat out.

You're making a lot of assumptions here:
- About the strength of the effect of non-uniform cooling on the Model A engine
- About how much difference in flow actually exists between a 1/8" bypass hole and, e.g., a 1.3cm bypass port in this particular application
- About the basis for later decisions to design bypasses in certain ways on different engines with different startup procedures

And you're coming to very strong conclusions based on data you don't actually have. Maybe it would be better to state that every approach involves trade-offs, and you personally don't like the mix of trade-offs involved in using a thermostat with the DIY bypass solution.

 

[Randy in ca]

I now have a thermostat installed and am debating with myself about what temperature t’stat I should install. I know that typically 160 degree t’stats are commonly used but I think possibly more in the 180-190 range might be best.

It seems things might have gotten off course here, wrongly assuming you have intention to install an in hose thermostat assembly with a fixed temperature rating, rather than looking for opinions on what rating to install in an existing assembly (?). Have you installed something like these? Or?

-

 

[Y-Blockhead]

Years ago when I bought my Town Sedan, it had this restriction oriface in the water outlet. It worked well in the mild climate of Socal, temperature stayed around 165-170°F, but not sure about the extreme cold or hot areas.

 

[jeepguy1948]

Yes I have the Vintage Precision unit

 

[Randy in ca]

Yes I have the Vintage Precision unit

Well a lot would say you made a good choice. They normally come with a 160, why not just give that a try and the option is always there for an easy change to 180 if you think it might be worthwhile. The seasonal change in temperatures from one area to another is significantly different. Years ago in some areas it was fairly common to regularly change thermostats with the change of seasons. Good luck.

 

[Kurt in NJ]

This one is for 60hp flathead, mine is the same type except it has a built in sleeve to fit the hose.
There is a built in pin for sever overheating that locks it open.
Haven’t looked at it for 40 years.

 

[katy]

Thanks for the pics

 

[jeepguy1948]

Jim B, what do you think. Is the ideal temperature for a Banger, 180? 190? more?

 

[alexiskai]

These thermostats don't work like a house thermostat. The degree listing for the thermostat is when it begins to open. You may have a 160 thermostat, but if the feedback between your engine and cooling system means that your coolant spends all day at 170, or 195, then that's the temperature you're running at.

Leave the thermostat that came with the VP outlet in there and go drive the car. See what actual temp readings you get. Only then think about whether you need to change it. If you overthink this and put a 190 thermostat in there without adequate testing, you could damage the engine.

 

[jeepguy1948]

Alex, I did buy a Fail Safe t’stat (never heard of it until you mentioned it).

 

[jeepguy1948]

I drove it for a few days with the 160 t’stat and it ran steady 160 all the time (with 2 1/8” holes in the flange). Switched up to a 180 t’stat with (2) 3/16” holes. Now it will only get to 180 when running up a long hill. The rest of the time it goes to 170 and kind of hangs out around there. Apparently the 2 holes in the flange allow enough coolant to flow to keep it down to 170. This is all with water wetter no antifreeze.

 

[jeepguy1948]

Still waiting to hear back from Jim about his thoughts about the ideal temperature for a banger. I have pretty much been a hotter is better kind of guy going back many years.

 

[alexiskai]

Very interesting. The 180 that Snyders used to sell had a single 3/16” hole. I have two Fail-Safe thermostats here in the shop now and I intend to test them to see at what temp they start to open.