‘36 LB. temp ranges, thermostats?
 

Hi guys/gals. I have a 1936 LB in my ‘29 model A. I installed the engine this winter. I have been running her almost every day since the weather has gotten nicer. Every time I take her out, the day is a little warmer and the car gets a little warmer. Today on the way home the temp gauge was showing 210. I have no thermostats in it yet. Will thermostats keep her in the 190-200 range? If so what thermostats do you recommend? My ‘29 radiator I was told was good By a radiator shop and I had them modify it for dual upper and lower inlets. Today was only 82-84 degrees so I am a little worried about it when temps get higher as summer comes along. I did have a little coolant coming out the overflow tube when I got home.

Re: ‘36 LB. temp ranges, thermostats?
 

A peculiarity of 35-36 engines is that at high flow rates, the cylinder head mounted pumps tend to push coolant up and outta the overflow. Fitting thermostats in the top hoses can slow this down considerably. Even then, coolant will be pushed outta the overflow as it expands with heat, until it finds its own level. In my 35 I run the overflow into a catchcan; this ensures the radiator is always filled to the brim.
I think the surface area of a Model A radiator would be somewhat smaller than a 35-36 rad, although you've had the tanks modified, does the core have enough capacity to cool your larger engine?

Re: ‘36 LB. temp ranges, thermostats?
 

Thermostats are to help the car come to temp sooner, and warm up when it reduces load/cools (think cresting a mountain).

They will not limit high temp.

But.. The original '36 system included stats. Some find they reduce flow to help efficiency. I'd keep 'em.

The rad fluid seems scary low when my other car, a 35 rolls off cold. But after heating up it comes above the tubes and flows correctly.

Actual full is scary because it's below the top of the tubes.

Re: ‘36 LB. temp ranges, thermostats?
 

Very Tangled posted it, the thermostats help bring the engine up to operating temperature quicker and maintain a minimum temperature. On later flatheads something around 185 degrees is a good target (for the minimum temp), but not sure on the earlier pump in head design.

Re: ‘36 LB. temp ranges, thermostats?
 

I undestand how thermostats are intended to bring the engine up to temp quicker, but I am confused by people who say they don’t slow coolant flow. How can they not? The opening in a thermostat is quit small compared to an open hose. I am just wondering if coolant is moving to fast through my system and not having enough time to cool down in the radiator. Yes the ‘29 radiator is smaller than the ‘35-‘36 radiator. Has anybody installed thermostats that cured an engine from getting to hot? It did not move past 210 but I was not sitting and idling a lot. I have a ‘46 Ford mechanical fan up front.

Re: ‘36 LB. temp ranges, thermostats?
 

An obstruction over a very short distance has little affect on system flow. You have two thermostats on a flathead vs one on most large OHV engines, they are capable of maintaining proper flow. The engine was designed to work with thermostats.

I've never seen slowing the flow down helping with high temperature despite the stories from the 50s about installing washers or removing vanes in the pumps. Now days everyone seems to be moving to the higher flow pump designs.

Re: ‘36 LB. temp ranges, thermostats?
 

Ummm... We don't exactly know what your driving conditions are. Hills? Flat? Speed? So, I'll offer this opinion and experience... I have a 36LB in a 34 sedan. With 3.78 axle, which is the same as many Model A's. And, I have one of Skip's pressure valves on the radiator overflow. If I drive on the flat, and don't push it beyond 45, it doesn't boil or push water out. (No temp gage) If I push it, it wants to throw water out the overflow, and it wants to heat up, sometimes to boil. I live in the mountains, and almost any driving involves going from 6000 ft elevation, to less than 1000. And, back up. So on a hot day (easily 100+ at the base of the hill), it's quite a challenge to drive up the hill to home. Back in the day, when I was a little guy and my parents did the driving, they never did the hill, mid-day. Always early AM, or well after dark at night. So, what I'm saying, these old cars, even when new, had heating issues. And, whatever make, not just Fords. So, to drive up the hill during warm weather, I count on a few stops to add water. Just the same as what my parents did 70 years ago. On the other hand, when driving flatland, and holding to 45 or less, I can go hours without adding water. Obviously, just opinion and my experience. (and, I have run with, and without thermostats.)

Re: ‘36 LB. temp ranges, thermostats?
 

IMO a stock '29 A radiator will not cool a V8 flathead motor in hot weather. No band-aids will fix the problem.
A Walker radiator would fix it.

Re: ‘36 LB. temp ranges, thermostats?
 

Thanks 42merc. I was worried about it’s cooling ability.

Re: ‘36 LB. temp ranges, thermostats?
 

Not many hills here in Michigan. I drive it as the speed limit dictates. I like running it at 55, it is the sweet spot.

Re: ‘36 LB. temp ranges, thermostats?
 

Hopefully this holds them in place.

Re: ‘36 LB. temp ranges, thermostats?
 

With 180 thermostats in and water wetter the temp got up to 200-205 so I brought it home to avoid it going any higher. Dang. I do not have the cash for a new radiator.

Re: ‘36 LB. temp ranges, thermostats?
 

How to get the most cooling from a probably too small radiator?

Chemistry first: a 50/50 solution of ethylene glycol/water is 17% less efficient at absorbing/transferring heat than plain water. That is huge. I believe that is a root cause of overheating in cars that were designed to run with plain water and alcohol as the antifreeze. Then physics: surface tension of water effects the contact of cooling water with the engine surfaces, allowing tiny bubbles to form at the surface, which insulates the surface and slows heat transfer from metal to coolant.

I Williamsburg the temperature rarely gets to single digits, and not for very long. So I use 20/80 antifreeze solution. The cooling system chemical protection is preserved, and it protects from freezing down to about 15 degrees. I also add two bottles of Redline Water Wetter (24 oz), which actually works against the surface bubbles.

This combination keeps my hot headed flatty below 200 degrees, idling on hot days.

Plain (distilled) water (0/100) and WW would be even better, but you would need to add something for corrosion and water pumps.

Maybe give this a try and report on results? About $30 versus $800 for the Walker solution.

Re: ‘36 LB. temp ranges, thermostats?
 

I have it now to about a 30/70 mix as when I puked all the coolant I replaced it with just water and one bottle of water wetter. It still went north of 200 but slowly. Yesterday I pulled the hood and took it for a drive. I stopped a bunch of times and let it idle for a bit, then I would move again for a mile or so and repeat the stop and idle. It never got over 185. I am wondering if my hood was trapping all the hot air. With the hood on, hot air was pouring out the side louvers. I will give it a few more test runs to verify.

Re: ‘36 LB. temp ranges, thermostats?
 

Guess your just going to have to move up another step in the Hot Rod world! :)

Re: ‘36 LB. temp ranges, thermostats?
 

Been awhile but I am still at it. Decided to make a custom buy factory looking fan shroud. Test drive tomorrow to see how it does. There is no air movement now outside of the shroud.

Re: ‘36 LB. temp ranges, thermostats?
 

Lookin good!

https://www.fordbarn.com/forum/attac...6&d=1593043189


https://www.fordbarn.com/forum/attac...7&d=1593043212

Re: ‘36 LB. temp ranges, thermostats?
 

It's kinda hard to see, but it looks like some very nice work on that shroud. The curve at the top looks very professional.

It will be interesting to see how much it helps. Keep us posted.

Re: ‘36 LB. temp ranges, thermostats?
 

A shroud should help, be interesting to see your results.

Re: ‘36 LB. temp ranges, thermostats?
 

Well the shroud did not help that much. I ran it the other day, about 80 degrees out and she went north of 200 again. Any other suggestions before springing for a new radiator?