1935 coupe overflow tank recommendations
 

Has anyone installed a radiator overflow catch tank on a 35 coupe? Need ideas / recommendations on how best to do it.
Bullshark

P.S. I have the later style "B" radiator with the overflow tube front center on the radiator behind the grill.

Re: 1935 coupe overflow tank recommendations
 

There are several ways to add an overflow tank. What I did to my '35 was to add an overflow tube (available from many sources) to my radiator housing. I pop riveted a couple of case nuts to the radiator side panel, bolted the tube to the radiator frame. Finally, I just ran a rubber hose from the radiator overflow to the bottom of the reservoir. The second hose is an outlet for the overflow if it fills up.

Hope this helps.

Re: 1935 coupe overflow tank recommendations
 

Just curious if you are doing this because your radiator/temp pushes coolant out? If so - curious if you did the normal checks for actual coolant temp with a heat gun ... if your thermostats are working properly and your water pumps are doing their jobs. Just a thought if you are blowing water .. an overflow tank may be a band-aid ... but not the cure.

Re: 1935 coupe overflow tank recommendations
 

Car runs cool with adequately filled radiator. Pretty stock car, No thermostats installed. Running down the road 40-50mph with 4:11 differential, radiator fills up and blows out overflow tube. Then the syphoning takes over. Will probably have to get a pressure radiator cap as well, not sure. I have been told that large washers or punched out thermostats installed at water pumps to slow flow may fix.it but that comes later.

Re: 1935 coupe overflow tank recommendations
 

Why are you not running thermostats? It is very beneficial to the engine to bring it up to temperature as quickly as possible and maintain a minimum temperature. Something at least in the 180 - 185 degree range. IMO 190 would be better.

Running an engine to cool increases contaminates in the oil, increases engine ware and decreases engine efficiency.

Re: 1935 coupe overflow tank recommendations
 

First, be very careful pressurizing your stock radiator, they are not designed for that and you could ballon your tanks, or worse yet bust a seam. There is a pressure valve available that keeps it to around 4lbs. that is available. (someone can chime in with where they are available, I know they are listed in the V8 Times).

I just wired a plastic bottle near the bottom of my grill to catch any overflow, I can pour it back in the radiator if necessary. My car like your runs cool and only pushes out coolant at higher speeds. My level normally runs below the top of the tubes, if I fill to top of tubes, coolant is being pushed out at lower speeds, and the car does not run any cooler with that extra coolant.

Re: 1935 coupe overflow tank recommendations
 

The car never had them initially I'm told. I dont drive it in colder weather and as a result it doesn't take long to stabilize at normal operational temperatures. I will be looking into that after I tackle the overflow tank. Today's oils are much better with temperature extremes. Do you guys use zinc additives for the valve train on these old flat heads? As far as engine efficiency, my old IC engine course taught us best efficiency comes with large temperature differential between intake air/ fuel vs combustion. I run my race engines with 160° Thermostat. Big difference between that and these old flat heads I know. Lol

Re: 1935 coupe overflow tank recommendations
 

Thanks for the heads up Cali.

Re: 1935 coupe overflow tank recommendations
 

Some bad info here! If you were told they didn't have thermostats originally you were told wrong. Original thermostats were in the 160 range. This was partially because of the alcohol based antifreeze. Ford raised the thermostat temperatures through the years as other factors allowed it. Ford engines understood thermodynamics, but there were other practical reasons that limited the ideal, and a lot of these limits do not exist in todays world.

Second issue, there is a big difference between carburetor intake temperature and engine operating temperature. You want the coolest intake temperature (for performance, not necessarily for daily driving) you can get. That is totally different from engine operating temperature and has very little to nothing to do with thermostats. Internal combustion engines are heat engines, you are taking in a fuel/air mixture and converting it to heat. Any lost heat is lost energy. One of the goals of modern engines is operating at and maintaining increased temperatures, which is higher efficiency. That is the principal behind turbo changers, you are recovering some of the lost heat energy in the exhaust gases.

The greater the operating temperature of an engine the greater the efficiency. On a flathead engine with an unpressured coolant system the best you can do is in the 190 to 195 temperature range.

If you are running a race engine with 160 degree thermostats you are losing performance potential. You want the intake air cool, but the engine at as high an operating temperature practical. Any heat loss to the cooling system, exhaust, etc is lost heat energy.

Re: 1935 coupe overflow tank recommendations
 

Not sure this is the fix to Bullsharks' issues but Skip Haney sells the pressure valve setup.

Re: 1935 coupe overflow tank recommendations
 

If you are looking just for a catch can any old empty beer can, conveniently located will work.
A catch and recover system requires a recovery cap and filler neck that fits the cap, along with a recovery tank.
https://www.fordbarn.com/forum/attac...9&d=1592748953


https://www.fordbarn.com/forum/pictu...ictureid=42585

Re: 1935 coupe overflow tank recommendations
 

A catch and recover system requires a recovery cap and filler neck that fits the cap, along with a recovery tank.


Not so in this case....with this style radiator, the overflow tube is mounted at the uppermost part of radiator. If you run the other end of the overflow tube into the bottom of a catchcan, as coolant expands, it will fill the catchcan, as coolant cools, the coolant in the catchcan will by the vacuum created, be drawn back into the radiator; the radiator will always be full to the brim, irrespective of coolant temperature....the secret is that the radiator cap must seal perfectly. I run this setup in my 35, have done for years with zero problems

Re: 1935 coupe overflow tank recommendations
 

A little different but on my Model A with a Quail radiator cap I made sure it sealed, bought an aftermarlet plastic tank at NAPA I think, ran a tube from the overflow tube to the tank, as stated above after shut down anything in the tank was sucked back into the radiator.
Paul in CT

Re: 1935 coupe overflow tank recommendations
 

Thanks for everyone's input here, much appreciated. I think my take away will be along the lines of finding a inconspicuous catch can/ overflow tank small enough to fit in front of the radiator and behind the grill connected as described above so it sucks coolant back after cooldown. Hopefully larger than a beer can. :) I would like to keep the car looking as original as possible to the casual observer. Sorry for the "BAD" info J. I believe some car show guy that told me about large washers to restrict coolant flow and led me to believe the car didn't incorporate thermostats back then. I'll probably look into putting them back in if for no other reason than to help restrict the coolant flow to the radiator during high rpms.
In my case, the contribution of the thermostat value (160 vs 190) to engine thermal efficiency is very low, at least the way I understand it. Please chime in if I'm wrong J. I blow through the temperature range that the thermostats do any control in less than a few minutes. What is the thermal efficiency of these old 85hp flatheads anyway? Less the 20%? Much more sensitive to engine performance is probably combustion efficiency. Beyond the manual choke, I'm ignorant of how best to approach that on these old engines. :D

Bullshark

Re: 1935 coupe overflow tank recommendations
 

The washer idea comes from back in the 50s/60s. It was believed that slowing the coolant flow down gave it more time to exchange heat in the radiator. Don't think that idea holds up, but IMO at higher rpms the volume of water flow can overcome the rate of flow through the radiator cooling tubes and get pushed out the overflow. These early flathead cooling systems are non-pressurized.

160 degree thermostats are sure better than nothing. 175-180 would be much better and 185 to 190 range better yet. :)

Re: 1935 coupe overflow tank recommendations
 

I was told to not fill the radiator to the max. but leave it over the top of the fins but allow enough room for the expansion of the water without getting it the overflow tube. this allowed for expansion and did not allow for the siphoning action to occur.. Worked for me.. kx