35 water pumps

D

drezin

Member
I have a 35 with stock motor. And new higher volume water pumps. Recorred radiator and no combustion leaks. At 45mph no problems, but at 55 mph t will throw about 3 qrts. out the overflow in about 10 miles. Flow Is a lot of volume even at idle.I am thinking of removing the impeller shafts and turning about 25-30% off the bavk side of the finns. Any body else have this problem in a 35? I have thermostats in it.
 
How full is your radiator before you start? I could be your starting with it too full. If your starting with it just below the filler neck then it’s too full, it should be about an inch or so above the tubes.
 
1935 Fords had various design radiators; one design, subsequently dropped from production, had the overflow tube located in the vicinity of the filler. At higher engine speeds, coolant is pushed directly outta the tube. A later factory improvement placed the overflow at top centre of the header tank, under a little cap. Which design radiator do you have?
 
With respect, both the small tank and large tank '35 radiators were used until the end of '35 model production. According to the engineering release forms at the Benson
Ford Research Center, the small tank radiators were used by U.S. assembly plants located in cooler climates and the large tank radiators were used by U.S. assembly plants in warmer climates.
 
doesnt seem to tempature related. More rpm related. I think the new pumps are pumping more coolant than the original and the new core can handle.At 45mph there is no coolant loss,but at 55mph it will loose 3 qt in 10miles. It does this with the temp. at normal and then heat up. I start with coolant half inch above cores. There is a lot of difference in the impellor in the original pumps vrs. the new pumps.
 
Also I have the small tank and the overflow is top center. Stats are opening. I think the new improved pumps are just pumping too much for my system.I think I will work on the impeller.
 
David, I respect your wisdom on early Fords, particularly 32's. No where in my dialogue did I mention tank size, rather I was talking about the position of the overflow. Ford encountered the very problem Drezin is experiencing, when, with the overflow tube located under the filler cap, at higher engine speeds the flow from the pumps would push coolant straight out the tube. As a fix, they relocated the overflow tube to the very topmost portion of the header tank. Drezin has advised that his overflow is located at that position. So, obviously his new pumps are 'too good'!
There are two possible fixes, apart from whittling some off of the impellers as Drexzin suggests;

There is a guy who offers a 3 lb check valve that installs in bottom of overflow tube.
Or, what I do, and various members on here pooh pooh the idea, is to run the end of the overflow into the bottom of a catchcan. The radiator cap must seal for this to work. Fill the radiator to the brim. As coolant heats and expands it goes into the can, as it cools it siphons back into the radiator. The radiator is always full to the brim, irrespective of engine RPM's or temp.
 
I read the whole thread, and it seems clear to me that he is starting with the coolant slightly above the core, and it it will throw water out at higher speeds until it gets to a state where it starts to heat up.

At least that is what I am reading.
 
Tubman: you are correct, I am going to reduce the impellor to reduce the flow. Thanks everyone for your input

\\
 
Let's think about this for a minute. Facts: Water half an inch above core is pefect. The water is not being boiled out, it is being pumped out. The problem only occurs as speed is increased.



What could cause the water in the top tank to build up to the point that water is forced out of the overflow? The only thing I can conceive is that the pump is cavitating and essentialy blowing air into the block and forcing water up into the top tank. Cavitation occurs when the pressure inside the pump drops below the vapor pressure changes and turns liquid into vapor which can happen when there is insufficient pressure at the suction end of the pump.

If your radiator is clogged and not flowing freely, that would result in reduced pressure at the inlet side of the pump, promoting cavitation. Probably not the case since your radiator works fine otherwise. That leaves the possibility of the water pump being overdesigned and causing cavitation at too low pump rpm.



Maybe go back to stock pumps or Dennis Carpenter pumps which are only a slight improvement over stock. Which is good for cooling at idle but not prone to cavitation at high RPM. Maybe cavitation was the reason that racers on the old Modified Sportsman class of stock cars removed half the blades on their flathead water pumps. Maybe Ol' Ron can fill us in.
 
I would suggest that if it is financially feasible, I would opt for a set of "less aggressive" pumps and try them. No sense in messing with reputedly good parts unless you are absolutely sure where the problem lies.

I expect that was what you are planning but just want to make sure.
 
Where did you get the HP pumps and who makes them? I didn't know they were available for early motors.
 
You must log in or register to reply here.
Back
Top