Radiator Cap

[1950 Special Deluxe]

On my 1950 Dodge Special Deluxe (Canadian version), I had to get my rad re-cored. The local old time shop I took it to was very knowledgeable. They knew it was a 0 pressure system. But, when I picked it up, it came with an included new 6lb. cap. Since my overflow is under the cap unlike some of the pictures I see on the earlier models, I think it will be under 6lbs. pressure if I use the new cap. I will include a photo showing both. I painted the old cap and figure on using it. Am I correct?

Thanks

neil

[Young Ed]

I believe you are right and with a brand new core I'd be using the 6lb cap.

[1950 Special Deluxe]

I had it running last week when I replaced the rad, first I ran it with the old cap. Then I put the new 6lb. cap on and let it run. After I turned it off, I removed the cap and it was under pressure. So with the overflow under the rad cap, the 6 lb. cap is working as expected. I realize it will take more to overheat with the new cap, is this better?

Thanks

Neil

[Rusty O'Toole]

With a 6 pound cap you can run a hotter thermostat, you can also add a coolant recovery container.

By doing this you will improve cooling, reduce the chance of overheating, increase the life of your engine by eliminating moisture and gas in the oil, and get more power and better gas mileage. There are no downsides as long as your cooling system can stand the pressure.

[oldodge41]

Any circulation issues since the water pump is designed to work at 0psi?

[Don Coatney]

Any circulation issues since the water pump is designed to work at 0psi?

The water pump is designed to pump water in a liquid state temperature irrevelent. It will do so as long as the water remains liquid and does not flash to steam. Pure water at 1.4 Bar heated to 228F will flash to steam. The flash point with an antifreeze water mix will be higher depending on the concentration. That should be enough information for you to figure it out.

Edited October 22, 2011 by Don Coatney

[oldodge41]

I understand water and steam. I work in a coal fired steam plant. I was more concerned with any difference in volume of liquid pumped at 6 psi vs 0 psi. Maybe none but I just can't wrap my head around it right now.

[Rusty O'Toole]

Should make no difference to the pump, as the pressure is the same on the inlet and outlet ( no pressure differential). If anything, the pressure would guarantee no cavitation and no steam pockets in the system. So the pump should work more efficiently especially under severe heat conditions.

The only thing to be possibly concerned about would be extra pressure causing the water pump to leak. I don't think this is a concern though. They used pressure cooling systems on the flatheads in the late 50s, I expect all pumps today are rebuilt using seals that are suitable for pressurized systems.

O ya if your heater core is iffy it could leak too.

[oldodge41]

]Should make no difference to the pump' date=' as the pressure is the same on the inlet and outlet ( no pressure differential).[/u'][/b]

I'll buy that. Differential is what I was thinking. But this makes sense. Thanks Rusty.

[Don Coatney]

I understand water and steam. I work in a coal fired steam plant.

I also have been there and done that. You must be up to speed on twears and opacity monitors.

[oldodge41]

Opacity monitors, yes, we just installed a new one in the last year or so. What is a twear?

[Don Coatney]

Opacity monitors, yes, we just installed a new one in the last year or so. What is a twear?

The two coal fired boilers in the cheese plant where I worked were built in the late 1930's. The grates for these boilers were called twears. These boilers generated there last pound of steam in 1986. Most likley these twears are no longer made.

[1950 Special Deluxe]

At the moment, I am going to put the original cap back on and keep the 6lb. cap as a future replacement. I did not change the short (1.5") piece of hose between the waterpump and the bypass. Also, not sure of the condition of the heater core and the waterpump itself.

Thanks for the help.

Neil

[oldodge41]

The two coal fired boilers in the cheese plant where I worked were built in the late 1930's. The grates for these boilers were called twears. These boilers generated there last pound of steam in 1986. Most likley these twears are no longer made.

Hey Don, I checked today and the proper name for the individual grates in our boilers is twears. We still buy some occasionally too.

[Niel Hoback]

Sounds like a good name for some of those kids I saw at the mall Saturday night.

[Mark Haymond]

I had the radiator on my 50 Plymouth re cored ten years ago. With a good water distribution tube and the sludge cleaned out of the bottom of my engine's water jacket, the car has never overheated. And I live in a hot climate with 105 temps common in the afternoon, freeway driving and (gasp) the dreaded stop and go traffic that challenges all engines. I am running the stock four blade fan and a 50 50 mix of antifreeze and water. I think you are going to have the same reliability.

[Don Coatney]

Hey Don, I checked today and the proper name for the individual grates in our boilers is twears. We still buy some occasionally too.

Can you post a picture of these boilers?