Pressurized vs non-pressurized cooling system

[Gary_Ash]

I'm building a replica of a 1932 Studebaker Indy car [see thread in Speedsters], and it's time to order a radiator.  The engine block I'm using is a 250 cu in straight 8 from a 1937 Studebaker President sedan which has an external water pump with a packing gland.  The original cooling system probably was not pressurized, but I'm thinking of going with a 4 psi cap to keep the coolant boiling point up (gain ~2.5 °F per psi).  The engine will be running 4 carbs with a high compression head, and perhaps putting out 190-200 hp versus the original 115 hp, so cooling will be an issue.  I think the water pump gland will take this pressure, but I'm leery of going higher.  I expect that the block will take the 4 psi pressure.  I'm having a new radiator custom built from my Foamcore model, so that will be OK with 4 psi.  Have other people gone to pressurized systems on cars that were not originally pressurized?  Are there any issues I missed?

 

It seems there is an almost infinite variety of filler necks for radiators.  The old ones from the 1930s used two or three internal tangs, like a gas tank cap and neck, while modern filler necks use a cap with two claws on the outside.  The width of the claws is changed with the pressure rating to prevent putting a 14 lb cap on a 4 lb system so that the radiator won't blow up.  Nominal pressure ratings are 4, 7, 10, 14, and 16 psi.  Additionally, there are several diameters of necks and caps, further complicating the choices.  The details of necks and caps are covered by SAE specification J164.  I'm thinking of using the "medium" size (1-5/8" i.d. neck x 3/4" deep), as was common on 1960s cars, etc.  I'll have to adapt a cap sealing mechanism to fit under the 5" diameter cap from 1932 that originally used three tangs.

 

The original Studebaker Indy cars used modified radiators that might have come from Ford AA trucks.  I've seen one of the originals with a Long Manufacturing label having the model number 427Y.  Can anybody verify where that Long part number was used?

Edited April 18, 2017 by Gary_Ash (see edit history)

[Rusty_OToole]

It's impossible to be sure but the pump and seal look a lot like what is used in home hot water heating systems that run 20 - 30 pounds of pressure. I think you should be safe with 4 pounds. My main concern with putting pressure on an old non pressurized system would be the heater core and rad, and you have taken care of that.

[edinmass]

Gary, are the head bolt/studs wet? The packing on the pump probably won't like the pressure. If you only concern is picking up a few degrees before you boil, just run Evans Coolant. I don't see the need for it, but evens in an open system won't boil until 325 degrees if memory serves me, It's more likely you will need to slow the pump down if your spinning the motor fast, or, just set up the head for a modern thermostat. Were you planning on running an electric fan? You may find out at low speeds you need more airflow, and at track speeds you will be fine. Making the radiator too large can also be a problem. I know the best radiator guy in the world........yup it's a big statement but I am sure it's right. PM me if you want to get his contact info. They use engineering equations of fuel,rpm, ect to properly figure out one off radiator sizes. He has faced much more difficult situations than your dealing with. Ed

Edited April 18, 2017 by edinmass (see edit history)

[edinmass]

PS-I wouldn't use a packing on any water pump for any car I have. I install modern ceramic seals that last for ever. My 36 V-12 is twenty years out of the shop with 20k on it. It's never leaked, and has sealed bearings so it never needs to be serviced. Ed

Edited April 18, 2017 by edinmass (see edit history)

[Grimy]

I agree with 4 psi AND with Ed's comments about ceramic seals and their longevity--I have four cars with the ceramic seals installed 10-22 years ago with no issues.

 

For the 4 psi (no more than that), consider using a remote fill tank (was mounted on inner fender panel) from an early 1960s FoMoCo V8 with a neck ready for a pressure cap and an overflow tube.  These are metal and can be mounted low, on the frame--but if done that way you will have to fill through the OEM neck, which needs a good seal.  I have a couple of similar BMW plastic remote-fill tanks around the shop too, but they won't look right.  A friend has the FoMoCo units on the frame on his '27 and '28 Buicks and only has to top off annually.

[Curti]

Yes, ceramic type 16 pump seal on both sides. You will have do do a bit of machine work but is is well worth the effort. 

[Ron Lawson]

From my experience it is not the pump seal that is the problem If the radiator core is the Honeycomb type they are NOT suitable for a preasurised system 

[alsfarms]

Hello Gary,

I am interested in how you turn out with your custom radiator build.  I also will be having a custom radiator built.  I like the concept of using a brass FOMOCO overflow tank with the pressurized system you are designing.  Good luck and please let us know who you choose for fabrication and how it all comes together for you.

Al

[Gary_Ash]

My current plan is to have The Brass Works (www.thebrassworks.net) build the custom radiator using a 4-row, 3-1/2" deep core with modern tube style.  Core size will be ~18" wide x 17" high, plus upper and lower tanks.  Heater core?  We don't need no stinkin' heater, LOL!  The original Studebaker Indy cars did not have fans, but if you are driving 120-140 mph, a fan isn't needed.  But, don't try driving in stop-and-go traffic.  The mounting point for the fan at the front of the block is so high up that the blades would cut through the radiator hose and hood, so I can't use a standard fan anyway.  I'm planning on a 16", 12 volt electric "puller" fan and shroud on the inside of the radiator.   The Brass Works also offers a selection of overflow tanks.  However, I think one needs to use a modern 14 psi cap and filler neck with the overflow tanks to get the radiator to suck the coolant back into the radiator, as well as all of the correct line fittings.  Frankly, it seems much easier just to go with a non-pressurized system and the old 2-tang cap, and give up the potential benefits of higher pressure.  Using 50%-50% antifreeze and water will raise the boiling point anyway compared to the plain water they used in the 1930s, and the 4-row core will make a big difference, too.  The alternative is to just mount the old-style radiator cap or bird mascot as an ornament and have a pressurized filler cap under the hood and out of sight as part of the upper radiator hose assembly, like the streetrodders do.   

 

I did see something in a Model A Ford catalog about using a sacrificial zinc anode in the cooling system when one has an aluminum head.  Anyone have experience with that?  

[alsfarms]

How soon do you plan to have your radiator building project in motion?

Al

[Gary_Ash]

Al, I'm hoping to send them my Foamcore model and drawings with dimensions in about 2 weeks.  I just need to pin down the final height of the filler neck and the type of cap mounting.  I'm waiting for a call back from The Brass Works this morning.  The guys at The Brass Works said previously that an exact size model in wood, cardboard, Foamcore, etc. was better for them than a technical drawing because the model leaves little to the imagination and is a better predictor of a good fit.  I did find that I had to shave the backs and corners of some of the fins in my grille to get my model to sit in the right place.  I want to get all the mounting holes and trimming done on the shell before I send it to the platers, so having a radiator in hand is key. 

[alsfarms]

What is the lead time projected by Brass Works to custom fabricate a radiator for you?

Al

[Guest BillP]

With a packing gland, my experience is to give that zerk a shot of grease before turning the engine if it has not run for more than a couple weeks. I suspect that the coolant seepage dries and slightly crystallizes, cutting the seal.