pressurized radiator work around

[bigd1101]

I am going with a pressurized radiator in the A for a reason that might not make a lot of sense. After having boil overs and hot antifreeze in my face on a few occasions, I got a Brassworks pressurized radiator with an overflow tank because my old radiator was shot and the above reason. I'm sure at this point, the boil-overs should be done and I'll deal with it if they are not because of something else, which I've crossed off the list (timing, head gasket, flushed out water jacket, etc.) Now, the pressured system problems that could arise have all been discussed and I'm thinking that I just might use a zero pressure cap and avoid the potential problems and still get a closed system where I have an overflow tank and a good cap that is not going to spew at me while driving. I'll still have the Quail cap on a fake inlet on the radiator top. Can anyone see why this wouldn't work for me? Right now I haven't installed the radiator yet and it has a 4 lb cap.



Don

[Dave in MN]

The zero pressure cap on the closed system neck will work good. The water that moves to the overflow tank will draw back into the radiator with the zero pressure cap. I have the system you have described with the zero pressure cap in a recently built car and have driven it about 7,000 miles. Some of the driving was to Branson this past summer where the temps were close to 100 degrees.
Good Day!

[bigd1101]

Originally Posted by Dave in MN

The zero pressure cap on the closed system neck will work good. The water that moves to the overflow tank will draw back into the radiator with the zero pressure cap. I have the system you have described with the zero pressure cap in a recently built car and have driven it about 7,000 miles. Some of the driving was to Branson this past summer where the temps were close to 100 degrees.
Good Day!

Perfect! Thanks! I assume it's a standard size cap?

[Jim/GA]

Originally Posted by bigd1101

Perfect! Thanks! I assume it's a standard size cap?

Yes, it is.

You can turn any pressurized cap into a zero pressure cap by cutting off the little brass button that sits in the center of the smaller sealing gasket inside the cap.

[Jacksonlll]

It won’t work with the Quail. You will never get it to seal and hold any pressure or vacuum. Use a tight 16 pound cap , or less, and it should work. All you really need is a full flowing core. No matter what you use, you won’t overheat. The new core will fix that.
We had a pressure system on a short tour and it blew and he lost his engine. Good luck

[bigd1101]

Sponsored Links (Register now to hide all advertisements)

Originally Posted by Jacksonlll

It won’t work with the Quail. You will never get it to seal and hold any pressure or vacuum. Use a tight 16 pound cap , or less, and it should work. All you really need is a full flowing core. No matter what you use, you won’t overheat. The new core will fix that.
We had a pressure system on a short tour and it blew and he lost his engine. Good luck

I'm not using the quail cap for pressure, just for looks. The inlet is under the hood off to the side on a Brassworks closed system radiator. Thus my using a zero PSI cap, so basically its a closed system that is not pressurized and should function like a standard A cooling system with an overflow tank, but no spewing out the top of the top inlet cap if any overheating happens. I have an inlet temp gauge to monitor the engine temp.

[Synchro909]

On the car I am putting together now, I intend running a hose from the overflow to the bottom of a container with no lid mounted on the splash tray. With a standard, sealed cap, I expect most of the coolant caught in the container will be drawn back into the radiator as it cools neven though it will not be a pressurised system.

[30 Closed Cab PU]

Works well if filling the radiator to the top of the overflow tube, radiator cap is sealed well - normal expansion/contraction of the coolant. Container would have to be larger if coolant overheats/boils out through the overflow.


Some use a cap on the container with a vent hole/tube to minimize chances of spillage out of the overflow container.

[Dave in MN]

Originally Posted by bigd1101

I'm not using the quail cap for pressure, just for looks. The inlet is under the hood off to the side on a Brassworks closed system radiator. Thus my using a zero PSI cap, so basically its a closed system that is not pressurized and should function like a standard A cooling system with an overflow tank, but no spewing out the top of the top inlet cap if any overheating happens. I have an inlet temp gauge to monitor the engine temp.

bigd1101,

The size of a zero pressure cap is the same as the 4# cap and they both fit the Brassworks radiators.

A few guys commenting do not understand what radiator you have, I do. I have two pressurized systems with the radiator you name.

I am currently running a sealed (pressurized) Brassworks in my Phaeton with a 4# cap hidden under the hood. I have a Motometer on the car...as you say about your Quail, the Motometer is just for looks.

The second system is a Brassworks sealed system radiator but due to a low spot on my block, I can not hold coolant in one corner if I used a 4# cap. My temporary solution was to use a zero pressure cap on the under-hood opening.

I have used the pressurized system in my Phaeton for over 90,000 miles with no issues. I have used the zero pressure system in my '31 S/W Town Sedan for about 7,000 miles.
I currently have the engine out of the '31 S/W with the zero pressure cap to flatten the top of the block. I do plan to use a 4# cap when I put it back in the car.

Your plan to use the zero pressure cap and a reclaim tank will work. Obviously the reclaim tank should be vented to atmosphere.
Good Day!

[Smog Tech]

Not all pressure caps will work with an overflow tank. You need a pressure cap with two rubber gaskets, one to seal the pressure and one to seal the cap. You can remove the rubber gasket from the pressure seal and run "O" pressure.

[1931 flamingo]

I'm running a plastic overflow tank hanging from the hinge rods, quail,hose from rad to the tank. Water flows into the tank, drawn back into rad at shutdown. Probably zero to 1 lb pressure.
Paul in CT

[eagle]

Originally Posted by 1931 flamingo

I'm running a plastic overflow tank hanging from the hinge rods, quail,hose from rad to the tank. Water flows into the tank, drawn back into rad at shutdown. Probably zero to 1 lb pressure.
Paul in CT

Yeah, I too have a quail and it doesn't leak a drop. Don't run pressure but in the spring I always top off the radiator with antifreeze and it spews out some out the overflow until the level is right so if the cap wasn't quite well sealed wouldn't it leak then? I can't see any reason to run a pressurized system. What would be the advantage? If my engine is over temp,(boiling) I would want to know. If you like to keep the radiator completely full do like 1931flamingo does and connect a hose from overflow to a tank. Not trying to be contrary just wondering what the reasoning is? I know the OP was talking about a sealed system, not pressurized.

[bigd1101]

Originally Posted by Dave in MN

bigd1101,

The size of a zero pressure cap is the same as the 4# cap and they both fit the Brassworks radiators.

A few guys commenting do not understand what radiator you have, I do. I have two pressurized systems with the radiator you name.

I am currently running a sealed (pressurized) Brassworks in my Phaeton with a 4# cap hidden under the hood. I have a Motometer on the car...as you say about your Quail, the Motometer is just for looks.

The second system is a Brassworks sealed system radiator but due to a low spot on my block, I can not hold coolant in one corner if I used a 4# cap. My temporary solution was to use a zero pressure cap on the under-hood opening.

I have used the pressurized system in my Phaeton for over 90,000 miles with no issues. I have used the zero pressure system in my '31 S/W Town Sedan for about 7,000 miles.
I currently have the engine out of the '31 S/W with the zero pressure cap to flatten the top of the block. I do plan to use a 4# cap when I put it back in the car.

Your plan to use the zero pressure cap and a reclaim tank will work. Obviously the reclaim tank should be vented to atmosphere.
Good Day!

Hi Dave.....very helpful post. Your car is a twin of mine in paint and body style. I'm going to try the pressurized cap first. I flushed the engine block quite a few times with a pressure washer after two Thermocare treatments, and a vinegar flush, top inlet and then the bottom inlet until no more "stuff" came out so I think it's pretty clean. The car was boiling over under load at 45 mph and the old radiator was clogged and worn so I went with a new Brassworks closed system. Set the timing too so I should be good to go in the Spring.





Don

[40 Deluxe]

Originally Posted by bigd1101

Hi Dave.....very helpful post. Your car is a twin of mine in paint and body style. Set the timing too so I should be good to go in the Spring

Don

Actually, unless you're running a B distributor, you are setting the timing whenever you move the spark (timing) lever. Fiddling with the timing pin in the front cover and the points cam in the distributor only sets initial timing for starting purposes, and never changes as long as you keep the points gapped correctly (or the timing gears wear out). If you don't advance the timing enough with the lever as you drive, the engine will overheat.

[BillEbob]

Didn’t intend to hijack your thread but topic seems appropriate to interject a question. Would one of you experts please explain the usefulness of a pressurized system in an “A?”

I think maximum pressure is 4 pounds. Each pound give an additional 3* for a maximum total of 12*

I can’t envision what 12 measly degrees will mean to your driving experience. Can’t you simply slow down on that hill and accomplish the same thing?

Bill

[bigd1101]

Originally Posted by BillEbob

Didn’t intend to hijack your thread but topic seems appropriate to interject a question. Would one of you experts please explain the usefulness of a pressurized system in an “A?”

I think maximum pressure is 4 pounds. Each pound give an additional 3* for a maximum total of 12*

I can’t envision what 12 measly degrees will mean to your driving experience. Can’t you simply slow down on that hill and accomplish the same thing?

Bill

Being no expert too.......read my 1st post and why I opted for the "pressurized" system. I really wasn't looking for the higher boiling point in my case. I might end up with a zero lb cap in the end, but I won't have hot radiator fluid in my face ever again if the car overheats for ANY reason. BTW, the price was the same for a stock rad and the pressurized rad.



Don

[Dave in MN]

“I can’t envision what 12 measly degrees will mean to your driving experience. Can’t you simply slow down on that hill and accomplish the same thing?”

Bill[/QUOTE]

Bill,
I am no expert ...just someone who drives his Model A's a fair amount. To help you envision what 12 degrees means to my driving experience, I respectfully offer the following:

I have a stock '28 pickup with an open system that I rarely drive over 55 mph. It works fine. On the days it gets over 100 degrees, I do just as you suggest on the long hills. I slow down. IMO: If you have a stock engine you do not need a sealed system.

I also have a '29 Phaeton with a fully inserted touring engine, mildly ported, touring cam, 5.9 Brumfield head and a few other modifications to produce a little more power. With more power comes more heat. I often drive this car on a freeway in the slow lane. To be safe on a freeway, in my opinion, I need to be moving close to the speed of the traffic. An open system will not work as I choose to drive when the outdoor temps are approaching 100 degrees. I know as I tried it with an open system. I have driven this car with a sealed 4# system for over 90k miles and the cooling system has never boiled over or even needed coolant added during long road trips. Bill, During the summer of 2013, we traveled from east of Albuquerque (where you are from) to Needles, Calif. and when we arrived at Needles at 11:00 am, it was 118 degrees when parked on the blacktop of the motel. My wife and I both overheated that day but our car did not.

I am currently building and testing a '31 Slant Windshield Town Sedan for long trip touring. I plan to pull a camper designed to look like an era correct teardrop. I have installed a Ken Davis air conditioning system (AC) in this car because my wife is on a medication that makes her ill if the air temps are over 90 degrees. I also chose to use an overhead valve head that puts out more horsepower (and heat). With the AC load and outdoor temps over 100, a standard system will not work in this car. I ran it this past summer with a zero pressure cap and we needed to avoid driving when it was much over 90 degrees. When I was doing early testing, the 4# cap allowed the car to operate in 100 degree temps.

Yes, I could choose to slow down on that hill, stay off the freeways and avoid driving when it is over 90 degrees and accomplish the same thing but I choose not to.

I know this site is dedicated to maintaining the originality of our cars and therefor many passionately consider straying from original as disrespectful or wrong. I get it and respect that opinion. Off this site it’s a hobby and we all get to choose what we do with our cars. Don asked the question and some of us tried to address his question without regard for whether it should have or should not have been asked on this forum.

I should add a couple comments: No Model A's were harmed in building my two modified "A's"! Every part I replaced with a modified one was saved in the event that the next owner of my current cars wanted to return them to stock condition. I have two organized collections of parts ready to be passed on.
I build engines for myself and others. I am often asked to build an engine with a little more power than stock. My dabbling in performance engines for myself is a means of testing engine modifications before I offer them to customers. What is most important to me when building and using these engines is durability and performance.

Good Day!

Dave Gerold

www.durableperformance.net