pressurizing the radiator...

[39portlander]

In the V8 Times, Skips got a set up to convert the cooling system to a 3lb system. I want to add it to my new radiator/fan/shroud set up. I plan on ordering it and I wanted some input from the barn. I'm thinking it will work great with my "Skips pumps"

[ford38v8]

Skip's item is in tended for radiators having the overflow pipe separate from the radiator cap location. If yours is there under your cap, simply use a 7 lb pressure cap and you're good to go.

[G.M.]

See if the over flow comes from the filler neck or off the top of the top tank. If from the filler neck you only want a 4 lb pressure cap. I have had some radiators that had the over flow off the tank but had the washer seat down in the radiator. On these I cut the over flow tube off the fitting at the top of the tank and plugged the tube. Drill a hole in the filler neck smaller the the OD of 1/4" copper tube and dimple the hole out from the inside slightly. Put a SMALL flare on the end of the 1/4" tube. Cean the flare and around the new hole inside and out. Slide the straight end of the tube through the counter sunk hole from inside of the neck and shape the tube down the corner of the radiator. Solder the tube in the neck. There is a problem with a lot of these old radiators or the pressure caps, they don't seat down on the bottom seat in the neck. If they don't seat you don't have a pressure cap only the top is seating. When you put the cap on before twisting to lock it push it down and you should feel the bottom spring compress about 1/8" before the top seat hits the top of the neck. I have some I had to put a rubber or fiber washer down on the bottom seat. I clean the bottom seat good and put a little silicon on the seat to hold the washer in place. Skips 3 lb valve works for radiators without a provision for a pressure cap. The idea of the pressure cap is only to keep the coolant from free flowing out the over flow tube. When the over flow is open all the time the back flow resistance from the 144 radiator tubes causes the coolant to back up in the tank and out the over flow. The pressure cap or valve allows the pumps to force the water through the tubes and allows you to fill the coolant up into the radiator neck and it stays there for months. More water equals better cooling. The pressure cap or valve on these engines has NOTHING to do with raising the boiling point it is only to keep the water in and is also a safty valve incase of a problem releasing the pressure. At 210 degrees there is less than 2 lbs pressure in the system. If the temperature ever gets that high you have a cooling problem. G.M.

[39portlander]

Originally Posted by ford38v8

Skip's item is in tended for radiators having the overflow pipe separate from the radiator cap location. If yours is there under your cap, simply use a 7 lb pressure cap and you're good to go.

Talking w/Walker radiator a 7lb is what they reccomended.
George, thanks for the info. I treat your posts like technical bulletins

[G.M.]

If the pressure under normal conditions on a stock engine never gets over 3 lbs a 4 lb cap is all that is required which is what was used on the early modles. The cap on these engines is only to seal the over flow and act as a safety valve. The less pressure in the system the less chance of damage to you and engine parts. G.M.

[Coupe35]

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The 3 pound valve for me never worked. I would still lose water. The engine heats up, the valve opens and out goes the water. It never kept anymore water in the system than there was without the 3 pound valve. I’ve found the best idea is to use an over flow tank. When your in traffic and the motor heats up the water goes to the overflow tank. When you rev the engine up the engine cools down and water returns to the radiator. Since I’ve installed the overflow tank I have not lost a drop.

[G.M.]

Hundreds of people use the 3 lb valve with good results. You must have other problems if it didn't work. Probly a small compression leak. G.M.

[oldford]

It's the same old story. When ever somebody has something negative about the 3 pound valve not working, you always say its a compression leak. No way could it be the fault of the valve. I agree with coupe. Not sure about the 3 pound valve but an overflow tank is a must with these old engines. And it's true. When the engine gets hot, a mere 3 pounds is not going to keep the water in.

[Brian]

Ditto what old ford says- I've run a catch can in my '35 for years. The radiator is always full to the brim and I have no overheating issues. Prior to fitting this unit I always found the coolant was pushed outta the overflow and lost which meant I was continually having to replenish coolant. I am not saying Skips valve doesn't work; I've never used one, but it is so easy to find a plastic overflow bottle out of some junked modern car that will fit your particular application and fit it and never experience loss of coolant issues with your old Ford. [Just the Scotsman in me I guess!] Brian

[G.M.]

Oldford I say that because it's true. If the 3 lb valve don't work there is a problem with the system or the valve is stuck from excessive crude. It's very easy to remove one hose clamp and put the valve under the water hose and flush it out. When working the water will flow in one dirrection and be blocked the other. This is in the instructions that come with the valve. There are over a thousand in use and if someone has a problem with one all they have to do is call Skip. I have them on all my drivers that don't have pressure caps and never add water for 6 months or more in 90 plus degree weather. Also evryones idea of hot varies. In the old days hot was when it boiled over. Hot to me is 200 degrees. The 3 lb valve will hold the water below 210 which my cars never get anyway near. At 200 degrees there is less then 1 1/2 lbs pressure. Most all off these engines have slight compression leaks and need Barrs stop leak to seal them which is also in the instructions with the valve. G.M.

[rotorwrench]

3 PSI in the system will hold the boiling point to a fair bit above 212 degrees F. If pressure in the radiator is pushing the PSI over 3 lbs and the temp is below boiling, that extra pressure is coming from somewhere. A compression leak, even a small one, will increase pressure in the system & blow out the valve. Water/coolant mix doesn't expand much unless it starts to boil.

[FlatheadTed]

I talked with a old Radiator guy with 45 years esperance in building Radiators, he rebuilt one of the cores in one of the cars that threw water coming back from the nationals .I have yet report on the result .But he did say some of the problems encountered in the rebuild ,The core was to small ,this is critical on 32 to 36 for grill fit . The top tank needed panel work the neck was low. the baffle was not in place this he said is critical to limit throwing water ,Lime deposits in the tubes insulating the heat,

[38 coupe]

The volume of 5 gallons of water at 59°F increases by just over 3 cups at 203°F. Pressurizing the radiator won't hold this in, this is a liquid volume change not a gas volume change.

The math to calculate is as follows:
first find the mass of 5 gallons of water at approximately 60° F

and using the density of water at 59°F since that is what I easily found

(999.2 kg/m^3) * (m^3 / 264.17205 gallons) * (5 gallons) = 18.91 kg at 59°F

then find the volume of 18.91 kg of water at 200°F

and using the density of water at 203°F since that is what I easily found

(18.91 kg / (962 kg / m^3)) * (264.17205 / m^3) = 5.193 gallons
which is an increase of 0.193 gallons
and
0.193 gallons = 3.088 cups


and the properties are from here: http://www.engineeringtoolbox.com/wa...ies-d_162.html

[Straightpipes]

I have ran mine for years without any pressure other than the stock cap and it never overheats. I never overfill the radiator to allow for expansion.
When I built the engine I took out about a quart of casting sand and a lot of other crap. Then had the radiator recored. A lot of this overheating bussiness is timing or else the block has never been properly cleaned.......

[JM 35 Sedan]

I'm a happy customer with Skip's 3# pressure valve and water pumps on my '35 fordor sedan. Prior to adding these items my rebuilt '35 221 engine would continuously lose coolant and then over heat. After adding the relief valve the coolant loss stopped. When I installed the pumps I got a 10-15° temperature reduction. It is possible to put the relief valve on wrong if directions are not followed. I drove 150-200 miles on the Saratoga covered bridge tour with no problems while some needed to add water every time we stopped. I'm a happy camper thanks to Skip Haney.

[FlatheadTed]

There is a way to check for a cylinder leak , that's with a clear plastic tube on the over flow with a glass or other container .When the leak starts you will see bubbles coming along the tube. The Radiator cap must be tight .I thought 38 coups post was interesting I always wondered about expansion .

[35cab]

Interesting discussion, thanks guys. Now a dumb question, in my 35 I have a modified original rad with a filler cap with overflow outlet off the top tank, takes a modern 7 lb cap, also have a catch can.
After running it gets hot and checking the catch can there is no water in it.
I suppose there could be an air lock or other form of blockage, or the cap is faulty?
Going to having a look at it tomorrow, appreciate any advice.
Thanks.

[Coupe35]

Again I say, you can not fill the radiator to the top and expect the water to stay in with the 3 pound valve. As the figures suggest, water expands. The ones that are using the 3 pound valve most likely have the water level down in the radiator far enough that it will not come out, valve or no valve.

[G.M.]

Wrong the water stays filled for months. Maybe the hoses expand enough but the 3 lb valve or a 4 lb pressure cap will allow the coolant to be filled up to the neck and stay there. G.M.

[ford38v8]

I knew George couldn't let that one go!

[JM 35 Sedan]

Before I installed Skip's 3# valve, there was no correct coolant level that I could find that would prevent water loss. As more and more water escaped the temperature would go higher and higher until it reached the boil over point. Maybe a recovery tank would have stopped this, I don't really know. I also know that rust/crud build-up in the pressure release valve will prevent it's proper function.

[G.M.]

JM one has to install the valve with the red dot up toward the radiator so the valve is working in the proper dirrection. Installed upside down the valve will be closed at all times blocking the over flow pipe. G.M.

[JM 35 Sedan]

George, my check valve is working well with only a few visible drips of coolant after a long run at 50-60 MPH at 90° + temps. I also recently installed a nice NOS '35 radiator cap that I bought from a fellow Fordbarner. I drove my '35 fordor ~ 200 mile on the tour at Saratoga Springs with no problems. I am planning to remove the check valve and make sure it's clean internally before heading to Auburn next month. I really do not want to install a recovery tank on an original rouge class car.

[G.M.]

I see no need for a recovery tank as you also descovered. It is best to run the engine WITH THE CAP REMOVED until the engine warms up to about 150 degrees. This gets rid of all the air in the system. keep topping off the coolant as it warms and fill up to the neck. With the valve or a working pressure cap and no compression leaks the coolant remains at that level for months. G.M.

[FlatheadTed]

I know a check valve is less intrusive than a over flow tank put on a Rouge class car but it still a modification I have found a over flow tank works two .These are all fixes for a poorly functioning system .as in my car that has 20 od less tubs than what Ford put in .This is not a put down of Skips valve it obviously works as well.On a modern car if you top up the water it will dump water into the over flow tank after it gets hot .When it cools of it sucks it back insuring that it is always full .This system is used universally .They obviously did the R&D . in saying that you will still need to top up occasionally .

Originally Posted by JM 35 Sedan

George, my check valve is working well with only a few visible drips of coolant after a long run at 50-60 MPH at 90° + temps. I also recently installed a nice NOS '35 radiator cap that I bought from a fellow Fordbarner. I drove my '35 fordor ~ 200 mile on the tour at Saratoga Springs with no problems. I am planning to remove the check valve and make sure it's clean internally before heading to Auburn next month. I really do not want to install a recovery tank on an original rouge class car.

[G.M.]

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You can't compare modern cars with the old Fords. They are made to run at much higer temperatures which makes higher pressures. You won't find a radiator with large flat sides on a newer car like the old Ford radiators the higher pressures would puff the sides out and cause damage. G.M.

[flatjack9]

I run my 39 at 190 deg with an original radiator and have no problems with overheating. I do not fill it to the top of the neck and do not have to add water. I keep the core covered.

[JM 35 Sedan]

Originally Posted by flatjack9

I run my 39 at 190 deg with an original radiator and have no problems with overheating. I do not fill it to the top of the neck and do not have to add water. I keep the core covered.

Are you running a pressure cap? If so, how many #'s?

[flatjack9]

No pressure cap. On my 39 radiator, the overflow comes off the top tank, so I couldn't use a pressure cap unless I altered my filler neck. I've driven this car for 17 - 18 years now with no problems. I did install a fan shroud as the crank driven fan didn't move enough air if I was in a parade or heavy traffic. This is a 276 inch engine. Had the car out today to a car show about 25 miles away. 94 deg out and the engine ran at 190 just like always.

[Ian NZ]

I have a 3lb Skips valve on the overflow pipe of my radiator and I had Bars leaks in the radiator and it blocked the Skips valve and the radiator overpressured and it blew a hole in it. Now before I go on a run I check on the overflow pipe with the valve to make sure it is clear.

[FlatheadTed]

A 21 stud pre 37 differs from the 24 stud in that It took Ford a while to realise that since the 21 stud was sucking the water through the block as opposed to the 24 stud.pushing the water through ,that is it was building in a low vacuum component ,As a pressurised system increases the boiling point so you get the opposite affect with a low pressure one as in the pre 37 it decreases the boiling point .in a 24 Stud you get a back up of pressure at the thermostat ,this increases the boiling point .This hard to replicate in the early motor ,you get the top tank pressurising but then it goes out the over flow ,