Car has clean radiator and block and cast iron head with new copper head gasket installed correctly and torqued to 50 ft/lbs and re-tightened after several run cycles. Also has all new stainless valves lapped-in and set at .013" It seemed to run cooler with the water pump installed...(I know, that's Kryptonite to some T folks). What is odd is that it didn't seem run as hot until I took the water pump off to see what difference it would make in cooling. After 20 minutes or so of running at half throttle/moderate advance, I notice water bubbling (boiling) from under the radiator cap. When I stop the engine, I hear lots of heavy rumbling & gurgling from inside the radiator tank along with hissing and water loss from the overflow tube. I don't detect any signs of a blown head gasket. Any thoughts or suggestions would be greatly appreciated.
....running at half throttle and moderate advance.
You may want to try pulling the advance lever all the way down while running at half throttle.
How full did you fill the radiator?
if it's doing this when it's just sitting idling, then what you're experiencing is not abnormal on many cars. Now you know why the previous owner fit a waterpump. My guess is it would run fine if you were on the road and had some air coming through the radiator.
Also, "moderate advance" may be too retarded. This will really add heat to an idling engine if this is the case.
Is it really hot or did you just fill the radiator to the top of the tank.
If it is only slightly hot, antifreeze helps with overheating. About 2/3 antifreeze or more and the rest water has fixed at least one of my cars.
Are you sure it's actually over heating? The noise and over flow when you shut it down is not unusual. It might have been over filled when you began your experiment and blew out the excess. They do that. Re-filling after it cools only causes a repeat performance. You probably know this already. As to the water pump: my last T (23' Touring) had a water pump that was installed by the former owner. He claimed it cured his overheating in a parade problem. Some will say "bad radiator". Perhaps. I never experimented with removing it. It ain't broke ect.
To clarify, I experience the above condition while going down the road at a good clip, say 35-40 mph with plenty of air flow - not idling. The radiator was filled to just below the baffle in the tank with plain water; no coolant added. I also made sure that the fan belt was adjusted correctly. The fan blades all have the correct pitch to them and it seems to be drawing lots of air through the radiator - even at idle.
Two things can cause overheating on a Model T (assuming a decent rad..) retarded spark and or, too lean a gas mixture. Some 'gurgeling" not uncomon after shutting down. Sounds like you need to advance your spark setting. good luck--paul
Sounds more like the bad rad or incorrect timing clubs are on to something.
I don't believe I saw where you said how old the radiator is. If it is original or even a replacement from decades ago, my money is on the radiator. What happens is that through years of vibration, the fins no longer fit tightly to the tubes and therefore can no longer carry the heat away and into the air. They can be clean as a whistle inside, but still not cool.
You might try advancing the spark more. Certainly won't cost anything to try, but my money is on the radiator.
I'll work on the timing advance and mixture settings and see what happens. Thanks all for the helpful tips!
My personal opinion is that if it runs cool with a pump, and hot without it, the radiator is telling you something. I would reinstall the pump and start looking for a shop that can re-core the old radiator.
Yep, the pump is going back on and I am suspicious of the radiator even though it was recently cleaned at a reputable radiator shop.
As Hal says, an old radiator may not work no matter how clean it is, for the reason he explained. On brass era radiator, if the tanks are good I would go with a recore rather than a new radiator, for a couple of reasons. For a black era car, I'd get a new Berg's.
Several things I can think of. The previous owner or someone must have had a heating problem and that's why the water pump was installed. Here are some questions. You live in Texas. Is it hilly or flat where you live? How hot was the weather? Another question, did you also replace the pistons or rings? They will run a bit hotter until broken in when you replace pistons and rings.
Here is a suggestion, run the engine as you have at night and then when it gets hot, lift the hood and check the exhaust manifold. If it glows red hot, you have either or both, retarded spark, lean fuel mixture.
I live in the mountains and sometimes it gets to 100F or more I can drive it uphill and it will not boil, but when I shut it off the water will gurgle. No bubbling out of cap or overflow, and after it cools I can check the water level. It is about even with the Ford emblem on the front of the radiator. If I fill it fuller it will overflow until it reaches that level. That is normal.
An old radiator can be clean and without leaks and still not efficiently cool the engine. With your Express wagon, you might have a bit more weight than the average T. That could also cause it to run a bit hotter, but it should still cool well if you run it along.
It seems that I commented on this several days ago but I'll give you another 2 cents worth. I had the same problem and found that a baffle got loose in the top tank and covered the top of the core. I didn't realize this until I ordered a new radiator in desperation and took the old one off. Hence a rattle rattle and the realization of the cause.
Our #22 Speedster always ran hot from the day we brought it home. Upon close examination we discovered that it had a two row round tube radiator. We had it rodded and boiled out and it still ran hot. We had a custom five row pressure radiator made and the core comes almost all the way back to the rear of the top tank. We installed an overflow tank and it runs rather cool now even without a water pump.
The fins of any radiator must make contact with the tube in order for the heat to transfer from the tubes to the fins where the air passing by removes the heat. You can paint a questionable radiator the the paint will transfer heat from the tubes to the fins. but you will only get a marginal improvement. If it does cool better ,get a new core. Most radiator shops will not install the mounting plate that spans across the lower part of the radiator and it will not look right, but I have three go fast Speedsters and don't care about originality.
We use a seven pound pressure cap and an electric cooling fan with no water pump. Some Speedster runs don't like our set-up but we do and it runs very well. Several first place hill climb trophies including F.A.S.T. and the Lincoln Nebraska event hang on our walls.
IF it is an old round-tube radiator, I am guessing that there are several tubes that are clogged. I've had two of those old radiators cause the car to boil and both were cleaned by reputable shops. Both had about 30 tubes that were clogged solid. Problem is, the sloosh they use these days is made to be "green" friendly and doesn't have enough strength to clean out the tubes if they are clogged. You probably need to pull the bottom tank and rod out the tubes.
I don't care how clean the tubes are the radiator will not cool adequately if the fins are not making contact with the tubes. That is the only way a radiator can dissipate heat effectively. I have 2 beautiful water tight brass radiators with all the tubes wide open and neither of them cool adequately because over years of vibration the fins no longer make contact with the tubes. They are both sitting on a shelf and were replaced with Bergs brass radiators when he was still making them.
Frank - You said,....."Most speedster runs do not like our set-up,.....Just curious,.....what is it that they object to, the pressure?
Age will usually catch up to original radiators no matter how good they look.