Royce.....Here's where I'm at so far. The engine will idle and get warm. OK, that's at it should be. But, drive it for 3 miles and she boils over like Mt. Rainier is about to blow. I pulled the Z head, could not see any cracks in the head or block. Dosen't mean there's not one, just couldn't see one. The gasket was OK as well. The water pump is working as it should. The radiator is clear. The point is the car was running cool, the belt stretched and the pump/fan quite working. The engine got hot. I was on the return trip to Lufkin and no where to turn off. When I could finally pull off she was HOT. After I got things working again I found I had about a 3 mile limit before a repeat performance. I'm about to conclude I have a cracked block. I'm going to take it to Ross L and do a replace head to rule that out. The engine runs well until she get to boiling over and then she runs rough, misses.
I tried the liquid glass treatment and no go. I suspect I'm going to be looking for another 26 block. Let me know if you come across one. A complete engine, restored or not will work as well. Need to get Ole Black running again.
Sounds like retarded timing, nothing more.
A cracked block or warped head would leak but not normally make it run hot unless you loose too much water. Is it leaking or blowing steam/water vapor out the exhaust?
Did you check and rule out each of the following?
Running the mixture too lean or maybe a partial blockage of the main jet.
Running with timing retarded.
Water level below the top of the radiator core.
Blockage of water flow.
Working the engine hard and low speed, in other words lugging the engine.
Restriction in the exhaust system.
Lack of air flow through the radiator.
Old tied radiator.
I would suggest that you find the exact cause before thinking of replacing the block or head.
I'd certainly check out everything on Jim's list above. From what you have said I suspect it's either timing retarded or the mixture is too lean. They're what I'd check out first.
Good luck and let us know how it turns out!
Jerry - You said,...."the belt stretched and the pump/fan quite working."
Did you mean the pump/fan QUIT working? That is, quit as in stopped and no longer turning?
If so, I'd tighten the belt and make sure the pump/fan is again turning. In fact, there are many on this forum (me included) that would suggest taking the pump OFF and running without it. A bit of rumbling and gurgling of the cooling system after a run of several miles is quite normal. For what it's worth,....harold
If the pump isn't turning its actually causing about a 90% blockage. Toss the pump...
Could be the pump impeller is rusted away? In any case I would try it with no pump Jerry.
Sorry Jerry but you really went about this from the tail end first. Jim's list saves me some typing and is the route you should have followed. Honestly you get so hot so fast that a leaking head gasket or a crack would be on my mind too but that's not where to start checking. Right now I'm with the blockage in the cooling system crowd and that pump is #1 on my list. Remember also that anti freeze will billow white smoke out the tail pipe if it's getting into the cylinders and the spark plugs condition could indicate a leak of this type too.
Know I don't have a radiator/fuel mixture/timing problem. I'm caving in to Tim Eyssen and will go w/o the water pump. I don't see that as the problem or a solution but running out of options. I took the pump off and the impeller is fast to the shaft so I know it moves water. In 45 plus years of model t/ing I/ve never has this to happen. Everything else, yes, but not this. Beat's me....
One of my speedsters had a waterpump that , after putting a new radiator on it, circulated the water so fast it couldn't cool. I drive that car 50-55 and sometimes faster, and it's not overheated since removing the pump. Waterpump was a good crutch until I could get a new radiator.
Mike, Exactly, Racing sprint cars for many years, seen many cars that had the same problem, NEW radiator and pump and only made over heating worse, Until we put a restrictor plate in line,
Circulating water so fast it can't cool I'd have to see to believe. However cavitation because the pump is pulling harder than the the source can supply is common. The cure for cavitation is to slow the pump, or restrict the output, or increase the supply flow.
Cavitation is the formation of vapour cavities in a liquid – i.e. small liquid-free zones ("bubbles" or "voids") – that are the consequence of forces acting upon the liquid. It usually occurs when a liquid is subjected to rapid changes of pressure that cause the formation of cavities where the pressure is relatively low. When subjected to higher pressure, the voids implode and can generate an intense shockwave.
Cavitation is a significant cause of wear in some engineering contexts. Collapsing voids that implode near to a metal surface cause cyclic stress through repeated implosion. This results in surface fatigue of the metal causing a type of wear also called "cavitation". The most common examples of this kind of wear are to pump impellers, and bends where a sudden change in the direction of liquid occurs. Cavitation is usually divided into two classes of behavior: inertial (or transient) cavitation and non-inertial cavitation.
Inertial cavitation is the process where a void or bubble in a liquid rapidly collapses, producing a shock wave. Inertial cavitation occurs in nature in the strikes of mantis shrimps and pistol shrimps, as well as in the vascular tissues of plants. In man-made objects, it can occur in control valves, pumps, propellers and impellers.
Non-inertial cavitation is the process in which a bubble in a fluid is forced to oscillate in size or shape due to some form of energy input, such as an acoustic field. Such cavitation is often employed in ultrasonic cleaning baths and can also be observed in pumps, propellers, etc.
Since the shock waves formed by collapse of the voids are strong enough to cause significant damage to moving parts, cavitation is usually an undesirable phenomenon. It is very often specifically avoided in the design of machines such as turbines or propellers, and eliminating cavitation is a major field in the study of fluid dynamics. However, it is sometimes useful and does not cause damage when the bubbles collapse away from machinery, such as in supercavitation.
Most model T water pumps i have seen are not really pumps but stirrers as the have flat paddles to try to move water,there is no negative pressure side (intake) nor a positive (outlet) pressure, the twisted vane type will actually pump water. I read in one of the many articles that the Ford dealers were putting pumps on in the 26/27 models because of the two row radiators,they would need more tan a pump for those units, my 26 had one when i purchased it and having dealt with hot water and steam, i could tell it wouldn't be enough, i sold it to a friend who put it on a roadster that would never be driven as the person just wanted a model T.
Save your money and get a new radiator ditch the pumps and enjoy driving without having to stop for water every few miles.just my 3 cents.