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Purdy Swoft · 07-07-2010, 05:48 PM

Running the engine with the spark advanced only 4 or 5 clicks down the quadrant is WAY WAY TOO retarded and will cause overheating. I crank my model A with the spark all the way up. when the engine cranks I quickly pull the spark all the way down. I only slightly retard the spark as needed to control buck at low speed in high gear or in a hard pull as in topping a hill. I have practiced this method for 50 years. There is No advantage in running with the spark retarded, it only causes the engine to struggle and over heat and loose power. If it won't run with the spark fully advanced the timing is off. Antifreeze used in hot weather only contributes to ever heating. I have never found that antifreeze helps control rust in the cooling system. Antifreeze will also leak in places that straight water doesn't leak.

As for the water pump, my bet is that you have ruined it by over tightening the pack nut. It is allways best to back off the packing nut, grease it and then tighten only enough to stop the drip. If you plan to use packing use the teflon rope type. Lead packing wears the hell out of the water pump shaft, I quit using lead packing years ago. I build my own leakless water pumps that need NO packing. I don't and have never used a thermostat in any of my model A's . A thermostat may help as a restrictor on an engine that the radiator can't handle the flow of the water pump. Model A water pumps have a tendency of pumping so much that water is forced out the overflow pipe. When I build my water pumps I grind some material off the tips off of the impeller to slow the flow and keep the water in the radiator. It also helps if trying to remove the water pump without having to remove the radiator. I think that improper spark lever setting is the main reason for your over heating. Good luck.

07-07-2010, 05:48 PM	#12
Purdy Swoft Senior Member Join Date: May 2010 Location: Alabama Posts: 8,099	Re: Cooling system problem Running the engine with the spark advanced only 4 or 5 clicks down the quadrant is WAY WAY TOO retarded and will cause overheating. I crank my model A with the spark all the way up. when the engine cranks I quickly pull the spark all the way down. I only slightly retard the spark as needed to control buck at low speed in high gear or in a hard pull as in topping a hill. I have practiced this method for 50 years. There is No advantage in running with the spark retarded, it only causes the engine to struggle and over heat and loose power. If it won't run with the spark fully advanced the timing is off. Antifreeze used in hot weather only contributes to ever heating. I have never found that antifreeze helps control rust in the cooling system. Antifreeze will also leak in places that straight water doesn't leak. As for the water pump, my bet is that you have ruined it by over tightening the pack nut. It is allways best to back off the packing nut, grease it and then tighten only enough to stop the drip. If you plan to use packing use the teflon rope type. Lead packing wears the hell out of the water pump shaft, I quit using lead packing years ago. I build my own leakless water pumps that need NO packing. I don't and have never used a thermostat in any of my model A's . A thermostat may help as a restrictor on an engine that the radiator can't handle the flow of the water pump. Model A water pumps have a tendency of pumping so much that water is forced out the overflow pipe. When I build my water pumps I grind some material off the tips off of the impeller to slow the flow and keep the water in the radiator. It also helps if trying to remove the water pump without having to remove the radiator. I think that improper spark lever setting is the main reason for your over heating. Good luck.