1955 runs hot- water pump smaller diameter pulley

[zeroroadkill]

Advice wanted: Some articles I've read mention that below 850rpm's there is little water flow even with the high output water pump, modified spacer and big mouth thermostat. Some suggest replacing the stock water pump pulley with a smaller diameter pulley. Has anyone changed out the stock water pump pulley with a smaller one and if so what diameter would you recommend? Did it help? Did you have to use a smaller fan belt?

Thanks in advance.

This page contains affiliate links for which I may be compensated. As an eBay Partner, and Amazon Associate I may be compensated if you make a purchase at no cost to you.

 

[John Vierthaler]

Advice wanted: Some articles I've read mention that below 850rpm's there is little water flow even with the high output water pump, modified spacer and big mouth thermostat. Some suggest replacing the stock water pump pulley with a smaller diameter pulley. Has anyone changed out the stock water pump pulley with a smaller one and if so what diameter would you recommend? Did it help? Did you have to use a smaller fan belt?

Thanks in advance.

I don't know the answer to this but I would question if the faster flow of coolant would shorten the time going through the radiator thereby lessening the cooling effect.
John Vierthaler
Black '55

 

[Ward 57]

I don't know the answer to this but I would question if the faster flow of coolant would shorten the time going through the radiator thereby lessening the cooling effect.
John Vierthaler
Black '55

Why do people think that faster flow will not let the coolant cool enough? I think that would only happen if the radiator is too small. Not likely with a stock radiator.

 

[zeroroadkill]

I’ve replaced the stock radiator with a custom 4 row radiator, high output water pump, big mouth thermostat, six blade fan, modified spacer and she still gets very hot in slow traffic on a hot day. Not sure what to do next. I thought of an electric fan but want to keep her as stock as possible. Only 56k original miles. Two Engine flushes showed no rust or sediment. Antifreeze clean and green. Wondering if pump speed would help?

 

[Ward 57]

I’ve replaced the stock radiator with a custom 4 row radiator, high output water pump, big mouth thermostat, six blade fan, modified spacer and she still gets very hot in slow traffic on a hot day. Not sure what to do next. I thought of an electric fan but want to keep her as stock as possible. Only 56k original miles. Two Engine flushes showed no rust or sediment. Antifreeze clean and green. Wondering if pump speed would help?

How hot is very hot. These engines are known to run hot and don't mind a bit. Over the white line in slow traffic is not unusual and not harmful. 20-40 or even 20-50 will keep everything fine.

 

[zeroroadkill]

Maybe I’m chasing a ghost? At slow traffic or a long light on a hot day she will get to the end of the white bar, never reaches the final mark. Maybe I’m used to engines running at 190° or 210° . I need to laser check the the radiator temperature when she indicates over normal. Running she runs about 60%-75% on the gauge. On. 100° day in traffic she reaches the top of the white line. Am I being too paranoid?

 

[Critterpainer]

Add a temporary mechanical temp gauge on the rt head just to do a reality check. Also see what happens when you turn the heater on when you think the engine is too hot.

 

[Ward 57]

Maybe I’m chasing a ghost? At slow traffic or a long light on a hot day she will get to the end of the white bar, never reaches the final mark. Maybe I’m used to engines running at 190° or 210° . I need to laser check the the radiator temperature when she indicates over normal. Running she runs about 60%-75% on the gauge. On. 100° day in traffic she reaches the top of the white line. Am I being too paranoid?

Sounds perfectly normal to me. My '57 reacts the same way with no issues.

 

[CSPIDY]

I found with the modified spacer, I have flow at 600 RPM idle

If the engine is not overheating, ie blowing steam and pegging the temperature needle past the high end

There is no problem

I agree with Ward, 190 degrees would be ideal, on my water temp indicator that is at the very high end of the arc line

 

[Gforni]

With our '55, it was running hot/overheating, and I swapped out the stock fan for the 6 blade, installed the high flow water pump and 190 deg thermostat. I also had the radiator boiled and cleaned, as well as installing an overflow tank (while not stock, it is very functional.) Using the stock temp gauge is somewhat misleading, so I use the laser temp and checking the top and bottom of the radiator, the thermostat housing and other areas, the car does not get much over the 145 to 190 degree temps, with the gauge in the 'center' bar area. We live in the South, so we get some warm days, and the car seems to do fine now since we swapped those parts out. The laser temp reader is worth the piece of mind.

 

[jack-in-sac]

I have observed over the last 25 years that many overheating complaints are either overstated or caused by other engine issues.
First How do you know you are overheating? Are you dumping coolant all over the ground? Just becasue you standard gauge says hot is often not a true indicator.I suggest a second sender installed in the other cylinder head and a quality aftermarket gauge.
Second Endemically the castin in the fifties was not as precise as later say in the 60s. Questions are: has your engine been rebuilt and if so bored out how much? Are all your other engine systems and components working properly? Are you using a Mallory distributor? There are mot questions but in answer to the above; If rebuilt,how much are the cylinders overbored? this iis not a common problem but does occur when the cylinder walls are thin. A faulty vacuum advnce can run the engine hot, timing an engine with a few miles on it to the timing mrks can be incorrect. This can result in poor performance and other associated problems. I suggest timing by vacuum. Have you recently or ever adjusted the valves? an out of adjustment rocker arm can result in a burned valve and a poorly and perhaps hot running engine.is your engine's carburetor jetted properly. A common change to a too large "modern" carburetor. For instance an Edelbrock 600c.f.m or greater is overkill. That carburetor out of the box is for a Chevrolet 350c.i. engine A 500 c.f.m carburetor is much closer to your actual needs.
The sum of my comments is: make sure all your other engine systems are correct before spending a lot of money on fixes tht may help but not solve your problems. I have a C code '57. It runs consistently 190 to 195 at extended distances at 70 to 75 m.p.h. with the air conditioning on. In town in traffic no real problems. Only occassionally in mid summer climbing a very long grade like Altamont have I ever had to turn the air-conditioning off. I took advice from Walt Nuckels and Jimmy Skoggins years ago to have a cool runnig engine and have been happy ever since. I also run a standard radiator and distilled water.

 

[Rick Worth]

Why do people think that faster flow will not let the coolant cool enough? I think that would only happen if the radiator is too small. Not likely with a stock radiator.

The speed the water passes threw the radiator does make a difference, the longer the water is in the tube the more cooling air passes by it. Personally I have never found an issue, but it is a possibility.

I’ve replaced the stock radiator with a custom 4 row radiator, high output water pump, big mouth thermostat, six blade fan, modified spacer and she still gets very hot in slow traffic on a hot day. Not sure what to do next. I thought of an electric fan but want to keep her as stock as possible. Only 56k original miles. Two Engine flushes showed no rust or sediment. Antifreeze clean and green. Wondering if pump speed would help?

Before you drive yourself crazy trying to cool it down, are you 100% sure it is running too hot? How reliable is your temp gauge? have you tried a mechanical gauge? How hot is it running. How high does the gauge get now, and does it stop rising at any point or does it continue to rise until it boils over?

 

[Oly Bob R]

I bought a 55 and had some minor over heating issues. I installed an oven flow tank and my problem has gone away. I must admit that I have no idea what the thermostat settings is however I am pretty sure that the radiator has been boiled out after looking inside and a fresh paint job

 

[Ward 57]

I bought a 55 and had some minor over heating issues. I installed an oven flow tank and my problem has gone away. I must admit that I have no idea what the thermostat settings is however I am pretty sure that the radiator has been boiled out after looking inside and a fresh paint job

Just member the radiators don't like to be totally full. 1-1/2 inches below the lip is normal. It will spit out any overfill it doesn't like.

 

[Oly Bob R]

Just member the radiators don't like to be totally full. 1-1/2 inches below the lip is normal. It will spit out any overfill it doesn't like.

Oh so true

 

[zeroroadkill]

I dropped the water level about 1" from the neck and it quit spitting out coolant!?

 

[dmsfrr]

I dropped the water level about 1" from the neck and it quit spitting out coolant!?

Yes, as the coolant heats up to operating temperature it expands and has to go somewhere. If you don't leave empty space at the top of the radiator (or add an overflow tank) the excess will be pushed out.
An inch or so down will balance itself itself out and should stay at that level just fine.

 

[jack-in-sac]

When you look in the radiator cap inlet you will see a baffle with a round hole right below the cap inlet. the radiator is to be filled to that level. anything above the baffle level is generally expelled when the engine warms up. It is essentially a built-in overflow tank. Another overflow tank is usually carrying coals to newcastle.

 

[jack-in-sac]

The speed the water passes threw the radiator does make a difference, the longer the water is in the tube the more cooling air passes by it. Personally I have never found an issue, but it is a possibility.


Before you drive yourself crazy trying to cool it down, are you 100% sure it is running too hot? How reliable is your temp gauge? have you tried a mechanical gauge? How hot is it running. How high does the gauge get now, and does it stop rising at any point or does it continue to rise until it boils over?

Overheating is not always the radiator problem or the water pump or the fan pulley. It can be helped by installing a 6 or seven bladed fan. The original lower shroud does not cover all of the lower portion of the radiator for pulling air through the radiator.. You have two triangles that do not have air pulled through them. Their are other reasons for overheating besides thinking you have an overheating problem when you do not. Make sure all of your other engine adjustments and devices are correct.

 

[Brax]

I’ve replaced the stock radiator with a custom 4 row radiator, high output water pump, big mouth thermostat, six blade fan, modified spacer and she still gets very hot in slow traffic on a hot day. Not sure what to do next. I thought of an electric fan but want to keep her as stock as possible. Only 56k original miles. Two Engine flushes showed no rust or sediment. Antifreeze clean and green. Wondering if pump speed would help?

Do yourself a favor remove the thermostat and drive the car with out it let it idle and drive it on a hot day the car should run at lower temperature and if this fixes your problem put a 160 degree thermostat in it and be done. Y blocks don’t have any overheating problems they have been used in cars and trucks up to 1964