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A few weeks ago i posted about my nova overheating here is the post.
I have been trying to get my 62 nova to run at 180 temp all last summer. Well new summer and have the problem all over. Please could anyone give me help on this. Today it is only 84 outside. on the freeway ran 220 temp with out my air on. In town around 190. I have installed a new GRIFFIN #6-70148, HAVE TWO PERMA COOL 12" 1,650 CFM fans. Run distilled water, water wetter and some anti-freeze. One thing is the condenser for Vintage Air sets right in front of radiator and takes up a lot of space. Timing is set at 12 and total around 28.

Well after i installed a new griffin radiator did not help at all. BUT i found out a few things along the way.
1. check the temp at inlet & outlet. if the radiator is doing it's job you will have a difference of 25-30 degree MIN. I have about 50 degrees in my new radiator but engine overheated still. Well to make a long story short it was the NEW water pump i installed when i built the engine. Installed a new STEWART PUMP AND THERMOSTAT. engines runs cool now. So check your radiator temp difference top and bottom to rule out the problem being the radiator
 

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Glad to see that you solved your problem. Also, great cooling system trouble-shooting tip. The problem gets discussed often, and I think this is the first time I've seen the suggestion of checking the temperature difference to rule out the radiator. Thanks for posting.
 

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Discussion Starter #3 (Edited)
temp difference

Yes i was talking to Griffin Radiator people and he gave me this to do. the first one was to check the temp difference between inlet & outlet. I had NEVER read that any place. Min of 25-30 degrees. if i would have known that could have saved myself $1000.00 for the new Griffin Radiator. Hope others read and check this temp difference FIRST !

YES the old water pump was captivating, and not pumping much water into the radiator.
 

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Did you ever figure out what was wrong with the water pump?

Those thermoguns are a nice investment. I used mine looking for bad insulation spots in the house.
 

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Those thermoguns are a nice investment. I used mine looking for bad insulation spots in the house.
And they're great for finding a bad cylinder by measure exhaust temperature too!
 

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You should be running way more total timing than that as well, and more initial. That will help with engine temps. Run at least 15 degrees initial, and vacuum advance hooked up to full manifold vacuum.
 

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The temperature drop across the radiator just determines the average radiator temperature. If you have a 200° inlet temperature and a 170° outlet temperature, the average radiator temperature is 185°. If you were to maintain a constant load and increase the flow through the radiator so the outlet temperature was 175°, the inlet temperature would drop to 195° to maintain the average radiator temperature of 185°. The physics of heat exchanging works on the temperature difference between the coolant and the ambient air, so the closer the coolant temperature is to the ambient air temp the less efficient the heat transfer is. By decreasing the inlet temperature you will also reduce the chance of boiling over.

What would happen if we increase the coolant flow? Will it go through the radiator so fast that there won’t be time for cooling to take place? Not at all, from the expression, we can see that if the heat load is constant, increasing the coolant flow rate will reduce the coolant temperature drop through the radiator, resulting in a higher bottom tank temperature. If the bottom tank temperature is increased, the top tank temperature must go down to maintain approximately the same average core temperature. This is what we were hoping to achieve. With the top tank temperature now less that 190 degrees F at the reduced power point, we can expect that the system will be better able to run at 240 hp without overheating, In fact, because the increased coolant flow rate results in a higher coolant flow velocity and better “scrubbing action” in the tubes, the average coolant temperature decreases slightly while transferring the same heat load to the cooling air, further lowering the top tank temperature, resulting in better cooling performance.

From the old 14 Rules for Improving Engine Cooling System Capability in High-Performance Automobiles
 

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Hmmmm.....back in the late '60s when we first built a dirt circle track car we found that running a traditional thermostat would allow the coolant to overheat because it was staying open all the time and the coolant was being pumped through the radiator to fast. The thermostat was doing what it was designed to do but it was also compounding the overheating problem. My mechanic found out from other race car mechanics that they were disassembling the water pumps and grinding the impeller fins down to slow the flow of coolant and also instead of the thermostat we experimented with washers until we got the correct size hole to allow the engine temperature to be correct. Also, he would adjust the thermostat housing washer size hole according to the outside temperature. Different washers for spring, summer and fall. Pushing water to fast through the radiator did cause the coolant to overheat. Of course, these engines did not idle for very long periods of time and stayed in the higher RPM range so the coolant system was adjusted for that. I know this sounds crazy but this did solve our overheating problem. Shade tree mechanics were very abundant back in the early days of racing in South Georgia.
 

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How did these shade tree mechanics measure the mass flow of coolant through the radiator to arrive at the conclusion that the coolant was moving too fast?

Do you suppose if the pump wasn't designed to work at the rpm range you were running it might cavitate?
 

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Mike Goble... after all the years I've been on and off this site, your knowledge & wisdom has been a constant. If More folks listened to you their Own knowledge would increase. But I'd be willing to bet your knowledge, and way of expression, is still unheeded by many.

Sir, I've thought of you often during my times away and I've always remembered you with a high level of respect, which in my earlier years, I lacked but then learned.

Nice to read your words again Mike.


Johnny.
 

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I have no idea about cavitation in the water pump and all I was doing is passing on experience of what we ran into back in those days. Whatever the cause was, that was what was done to slow down the flow, or decrease the possibility of cavitation if you will, and it worked. I was told it slowed down the flow and that was what I passed on as info that I was privy to. I certainly didn't try to pick it apart using scientific calculations or the sort. :no:

Back in those days, my guys would look at others cars and ask questions about what they were running and how they did this and that. Dirt tracks in those days were just coming into existence and the drivers/mechanics were more willing to share info so others could get into the races. The more the cars the bigger the crowds and the bigger the crowds the bigger the purses.

Before every race my mechanic would change out the washer in the thermostat housing. Early on I asked and he said it was because of the air temperature at that time. Water was the only coolant allowed so dumping the fluids on the ground at the track wasn't a big deal back then and we took replacement water with us. That's just the way it was back then.

Maybe I shouldn't have even added this dit-bit of info from my past as it isn't even relevant to the original questioned asked anyway. So please excuse me.:yes:
 

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I agree on whatever works to keep your car cool is great. Pass the info on. I've seen in certain applications where all the scientific info and hype doesn't really work all the time....just my experience.
 

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I agree on whatever works to keep your car cool is great. Pass the info on. I've seen in certain applications where all the scientific info and hype doesn't really work all the time....just my experience.
Physics works all the time. We don't have the 'suggestions' of physics, we have the laws of physics. Thermodynamics isn't a developing field, Newton was on to these things long before and cars were circling a track.

I understand about the methodology to get the cars cooler, but I disagree with the suppositions on why it works. If we had a fully instrumented cooling system and actually measured the mass flow, temperature, cavitation, system pressures, etc., we would know what happens.
 
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