and this would be the inefficency that creates overheating....although i can't imagine the speed it would have to be running not to pick up heat...you can do this experiment your self just make ice coffee by pouring hot coffee over ice cubes and immediately pour it back out again...its still hot now let it sit there for a moment and its starts to get cold

 

Except: what we are measuring is coolant temperature--not head temperature.

 

i don't know about that... the point is both will go up, its just that at some point you are losing that magical flow where convection happens the best....now having said that my practical experience is the same as yours....but i can see if you had a super high flow pump that you could create ineficencies by too fast of a water flow

 

I studied Nuclear Reactor design in college and i agree with you. There are different modes of flow. Turbulant and laminar. Nucleate boiling tends to dramatically increase cooling due to latent heat of vaporization. On the other hand forcing water through a system causes friction and can add to system heat. On boiling water reactors they run the circulating pumps on high speed to bring the water up to temperature.

Neglecting any of these special conditions the bottom line is the maximum Q released from the system is based on temperature. The higer the temp the greater the delta Q. If you hold the water up and it starts to cool too much in the rad the delta Q decreases causing a less efficent system.

 

Maybe, but what you want to do in this situation is change from laminar flow to turbulant flow--increasing coolant velocity does that.

Also, what the radiator is doing is transferring heat, not cooling the coolant--though it has that effect. The hotter the radiator is--the broader the front of higher temperature coolant the airstream sees, the better it works. For instance, if we were using liquid sodium metal as a coolant, the radiator could be smaller than a heater core and transfer the same amount of thermal energy.

 

Your post brings back memories: 100% reactor power-->Switch main coolant pumps to fast speed, main sea water pumps to fast speed, condesate pumps as well. Gods, I hope I don't have a 'I'm still in the Navy' nightmare tonight!

 

you go ahead and dream about reactors and i'll dream about one of your models.

 

I have nightmares about some of my models too.

 

iv ask this question many times but not here,,,,not talking about the cost ,,,, does the aluminume radiator cool that much better than a 4 core std. steel construction thanks,raymond

 

That's probably something most people can't answer. Perhaps someone who engineers cooling systems will know.

I would think that is a fair statement. The greater the difference between the air temperature of the air flowing through the radiator and the water in the radiator the greater the cooling.


That's the part many are disagreeing with. Their thought is that he coolant is leaving the radiator at a higher temperature. I believe its best to look at things in whole. The shorter the amount of time the coolant is in the engine the less heat it will pick up. The water entering the radiator will be cooler so it will than leave cooler; not hotter as others have noted.

In my opinion a car is operated over various temperatures and conditions. The cooling system has to be designed to be flexible, reliable, and affordable. The engine will generate heat and a properly designed cooling system will disapate the heat under all typicall driving conditions the car was intended for.

 

Too bad the C3's system wasn't properly designed.

It needs to breathe.

I re-engineered mine.

 

please don't share those photos

 

Raymond,
Standard 4 cores are generally a copper/brass combo not steel. The aluminum radiator people promise a 20 deg difference in temp with their product.
ESU

 

i beg to differ. please do. its nice to see some off the wall stuff once in a while.

 

There's got to be issues to cause the heat problem. If the rad, pump, hoses, belts, air dam, shroud, fan clutch and timing (have I forgot something?) are OK then over-heating should'nt be a problem. My built 355 in my 79 runs at 190-210 on a hot day with the AC on; otherwise I usually see 180-190. There is nothing special about my setup since it is just new OEM 4-core rad and Autozone belts, hoses and water pump

My 79 runs fine with the air on or off new..rad...pump...hoses... belts...seals...clutch fan... all delco stock execpt for the rad a local shop re cored it. 180-190 all the time...there has to be something missing in your set up.... they may have cooling issues but that's cause someone may have removed part of the shroud or some seals around the rad...it's all gotta be there for them to work good.

 

Yes...the design of our coolant systems is fine. The only change I would make in case of overheating is higher flow rate. I'm taking thermodynamics next semester...I'll pay special attention to systems which run 10º lower than boiling point just like most automotive systems. The course will even include vapor pressure and how the vapor effects pumps and turbines. My main concern will be flow rates and heat transfer rates.

I know that there are two main types of heat trasfers...convection and radiation. Radiation transfer occurs at near the speed of light, but I think it accounts for only a small percentage of the total heat transfer in our coolant systems. Convection rates I believe depends on the delta T (difference in the temperatures between the walls of the water jacket and coolant as well as the difference in the temps between the inside of the radiator and coolant, plus the difference in the temps between the outside of the radiator and the surrounding air) as well as the materials involved in these three transfers.

My gut tells me that heat transfer rates are fast enough in each case such that increased coolant flows and air flows would solve almost all of our overheating problems unless there is a damaged component. But, I'm going to do the math to make sure.

 

I think maybe you are running lean and that is what is causing
your engine temps to be high. I am having a similar problem with
my 79. Won't know for sure though untill I can confirm that
my radiator is partly clogged or not or both. I can drive around
pretty much all day at about 180 but if I drive too far, too long and
too hard that is when the temp start to get up to about 200.
Then I pull over just to be safe, don't want a blown head gasket.
My 79 does not have an aux. fan either. I am pretty sure that
would help alot. HTH

 

If any one has had a chance to read my other threads then you know this is a problem that I have been searching to find a cure for. The no thermostat fix made no difference for me same temps with or without. I installed a Edelbrock high flow water pump, no difference, new fan clutch etc... I have been trying to pay particular attention to the locations of people who say they do not have cooling problems. (highway temps +220), maybe your in a colder location, I am in South Georgia. ESU I know your in NY which would seem cooler but I know your situation. (have you tried the tranny cooler yet?) I know that looking at the weather channel it's been hot all over. But my '79 seems particularly sensitive to the ambient tempertures. I can drive into work in the morning when it's 72 degrees and run the air, drive 60 with no problems. But the afternoon drive home is different, 95 degrees I don't use the air and I get to about 220 at highway speeds. Now, what was that I just heard??? A big DUH! Yes I know that if you start with warmer coolant that it will reach a hotter temp faster but my F-150 reaches a operating temp and stays there no matter what the outside temps are winter or summer. More later have to go move a submarine.

 

Capt. Have you tried useing any cooling system flush? It is supposed to remove the scale that will build up on the top of the combustion chambers in the water jacket. It is very thin, but according to my dad (50+ years diesel mechanic) it will make about a 30% increase in heat buildup in the head.
One of those Prestone plastic T in the heater hose flush kits should clean it up. sposed to get all the junk out of the rad too.

 

Keeping temps down w/o AC should be no problem. Getting a C3 to run 190-200 w/AC on is not easy. I solved my problem in stages. Getting fresh rad seals helped as did the other fixes. Getting past that took time/money.
I added 1.6 RRs. Reduced temps 10* and sweet spot in power went up 200-300 rpm. Oil cooler brought temps down 5* more. The 7 blade fan and elimination of fan clutch kept temps down and mpg down.
When the engine was rebuilt, so was rad from 3 core to 4. Now the temps are 190 w/AC on Hwy, In town the dual Spals take care of business. Hope this helps.

Rick