Over heating while getting on it

[chargerman67]

I Finally have been able to start driving my 67 440. I bought a 3 core aluminum radiator off ebay and still use the stock fan. I purchased a milodan high volume water pump and all that stuff. The car runs at about 180 degrees. If I am cruising it will get up about 180-200 and then the tstat pops and it drops down to 180 again. It looks perfect..... BUT if I start driving it hard and speed around it starts to over heat and the tstat wont pop and make it drop to 180 again like it is supposed to. It gets about to 215-220ish and I of course stop the car and let it cool off a bit. Again if I drive around conservatively I could drive for hours and it would not over heat. I am curious if any of you know what I can do to it to make it not over heat when I get on it. I want to be able to get on it whenever I want to and it to stay cool. A friend who has a 68 road runner told me to drill a hole in the thermostat and it should help.
   Any advice would be awesome...
Thanks,

Luther

[billschroeder5842]

Buy a 165 t-stat and you are good. Mopars like cool running motors.

[Cooter]

Well, My own experience with the 440 is this...Some run hot, some don't...I gotta 440 ('74 HP) in the General Lee that won't get over 190 With the stock 3 row brass/copper radiator..On the other side, I gotta '70 HP Stroker 440 in the Dart that won't get UNDER 190 and usually runs in the 220-240 Range All the freakin' time, but doesn't blow over into the overflow...It has a 2 row ALuminum rad. with electric fan...
I gotta '66 440 in Christine that runs 200-220 ALL the freakin' time with a 3 row Brass/copper rad., with electric fan AND stock clutch fan...I gave up and decided that if it blows, it blows..F*ck it...


Sometimes, you just can't get it in second gear even if 'ya double clutch it....

[elacruze]

A couple things to think about.
First, you should only see the thermostat 'pop' once or twice, while the engine and coolant are stabilizing from cold. If you see the temperature going from hot to cool to hot again after about 15 minutes of run time, you likely have air pockets in the cooling system. Air and coolant each have a much different effect on coolant sensors too, so the cycling can be a sign that air is passing by the sensor. Air also creates much higher pressure for given temperature than coolant. Be certain that you have no leaks and that your cap is functioning properly. Make every effort to be certain you have no air in the upper radiator hose, heater core, etc.

There are two things that are most often responsible for overheating (once the cooling system is working properly)
First is too much compression, second is too much timing. Both of these things raise cylinder pressure which raises temperature.
Other culprits can be early exhaust valve opening (not likely) and too *little* ignition timing-if the timing is late, the exhaust port sees burning fuel and combustion temperatures instead of only hot burned exhaust. This translates into the water jacket around the exhaust port.

So, here's what I'd do, knowing nothing about your build or install;
1. Verify that there is no air in the coolant.
2. Be certain that my fan and shroud work together-diameter and opening/fan relationship. (you do have a shroud right?)
3. Know my timing-If your timing seems off the mark either way, advance or retard it 2-3* and retest. 'The Mark' is generally around 35* total. Consider that you may be retarded at part throttle, if your curve advances late. Find out at what rpm your curve advances.

[chargerman67]

Thanks for the info guys... I'll check on all the above. Timing is something I have always been questioned on but know nothing about for this engine. It had been sitting on my parents driveway for 11 years. But I have been working on it pretty steady now for the past 2 years since I graduated college. 

[chargerman67]

One more thing, I don't know if you guys think this could do anything to temperature.. But Whoever had this car before me put what looks like a large Dawn soap bottle as the over flow reservoir. I don't know what the over flow reservoir looks like in a 67 charger but I doubt it should only be the size of a Dawn soap bottle.. and when it was heating up that little bottle was full of coolant and was bubbling (maybe it still had some dish soap in it? jk)

thanks again,

Luther

[elacruze]

Bubbles can only mean two things-

1. You have a lot of air in your system which is being purged
2. You have a leaking head gasket which is pressurizing the cooling system.

#1 will rectify itself over time, with a properly operating system and some attention to high spots.
#2 will not.

Find somebody with a coolant system pressure tester and check that your system can hold 16psi for 5 minutes.

Rarely, head gasket leaks will not show on a pressure test. If you have a shop with the appropriate equipment, they can test for exhaust in the coolant which is diagnostic for a head gasket leak.

Have you ever seen the coolant system expel more coolant than you thought it should, or see foamy coolant in the recovery bottle?

[chargerman67]

I will have to look into finding someone to do the pressure test. I have not noticed any foamy coolant in the over flow. All i saw a few days ago was that it was bubbling more like a boiling bubble. But as I stated before could it be because that over flow tank is too small? Here is a pic of the ghetto setup that I speak of...

[elacruze]

The size of the recovery won't make the coolant bubble or not, it will just overflow when it gets full.

If the radiator wants more than the recovery tank can deliver when it cools, it will draw some air which will come back out as bubbles, but this should not last beyond full operating temperature.

[chargerman67]

Well I have driven it the last few days and it seems to be running good. Didn't over heat once. And I was driving it pretty aggressive too. Maybe some of the possible air trapped in the system worked its way out? I don't know but it seems to be running quite nicely.

[elacruze]