350/ Overheating

[warpdriv]

The way it was explained to me by a mechanic was after the engine heats up the thermostat opens. The hot water in the engine gets pushed into the rad and the cooler water get pushed into the engine. Since the cooler water is cooler than the rating of the thermostat, the thermostat closes. Therefore the hot water stays in the rad and cools down. Once the cooler water in the engine heats up, the process starts over. So therefore you need the right thermostat and the capacity to cool the hot water.

HTH,

['74 UA FJ]

Originally Posted by warpdriv

The way it was explained to me by a mechanic was after the engine heats up the thermostat opens. The hot water in the engine gets pushed into the rad and the cooler water get pushed into the engine. Since the cooler water is cooler than the rating of the thermostat, the thermostat closes. Therefore the hot water stays in the rad and cools down. Once the cooler water in the engine heats up, the process starts over. So therefore you need the right thermostat and the capacity to cool the hot water.

HTH,

Yeah...that's the theory. You can cool 5,000 horsepower with enough water...

[mminter1973]

The thing about 40s is that you are limited on radiator size so every bit of advantage you can gain will help.

Lets get back to basics, Question? What makes heat? Compression. If you let off some of the compression off whether it be by head chamber size, camshaft, or whatever less heat will be produced, making it easier for a 40 radiator to cool.

[4x4 Station Wagon]

Hey I am not going to argue with your theory some one told me that you could turn water into gas and get better mileage and i laughed. Of course i tried it and now i get 6 miles to gallon better??????? So now i am starting to wonder if pigs can fly

[lucky 13]

Originally Posted by Cruisertime

If youre running a carb check that your not running too lean. Also, see if your cooling system doesnt have air in it. I know you burped it. But do a double check....

i agree.. my cruiser ran hot with the combination of several things.

1. the carb was running pretty lean, which is a no-no.
2. the spark plug gap was incorrect.
3. and worst of all, my timing would shift while driving.

The distributor hold down was an aftermarket chrome POS that wouldnt actually hold down the distributor once the engine was in time. Any hard acceleration would cause a moment on the distributor shaft causing it to tweak out of timing. i figured it out because of when this would happen, my cruiser would be a pain in the butt to start, and ran rough until higher RPMs, and got extremely hot really fast.

[Bret]

FWIW I am running 383 mild cam (approx 300HP), a generic 427 in^2 AL radiator(similar to Summit unit) with MK VIII fan, hi-flow H2O pump, hi-flow 180' thermostat with three 1/16" holes drilled into the thermostat (not by me-came from MFR that way). The fan is set to turn on at 190' and has not gotten above 195 in stop and go traffic with 100' Florida heat.

I went with the more air to absorb the heat, more water circulation to move the heat (especially at low RPM's) and remove the heat. I would think that under normal use it would be hard to push so much water through a radiator it wouldn't cool. But I've been wrong before...

Would a blockage in the water jacket cause this? water pump not pushing water to both sides evenly?

You might try putting a thermocouple/thermometer on the hot side of the radiator by the inlet and get some temperature measurements around the radiator, see if your getting flow everywhere, then see what the temp drops to at the outlet going back to the block with and without the fan. Might tell you if you need more water flow, more air flow, or more even flow.

Might be cool to take a picture with a thermal camera of the radiator as the thermostat opens up and when the fan kicks on. I will see if there is one at work.