Cooling Question
 

My 55 is running a little warmer thanI would like it to. I won't mention what motor (C%&$y) I am running in fear of loosing your interest. But anyway,, I have changed thermostats to a 165 deg. I have been told that will hurt me more than help by not letting the water in the radiator cool enough before it enters the engine again. I don't know if that makes sense or not. I have a home made shroud that is only about 3/4" away from the radiator with an electric fan pulling air through. I have been told that it needs to be farther away from the radiator ( 1 to 1 1/2" ). I have also been told that if the motor is running lean it will make it run warmer. I have an Edlebrock carb. Not sure what size. That brings up another question... How do you ID an Edlebrock carb when it has been polished ( Endurashine ) and the numbers are gone off of the base?
Sorry for being long winded but I know someone here can help me.
Thanks:-banghead

Define "warmer than you'd like." How hot is it getting?

You don't say when it is running hot, whether idleing or running down the road. If it heats up idleing then it's usually going to be lack of air flow, maybe too small of a fan or not enough CFM capacity. If it is hot while running down the road it could be lack of air flow, not enough coolant capacity or a combination of both.
You mention a home made shroud, this could be blocking a lot of air flow though the radiator at speed, I had a serious problem when I put one on my truck, try mounting the electric fan directly to the radiator core.
You touched on the thermostat issue, yes, in certain conditions a lower temp can cause overheating , try a 195* and see what it does.

It might not be hot at all.


You need to determine that it is actually running hot. Get yourself a cheap Infrared thermometer (like the one from Harbor Freight for about $30)

Point it right at the t-stat housing to measure. Another way would be to get another sender and gage.

Regards,


Rick

It will run close to 220 on a hot day at speed. Thats with no air on.
I have shot it with a temp gun and it doesn't seen to be as hot as the gauge says, but on a cool night it will show normal. I was just trying to get to where I could run the air if needed. But so far I have been afraid to try it out on the road.
I did have a 195 when I first got the truck out.

I spent a long summer year before last trying all the same things to solve my heat problem..
fans didn't matter, shroud didn't matter, tranny cooler inboard didn't matter, making the carb more rich didn't matter

net, for me the problem turned out to be a too restrictive thermostat, keeping the water IN the engine too long. we proved this by taking a thermostat and chopping off the bottom, leaving only the hat.

I have since used a 190degree stat with the same top and all is good.. temp is solid as a rock. with and without air on..

you should also be able to add a resistor to the temp sensor line (inline) to calibrate it to the gauge and laser temp I made a little adjustable version to find the right value to add.

the other thing we decided to do was to move the a/c condenser away from the radiator an inch which helped with stationary airflow, and didn't hurt when driving. my rad is a honkin 6 row.

Sam

the first pic is the one we ended up using and the one we cut for just the top
the second is the one I had originally and was the problem.

First thing I would like to say is all electric fans are not the same... What's the history of the radiator? age, kind, and condition? you may have a problem of air flow (mentioned before), but don't forget about water flow restriction.

Another thing to consider is airflow at speed. My shroud (from Griffin Radiator) has four squares cut in from each corner to help increase airflow when driving at speed. Air passes through the fan, but there is quite an area that is blocked by the shroud. These squares are covered by a somewhat thick, black nylon piece of material that covers the hole when the fan is running (suction) and flaps open when the fan isn't running and I'm driving at speed. I don't know if that would make much difference, but it's an idea. (I also hope this all makes sense) There's a picture of my radiator and shroud in my gallery.

I had the same shroud as Shane, but it came from Sac Vintage Ford. It worked Great. The homeade shroud sounds like a likely place to start. Take it off and see if the problem is better or worse. The relationship of the fan to the shroud is also critical. I could throw a shop towel in front of my rad and the wind current would grab and hold it. Does yours do that? Jag

Sam, My thermostat is like the first pic but a 165 deg. now.
Moe, My radiator is a 4 core alum. new from Tanks & Tabs in Nashville.

I guess I need a little Thermostat 101. I thought when the water temp reached the temp of the thermostat it opened and stayed open untill you cut off the engine and it cooled off enough to close. I am being told that it SHOULD open to let the cooled water enter the engine and let the hot water out into the radiator the close untill the engine water heats enough to open again and repeat the cycle. Which is correct?

This is pretty much the way they are designed to work.

Potayto, potahto. It's all a matter of semantics. What you're saying is the same thing, just worded differently. All of the water is cold before starting the engine. As the engine heats up and reaches operating temperature, the thermostat will open at a predetermined setting, which allows the water to flow and exchange the hot water from the engine for the cold water in the radiator. The water in the engine flows past the thermostat into the radiator. It's all moved by the water pump, which sucks from the bottom of the radiator. Whether it's hot water out or cold water in, either way, water will not flow unless the thermostat is open.

the thermostat should open & close as the water temp changes. its job is to keep the engine at optimal temp..

if u have a 165, and the temp should be around 185-190, then your stat will be open all the time. if u had a 195, then the darned thing shouldn't open til the wat is above 195.. (higher than u wanted it to be optimally)..

when driving down the road with all that air rushing over the rad, it draws the temp down too much, and the stat should close some/all the way til the engine comes back up to temp.. then open..


but too low is as bad as too high a rating.. I think you should have a 180/185..

if it opens too soon, and stays open, then the water cycles too fast and doesn't cool coming out of the rad, picks up a couple degrees in the engine and doesn't cool enough... and the temp slowly creeps up..

my problem was the reverse with same result.. stayed in engine too long, rad couldn't dissipate the heat, came back too hot, picked up more.. etc..

sam

I have to refute this popular notion that water can move through an engine too fast to pick up heat. That is just plain false. It does not comply with the rules of physics.

Now maybe there is some corrosion on the internal walls of the cooling jackets that inhibit heat transfer but that will result in less heat being absorbed by the water and hence less heat being given off by the radiator.

And Sam, if the water stayed in the engine too long, that means it stayed in the radiator an equal amount of time releasing heat to the atmosphere and would return to the engine colder than normal.

A mechanically sound engine will develope so many BTU and your radiator sheds so many BTU. Your radiator has to be able to shed more BTU than your engine can make or you will experience overheating. If you are overheating then either combustion gasses (extremely hot) are entering the water through a crack in the block or gasket. Or your radiator is not shedding the heat. Probably because of internal corrosion, mechanical restrictions or insufficient air flow across the radiator.

There are other causes but these are the most common. The speed of the coolant through the system has very little to do with overheating with the exception of too little flow caused by a worn out water pump or mechanical restriction in which case the water in the radiator will be cool and the water in the engine will be hot.

Hope I explained it so you can understand it.

>r but that will result in less heat being absorbed by the water and hence less heat being given off by the radiator.

exactly what I said.. because the water flows quicker than planned, it does not absorb the heat as designed.

thus MORE heat remains in the engine proper.

Sam