The Stovebolt Site Forums The Shop Area The HiPo Shop Overheating - Water Temp 240!!!!!!

Okay, at my wits end here on this one, so sending out an S.O.S.
My 1950 has started getting really hot water temp, it does okay on the hi way, ( water temp average of 170 to 190 or so ) but in town it starts heading towards the 240 degree mark.
The engine is a 350 bored 40 over with a roller cam, electric fan mounted to the radiator. I've done everything I can think of, which includes;

- putting in a new thermostat ( 160 degree rated )
- new upper and lower hoses
- flushed the radiator in case there was a blockage
- changed out the 13 lb. radiator cap and put a 7 lb. one on instead.
- Added a coolant formula that is supposed to lower your coolent temp by 20 degrees.

After all that, it's still getting to hot.
Any idea's??????

philzamatic3100,

how radical is your roller cam ? whats the lift ?

do you have underdriven pulleys ? some guys put the underdriven pulleys to gain a few horsepower, but dont realized their accessories, alternator, waterpump, are now turning slower.

i have had a few cars years ago that had radical cams, loose torque convertors, and they did not like the street at all. always would get to 220-240 while setting in traffic.

leonard

The roller is a Crane 109821 PowerMax Series Hydraulic Roller Camshaft, it has a basic operating RPM range of 1,600-5,800 RPM. Intake duration at 50" lift is 214. Exhaust duration at 50" lift is 222. did'nt do underdriven pulleys.

Sounds like the fan is not big enough. Perhaps a dual fan. You need about 2600 CFM or more pulling.

just checked the cam specs, and it is .488''/.509'' lift, intake/exhaust.
that is a pretty steep cam for the street.
i know, i know, guys have run bigger cams on the street, but that is a performance cam.
anytime you go with big cams and performance parts, it is a real pain to keep them cool.
i had a 66 chevelle with 454 and it killed me on the street, and a few other cars that were radical, and i could not keep them cool on the street.
good luck, i wish you the best

leonard

Is there any reason you haven't placed the blame on the radiator itself?

Stuart

I'm betting on the radiator being plugged too. I know it has been "flushed" but in my book, that never unplugs one. 50 years of sediment won't just flush away, it's permanent,
Scott

Could be that the water pump is beginning to fail too. Or, as I've just experienced on the Slant 6 in my '73 Duster, you could have a head gasket beginning to leave.

-Brad

my first few questions are:

what shape is the rad in?
what size fan?
What brand fan?
Stock or high flow water pump?
is the gauge accurate?

There is a good chance your rad is half toast, fix that first. Take it to a rad shop and have them rod out the core. You may even need a new core - your rad shop can help here.

Next, make sure you have air flow. Radiators require air flow, the more the better. They actually need more as much air at low speeds as they do at constant highway speeds because your engine is generating more heat under acceleration and getting the truck moving than it does at highway speeds. I would switch to an engine driven fan with a good fan shroud if you do any towing, however if you really have to have an electric fan, use a 16" fan from either Spal or Tri-Pac as these are the only electric fans that I have ever tested that actually move enough air thru a radiator. They are a bit more pricey, however they work. The Spal and Tri-Pac fans are rated at 2900 CFM with 0" of restriction, and drop to about 2200 CFM at 1.4" of restriction for the common rad core. The low dollar Hayden fans do not move enough air thru the restriction of the radiator core (about 900-1000 CFM at best). you will have to make sure you have straight fins on the rad as well. Damaged fins prevent air flow. Towing you will need 2400 - 2800 CFM thru the radiator, so you will need to start with about 3200-3500 CFM which you can only get with an engine driven fan.

Is your water pump stock, if so, you may need to switch that out to a high flow unit if you have a really radical cam with lots of advance. You will need more flow.

Red Line Water Wetter along with other coolant adatives do not work (I ran the tests in the dyno lab myself to prove it).

Dropping the pressure cap from 13psi to 7psi only lowered the boiling point of the coolant (and when your radiator boils over). Hot coolant is better than steam for cooling. I would recommend going back to the 13psi cap

Hope this helps

Scott

Don't get excited over electric fans.
80% of the time they will not keep up with the job asked of them when used simply bolted to the radiator, especially if they are placed in front of the radiator.

Use an eight blade flex type or even plastic original fan.
Combine this with the most important part....A shroud!....and you should see a significant increase in your cooling performance.

Another option is to find a shroud that will fit the core of your radiator and then purchase an electric fan to fit the diameter of the fan cut-out and mount it to that opening behind the radiator.
This way the whole surface area gets a sufficient amount of air-flow.......not just the 40 odd percent surrounding the area covered by an electric fan used on it's own.

Blocked cores, rotted and blocked fins etc. will only show up on high speed long distance drives......not putting around town!

Try it and let us know how it goes.

WOW....too slow, Scott got in first!

Just backs up the theory of air-flow at low speeds.
I had to over engineer this on my burnout car, as we are running a 5.0 litre at 6500 rpm in top gear at about 2 MPH !

Yep we need all the low speed cooling that we can get!

This brings me to a second point of the conversation.
Beware of smaller pulleys and hi-flow water pumps.
Your water actually needs to spend a fair bit of time lazing around in your engine to soak up all that heat out of the metal, and just as long a time to release all that heat back out and into the radiator core to be taken away by the air-flow and actually give you some nice cool water to return into your engine for the next round.

If you speed up this process..........you will have a steam train in no time !

Is it physically boiling over? I would think with all those changes you made that something would change. My thoughts are a faulty gauge. Find someone that has a inferred laser temp gun and check various areas with it.

Okay, think I have solved the water temp problem, with the help of posts above. I decided to chunk the electric fan and installed an engine mounted 7-Blade Radiator Cooling Fan that fits the 73-87 Chevy & GMC Truck equipped with a 305 or 350. I found I had about 1 and 1/2 inches clearence between the front of the 7 blade engine mounted fan and the rear of the radiator. However, I had to lower the radiator in it's housing by 2 and a quarter inches to keep the fan blades from biting into the bottem radiator hose ( required some slight fabrication and tapping new bolt holes in the radiator housing ). I then filled it with 1 gallon of antifreeze and the rest of the way with distilled water ( we have VERY hard tap water here ) and fired her up.

Result: Went from water temp of 220 to 240 to a water temp of 180 to 190 An average 40 degree drop in water temp. Waa-hooooo!!!

Thanks everyone for your ideas and posts, you guys are life savers.
Phil C.

Good going Phil !

Don't forget about keeping an eye out for a shroud though.
This will aid the cooling performance even better.
Most of the time you can cut down a second hand one to fit your requirements.

wow phil, that is a big drop.
glad you now got a COOL truck.

leonard

Before you do anything, find someone with a digital infrared temp sensor gun. You know the type with the little red laser dot? I was having some troubles with mine doing the same thing. Come to find out the temp gauge was way off. You may get lucky and find that the gauge is the real culprit. Just a thought.