cooling question

[f16n]

I have a Shell Valley Cobra with a 427 fe,I have a heating problem at high speed.When I travel on highway for a distance temp. begins to climb 210 or more degrees,When I stop at light temp falls down to 195 or so,changed water pump from eletric to manual,changed thermostats,adjusted timing.Think radiator capacity to small,radiator holds 5 quarts water alone,looking at double pass raditor, Any suggestions please,Thanks Toren

[Ron61]

I had a different make than you, but I took mine to a radiator shop and they made a 4 core radiator that fit in it for me. However my engine made its best power in the 210 to 215 degree range and at times I had to turn the oil cooler off as it wouldn't get above 185/190 degrees. So if your radiator is to small you may be able to buy a ready built one that will fit and take care of the problem.

Ron

[JGC]

Hi,

I second Ron's comment about making best power at 210 degrees. I ran my Pontiac's 10's of thousands of miles at 210 with no appreciable cylinder wear. I wouldn't be concerned and would actually want my engine to run near 200.

Remember if your oil doesn't get somewhat over 212 degrees, the water won't crack out of it and you will accumulate moisture in your oil. Not good for engines that don't get run everyday.


Jack

[Dominik]

You may not have enough airflow trough your radiator. That happens if it is not shrouded to funnel air, instead of bypassing the core.

Can you post a pic from the front of your car?

Dom

[f16n]

I have aluminum shrouding in front,have 2 pusher fans in front, 1 puller fan (perma cool brand)with shrouding behind

[xlr8or]

You might try removing the pusher fans in front. They can obstruct air flow and are useless at speed anyway. Also verify the puller fan is blowing the correct direction and sucking air through the radiator. Have you burped the block? Bring the temp up a bit and loosen the temp sensor in the intake to let out any trapped air.

[undy]

Your shrouding might be blocking too much air flow at speed. I know Spal utilizes one way flaps in their fan shrouds to minimze this.

[vettestr]

The guys are spot on about system being to small for the load. If temps increase above desired point only at speed the radiator is too small. You must be right on the limit if reducing the heat generated from the engine with lower speeds allow temps to recover or drop. The 200 to 210 would not concern me other than it is above the T-stat set point and it can not hold at the average temp. of your engine. When the weather heats up and is 40+ degrees higher you will wish it was a mere 210.

If temp increases only at low speeds but fall at higher speeds then more air flow is the key. It seems your air flow is good but system is at its limit. Watch your oil temp as a second clue to that happy place. Ideal is to reach 215 as soon as possible but hold there. The higher oil temp loads the coolant temp adding to system demands. In Phx. with highs in the 115 range adding an oil cooler can be just enough to unload the coolant just enough to keep her on the T-stat.

It is about impossible to have too much cooling capacity if T-stats are used for coolant and oil. I also check for and find many pulley ratio problems. With all new components like water pump, fans, rad. and so on cooling problems are almost always a design issue. Track only cars can run under driven W/P ratios and restrictors instead of T-stats but not street cars. Water pump pulleys need to be 10 to 20 percent smaller than crank pulleys with system pressure at or higher than 12PSI. Water Wetter and all the chemicals have been of little value to fixing a problem from my experiences. I like good old distilled water and an anti corrosion with pump lube. Anti freeze in what ever amount needed if freezing is an issue otherwise just watch your PH levels and ground everything to stop electrolysis. A ground strap on the rad. and engine also go a long way.

[Rick Parker]

Although it may be the sizing of the Radiator, I would also look at the possibility of the pusher fans creating a "wall" that is blocking the the incoming air while they are spinning.
[IMG][/IMG]

[vettestr]

Hey Rick,
I did some testing albeit a little crude with dual pusher fans. I hooked a high resolution amp meter in line to see if the amperage draw increased at a few highway speeds. My thought was if the airflow was higher than their RPM it would load the circuit and amps go up. I found the load or amp draw on the motors did not increase but dropped a small bit.

It would be easy enough on most applications to loosen set screw on fans and remove from the motor as a with and without test.

[patrickt]

Originally Posted by Rick Parker

I would also look at the possibility of the pusher fans creating a "wall" that is blocking the the incoming air while they are spinning.

Wouldn't the incoming air just spin the pusher fans and then continue on through the radiator? I've never had a problem with that, but unbolting them and taking the car for a ride at speed would be a pretty easy test for him, I guess.

[mr0077]

Also, a little out there, but check to make sure your lower radiator hose is not collapsing at higher RPM. This could restrict flow at speed, then "un-collapse" at idle or lower RPM for full flow and cooling.

An easy check, warm up the motor, then watch the lower hose while you rev the motor. If it doesn't collapse, that isn't the problem.

[Rick Parker]

When these were originally designed the engines were 425-500 HP, now displacement are larger, longer strokes, bigger bores lots more HP all creating more heat. The pusher fans aren't very efficient, this has been discussed at length many times. They look nice but.......

[patrickt]

Originally Posted by Rick Parker

The pusher fans aren't very efficient, this has been discussed at length many times. They look nice but.......

Well I know they don't work , I just don't ever recall anyone attributing their overheating to the presence of the fans.

[RICK LAKE]

f16n Toren I am going to repeat some of what was said. Things to check with the car hot make sure that both coolant hoses are not collasped. What pulleys are you running and what water pump is on the motor. You need to remove the back inspection cover and make sure there is a disc riveted to the impellor, if not Summit sells one for about $12.00. Install one. Thermostat in car? what temp is it. I run a 180F. High flow. The coolant and water should be a 50/50% with distilled water. Add a bottle of water wetter. Fans The puller fan need a shroud to make all the air come through the fan will help lower the coolant temps. Gaskets for the intake, alot of them partial block the coolant passage between the heads and the intake manifold. A lot of manifolds have casting left in them when they where poured. Some have casing that blocks up to 30% of the flow. Steel pipe for the coolant is the best way to go and just have short rubber hoses for the connections. Exhaust pipe works great for this. You will need to bead the edges for the rubber and clamp to hold on too. You could also cut a 1/2" ring and expandit over the pipe and tack weld it to hold the hose. Pulleys are next, which ones are you running and what size is the diameters? Both should be the same size or the crank one a little bigger to over spin the waterpump. A 3-4 core custom radiator may also be needed if you are high speed driving. I have a Griffen Aluminum in my car. My car runs between 160-190 with racing. It's all aluminum motor. I also have an oil cooler. The oil gets around 195-205 hot. I have seen no problems running at these temps. I have seen alot of intake gasket cause your problem. Check your oil returns too. The intake gasket partial cover the return port to the pan. I high-tac all my gaskets in the motor to stop sliding. Proper torqueing of the intake bolts is also important and following the bolt by bolt pattern. I take them down in 3 stages withthe distributor in the hole for a guide. 10 lbs, 20 lbs and final torque setting. Where and how is your timing for the motor? this will cause a problem with running hot also. Good luck Rick L.

[patrickt]

OK, Rick... you want him to pull the heads or water pump first? F16N, is this a new problem (meaning the car has just recently started to overheat) or has it always done this?

[Bob In Ct]

Does the ambient temperature have any effect on the problem? Would you have the same problem when it's 40 degrees?

Bob

[patrickt]

It's obviously one of two possible problems: Either too much heat is going in to the coolant, or not enough heat is coming out of the coolant.

[f16n]

I am running Eldebrock waterpump,used to run CSR electric waterpump but no difference,top hose is stainless pipe with hose couplings,bottom hose is summit racing stainless ribbed hose,running 195 thermostat but tried 160 and 180 high flow but no change,50/50 antifreeze and water mix with royal purple ice,have shrould on electric puller fan,blue thunder intake with all ports cleaned out,eldebrock heads,crankshaft pulley 6.75" dia. waterpump pulley 5.0" dia. with serpitine belt,northern aluminum radiator 18.5" tall by 24" wide with double 1" cores,oil cooler,timing set at 35 degrees total timing,MSD dist. without vacuum advance,MSD 6al control.

[Dominik]

I would drive without fans to test at higher speeds now to find out if they block airflow.

What speed and rpm are we talking here? How hot is your oil, measured in the sump?

Dom