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Discussion Starter · #1 ·
Okay here it goes.

Engine built high end for 1/4 mile racing, same with rear end, drive train and transmission to include a B&M 3600 Holeshot converter. Engine is 350 bored over .30 (355HP), OVH all steel ultradyne roller cam with Keth Black pistons and rings. Lower engine block (stock cast iron) as well the exhaust manifolds (stock cast iron). Milidon 6 quart oil race pan and pump with built in heat shield. Exhaust pipes and mufflers seperate dual flowmasters.

Ignition: MSD Blaster 2 Coil and MSD Series 6 igniton spak control.

Intake: Eldelbrock Performer RPM and 850 CFM Holley quad. carb.

Drive Train:TH350 Automatic with reduced gears, 4:10 posi rear (10bolt).

Has 5 blade Flexlite Fan for radiator engine cooling. (fan blades are 3-4 inches from radiator).

Fuel: I can only run SUPER, anything of a lower grade and the engine knocks.

PROBLEM: Overheating 230 - 240 degrees

I changed out the the radiator installed new 3 core top flow original style, intalled 160 deg. thermostat all new hoses, new water pump, had the entire system purged/flushed (which had all kinds of rust and brown particles in it), installed missing fan shroud. Had the system pressure checked. Had the engine checked for bad seals and leaks and any warpage as well as pressure checked for oil and compression. All checked good. No signs of problems.

The above worked well for about 250 miles, now the problem is back radiator loses about a quart of fluid after running for about 20 minutes on highway and a faint smell of overheated or slightly burnt oil. No smoke coming from anywhere, no oil loss and no water in the oil.

Anyone here a good cooling expert or have any advice.

The vehicle is said to be on the line of Prostreet/Race but barely street legal. Oh, I get 8 mpg highway, and 6 mpg street and she runs great otherwise and sounds excellent though I go about 5 feet chirp into second, and 7 feet and chirp into third. Wet pavement is a bit on the sketchy end. :sad:
 

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A fan spinning three to four inches from radiator will only help if you have a shroud that covers the tips of the blades. If left uncovered the air flies off the end of the fan blade due to centripetal force. This has the net effect of reducing your fan's overall diameter by a third.

Additionally the stock thermostatically controlled five bladed small block fan will move more air than the FlexLite flexing blades. The blades still consume energy even when flattened out (it takes the air resistance to flatten out those blades; so work is still being done, even though no air is being moved across the radiator when they are flattened out).

Finally if you want the most cooling for he buck; use a seven bladed big block fan, and shroud with the big block radiator (two inches wider and uses four cores instead of three). If your fan is thermostatically controlled it will not consume any more energy than needed to cool your car, free wheeling when the engine is cool.

I am curious why you run a cast iron log manifold with an aftermarket cam. The exhaust gas reversion will kill any hope of improved performance, and probably lower your net horsepower over the stock cam.


Big Dave
 

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Proper spacing of the stock fan in the shroud is to have the blades 1/2 way in (or out, depending on how you see things in life :D ) of the shroud. Also try a Robertshaw design thermostat. Much better than the Stant type. My turbo Buick used to overheat intermittantly and after replacing the thermostat with a Robertshaw unit my problems went away. Prior to that I had installed a bigger radiator, bigger fans and an electric fan. The stat was the problem and I had replaced it twice before with stant types. I now run a stock clutch fan and stock shroud and the car stays cool in rush hour traffic with the AC on in the lovely 105 degree summers we have.
Here are some photos of the Robertshaw and it repakaged as a Mr Gasket part.




 

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i would also recomend flow kooler waterpump or rivet one of there plates on the back of your pump impellar..they work very well and they also recomend a robert shaw t-stat..all these help coolant levels with the movement of more water
 

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Discussion Starter · #5 ·
Thank you for all the help. I'm going to try the high flow water pump and Robert Shaw thermostat. :thumbsup:
 

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Discussion Starter · #6 ·
Big Dave said:
A fan spinning three to four inches from radiator will only help if you have a shroud that covers the tips of the blades. If left uncovered the air flies off the end of the fan blade due to centripetal force. This has the net effect of reducing your fan's overall diameter by a third.

Additionally the stock thermostatically controlled five bladed small block fan will move more air than the FlexLite flexing blades. The blades still consume energy even when flattened out (it takes the air resistance to flatten out those blades; so work is still being done, even though no air is being moved across the radiator when they are flattened out).

Finally if you want the most cooling for he buck; use a seven bladed big block fan, and shroud with the big block radiator (two inches wider and uses four cores instead of three). If your fan is thermostatically controlled it will not consume any more energy than needed to cool your car, free wheeling when the engine is cool.

I am curious why you run a cast iron log manifold with an aftermarket cam. The exhaust gas reversion will kill any hope of improved performance, and probably lower your net horsepower over the stock cam.


Big Dave
Well, the race guys that were engineering and building the engine for 1/4 mile racing suggested the all steel ultradyne rollerrocker OHV cam based on fuel and combustion ratios. I miss typed the Holley 4 bbl. it's a 950 cfm. Also, i'm running very rich and hot. The engines rpm at 55 mph is 4950. I wanted to go with more alluminum for faster heat transfer and disipation but was told too many pieces would warp and contort between running hot and cooling down. Gasket sealing would become an issue. The highrise valves covers and and the intake manifold are alluminum for two reasons. Cooling the oil, and the intake to prevent flash combustion up through the carb even though i have the carb flash protected. If I didn't change the intake manifold there would be a good chance of ruining the secondaries constantly on the carb.
 
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