hey guys, i know this has ben gone over many times but i cant seem to figure out which route is the best to take.

to begin with , i have a 514 with approx 600hp in an 86 f150. big lift 44 inch tires yada yada. anyways i built this rig 20 plus years ago. it has a radiator out of a f600 in it with a 160 degree thermostat.

now when i originally built this truck the temp never got over 160. ac , summeertime, it didnt matter. after a 6 hour road trip that i never should have taken , the temp started climbing. a jump to 180 and then a slow climb from there. i never could determine where the heat was coming from. the truck wound up sitting for many years due to a snafu with a paint and body shop . so after about 5 yrs i tried to get it road worthy again. changed all the fluids and filters multiple times. it seemed ok but it did have a little miss in it. so i finally tried to drive it to work one day ,about 15mi. on the way home the temp got a little over 200 but it was steady. i finally lost oil pressure and shut it down immediately.

i tore it down and found a stuck valve which spit a lifter out which caused the oil pressure drop. the cam was wiped out too. bearings had a few light scratches but the crank polished out.

so anyways i replaced the cam and lifters went through the block . no need for boring. new bearings . pretty much went through everything except the pistons.

i assumed this would take care of whatever my problem was. i did take my radiator to a shop and had it cleaned. well yesterday when i tried to break the cam in the motor was hot within 5 minutes. i advanced the timing a little more which helped me get through the rest of a 20 minute break in . but the temp was still just barely shy of 200.

my question is, should i go with a new radiator like the one that i have (big f600)or go to an aluminum radiator? which im sure would be smaller? how do i know which would be better? i know aluminum is supposed to have better heat exchange properties but the f600 radiator is much larger. it held at barely under 200 but i also had a big shop fan blowing through the radiator . im not concerned with weight but getting this motor temp down is paramount for me .

or can yall think of something else i might be missing? this has been quite frustrating and dissappointing to say the least

 

Do you have a fan shroud?

 

You need a shroud, and a working fan clutch
Also with the 160 thermostat, that means it is open all the time essentially, and that leaves the radiator little to no time to cool the hot coolant
Switch to a 180
Good luck

 

thamks for the replies! i dont have a shroud and ive heard that helps alot but i never had one to begin with.and it seems like years ago i tried the 180 degree and it didnt help (but it has been a long time) when i originally built it it never ran overt 160 with a 160 thermostat. and now im running a full mechanical fan. i would think that would be more than a clutch fan

 

The old story about coolant flowing too fast is a myth.

 

What do you mean by too fast?
Not to me it sure isn't
The coolant has to stay in the radiator long enough to be cooled
With a piping hot motor and the thermostat open, sure the coolant flows
It is still in the radiator 2 to 4 minutes to cool before the swap is complete
Also, with no stat, or a washer in it's place for racing, it gets worse for overheat, lacking sufficient time for the radiator to do it's job

 

What you're saying is false. Why?

The coolant has to remove a certain amount of thermal energy from the engine, take it to the radiator where it is transferred to the air surrounding the radiator. The coolant can pass through very quickly and have very little temperature delta across the radiator or it can travel through very slowly and have a great big delta yet still remove exactly the same amount of heat from the engine.

What having the restriction in the system does is make the pump create more dynamic pressure inside of the block. This causes it to cool better because it keeps the coolant in small areas of the engine and particularly the cylinder heads from boiling. The system can have a pressure cap which creates static pressure and that helps raise the boiling point but the pump can easily produce 20-50psi more with the outlet restricted. I was discussing this one time with a guy who used to work for Elliott. They had a certain specific dynamic pressure number that they shot for inside of the engine. Too low and it doesn't cool well, too high and it just wastes more power. They would speed up or slow down the pump or make the restrictor larger or smaller.

Some circle track racers are big believers in double pass radiators in their cars. They think that it cools better because it slows the water down yet what really happens is that they're making it about 4x more restrictive. 1/2 the core 2x times. It makes more dynamic block pressure yet moves the same number of BTU's.

That's how it works.

 

New temp sensor, 180 thermostat and an all aluminum 4 core radiator with a proper fan shroud and functional fan clutch. IF you are still having temp issues after all of that and it isnt leaking coolant you have bigger problems.

 

Ford masters school is where I got my info and 25+years of dealer experience
Still fix cars daily
Mercedes Audi all the same to me
They all have a radiator for a reason
What you are saying is nonsense to me

 

I take, and ask, for your advice, but do not take it all as fact

 

Did you feel around the radiator core for cool spots while it's hot ? If the radiator shop just cleaned it then you still don't know if it needs rodded out. If there is any doubt I'd take it back and have them take the top off and see for sure.

 

what kind of bigger problems? this is what im worried about , like i said it cooled great. and then suddenly it didnt. and i havent been able to determine what went wrong.

 

thanks ffor all the insight guys. a lot of food for thought. im not conviced the radiator was cleaned out sufficiently but with no other radiator shops anywhere close im kinda stuck to getting a new one. but looks like to the tune of $500+. i just dont know what the best one is

 

Best?
Simply get a lifetime one (Autozone or 1-800-Radiator)(ebay)
They are easy to replace
I would be looking at around 140.00 for a cheap aluminum one, with plastic tanks, (or whatever radiator they sold me for the application)

 

You should because what I'm telling you is correct and how the cooling system works. Thinking that the coolant moves too fast to either pick up or radiate heat is nonsense.