I have a 69 camaro big block built 427 has about 700hp. Compression is 13.5. The car has a aluminum radiator that supposed to be good for my application and a csi electric water pump. Car gets passed 200. Just wondering what the problem could be?

 

Is this a proven motor, one that you have driven before and never had this problem, or have you just swapped something out and are now having this problem, could be multiple possibilities. Generally nature of the beast, with that much power and compression in a traditional big block, cooling system needs to be flawless, I had a pontiac 462 in my bird and bought a be cool radiator rated for like 1000 horsepower, and still overheated, my solution was a cooling fan from a lincoln mark 8. I would say if you just swapped the radiator, make sure your fan is on and sitting 1/2 in the shroud opening if you have a mechanical setup. If an electric make sure it is pulling the air and not pushing it. Just a few tips, let us know more and maybe we can figure the problem out.

 

200 doesn't seem like its overheating too badly, does it ever go past 200? say 210-220 ?

 

Actaully. We bought the car a long time ago. It was strictly a 1/4 mile drag car. We been working on it for a couple years. We only been driving it around the block here and there. It takes a while but slowly goes up to around 220 - then we shut it off.

 

Is that not a little high mine 427 goes to 190 top,

similuar engine that he describes, but with 12,5 compression

 

Do I have to run a thermostat?? What's your set-up

 

Yes 200 is a 'little' high, but not drasticly high. Especially from an engine running that high of comp.

OP- This might sound obvious but did you make sure you have the right/ a working thermostat, and that all the lines are air free?

 

if it crawls up to 220 it will probably keep going till meltdown. Generally the optimum temp for your engine should be around 180 degrees, 220 is too hot. First make absolutely sure that the electric water pump is hooked up right, (pushing water thru the engine not pulling it). Second Like I said earlier, be sure your fan setup is working correctly, another thing you want to be sure of is that your lower radiator hose is not collapsing when the engine is pulling the coolant thru, if it sucks closed there will be no flow into the motor and that will cause an overheating problem. if all that is ok, The next step is to check your timing, make sure is is set correctly, if it is too advanced or especially retarded it will make the engine run Hot, run a compression check on the motor, because a blown head gasket can cause overheating too. If the engine is in tune, and sound, and still getting hot, then start working on your water flow, I believe you said you didnt have a thermostat, if that is the case, try running like a 160 high flow thermostat. On my pontiac 462 roller, I could not run without a thermostat, You have to think of it like this,,,,a thermostat keeps water from flowing into the radiator to be cooled until the motor reaches a certain temp, thats fine, but when you increase things like HORSEPOWER, and especially, water flow, aftermarket water pump, and high flow radiator, You have to pay close attention to the motor. If the coolant system does not have a thermostat then it may be rushing water from the radiator thru the motor then back into the motor again, moving too fast for the coolant to dissapate the heat, so what you would want to do is slow it down a little. That is where a thermostat comes in, reaching a temp, then opening but still creating a restriction, allowing to coolant to circulate thru the radiator and cool before re-entering the engine. My Pontiac would overheat with a thermostat and without one, My solution ended up being using a restrictor plate summit sells them, http://www.summitracing.com/parts/MOR-63440/ Thru the combination of my high flow cooling fan and the small restrictor, I was able to keep my Iron headed big block from eating itself up, Hope this helps some.

 

i have had alot of luck with the moroso restrictor plate also. My buddy 540 ran at 220 degrees and it was fine. to hot for me so we put and electric wp and and a be cool dual 11' fan set with the restrictors and it doesn't go above 190.

 

Another of the simplest things not mentioned is when the car starts getting hot, is it releasing coolant out of the overflow tube, If it is then you may want to start with the radiator cap, if it is not holding the pressure in then it will overheat also.