Thread: BBC Operating Temp

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What is the best operating temp for my 402? It seems to be running a bit hot....anywhere from 195° to 200°. I think that is a little to high. What do you guys think? It has a 180° t-stat and a 3 row BBC radiotor...brand new. What can i do to cool it down?

Thanks!!!!!!!!!!!!!!!!

I am getting the timing checked. Maybe that is the problem??

195 to 200 is ok. If its not boiling over you are not overheating.

thats a good temp. a lot of people wish their big blocks ran that cool.

Originally posted by Joe Scalley
195 to 200 is ok. If its not boiling over you are not overheating.

have had big blocks run at 210 all the time you could try playing with the water speed this is done with pulley size .a big fan or fan shroude fix blade fan a better water pump with equal distribution to both sides of the pump like edelbrock victor or the steward pump .and you can try some more timing run vacum advance and you can try high volume water thermostat make shure you have a good rad cap and royal purple purple ice

Originally posted by lt1s10
thats a good temp. a lot of people wish their big blocks ran that cool.

YES they do

Awesome guys!! Thanks!! I will maybe try some of the suggestions to make sure it maintains a steady temp at all times. The only time it boiles over is when i cut the motor off. I guess that is to be expected though. Is there a Max temp to look out for? I have been afraid the high temps, especially after shut-off, may do some damage, but if you think i am ok then cool.
You guys are great!! THanks!!!

this is the truth, but nobody will believe it, but i had a 1980 el camino, 454, 671 blower. put over 75,000 miles on the car in about 13 yrs (daily driver). the problem was keeping it cool on a hot day, in traffic, I'm talking 85 degrees and above. tried everything, had 2-4 row radiators on board (1 in the bed) didn't help, so what to do. bought some stuff that they said wouldn't boil, and put it in the motor. on an 100 degree day i could go anywhere i wanted, without a problem, the temp stabilized at 260 degrees. at 260 you could stick you finger in the radiator and the stuff was cool. ran a cap with no pressure on it. damnedest stuff i ever seen, and i didn't see where it hurt anything. they said that a motor could run at 300 degrees without hurting anything as long as the fluids covered every thing. when water boils in a motor the water moves away from the surface its trying to cool and it cant keep it cool because its boiling. If the liquid don't boil, it will cool up until the metal cant stay together anymore. It cost 35.00 a gal.

the purple ice seams to work and so dose the steward water pump and as how hot is to hot?? had a bigblock run at 230 all the time and when i took it down it look like the day i put it together if you get to hot the oil psi will drop so i look at my oil psi this tell you if it is getting way to hot hey it1 s10 called EVER CLEAR

do you have a cross flow rad. HotRod65? if you do a recovery system will fix your problem.

If your water temp was 260 and you could stick your finger in the radiator tank, that means your tstat wasn't opening or you weren't getting the water out of the block quickly enough.

Originally posted by 76GMC1500
If your water temp was 260 and you could stick your finger in the radiator tank, that means your tstat wasn't opening or you weren't getting the water out of the block quickly enough.

i dont know 76 it wasn't water and it couldn't have been 260 at the rad. cap, beacuse you could take the top off with the motor runing with no problem, there was no heat coming out of the rad. that you could see. it was like the block was 260, and the fluid wasn't. i may over stated cool, but it wasn't to hot to work around. the only problem i had was at 260 the starter wouldn't work, it had to cool down to around 240 and then the starter did ok.

LT1 - Cross Flow radiator? Ok, I must show my ignorance. What is that? It is a brand new 3-row radiator for a '66 chevelle big block.

Thanks man!!

Originally posted by HotRod65
LT1 - Cross Flow radiator? Ok, I must show my ignorance. What is that? It is a brand new 3-row radiator for a '66 chevelle big block.

Thanks man!!

New cars have come equipped with crossflow radiators for more than 30 years, and today many modified cars from the ’60s and earlier have them installed. Crossflow radiators are superior to upright radiators because the radiator cap is positioned on the low-pressure (suction) side of the system, which prevents the pressure created by a high-flow water pump from forcing coolant past the radiator cap at high rpm. Upright radiators typically have the cap on the inlet side and thus subject the filler cap to the pressure drop of the radiator’s core in addition to the system pressure.
The coolant recovery tank is an expansion reservior. When the engine heats up, the coolant expands and flows into the tank. When the engine is turned off and cooled down, the coolant contracts and creates a partial vacuum to pull the coolant from the tank back into the radiator to keep the rad. full all the time. The radiator pressure cap severs as a valve to control this process.
your 66 probably has a up-right rad. and i don't think the recovery system will work on those. on a up-right rad. the fins run top to bottom and on a crossflow rad. they run side to side.

My 496 runs at a constant 180-195 sitting in traffic. I am a HUGE fan of electric cooling fans since i built this motor.

Originally posted by lt1s10
this is the truth, but nobody will believe it, but i had a 1980 el camino, 454, 671 blower. put over 75,000 miles on the car in about 13 yrs (daily driver). the problem was keeping it cool on a hot day, in traffic, I'm talking 85 degrees and above. tried everything, had 2-4 row radiators on board (1 in the bed) didn't help, so what to do. bought some stuff that they said wouldn't boil, and put it in the motor. on an 100 degree day i could go anywhere i wanted, without a problem, the temp stabilized at 260 degrees. at 260 you could stick you finger in the radiator and the stuff was cool. ran a cap with no pressure on it. damnedest stuff i ever seen, and i didn't see where it hurt anything. they said that a motor could run at 300 degrees without hurting anything as long as the fluids covered every thing. when water boils in a motor the water moves away from the surface its trying to cool and it cant keep it cool because its boiling. If the liquid don't boil, it will cool up until the metal cant stay together anymore. It cost 35.00 a gal.

All I have to say is WOW!!! WHAT A STORY.