View Full Version : gen iv 454 running hot

05-10-2011, 07:08 PM
:bang: i guys i need some help here , i have a 454 out of a 1973 corvette i have had it rebuilt bored 60 over 9-1 dome pistons 305/305- 514/514 lift elgen cam springs to mach , 750 cfm holly man chock macan secd, have a new 4 row radeator, new hi flow long water pump new hi flow raceing thomo {180} new airgap intake {2} 12" elect fans cooling radeator 480 hp with 500 ft tork tci street fighter th35o trains with 3000 stall along with a trains cooler installed . the truble is the thing runs hot pushes coolent out over flow at around 195- 200 i havent let it go any farther then 200 befor shoutting down the motor for fear of hurting it , iv been told that the norm for a bbc is frm 195 to 210 but i know im running hot as for the coolnt running out of the over flow, iv ck and re ck the timming all ok ck for flow in rad, all ok, ck that thormo is working and it is , im LOST AND IN NEED OF HELP any one have ANY IDEAS? thanks so much

05-10-2011, 11:06 PM
Make sure the water pump you have is aluminum and is flowing correctly. Oem pumps are junk imo. Take cap off radiator while running to see if it is flowing well.
What is your timing set on? I ran 36 degree at idle with my old setup. At least needs to be 20-22 at idle.
Also I would swap out the 180 thermostat for a 160. I run a 160 and it generally stays between 170-185 even in 100 degree weather.

05-11-2011, 06:54 AM
Check to make sure your radiator cap is good. If it's not holding pressure, it will run hot. I don't care if it's new or not, a new one could still be bad.

05-11-2011, 06:48 PM
ok my timeing is set at 36 total timing and 23 idel, i have look into the radator and can see it flowing in all 4 rows so seems ok, the water pump is a alum hi flow pump as well, i will try another cap just to see if thats a problum, let me ask this i had a shop tell me to gut out the thurmostate and use it as a restrictor? and all so does the bypass hose frm the intake to the water pump have to be on it as i was told that it does not just to cap them off, but it seems to me that if the water pump is trying to pump water into the intake thormsate when the motor is cold and the state doesnt open tell it reaches the propper temp , withe the bypass plug off that would make a dead head and psi and temp would rase qwicker then the thrmo would open and serpass the setting on it and by the time water starts to flow the temp is all ready to hot and the radeator and fans cant kool it down enouth? are am i just thing wrong?

05-11-2011, 08:40 PM
Timing sounds good. On my wifes 489, we have no bypass and a gutted thermostat. It will get warm after a 1/4 mile pass after she gets on the return road. Her car is not a street car. My buddy's 68 Camaro with a 468 has a gutted therm with the bypass hose still installed and it runs up to 200 on the highway.

05-12-2011, 10:06 PM
ok guys tell me what you think about this , i bought a radeator cap with a temp gage made on it and i put it on my radator, and put the reg, cap i had on the intake perge tank, i started the car and let it run for a good wile, watching the temp gage in the car i put in and allso watching the gage on new cap, the cap naver got past 190 the one in the car got up to 220 223 but i naver push any coolent out oh eather over flow ports one on radeator and one on purge thank on intake, im begening to think my gage is bad?

05-13-2011, 07:26 AM
Very possible you gauge could be bad. Just now got me to thinking (which is pretty rare) that you might also have an air bubble where the guage hooks up in the intake. With it running, slightly loosen the fitting and see if you can purge any air out of it. If there is no air, then you might see if you can get another gauge.

05-13-2011, 07:31 AM
Oh yea, that side of the radiator is the "cool" side, so it will show a lower temp reading than by the therm housing. Hate to bring htis up, but could be core shift in the block and when you bored it, it could be thinner cylinder wall on some of hte cylinders. Only way to check this is pull the engine apart and have in sonic checked. :(

05-13-2011, 01:06 PM
You need to keep a thermostat in the system or it will overheat. Drop down to a 160 that should help it out.