Thread: What Is The "high" Normal Temp Fro A 454 At Idle??

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i DON'T KNOW IF i AM CONCERNED ABOUT NOTHING OR NOT, i HAVE A 39 CHEVY COUPE WITH A WALKER 4CORE RADIOR,, A 3,000 CFM PULLER FAN. DRIVEING THE CAr at speed it runs arond 190, but if I sit & idle for around five minutes the temp will climb to 225 & stay(it is a electric temp gauge) is 225 too high or is it o.k.?? I have hooked a mechcanical temp gauge to the head & it read 215 so maybe the elec. gauge is reading alittle high. But i do want to know what the highest safe temp a engine can run without damage. also what is the norm for a 454 to run at idle.?

My sender is on the intake and indicates about 210-215 at idle on a HOT day but quickly drops back to 190-200 once I roll. The ambient temperature over a blacktop road is pretty high so IMO you are doing okay if this was your typical summer dog day. On a cool day, I would be lucky to see anything over 200.

If it keeps climbing then I might be concerned (I would say 230 max) but others may tell you different. Some people manage to keep it below 190-200 no matter what the weather. Maybe they will chime in with ideas or opinions...

Some things you could research and check....your timing, your fuel mixture, and your air flow (or lack of). Good luck.

btw: I am running a 454 also.

WHAT ARE THE DIFFERENT TEMPS. WITH THE SENDER IN THE BLOCK VS IN THE INTAKE? OR IS THAT A NO NO.

Don In Austin

i have been told that there is a 10-15 degress differents between the head & intake on temps. readings, & for the most correct reading the temp sending unit should be in the head. but I don't know that for a fact

called TPI tech instruments.(the gauge is electric) they said that the sending unit , which is installed in the head is asorbing heat from the headers which is probable making the temp read higher than it really is!!!!!!!

now I am really confused, is there any truth that the sending unit can be asorbing heat off the headers at idle, or is that a much of crap??? if so where is the best place to install the sending unit to get correct reading on the engine temp????

My sender is on the head and I am running about 200-210. It pegs to 230-250 after I turn the car off. I am concerned as well but feel better after reading the threads. I have a 180deg thermastat so I thought gauge temp should be similar.

The head is the hottest and best location to measure. I use the intake manifold because it is more conveneint and I like seeing lower temperatures. The sensor is in direct contact with the water and thus the headers should not adversely affect the readings as long as the sensor housing is not touching the headers.

The boiling point of 50/50 EG water is 265F at 15 psig. As long as you are reasonably under this (220F), not boiling off coolant, and your idle mixture and timing suit the temperature you should be OK.

It is certainly preferable to operate cooler (190F full time would be great) but it may just not be practical. A 220F head reading might read 200F or so at the intake? This would be considered acceptable for me.

Kitz

well I put a mech. temp gauge in the intake, next to the thermostast & left the elec. temp sending unit in the head.
as I have stated it it a bbc 454

at idle after 15min. 800 rpm.

electric in head reads ...225 and holds there
mech. in intake reads ... 155 after thermostat opens at 180, close until it gets to 180 again then drops back to 155

at 60mph after 15min warm up.

elec. reads 225 & holds
mech. reads 160 and never got to 180 until a stopped & idled for a min. then back down to 155

does this sound like a acceptable heat range for the motor

Your temp. at the manifold is reading what the thermostat is doing. So if your only running 180, your good. My electric fan doesn't come on until 205. I only have room for a 2 row radiator. 35 chevy master coupe.