[Guest]

I warmed my car up and went fo

I warmed my car up and went for a spin. Coolant temp at 195, fans on shot temps at exhaust manifold with my infrared thermometer. I tried many different areas.
My first reading was right in the middle of the heat shield covering over my headers on my 85' QV. It read 1854 deg. F. I thought this couldn't be right. I shot it again in a diff. place and got 1800 deg. F.
I then turned the car off and shot the temp about 30 secs. later and it was 580 deg. F.
Could 1800 deg. F be correct when the car is running? It seems strange that 580 would be there within 30 secs.
What could be causing these high header temps.?
I thought a lean mixture but my plugs look ok. I will try to post some pics of them. Any other ideas. Maybe my thermometer isn't reading correct. Thanks.

 

[Guest]

Rich,

500-650 degrees sound

Rich,

500-650 degrees sounds like a normal range for 308 headers imo. Could be the way you are taking the readings ? I think most IR thermometers have calculations that have to be done for some types of measurements.

Regards, JRV

 

[Guest]

The high voltage from the igni

The high voltage from the ignition system plays havoc with some IR thermometers, to the point of damaging the unit. We fried two Raytech thermometers at our shop before figuring this out. Fortunately, one of them was new enough that it was repaired under warranty.
Most of the cars that we work on have no resistors in the secondary circuit for radio noise suppression, so this may affect the IR thermometers more than a newer car would. After ruining my Raytech thermometer, I will only use one in the engine compartment when the motor is stopped.

Brian Brown
Patrick Ottis Company
Berkeley, CA

 

[Guest]

Thanks for the tips guys. I a

Thanks for the tips guys. I appreciate it. Sounds like my temps are normal then. I never got anything higher than 580-590 with the engine off.