If anyone has an IR thermometer out there can you check/shoot your exhaust temp on your exhaust manifold at each pipe port at all cylinders and tell me what you get at idle and 3K RPM. If you have a header installed it would be best. I have tried everything in the free world to get the #1 cylinder to read as high as the rest. I am gettng number like 250, 600, 600, 650 deg. F (1,2,3,4).

Greg B.
1970 1800E

Greg;

Does "everything in the free world" include directly measuring EGTs with thermocouples and not indirectly with the IR thermometer...maybe its time to change your method.

I'm trying to think of what might be the cause of the difference with No.1, and I have to admit I can't think of much... maybe a leaky injector causing a (very) rich mixture, but you'd see evidence of that on the spark plug....

...besides, I question the value and usefullness of IR thermomometer measured temps....unless you have the car on a dynemometer and under load at the time you're cheching, and taking the readings, they are only unloaded temps...I would much rather be able to monitor EGT under load.

The homebuilt aircraft supplyers such as Wag Aero have thermocouple EGT kits which you might want to try. You can either work thermocouples directly into the exhaust stream, or use the much simpler, but less direct, "under-the-spark-plug" type.

Cheers

Ron,

The under the sparkplug ones (Cylinder Heat Temp, CHT) I have used but they less reactive than the EGT ones due to the head/plug mass. See other post for the rest of the response.

Greg

Have you removed the fan blades and/or turned your thermo fan off?
Do the spark plugs all look the same?

Yes pulled the Fan belt. Negligble diff. I had one guy on the 1800list do this and he got the same thing (350, 700, 700, 700) on an ES header after a drive. I am beginging to think this is normal I have used EGT's on snowmobiles and did not want to drill the pipes for them as I am not racing it. I think the IR is ok for general diagnostics. It is telling the truth. I think it is the head design and #1 first to get the cool radiator flow. Volvo must have not balance the head for coolant. #4 is hotter than #2/3 by a little and is farther away. I felt something was wrong as the diff was so much. Usually in other motors it means a a cyl is down on power (plug fouled etc. )...

The 1st cylinder's exhaust is alway going to be cooler, it gets plenty of air around it. An IR thermometer isn't going to be able to tell you how hot the exhaust gas is for each cylinder anyhow. As for cooling, not many cars have a superior cooling system to the B20.