Inliners International Forums General Discussion Engines neasuring exhaust temperatures at manifold

Has anyone measured the difference between the single and double exhaust port temperatures on a chevrolet 194-292 engine?

I'm reading about a 120 degrees higher with an infrared gun on both double ports vs the two single ports.



Is this because of the pairing of the cylinder?

Thanks for your help.

Hi true blue 6 . . .

Your measurements make sense as does your conclusion. The firing order of a Chevy Six is 153624 with the cylinders ordered from front to back:
| 1 | 2 | 3 | 4 | 5 | 6 |

This means that the outer most ports (from valves 1 and 6) only blow exhaust every other rotation of the crank - whereas the siamese ports get a blast of exhaust every time around . . . the first time around from valves 2 and 4 . . . the second time around from valves 3 and 5 . . .

Curious though. What prompted you to measure this?

regards,
stock49

Thanks for the reply. Sorry for the delay in answering. I was referencing an earlier exhaust gas temp measurement on a Chevy LS V8. The correct temp at idle is around 450 degrees. Because I'm starting the six for the first time in about 5+ years, I'm repeating my V8 habits even though this engine has no injectors. I was alarmed at 700 degree siamese port exhaust temps and found the timing retarded a little. Advancing the timing corrected all temps cooler but the siamese ports are still warmer than the single ports . I had a hunch this is normal but just wanted a dedicated inline six cylinder answer. Without the fancy tool, we would check and correct the timing without knowledge of the exhaust gas temps. Thanks for the reply stock49.

cylinder might have different compression ratios which will affect temps also shoot temp closest to cylinder head to get more precise temp. jmo
bob