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**HO455** · 06-14-2019, 07:10 PM

Unfortunately in these modern times of ethanol gasoline, every brand having a different mix of additives, and the change in fuel mixtures for the different seasons of the year, being able to read a spark plug with any kind of accuracy is impossible. If you were to run only straight AvGas then you would be able to read a plug like in the days of yesteryear.
On the up side of these modern times we now have wide band O2 sensors and the ability to read air/fuel ratios on a guage with far greater accuracy than what you can get by reading plugs. For example:

http://67-72chevytrucks.com/vboard/s...d.php?t=713728

06-14-2019, 07:10 PM	#3
HO455 Post Whore Join Date: Feb 2016 Location: Portland Oregon Posts: 10,807	Re: Spark Plug reading Unfortunately in these modern times of ethanol gasoline, every brand having a different mix of additives, and the change in fuel mixtures for the different seasons of the year, being able to read a spark plug with any kind of accuracy is impossible. If you were to run only straight AvGas then you would be able to read a plug like in the days of yesteryear. On the up side of these modern times we now have wide band O2 sensors and the ability to read air/fuel ratios on a guage with far greater accuracy than what you can get by reading plugs. For example: http://67-72chevytrucks.com/vboard/s...d.php?t=713728 __________________ Thanks to Bob and Jeanie and everyone else at Superior Performance for all their great help. RIP Bob Parks. 1967 Burban the WMB,1991 S(stink)-10 Blazer,1969 GTO, 1970 Javelin, 1952 F2 Ford 4X4, 29 Model A, 72 Firebird. 85 Alfa Romeo If it breaks I didn't want it in the first place The WMB repair thread http://67-72chevytrucks.com/vboard/s...d.php?t=698377