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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: 10,883	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),1988 S10 Blazer (the Stink10 II),1969 GTO (the Goat), 1970 Javelin, 1952 F2 Ford OHC six 4X4, 29 Model A, 72 Firebird (the DBP Bird). 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