Spark plug fouling- 1971 350 engine
08-13-2017, 08:09 PM
#1
5th Gear
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Spark plug fouling- 1971 350 engine
What would cause the spark plugs to be tan half-way around the anode and oil coated on the other half of the anode? This is common to all spark plugs. Valve guide seals replaced last year, 2016. Piston rings condition unknown. Cylinder compression between 175 and 180 psi on all cylinders. Car runs decent and no discolored exhaust. I have tried different brands on plugs, have E3 installed now with same results.
08-13-2017, 10:02 PM
#2
Race Director
Oil is making it past the piston rings, goes up into the intake during valve overlap and then back into the cylinder hitting one side of the plug. If your oil turns black very quickly after you change it, that's further indication of a ring issue.
That's assuming you checked the easy stuff like a stuck PCV valve.
Running a hotter plug and thicker oil will help.
That's assuming you checked the easy stuff like a stuck PCV valve.
Running a hotter plug and thicker oil will help.
Last edited by zwede; 08-13-2017 at 10:04 PM.
08-15-2017, 08:25 PM
#4
Team Owner
You need to do a leak down test to tell you engine health. compression testing is a waste of time and effort.
