Spark plugs out of 1977 2F. I put these in like a year ago, not a lot of miles - maybe 1-2000. Anyone have an analysis? Ordered from front to back. #2 looks the oiliest.
Spark Plug Analysis
- Thread starter Ztrx
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Number 1 lean….number 2 and 5, oil foul….best guess….
You need a picture looking down onto the center electrode.
And after miles of various driving conditions, reading the plugs is questionable. Best method, buy a new set,,,,go find an empty road….change plugs next to the road…..then 2 full throttle runs up 1/2 mile and back 1/2 mile….then pull and read.
Be good…..see ya at the drag strip….
You need a picture looking down onto the center electrode.
And after miles of various driving conditions, reading the plugs is questionable. Best method, buy a new set,,,,go find an empty road….change plugs next to the road…..then 2 full throttle runs up 1/2 mile and back 1/2 mile….then pull and read.
Be good…..see ya at the drag strip….
- Thread starter
- #3
Number 1 lean….number 2 and 5, oil foul….best guess….
You need a picture looking down onto the center electrode.
And after miles of various driving conditions, reading the plugs is questionable. Best method, buy a new set,,,,go find an empty road….change plugs next to the road…..then 2 full throttle runs up 1/2 mile and back 1/2 mile….then pull and read.
Be good…..see ya at the drag strip….
#1 appears to be good. You need better pics. The ceramic around the center electrode is an important factor. I dont believe that style plug was originally used in a stk engine. What's the compression #'s.
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- #5
Sorta the same order...well, I already swapped them out so I'll have to try the drag race test another time!
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- #6
I still need to do a compression test...good tip.
Dry and wet compression test numbers will tell you more. I would pull the plugs on a hot engine and then give each cylinder a spoon full or two of marvels' mystery oil - bump the starter to distribute the oil, let soak for a few days - goal try and free up the rings.
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- #8
Cool, just going into town so I can try this today when I get back.
Verify plug gap as well. Old ones look excessive.
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- #10
I had them gapped higher (close to .50) for an HEI distributor - bad idea?
My 2 cents. Oil fouled is ring related. Lean is a vacuum leak unless they are all that way. I spent weeks working a spark plug break down tester. Even new plugs could have the spark blown out at like 60 psi. A properly adjusted plug with a squared edge would often fire at 150 psi the limit of shop air pressure.
I'm not a fan of black box ignition. Been stranded way to many times. Points, yes I have had to adjust them. Only once in 60 years of driving the points arm broke off ( on a state highway dept dump truck) and it was stranded - they would not let me carry any spare stuff other than for the unique road testing equipment we used.
I'm not a fan of black box ignition. Been stranded way to many times. Points, yes I have had to adjust them. Only once in 60 years of driving the points arm broke off ( on a state highway dept dump truck) and it was stranded - they would not let me carry any spare stuff other than for the unique road testing equipment we used.
And just remember, gas additives affect plug color, Marvel leaves white crusties, long term. And ethanol laced look a bit lean……drag race test a sohw us your results.
0.50” or 0.050”? Normally 0.032-0.036” standard distributor on an F/2F motor. I use around 0.045” on my SBC 283 that has an hei dizzy. Your picture above looks a lot more than 0.050.
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- #14
I mistyped, should have been 0.050...
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- #15
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- #16
Not really a drag race but these are what they look like after about 25 - 30 miles. I took individual shots too but you can kind of see the ceramic tops here. I regapped these to about 0.045.
Those look much better.
They look better, but still think you might take a look at 6, looks a little oily. Does rig use any oil? 1/2 a quart now and then?
Maybe a compression check is in order.
Maybe a compression check is in order.
I agree, compression check on a wsrmed up engine. Your plugs show inconsistencies. Do all dry 1st, then sqirt some oil into the cylinder your going to check next.
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- #20
Yeah, I need to go get a tester, been meaning to do that. The inconsistencies I saw were why I posted...thought it must mean something.
It doesn't consume a lot of oil, but there's also leaks. I haven't really tried to quantify the amount lost per mile because of how infrequent it gets driven. The intention is for it to be driven more though!