Messing With Spark Plug Gap

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RustRocket

Master Mechanic
Sep 8, 2014
351
86
28
Las Vegas, Nevada
Hello all, I have a sort of strange question. How much can gap adjustment of the spark plugs effect the overall running of the car? I ask because I found it strange that the gap for my 231 is supposed to be set at .80. That seems like a little much for a low compression V6 engine. Currently my car is running in limp mode, or full rich. I'm wondering if my car would run better with a smaller or larger gap. I'm just trying to get this thing running as good as possible, and I was thinking perhaps re-gapping them may make a difference. I'm using some Autolite 666's, I just replaced them last month, and the car hasn't been driven, its only been run for about 10 minutes since I put them in.
 

Dayzedandkonfuzed

G-Body Guru
Feb 9, 2010
971
1,268
93
Anglemont, BC
Don't know much about your build, but ngk has a rule of thumb for gapping plugs in performance motors. Don't quote me but I think you close up the gap .010 for every 100hp you're making over stock
 

RustRocket

Master Mechanic
Sep 8, 2014
351
86
28
Las Vegas, Nevada
Don't know much about your build, but ngk has a rule of thumb for gapping plugs in performance motors. Don't quote me but I think you close up the gap .010 for every 100hp you're making over stock
Thanks but my car's not "built", it probably doesn't even make 100 hp
 

RustRocket

Master Mechanic
Sep 8, 2014
351
86
28
Las Vegas, Nevada
Lol fair enough. If it means anything when I look up the plug for that car it calls for a .060 gap...

EDIT: NGK calls for .060, autolite calls for .080
Interesting. Thanks for the info, it's good to get some more knowledge
 

truracer20

Master Mechanic
Feb 16, 2014
492
31
28
western PA
Without the computer go with the R45TS gapped at .040" That is the plug called for in 1980 for non CCC 231 V6 VIN A Cutlasses. Of course you can use an equivalent plug of another brand but don't use the TSX or the .080" gap.
 

jacobdavis1979

G-Body Guru
Feb 18, 2011
700
14
18
In all honesty i think a 231 was actually the last time i ever messed with spark plug gap. .80 doesn't seem ridiculous but does seem excessive. I think i started off at like .20 and tweaked it a dozen times till i hit .60 and at that point i think it started idling rough on me. It didn't misfire just rough. i don't remember my final tweak though to many years ago. i wanna say around .35 to .40
 
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