Spark Plugs are Different Colors
Thread Starter
Safety Car
Joined: Oct 2004
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From: Minnesota
Spark Plugs are Different Colors
I pulled my plugs today to do some carb tuning based on color. It looks like that may be difficult since four of the plugs are very light tan, almost white, while the other four are black. I checked the compression to rule out any problems there and it all checks out OK. What's going on here?
Thread Starter
Safety Car
Joined: Oct 2004
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Likes: 5
From: Minnesota
Originally Posted by vetteguy75
Are the plugs that are the same color, on the same side of the engine?
Thread Starter
Safety Car
Joined: Oct 2004
Posts: 3,725
Likes: 5
From: Minnesota
Originally Posted by zwede
Do you have a dual plane intake where 1,7,2,6 feed off one side of the carb?
Safety Car
Joined: Aug 2001
Posts: 3,892
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From: Pettis Performance 565 with two stages of Nitrous Supply nitrous 1.082, 4.61 at 155, 7.17 at 192
Unless you make some passes at the track and then pull the plugs it is hard to tune a motor by pulling plugs that have been run for a while. If one cylinder is getting a little oil past the rings or valve guides it will color a plug. If the idle cuircut is a little off it will also color the plug.
Here is a plug I pulled out of my nitrous race motor. The ring around the porcelain is what you are looking for when tuning for A/F ratio.
Here is a plug I pulled out of my nitrous race motor. The ring around the porcelain is what you are looking for when tuning for A/F ratio.
Pro
Joined: Oct 2005
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From: Boynton Beach Florida
sounds like the carb has to be balanced,, if you have a tach and dwell.back out the left and close the right mixture screw, then open the right screw 2 1/2 turns,then close the left screw and open it 2 1/2 turns now there balanced , watching the tach to get the max rpm,adjust the screws in sync so that they remain equal to each other.. you will probably end up about a turn and a half out on each side
