lpeeff

I'm working on my 7 that i rescued(dosent want to idle), and wile i was doing a compression test to rule out bad seals, i found these. the blacked set came out of the front rotor, and the weird orange(tan?) plugs came out of the rear rotor, what is this crap? any help would be greatly app! thanks guys!

rx7racerca

iTrader: (1)

Light tan is good, indicates relatively stoich mix and clean burn. The black is either carbon from unburned fuel (if dull and sooty), or if shiney and/or hard, oil consumption. The photos are blurry, so it's hard to tell what condition the electrodes are in, you might just need new plugs if they're eroded a lot, or the deposits might be a sign of other problems, but without a clearer view, hard to say if they are normal or not.

Go48

iTrader: (7)

The important thing to look for is the color of the center insulator (red area in drawing). In general, as the previous poster says, tan is good, meaning a near-complete burning of a proper A-F mixture, black means an overly rich mixture or incomplete burning of the mixture.