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'82sc Help me read my spark plugs
Using this time to do a major service on the car - New plugs, cap rotor and wires and valve adjust. Never done it before so going slow and steady. Car has approx 130 k miles and if it has been sitting for a week or 2 it blows some smoke on startup - which I have been told could mean worn valve guides.
Just pulled the plugs and was hoping someone in the group could put their eye on it and tell me their thoughts. Cylinder 4 & 5 seem to have some whiteish coloration and google says is consistent with worn valve guides and oil getting in. Car runs pretty good ish (when I put it away before winter), have a hot start problem and a bit idle hunting at times so am starting with major tune up before looking at CIS. Thanks in advance
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82 SC Triple Black |
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Those look pretty good to me. Depends somewhat on mileage. 10,000??
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A little puff of smoke on start up is normal. The plugs look fine.
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Sweet - thanks. Not sure exactly how many miles - I havent changed them ever in the +/- 15k miles I have owned the car.
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82 SC Triple Black |
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I think a little more than a puff at cold startup is even normal. On cold start it can take a few mins to get hot enough to evaporate all of the condensate left in the exhaust from the last shut down. Blue smoke that smells like oil for a long time is an issue but white smoke accompanied by a few water drops for a minute or two is perfectly normal. You will find this even on a brand new modern car.
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#5 looks like it pretty light to me. Indicating a lean condition. Could just be the pic though.
The rest look good.
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81 Pacific Blue 930 Euro coupe slicktop on a strict diet, Rarlyl8 headers, Blowzilla turbo, Tial waste gate, Full bay I/C, Home made center out exhaust, Leask WUR, MSD 6AL, PLX wideband Wevo shifter, LSD. Next up, Cams, Heads and port work |
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Yeah, 4 and 5 are both a bit lighter.
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82 SC Triple Black |
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I'd say 4-5 are what they all should look like.
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Kent Olsen 72 911 SCT upgraded 3.0L McMinnville, Ore |
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Under the radar
Join Date: May 2007
Location: Fortuna, CA. On the Lost Coast near the Emerald Triangle
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I'd say if your motor isn't burning oil, and it doesn't look like it from the plugs, you are good to go.
BTW, what plugs are those?
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Gordon ___________________________________ '71 911 Coupe 3,0L outlawed #56 PCA Redwood Region, GGR, NASA, Speed SF Trackrash's Garage :: My Garage |
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Solid, thanks - She burns about 1.25 litres between oil changes - which I figure is normal ish - coupled with a small oil leak from my main seal
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82 SC Triple Black |
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Oh, shoot - I threw sparkplugs in a box that I cant get at (have broken collar bone) - when i get it down I can check then - may be a 2while.
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Could be the photos, but #4 & #5 look a little lean. Assuming it is still the original CIS injection, those injectors might be dirty?
Side shots would've helped with a reading. Looking at the black carbon on the ring, by the threads, is darker than the "tan" I'd be hoping for. Again it could just be the photos. However, I don't see any "shine" in that black, so not an oil problem. Just a bit rich/cool. Better than lean. Don't top off the oil. Let it sit a quart to half quart low. (I keep mine in the middle, but I watch it fairly seriously.) That will cut down on oil getting by the worn guides while it is sitting/parked. |
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Reiver
Join Date: Nov 2011
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They look ok but to read plugs you don't idle the car as you are reading them at idle.
Back in the day when you really could read plugs (lead, no other additives etc) you'd pick an area where you could hit WOT...cut the engine and coast to a stop....then check plugs to see what you were doing under acceleration. My '83's plugs all look a bit less carboned at idle read.
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De Oppresso Liber Strength and Honor 5th Legion |
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Let's see what the pros say:
Cheers, Joe 87 Carrera |
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I'd say 4/5 are lean. If it's burning at stoich they should all look color of chocolate milk. The light gray is no bueno.
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Nick |
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Reiver
Join Date: Nov 2011
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Quote:
The OP's plugs are rich 'at idle' if he let the car idle before pulling the plugs.... this does not mean they will be rich at wot....
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De Oppresso Liber Strength and Honor 5th Legion |
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Thank you all for the feedback, feels like some solid wisdom. Tomorrow I will dig up the old plugs and get better pics.
Car hasnt been run since last fall - dont remember how it was put away but for sure not WOT. Reiver - if I understand correctly, are you say the colour of the plugs will change shortly after how the car was driven? ie after a day at the track vs a day stuck in traffic?
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82 SC Triple Black |
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Plugs telling me that yours is running a bit too rich.
And ... maybe I missed it, but I see no infos of which plugs are used!? See mine (all 6 do look the same), ... driving on my '82 SC an own built ECU where an ideal Lambda 1 based air/fuel ratio is provided to the combustion. ![]()
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911 SC 3.0, 1982, black, US model – with own digital CPU based lambda ECU build and digital MAP based ignition control All you need to know about the 930/16 and 930/07 Lamba based 911 SC US models: https://nineelevenheaven.wordpress.com/english/ |
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Reiver
Join Date: Nov 2011
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Quote:
About what mine look like but I run my euro SC (no lambda..wur controlled AFR) a bit fat as the Euro's like that. Even so the center porcelain is white and the advance working well. You can read that by looking at the electrode wire and the different coloration...you want half way up the fishhook coloration change there about....
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De Oppresso Liber Strength and Honor 5th Legion |
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Dug em out and here are close ups of each one - I have lost track of which order though. The brand are Bosche Platinum
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