Looking at my plugs, I mean it doesn't look too shabby. The electrodes turning dark right at the bottom, the porcelain stem is (as far as I can see down there) also almost white with not much of tanning until just above the bottom etc. But the blank parts are not just blank metal but really ashy. Could that be from the additive (gas stabilizer/valve protection)?
When I read a plug I look at the bottom of the porcelain for tanning and the 2 end threads for heat. If that’s a daily driver on todays regular gasoline with 10-15% ethanol and an electronic ignition I was say it’s correct to lean. I’ve never used multiple ground strap plugs.
No sir - Looks quite correct to me. I wouldn't mess with it at all, fuel wise. Check at the bottom of the porcelain for any thought of too much timing. It appears that you might want to try a few degrees more ignition timing. I see no heat at all on the ground straps, indicating the timing might be a little light. Add two, and check the porcelain for black specks. This indicates too much timing. Then add another one or two. Both power AND mileage will benefit from a little more ignition timing. Mike
That's a Bosch Super 4 - we call them "Bomber Plugs" here in Germany since that open 4 electrode design was first invented in the 1940s for WWII war birds.
I’ve been hearing for years that we can’t read plugs like “back in the day”. Not discounting anything that anyone has said, but decent A/F gauges can be had for under a 100$. (US). I sure there’s something similar in your area that can be purchased as well. If you don’t want to look at a modern gauge, make up a temp mount, after you’re satisfied unplug it and put it away until you need it again Kinda takes the guess work out of it.
I am with Budget36 on this one. Too many detergents, additives, and other chemicals added to gas these days, in addition to the variations in mixtures due to seasons, location etc. Too much guess work in reading plugs. A/F meters are the only way to go. Combined with a vacuum gage, much more can be learned and the tune dialed in even better.
Plugs look good to me. My first thought was that if we could see your ribs, then yes you’re running lean
Good plan - just got me a used Innovate LM1 with wideband sensor and exhaust clamp. Gonna give it a try these days.
Keep in mind when using an O2 sensor "stoich" is a theoretical number, it isn't actually seen very often. When an engine is under acceleration load the A/F ratio must be far richer than that, or burnt valves will result. On the other hand, at low load cruise the A/F ratio can safely be leaned out quite a lot, this is always where highway fuel economy is realized. There is never any performance benefit to wasting fuel. Tuning a carburetor is basically "curving" the fuel supply for both maximum performance and efficiency for every operating condition. A good idle mixture is important too, because plugs will otherwise foul very rapidly.
While I never was good at reading plugs to begin with, other than, those look NFG, 8 more required. Those that were able, should still be able and those like me will still say I need 8 more. Now the selection of the next 8, that was the debate. Really, at the end of the day, the way the plug looks other than to offer its visual status as a condition of other workings, it allows for a spark or it don't. The don't is the problem isn't it? Looking again at the plug and wondering about the advancements in making sparks, and the technology behind modern engine efficiencies, the advantage here is the spark has options where to jump. Is that better, I don't know. Necessary, hard to say. I called these 3 NFG. But the car did run they came from. Begs the question, is this plug good? Google say... Many people ask "Can I use a platinum spark plug in my old car?" The quick answer is "yes", but you may not want to. The copper plugs designed for older ignition systems were of a higher heat range than their equivalent platinum or iridium brothers. A hotter plug means it retains more heat in the core of the plug.Nov 23, 2015 I see this as it wasn't a hot enough fire to burn the evidence, it left a residue. In a modern 4 valve per cylinder head that might not be the case and maybe it would?
On a street driven car, a plug that looks like yours would be by me, considered good/ in the ball park. different load conditions will do different things and leave different evidence on a plug. I like looking at the color of the tailpipe deposits for an overall idea of the operating range, along with the “seat of the pants” feel for the quality of the drivability. If it runs well, and isn’t black or white in the tailpipe, it’s good to go.
Time was we all got paranoid over monitoring oil pressure and temps. Rpm got a look in. Mph irrelevant. Fuel, well... With an afr fitted permanently everything else goes out if the window. Takes a good while to learn to relax. When the gauge goes red and the reading is 16+ the heart rate monitor takes a leap while other evidence is gathered to compute that all is well. I have to make a conscious effort to check the assorted vital signs from time to time. Chris
When you install the O2 sensor, use a welded bung and have it angled so the sensor points slightly downward so debris doesn't tend to settle on it. I say use a welded bung because if you have any air leak, your readings will be inaccurate.
The Jalopy Journal
