I agree... It looks maybe, kindasorta, mildly lean to me, but the pic also looks a bit over-bright on my monitor too. Around the base, I don't see lean at all. The plug looks a little hot though, I would like to know if the heat range is higher than stock... That will affect how the tip of the plug looks. Dave
In my opinion (I am looking at the plug, not a poorly lit picture of one), it is a little more than "kinda sorta lean". Not "way too lean" or "dangerously lean", but lean enough to want to rich it up a little. I also have believed that this has been my source of extra heat since...I can't remember when, I have just been too lazy to buy the calibration kit until recently...I finally saved up the $32!!! I will try to bump it up to #23 and report back on any changes I see. Jamie, When I took my old heads off, they were really clean also. No carbon buildup, nothing. So in a way, I do believe that a little lean is "just right" until the engine begins to run a little hot. If I was not running up into the 200-205 range, I would leave it alone. But, I really want to run 180-190 in the dead heat of summer, so I am messing with the mixture to see if it affects the temp.
I understand Scott. Mine runs about 190 just driving around in the summer. It can get up to 225-230 pretty quick sitting in traffic in the heat of summer. Usually just putting it in Neutral and revving it to about 2,000 RPM's for about 15 second bursts will bring the temp back down. Although people in the cars around me look over like "what the heck are you doing?". My pistons were shiney also. I richened it up a little and now I just have just a thin coating of carbon on the top of the piston. I think I got it about just right. My car rarely gets above 170 now that it's cooled off outside.
just keep in mind that if you open your exhaust, either drop the pipes or open cutouts, you usually lean it out even more.
It has cooled down to 60s high here, but I still run 190 creeping up to 200. That includes sitting in traffic, which only is a problem in the summer. I want to be able to idle in traffic for an indefinite amount of time without crossing 200, preferably 190, while running as hard or easy as I want at 180. I might have to start looking for an aluminum radiator from the junk yard, or start saving for a new one, if the mixture doesn't cool me down.
Git'er richened up! I am curious as to what happens... I know you will tell us. I am hoping your temps drop and the car runs better. When tuning, before we used new-fangled sensors and analyzers, folks would intentionally start at a lean point and richen incrementally until the car slowed down. Then revert back one increment lean... that is usually the best mixture. Dave
Well, first of all, I was totally amazed at how easy it is to swap these rods. Just undo one screw, pull the old rod and plunger out, pull down the spring that holds the rod, slide in new rod, put it back into the hole and tighten down the screw...repeat on other side. I set it up like #23 above, and drove it around town first. Then took it to the highway for some wide open throttle. Did a good take off from a red light out in the middle of nowhere (2 lanes each way with a lane-sized shoulder each side, nice and flat coastal plains, can see for miles, no traffic, so no preaching... ) then just pulled over and cut the engine. The plug still had that darker brown spot (I assume from some sort of turbulence in the chamber causing a cooler spot on the plug?) but the remainder of the plug was a greyish-tan color. Dad always said it should be the color of brown paper bag or cardboard. The spot was that color exactly, but the rest was a bit lighter, but still what I would call an acceptable shade of greyish-brown. I can do a picture if anyone is interested, I will try to mess with the lighting so the picture is more true to life. Outside temps today are about 5 degrees cooler than yesterday, but the car ran right at 190, regardless of sitting at lights, idling, or running full out. That is a 10 degree drop from yesterday, and today I drove further and it stopped creeping up, where yesterday got to a little above 200 and continued a slow upward creep. I believe that the plugs are telling me it is running at the lean side of normal (approx 14:1 on A/F ratio if 14-15 is considered ideal). This is kinda cool. I might mess with other jets just to see what differences I get, especially when the track opens back up. I can see if leaner/richer makes any improvements on ET and mph. I like experimenting like that.
I don't agree at all that spark plugs are a snap-shot of the last time it fired. It doesn't soot or burn that fast. It's my opinion, but it seems like common sense and I can't imagine changing my mind... even if Nascar crews tune their cars that way. Dave
Dave, I think it's more to ensure you're not reading the mixture that it took you to get back to the pits - which you'd agree could be totally different than what the mixture is at wide open throttle. I can see that if you're rich at idle - and those turnaround roads being fairly long - the plugs would be less likely to indicate what your actual mixture is going down the track at WOT.
I can agree that driving a lap back to the pits would surely muddy the results of any plug reading when you wanted to see WOT... I can't agree with the "snapshot" effect previously mentioned. Now, we may also be able to agree with the following, which led to my post: Driving the car around after richening it up... This is what he did, and okay. During this test drive, he made it to a deserted road... Okay. Now he makes a quick blast, then shuts the car down and reads plugs. The last thing he did assumes the snapshot theory, and IMO that quick blast probably didn't even muddy the results of the drive to that deserted road. The plugs were probably slowly on their way to turning brown during the whole ride out there. Maybe they were all brown before his blast... We don't know unless the plugs are pulled right before AND right after the 'blast'. If that were to show extreme difference, then maybe the snapshot thing holds water, but I think it is unlikely. Dave Btw: Good discussion!
To clarify, that "quick blast" was not your average 1/8 mile shot. It was about 3-5 miles at 80 mph, with 3.80 gears, close to 3500 rpm, after a quick take off from the red light. I also drove the 70 speed limit for about 3 miles to that red light, with only 30-40 seconds idling there. I also don't agree completely with the "snapshot" theory. I would guess that a quick 1/8 would clean the plugs a bit, but give more of an average. But, I was trying to test two things on this run: the mixture/color of plugs, and rising temperatures, so I needed to do a pretty long run to see if the temps were going to stay cool. I figure 8 minutes or so of 3000-5000 revving would give me a better picture than just a short blast. Then the return trip doubling the distance at the speed limit to further test the rising temps, just to be sure they weren't creeping up.
