What Does This Spark Plug Reveal

Plug looks like you are running very lean. Check for flecks of aluminum and the insulator becoming unglued. If its as lean as it looks, you may be headed for burned pistons and/or stuck valves.

THere used to be a site where you could send pics (champion?) and get expert opinions. I dont think pics would show any melting of the insulator bonding though.

I am not a plug expert, the above is based on running a motorcycle at Bonneville. I assume it tranfers somewhat to cars.

 

Too hard to tell anything except about the fuel mixture etc because of the way the plug was used and more important how it was run the last few minutes before you took it out. The crust on the electrode looks a little excessive but hard to tell looking at a photo. I don't see any little shiney balls of aluminum on the porclean or anything really ugly. http://www.dragstuff.com/techarticles/plug-pictures.html

Look down inside the plug for the burn ring. Here are some good pics of plugs with the metal cut off around the insulator so you can see the burn ring. To really read the plugs you need to put in new plugs and do a plug cut. Run the car wide open and then cut the ignition before letting the car get back to idle and coast to a stop and pull the plugs. Not sure how much your turbo is going to like that?

 

Looks like it could be running lean but I have another question, what fuel are you running in the car? Does it contain MMT? What additives are in the fuel? My guess is your running leaded fuel and it's ash deposits from additives in the fuel, in other words it's running fine just need to clean your plugs or put in new ones.

 

lean. check your timing. maybe predetonation.

 

The crusty buildup has been explained to me before as additives as above poster noted. I'm going to go in a different direction because my comments don't cost anything. Plugs don't look to bad to me. Maybe a bit lean but not too bad. I usually like to see a bit of black at the base of the electrode. If it's a newer car, they are all designed to run lean. I give it a double thumbs up and a high five.

 

The plugs look pretty good. I would say that the white crusty stuff on the electrodes is from additives in the fuel of some kind. Were these brand new plug before the run, as the center electrode is pretty rounded, has lost all of the square edges on the electrode, so it may be getting a little too hot. You could use a colder plug. Fuel mixture looks pretty good, but you might want to run a lambda sensor to see what the actual mixture it

 

Looks pretty good for a race plug with some time on it. As others have said, it looks like you're running a little lean perhaps. If you're not sure, you can have a bung welded into the exhaust manifold and check your mixture dynamically (on the track) - there are nice electronic readouts with sensor that are available for around $300.

Looks like you run a pretty big gap in order to get a big spark, and probably have a Big Spark type ignition (electromotive or similar) with separate coils?

I wouldn't worry about the buildup. A race plug with a big gap, big spark ignition and turbo boost is going to have some buildup. Change 'em out every couple of races is what most guys do that I know.

 

Stay away from the Innovate LM2 as far as O2 sensors. It's junk. Go the LM2 forum on Innovates website and do a little reading and you will see what we are all complaining about and the lack of any help from Innovate

 

Your base ring is fully black with deposits, indicating a too-rich condition.

Your ground strap is ash fouled, which comes from over-advanced ignition timing, fuel additives (octane boosters are the worst), and/or poor cooling system efficiency.


http://www.ferrarichat.com/forum/showthread.php?p=136079421#post136079421

 

If you really want to get a picture of what is going on you will need to install a new set of plugs and run it hard for several laps and shut the car off at the end of the longest WOT section of the track and coast in if possible. You can then get an accurate reading of what the compustion process is by reading the plug. A wide band O2 sensor would be adviseable.

 

Yup, preignition going on there. The base rings has flecks on it. Use a colder heat range plug. It's hard to tell much else due to the condition of your ground strap. Get a fresh set of plugs, run WOT and then shut off. Pull the plugs and take some good photos and report back. The timing should heat up the ground strap so there is color just to the apex of the strap and no further. The ceramic insulator should be clean with only a ring of color at the very bottom (inside) the threads. Modern plug reading due to modern fuel is very different than reading plugs 40 years ago when fuel was totally different.

 

Thanks, I took the black deposits to perhaps be burning a little oil, also could contribute to the ash deposits depending on the oil additives...

 

If you're getting oil in there it would typically be on the first, second, and perhaps even third threads from the base of the ground strap, but yours appear dry.

 

too lean, too rich...

 

12 years, a bunch of miles, many track days. If you hear that you have the wrong injectors I think your response needs to be "shows how much you know" There is nothing ugly going on there. Enjoy your car. On a 1986 model if it blew up tomorrow you'd have gotten your money out of it. If you like the power and it aint broke, don't fix it.

 

We'll it seems like all the answers have been pretty consistant. Take the car to someone with a chassis dyno. Call around since there are wide range of cost. One guy in Mt Airy MD has a deal. 3 pulls for $90. Just whatever you do don't buy the Innovate unless you just want to pick up an old LM-1 which was a good product. The LM-2 is garbage

After one pull they will be able to tell what your air/fuel ratios looked like at the different RPMs and what to do to fix any problems.