Fouling Spark Plugs

Sure ... plausible. But, I want to see the results -- both ways, on the Dyno, before I my opinion changes. We'll agree to disagree.

 

There is a lot of information that shows indexing can help gain power as the following quotes suggest, but the original post was about plug fouling and I think indexing can help in that regard.

My old and tired 70 Baja likes the plugs to be indexed to the exhaust valve or they show signs of fouling (carbon buildup in the electrode area) at tune up time. I don't have a dyno to tell if I am getting more power by doing this but my 25 years of experience with this car tells me that the plugs won't show signs of fouling if I spend the extra time. I don't have that much experince with the bike yet, but I will experiment with indexing to see if it makes any difference in plug life.

On the flip side, Indexing doesn't make any difference in my 93 S10 (4.3 V6) Since the engines are radically different, there are probably a lot of variables working here that keep the truck's plugs clean. (Heat range of the plugs, fuel injection vs carbs, water cooled vs air cooled, driving style, etc...) There does seem to be a consensus that Indexing won't hurt the engine's performance so I do it.

"Real-world power gains vary. Some engines or combinations respond differently than others. In fact, all engines will pick up power, but some gains will be more dramatic than others."

http://www.advanceautoparts.com/english ... 001sp.html

"According to Dr. Christopher Jacobs (of Omni-Pak and Pro-Street ignitions from Jacobs Electronics), indexing sparkplugs 'never hurts and sometimes helps'. "

http://www.dodgeram.org/tech/gas/spark_ ... dexing.htm


From NGK's web site
"4. Indexing

This is for racers only !!
Indexing refers to a process whereby auxiliary washers of varying thickness are placed under the spark plug's shoulder so that when the spark plug is tightened, the gap will point in the desired direction.

However, without running an engine on a dyno, it is impossible to gauge which type of indexing works best in your engine. While most engines like the spark plug's gap open to the intake valve, there are still other combinations that make more power with the gap pointed toward the exhaust valve.

In any case, engines with indexed spark plugs will typically make only a few more horsepower, typically less than 1% of total engine output. For a 500hp engine, you'd be lucky to get 5hp. While there are exceptions, the bottom line is that without a dyno, gauging success will be difficult."


http://www.ngksparkplugs.com/techinfo/s ... S#indexing

 

Dr. Jacobs book was a worthwhile investment and the tech support has been top notch. Learned a great deal from his book that gave me a considerably larger understanding about optimizing an ignition system.

 

I having the same problem with my 82 XJ750 Maxim. I tried 6ES and it fouled them as well. I added seafoam in mine today and went for a ride. I have been told, mine is running a little rich, so how do I adjust for this. By the way what plug did you finally try. I'm willing to try the Champion.

 

I could not get the Champion at my local NAPA without a 2 day wait. I got the Autolite 63. I took them out last week and they look fine. Also added 4 oz of Seafoam to the last tank of gas too.

 

My '81 Seca seems to be partial to the NGK BPR7ES. Whenever I used the standard issue NGK BP7ES she idles high (3-4k rpm) and I look like a douche at stoplights 8) . Does the R mean an extra resistor? Why would simply swaping these plugs affect the idle?

 

R does indeed refer to an added resistance. The additional resistance makes for a hotter plug but does retard timing just a hair (takes a little longer for the secondary voltage to ionize the air gap and make the jump). That might be your lowered idle speed but I'm guessing now. Does anyone want to hazard a guess?