Worn spark plugs?

[reddy351]

Hey guys. I just got done swapping the plugs, wires, cap and rotor. I noticed that the plugs were open to about .058". I know that most guys run between .050 and .052. Would that much of a gap (and "burnt" electrodes) cause the car to ping at WOT? The electrodes actually looked really good, except for the excessively worn condition. The ground straps were chalky white. Nice! As a result of the excessive gap on the plugs, the cap and rotor both showed signs of tracing from excessive resistance. I guess 87k miles is too long to go to tune-up a Mustang. (Leave me alone, I "just" got it a year ago. )

I haven't had a chance to drive it, yet. I hope this means I can go back to 87 octane gas, for a while. (Just because that means the reason for the ping has been resolved and I can move forward to some upgrades.)

 

[S/CBlack95GT]

.058" is pretty large. I dont know if it would cause the pinging but it is a possibility if the spark being produced is not sufficient. Gap them down to .050" and see how it runs.

 

[reddy351]

Looks like that solved the problem. I never thought old plugs would cause that sort of problem. I guess it's a good idea to cover the basics, huh?

 

[HISSIN50]

Shaun is right-on. A healthy stock ignition should handle that gap without issue, but 100K+ mile ignition parts and some tarnish on the plug's electrode and ground strap can all add-up.

Personally, I leave room for error and run at 0.045- 0.048" to allow for fudge factor (I get hammered on the 5.0 Tech side for mentioning that I do this, for some reason. ). I see no issues however.

That all said, I've seen weaker ignitions than Ford's TFI (a fairly stout OEM ignition if you ask me) run at ~ 60% OVER the stock gap and not have noticable issues. That kind of gap will eventually reveal ignition weak points however.

Random ramblings.

Good luck.