Bugly87

Hello all,
1987 Corvette coupe auto. with 59000 original miles. I am changing my spark plugs while I am replacing my EGR vale and have a question. I have replaced the plugs before and for me it is a aggravating experience so I want to do it right the first time. When I replaced them 5 years ago the gap was .035. All I read says .035 although I have also read that some go with .045. The ACDELCO plugs that I got for the car were suppose to be pre-gapped at .035. I checked and they are .045. My question is...should I gap to .035 or leave them at .045? Is there any real difference? This is a summer car and I put maybe 2000 miles a year on it. No racing.

Thanks for any advice,

Kevin

antfarmer2

I would gap them to spec.

ddahlgren

99% of plugs come pre-gapped to very close to correct as no flat rate guy is going to check. 0.045 adds load to wires cap rotor and ignition system in general, how much not much if system is in good shape. At 2k a year it does not matter all that much. If you don't have the correct tools to bend the side electrode you are just as libel to break the center porcelain than to make it better in my mind. My guess is a later model car calls for the 0.045 and the reason set there. I have the tools to gap them so might but the ones in my '91 are at 0.045 and run just fine.

Bugly87

I have the generic tool on my spark plug gapper and have never broke one but they are close and may just install at .045. I will wait to see if there is anymore input as to which way to go. Are there any performance gains to have at .045?

WW7

Just gap them at .035 .. On a stock car your not going to notice anything different with .045...WW

antfarmer2

Two taps and cheak.

ddahlgren

That is how you can crack the electrode and why I said just leave it.

383vett

Spark plug gappers are only a couple of bucks. Gap them to specs. Look at your owner's manual.

Cliff Harris

In the past the ignition coil put out too much voltage and caused arcs and carbon tracking. They went to a coil with lower voltage output and changed the spark plug gap to 0.035" at that time.