Spark Plugs

L

LONG

Active Member
hello all. question about plugs. recently made a 900 mile round trip to Kentucky for the Bourbon Blitzkrieg Run and Beatersville. on the way back car was running pretty sick. pulled plugs and 1,2,7,8 plugs only have .004" gap. before the trip I took checked them at .025". this is a 263 in a 52. converted to 12V with pertronix. running autolite 86. I don't think the pistons are kissing them.....no witness marks. could timing or A/F ratio cause this? what is a good plug to run and at what gap for 12v? been running this set up for about 2 years and put over 7000 miles.
 
plugs

One advantage to electronic ignition is the ability to open gap to .040/.045. I have never seen a plug gap close down. Usually go the other way. I will be looking forward to learning the answer to this one.

Ben
 
As Ben said, plug gaps don't close. Unless you have some horrible carbon build up on the pistons to cause your "kissing" suggestion, the logical finger points to careless installation. Change them and see what happens.

To open your plug gap, you need a performance coil (a very good idea).
 
Bob said:
As Ben said, plug gaps don't close. Unless you have some horrible carbon build up on the pistons to cause your "kissing" suggestion, the logical finger points to careless installation. Change them and see what happens.

To open your plug gap, you need a performance coil (a very good idea).
Click to expand...

I can agree with carbon build up. any recommended plug?
 
after talking to NGK tech support, with my mill he suggested running XR5. if not performing correct then to drop to xr4. ordered XR5's [3332] and should have them today. going to start with .035" gap and go from there.
 
Jyrki said:
I'm running a 1.2 mm gap, but then again I have LS7 coil packs
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thanks. I have been to your site in the past. awesome set up. I installed these plugs and gapped to .035" tuned carb and tweaked timing. running great. plugs are clean. put in low range and brought car up to an uncomfortable rpm. no contact. so, not wristpin or bearings. in drive I got her up to 80 mph without hesitation. only at that speed for a short time. drove it to two local car shows on Saturday, about 90 miles. runs great. I don't know if the old plugs got hot and closed the ground electrode, or if there was so much carbon built up? next step is putting the original carb back on this and then sending the distributer over to Bubba's in Indy.
 
plugs, distributor

Het, Long, did you get Bubba to wave his magic wand over the distributor?

I just had [found] the plug gap closing thing!! And I am old enough to know better. Car has not been running right for months, but had not driven much. Had checked and rechecked timing. Finally, today, a light came on in my head. Pulled and regapped plugs. All good. Except #8. Closed completly. Set at .40 and I love my car again. Just hope it will forgive me for being neglectful.

Ben
 
firstofeight said:
Het, Long, did you get Bubba to wave his magic wand over the distributor?

I just had [found] the plug gap closing thing!! And I am old enough to know better. Car has not been running right for months, but had not driven much. Had checked and rechecked timing. Finally, today, a light came on in my head. Pulled and regapped plugs. All good. Except #8. Closed completly. Set at .40 and I love my car again. Just hope it will forgive me for being neglectful.

Ben
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I have not sent the dizzy to Bubba yet. I have put a ton of miles on it since replacing the plugs. all perfect. car runs great. I am still going to send the distributor to Bubba after car show season. glad you got yours happy again.
 
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