Heard a master tech say spark plug gap doesn't matter like it used to

Was at a shop in Portland yesterday waiting on parts and overheard this old guy telling a younger mechanic that factory gaps are fine 90% of the time now. He said coils are so much stronger than back in the distributor days that a .005 off isn't gonna cause a misfire like it would on older engines. Got me thinking about how many hours I've wasted double checking gaps on basic tune ups when the plugs come pre-gapped. Anyone else still gap every plug out of habit or have you stopped trusting the box?

2 comments

2 Comments

jana_hill2719d ago

Think about how that logic handles older engines with wasted spark or weak coils though. If you've got a car with 150k miles and original ignition parts, does that same .005 rule still apply, or are you just asking for a misfire? Ngl I had a BMW 328i that ran rough as hell on pre-gapped plugs until I set them to spec, so there's got to be some gray area here. How does a mechanic actually decide when to trust the box versus grab the feeler gauge?

charles_wilson19d ago

Read something similar from an old Bosch engineer who said modern coils have enough voltage to jump a 3mm gap no problem. Sounds like I got away with a few of those lazy tune ups back in the day.