Good to know! I was getting ready to look at the service intervals in the manual. Saved me the effort!
Spark Plug Gap Tool--Iridium
- Thread starter IndyFan
- Start date
Working in a shop setting, I visually inspect the gap then install the plug.
Working on a personal level off the clock, I check the gaps with a feeler blade and adjust via grabbing the sides of the ground strap from behind with pliers to widen or gingerly tapping the ground on something to close the gap. Typically i've found the gaps on plugs to almost always be notably larger than they state they are and far away from consistent even between plugs in the same pack.
I've always done this with my plugs, including iridium and never had an issue. As stated above, the tips are hard but brittle. If you try to get your feeler blade in and it seems too tight, open the gap a little then sneak up on your target gap.
I also like to use a blade a thou or two smaller than my target and aim for a lighter drag than I normally would when using a feeler blade on plugs with a fine tip.
Working on a personal level off the clock, I check the gaps with a feeler blade and adjust via grabbing the sides of the ground strap from behind with pliers to widen or gingerly tapping the ground on something to close the gap. Typically i've found the gaps on plugs to almost always be notably larger than they state they are and far away from consistent even between plugs in the same pack.
I've always done this with my plugs, including iridium and never had an issue. As stated above, the tips are hard but brittle. If you try to get your feeler blade in and it seems too tight, open the gap a little then sneak up on your target gap.
I also like to use a blade a thou or two smaller than my target and aim for a lighter drag than I normally would when using a feeler blade on plugs with a fine tip.
For the "do not adjust" plugs, I set them all out on the bench and visually compare the gaps to one other. If any look different, I'll check them with a wire gauge. If adjustment is desired, I use slotted adjustment blades.
I was taught (in the 1960's) to use a wire gauge; because most all ground electrodes are sheared, leaf gauges can return erroneous measurements because of the edge burr. IMO, it doesn't really matter what type of gauge is used, or how precision the adjustment is.
Most plug gaps back in those days were always spec'ed as a plus/minus. I adjusted gaps to the narrow end of the spec, as the gaps would widen in use.
FWIW, I still use this tool on "adjustable" plugs.
I was taught (in the 1960's) to use a wire gauge; because most all ground electrodes are sheared, leaf gauges can return erroneous measurements because of the edge burr. IMO, it doesn't really matter what type of gauge is used, or how precision the adjustment is.
Most plug gaps back in those days were always spec'ed as a plus/minus. I adjusted gaps to the narrow end of the spec, as the gaps would widen in use.
FWIW, I still use this tool on "adjustable" plugs.
Either way I just don’t think it matters anymore.
I remember a dyno compare on YT and there was no real difference in output from 10-60(?) thou? I work on engines running on natural gas (lean) and they require significantly more ignition voltage to start in poor conditions. I've ended up switching to platinum plugs and gapping @ 15-20 thou.
In my experience, cutting the gap in half with platinum NGK could keep the engine running another year with failing coils.
Sure that's great if you have a crystal ball and know they've never been dropped or mishandled in the supply chain.
Plus wildly inconsistent gapping is a trademark of fake plugs IME. There's nothing wrong with checking if you're careful about it.
I personally believe they tell you that because they're afraid the average Joe will damage the plugs. But I see no reason not to adjust the gap if you do it the right way. That's just me -- no one should follow my example.
Checking and adjusting gaps is something from grandpa’s days. You may go ahead check the gap on an Iridium plug but I would just return it if it’s incorrect. Chances are it won’t be incorrect anyway.
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Any pro shop knows time is money. The part in-hand is worth two in the store or six at the online retailer.
We all adjust or tweak parts slightly to make 'em fit or work when necessary. Why? Because we actually have it this very second. And yes, a good wrench knows the difference between a little tweak of a part and gone-too-far-into-hoopty-land tweak.
We all adjust or tweak parts slightly to make 'em fit or work when necessary. Why? Because we actually have it this very second. And yes, a good wrench knows the difference between a little tweak of a part and gone-too-far-into-hoopty-land tweak.
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