Cheap-o Spark Plug Gappers

9outof10mms

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Word of caution to those who do their own spark plug changes: don’t use those cheap-o 99-cent disc ones that are hanging a the register of every auto part store. Mine was off by a full 0.01”.

I was changing the plugs on the wife’s Jeep today (side note: simply old plugs can cause a hellacious misfire—damn temperamental Jeeps) and checked the gap on my “pre-gapped” Bosch plugs. Using my cheap-o disc thing, I noticed they were off by a good 0.01-0.015”. It wasn’t until the 5th one (of 6 total) that I thought to myself: mayb something else is off—there’s no way brand new plus would all be this bad. So I dug out grandad’s old metal shim gap set. Sure enough, I had now over-gapped my new plugs by a good (you guessed it) 0.01-0.015”.

Never again will I trust a cheap measuring device. Grandad’s old metal shims worked like a champ, and the little wrench tool it comes with is far easier to bend the spark arm in either direction without worrying about busting the electrode. I’m talking the “feeler gauge” style.
 
KD and Lisle in my toolchest. I check pregapped plugs before installing.
 
Never used one before, but own that kind too, thanks for the heads up
 
Hope y'all aren't trying to gap anythjng except old copper electrode plugs.

Why? Gap is Gap.

Sometimes the box gets moved and the plug hits the box end at the electrode. Also had some that were missing the platinum tip on either side.

Never would have noticed either if I didn't check the gap.
 
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That's what the sleeves they come in prevent. Modern fine wire, platinum/iridium plugs are easily damaged (especially with those ramp style gap checkers). I've learned to just toss the plug and get another one whenever I drop one. Not worth the customers getting mad and bringing the car back over a $10 plug.

Edit to your edit: that's just crap luck. In all my years as a mechanic I've never had a bad plug out of the box. Glad you caught it.
 
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Why gap them? My specs say I was supposed to be gapped at 0.043. The pre-gapped box said 0.044. I know; what’s 1-thousandth of an inch? It’s not right, that’s what it is. And since I was trying to problem solve a P-0300 misfire, I wanted everything to be as close to perfect as I could make it.
 
You missed that mark by using Bosch plugs in a Chrysler product.

:cool:


LMAO, I didn't even catch that part.....I wish the parts flunkies would stop pushing any old damn plug for every vehicle.....and I wish Autolite would simply go out of business.
 
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You missed that mark by using Bosch plugs in a Chrysler product.

:cool:
Who would you recommend? I got a good 50k+ out of the ones I just took out of the Jeep—unintentionally, of course.

And what’s the deal with Bosch and Chrysler/Mopar???
 
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Champions in a mopar, I have pulled several brand new sets of misc plugs out and fixed P0300s with champion plugs when I was at the CDJ dealer.
 
Champions in a mopar, I have pulled several brand new sets of misc plugs out and fixed P0300s with champion plugs when I was at the CDJ dealer.
Many many times.
The emissions label on the hood, lower left corner has the Champion plug number the manufacturer uses.
 
I’m pretty sure my Ram came with Bosch. I wouldn’t put money on it—and for the one set, it’s too late to verify since I’ve changed them once before. I’m due for a change of both sets. My ‘08 4.7 has two plugs per cylinder, but it’s not a Hemi. Bottom set gets changed every 100K.

I can’t believe there’s THAT much difference between brands, as long as you’re not putting a no-name crap plug. No???
 
Bosch is for BMW and some Mercedes. Champion goes in a Chrysler. NOTHING else. Motorcraft in a Ford. Acdelco in a GM unless it calls for NGK. Those are OEM for some new GMs. NGK or Denso for Asian imports. Autolites are good for fuel motors. We run the shit outta them in the funny car. That and E3's.
 
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What about Mercedez having their hands all over Mopar in the mid-2000's?

I hear you guys, and don't mean to question your experience or shuck your advice. I'm puzzled as to how I got 50k+ miles out of a set of plugs that "shouldn't work" in the vehicle...and it wasn't until the very end did I get any trouble.

As for my Ram, I don't believe there is another option for the exhaust side plugs--Bosch is the only brand I'm finding for those plugs--in a Mopar engine.
 
What about Mercedez having their hands all over Mopar in the mid-2000's?

I hear you guys, and don't mean to question your experience or shuck your advice. I'm puzzled as to how I got 50k+ miles out of a set of plugs that "shouldn't work" in the vehicle...and it wasn't until the very end did I get any trouble.

As for my Ram, I don't believe there is another option for the exhaust side plugs--Bosch is the only brand I'm finding for those plugs--in a Mopar engine.

50k vs 100k. And usually its the coils that pays the price. Some get lucky and survive, but many do not
 
Bosch is for BMW and some Mercedes. Champion goes in a Chrysler. NOTHING else. Motorcraft in a Ford. Acdelco in a GM unless it calls for NGK. Those are OEM for some new GMs. NGK or Denso for Asian imports. Autolites are good for fuel motors. We run the shit outta them in the funny car. That and E3's.

What are your thoughts on E3's? I thought they were gimmicky.
 
What about Mercedez having their hands all over Mopar in the mid-2000's?

I hear you guys, and don't mean to question your experience or shuck your advice. I'm puzzled as to how I got 50k+ miles out of a set of plugs that "shouldn't work" in the vehicle...and it wasn't until the very end did I get any trouble.

As for my Ram, I don't believe there is another option for the exhaust side plugs--Bosch is the only brand I'm finding for those plugs--in a Mopar engine.
Daimler had a part of the ownership over Chrysler. May still do. Not sure. As for the exhaust side plugs, call the dealer. I've got OE plugs in the aftermarket before for those, maybe from O'Reilly? I don't remember right off hand.
 
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