I have seen this referenced on a couple of forums for manufacturers of superchargers and I was wondering what you all thought of this. They recommend checking the gap on all of the spark plugs in any new factory engine. Their experience indicates that about a third of all "new" engines have spark plug gaps that are not set to factory specs.
What is the correct gap for the 6.4L engine and has anybody out there ever checked their own plugs way before they were due for their first factory scheduled replacement? I have a Scat Pack Shaker about to be delivered and I am considering asking the dealer's mechanic to pull all of the plugs and check for me.
Unnecessary or prudent considering the dollar value of this vehicle and the desire to keep it running efficiently and strong right out of the box and hopefully for many trouble-free years to come?
My opinion is one of two things will happen if you mention this to your dealer. They will either flat out refuse to do it and say absolutely unnecessary or second they will say we checked and all the plugs were fine but they actually never touched the plugs. They will not invest the techs time on the clock when nobody is paying for his time.
Dealers don't want to fix things that are really cause for concern so think about it do you REALLY believe this would get done?
Now if you're willing to pay for it then they will do it. Unless you're actually watching you'll never know if they actually did the work then either.
Just purchased a new Dodge Charger scat pack(6.4 L hemi) and the least of my concerns was the spark plug gap. If you are worried about that why not check to see if the tranmission is set to shift correctly. Or better check that lug nut torque it may not be 100 ft lb. I will however change the plugs all 16 of them, at approximately 35,000 miles. This is in case they are similiar to the Ford 4.6L engine. If I have the dealer do it I expect to get 16 used plugs back. I have 6 vehicles plus a Kenworth to keep running and if I worry about every little thing that is all I would do!
They shroud the spark kernel. They don't provide additional spark area. Sparks jump to the closest electrode so it has more than one theoretically lasting longer....all the while more mediocre plug performance. As an engine builder, if this was an easy gain...they would be used by builders and oem manufacturers.:thumbsup:
I would sooner stick hat pins in my scrotum than have a dealer mechanic do work on my brand new car. When the mechanic checks the plugs (at cost to you no doubt, since it's probably an unnecessary procedure in their eyes) and his belt buckle leaves a scratch on your fender from leaning into the engine bay, or you find his oily finger prints all over your engine, steering wheel, leather, et al., you will kick yourself for opening this Pandora's box.
My advice - forget it altogether, or if you are really adamant on having the plugs checked, then find a quality local speed shop or a place that works on exotics to do the work. You're practically asking for heartache having a dealer monkey mess around with it.
Even if they are gapped correctly, which I have not seen reported on a single 5.7 or 6.4, at least he would learn a little more about his car and how to replace them himself.
A minor incorrect gap wouldn't cause any issues. I have no doubts that many cars have plugs that aren't gaped perfectly. I always go overboard trying to make sure that the gap is dead on, however the factory likely doesn't care or have time to go to this trouble.
I would break the car in and, if it still concerns you, check them at 15k or so.
Worrying about the spark plug gaps is like worrying about your headlights. Do the work ok? Yeah, then don't worry about it. Same goes for the plugs. Does it run ok? Then just drive it. I did a bunch of gap experiments back in the late 70's and a wider than stock gap on my '77 360 did make a little more power, like 1.5HP. Not worth the work it took to yank them out and regapping them again. My 2003 Ram had 60K miles on the original plugs, and I guarantee the gaps were all over the place.
Im going to go against the norm and say check them yourself.
Every person that I have seen that has checked the gap on their factory installed plugs have reported that the gap was off.
I was battling some cold start and idle issues on my RT so I decided to change the plugs at 20k instead of 30k and sure enough, each one was off. Some were over gapped some were under.
I gapped each one myself and reinstalled and instantly noticed that it reduced throttle lag and it resolved my cold start and idle issues.
I wouldnt ask the dealership to check them as I believe even the 6.4 uses the crush washers so once you remove them you need to replace them.
Is it going to hurt anything? No. But people on this forum are spending $300 on an intake that really does nothing, so I dont really understand why they would just laugh or give someone a hard time because they want to ensure their car is running properly.
Oh, and each person who has checked the torque on their intake manifold bolts has reported that they are not within spec either. I checked and torqued mine down and it instantly ran smoother and helped with the cold start issues but did not eliminate it.
There are more important things in life to worry about. The coils have plenty of power to provide spark to plugs with too wide of a gap. I've changed 1000s of plugs in my life (used to be a tech). Pregapped plugs are usually very close and I've NEVER seen plug gap cause problems unless they were smashed shut. Go drive the car and have fun
Every single time somebody else works on one of my vehicles, I get it back with something wrong. A dent, scratch or what ever. There is no way I would have someone leaning over my qtr panels needlessly.
If I really thought it was an issue I would do it myself.
But I don't think there's any reason.
Just a note, if you use one of those little chrome plated, silver dollar size gap checkers, verify the indicated gap size with another instrument like a caliper. I found mine to be way off at some points (+.005).
I try not to even use it but my old wire checker doesn't go large enough for some applications.