Spark Plug Guide

[quicksilverdon]

Originally Posted by freetobejbp

I replaced them with NGK #4306 and i replaced the wires to just in case with a premium wire but the old wires did not look to bad still got them also. The new NGK #4306 plugs did the trick. I do not have grannies trying to pass me any more! It have a lower idle rpm and accelerates through the rpm range allot quicker and now i am up to 22.6 mpg. I do not think it was only the wires that made such a big difference. Sorry to say i was not very impressed with the performance of Champion #7570. NGK!

In our collective experience (this site and others) - it IS the wires. It is also possible that the Champs weren't gapped properly.
There is nothing wrong with Champions, plenty wrong with the stock wires - they have high resistance and don't last.
Good to always change both plugs & wires together.

[freetobejbp]

Originally Posted by quicksilverdon

In our collective experience (this site and others) - it IS the wires. It is also possible that the Champs weren't gapped properly.
There is nothing wrong with Champions, plenty wrong with the stock wires - they have high resistance and don't last.
Good to always change both plugs & wires together.

I admit i have had that experience in the past bad plug wires can make a car do crazy things! Wait everything i read says you do not gap platinum plugs. Because if you chip the coating on the fine wire tip your screwed the coating will burn through. Or is it you guys gap your platinum plugs and you do not worry about that? I saw on here a gap of .040 for non turbo? That sounds like a turbo gap? Is there a year model cut off for that gap? The up to date info i have says a gap of .048-0.53 on my NGK #4306 i am gapped at .052 the car seems to like that gap. But i want to get the best millage i can. Allot of difference between .052 and .040! The Champion #7570 plugs i took out look normal everything in the cylinders is ok.

[CREWZIN]

I'm glad you like your plugs. As QSD just said, the wires are a big cause of many problems. The stock wires are just plain crap.

As far as the double platinum plugs. The #7440 Champion Double Platinum's (for-runner to the #7570's) were pacifically made for the PT in a joint venture between Champion and the most knowledgeable mechanic on this and other PT forums. I seriously don't think your gain in mileage, smoothness in running and new ability to keep up with traffic had a whole lot to do with changing plugs from the Champion's to what yo have now unless as QSD pointed out that you were using the old gap (.050) instead of the new (.040) along with failing wires. Then changing to any new parts would make a difference.

[freetobejbp]

Originally Posted by CREWZIN

I'm glad you like your plugs. As QSD just said, the wires are a big cause of many problems. The stock wires are just plain crap.

As far as the double platinum plugs. The #7440 Champion Double Platinum's (for-runner to the #7570's) were pacifically made for the PT in a joint venture between Champion and the most knowledgeable mechanic on this and other PT forums. I seriously don't think your gain in mileage, smoothness in running and new ability to keep up with traffic had a whole lot to do with changing plugs from the Champion's to what yo have now unless as QSD pointed out that you were using the old gap (.050) instead of the new (.040) along with failing wires. Then changing to any new parts would make a difference.

Ok i read some were else on here i was using a plug specifically designed for my PT the NGK #4306. Ok if i drop the gap from .052 to .040 on the NGK plugs what is that suppose to do better?

[CREWZIN]

If you find that post on the NGK's please let me know.

Chrysler engineers are the ones that dropped the gap without saying why. We all took it that they found that the engine ran better for longer periods with the smaller gap. I haven't done any research on it but maybe the real reason it out there somewhere.

[freetobejbp]

Ok i got that info from here but it was a old post from 2004. I found the TSB about going to 0.40 gap. I got the right plug i just need to gap it to 0.40 no problem i can do that. I will keep you updated and see what type of difference it makes.

[CREWZIN]

It might not make any difference right away, since we don't know the exact reason they lowered the gap. It might be that the plugs were wearing out and the gap widened enough (too much) that in just 15-20,000 the plugs were causing problems. By lowering the gap, even when they wore out the gap stayed in a range were they were still good. Just a theory

[freetobejbp]

Originally Posted by CREWZIN

It might not make any difference right away, since we don't know the exact reason they lowered the gap. It might be that the plugs were wearing out and the gap widened enough (too much) that in just 15-20,000 the plugs were causing problems. By lowering the gap, even when they wore out the gap stayed in a range were they were still good. Just a theory

I just found out some cars had a hesitation and rough idle so they went to .040
some cars have the problem some do not. Maybe the wider gap does not do as good in colder climates.

[CREWZIN]

Originally Posted by freetobejbp

I just found out some cars had a hesitation and rough idle so they went to .040
some cars have the problem some do not. Maybe the wider gap does not do as good in colder climates.

If they would have checked their own crappy wires they put on those PT's they probably wouldn't have changed the gap, just the wires.

[freetobejbp]

Ok like i said i put in the NGK #4306 plugs and the car ran fine. Then i found out from you nice guys i needed to be running a .040 gap. Ok so today i pulled the plugs and lowered them all to a gap of .040 WOW! That really made allot of difference in how the car runs. It runs allot better. Ever since i got the car it would not run 120mph like it says on the speedometer. I did not think much of it because allot of cars will not go as fast as the speedometer reads. I got it out on the road today and hit that 120pmh no problem. My PT is a five speed and all she would get was 20mpg and i keep the tires inflated properly i knew there was something that could be done to improve that. I took another look at the original Champion #7570 plugs i pulled from the car maybe they had been in longer than i thought two of the plugs the fine wire electrode was shorter than the other two plugs. Oh well the plugs i got know are good for 30k miles and i only drive about 5k miles a year. I think i may try some iridium are platinum plugs on the next change. I get ants in my pants i may change them in 10k are 15k miles.