Spark Plugs, That much of a difference?

[Mopar-Charger]

I went from AutoLite 64s to autolite 65s.

The 64s ran amazing at around 180 degrees

The 65s run like crap, Misfire and surge, but much cooler at 160 degrees

I checked all the wires they all fire fine. Except under load at around 1500 rpms they surge?

Should I swap the 64s back in a see if there is a difference? only switched them because one cracked

 

[bigmanjbmopar]

I had found tiny cracks in the insulators on my old champion plugs causing misfire. I would check that first. It shouldn't matter which plug hotter or colder makes a small difference in carbon build on my car, I run ngk race plugs with good results

 

[Mopar-Charger]

The 65s are all brand new plugs. I was doing some research and the 64s i had were copper core. However, they ran like a beast, no complaints.

 

[Bb70charger500]

You might have got a bad batch. I bought a set of plugs once I put them in and had the same problem returned them to a diff store and got the same ones they ran great .

 

[Bruzilla]

When it comes to plugs, newness doesn't matter. I helped my roommate change the timing chain in his Superbird at the base hobby shop at NAS Jacksonville in the early 1980s. We decided to do a tune up at the same time. Once everything was back together we had a crank-no-start situation.

We took everything back out and double checked the timing marks on the gears, and they were fine. We reassembled and still no start. We checked for fuel and all was good there. We were about to go buy a new coil when The Old Guy (every auto hobby shop had a The Old Guy who knew everything) came over and asked what plugs we were using. We told him Champion and he said they were bad. We told him they were brand new, and he said they were bad.

We pulled the plugs and sure enough, five of the eight had tiny insulator cracks! We put the old plugs back in and the 440 fired right up. Never bought Champions again.

 

[HEMI-ITIS]

Ran Champs for years,they fouled too easy.Now using NGKs and I'm between 7s & 8s with the heat range.

 

[ckessel]

Regardless of which plugs you end up using, put a little anti-sieze on the threads. Makes you next removal much easier and will prevent the threads from rusting together/stripping or galling/stripping the threads in an aluminum head. My rule of thumb, if it does not require loctite/thread sealer and is not an internal engine bolt, antisieze them. your following removals make life much easier.

 

[Mopar-Charger]

I'll definitely have to remember that. Thanks for letting me know!

 

[Dennis H]

NGK's. Pulled them to look and put them back in.

 

[ckessel]

I always prefer a cad plated plug, ngk/bosch/champion etc, over a black oxided autolite/motorcraft/ac etc, because the black oxide finish like to contribute to helping the plugs to get stuck in the head. Regardless of which I end up using they get a little anti on them. Don't need any additional things to fix.