KR 428 CJ Spark Plugs Suggestions

[WT6066-2600]

Time for new plugs on the KR stock 428CJ driver, asking for recommendations(experiences) for readily available plugs.

Thanks, Joe

[Royce Peterson]

Not sure what is different about modern plugs - they seem to have the same attachment as originals. Kevin Marti sells a very nice set of plug wires for your car. Lots of us use them with zero issues.

[Road Reptile]

Hi
Check out Autolite plugs.They were in that engine when it was new. If you want vintage stuff check out Green Sales in Ohio-They still have tune up kits!!
Hope this helps.
R.R.

[WT6066-2600]

Had hope to get some feedback from those of you that drive your 428CJs as to modern spark plugs.

Autolite and the Cobra Jet Registry website list these:
A45 Copper Core
AP45 Platinum
APP45 Double Platinum.

Anybody want to share, Joe

[98SVT - was 06GT]

Copper is a better conductor but doesn't last as long as Platinum. Single has platinum on the center electrode double on the center & side electrodes. The platinum work great at 40,000+ volts. If you have a stock coil run the copper ones.

Performance
Copper spark plugs are often used in older vehicles and turbocharged engines, and can provide more power in performance driving situations.
Ignition
Copper spark plugs are appropriate for older models with low-voltage distributor-based ignition, while platinum spark plugs are better for modern engines that lack distributors

[WT6066-2600]

Appreciate you taking the time to share the info, Joe

[Royce Peterson]

To add to what Joe correctly said, modern high energy platinum plugs require a ignition system that you can weld with. If the ignition system is as old as the car, copper plugs (the cheapest) work best. Pertronix systems are like the points are brand new all the time - they work best with cheap spark plugs too.

[69 GT350 Vert]

I stopped using marti plug wires because their resistance is really high measured on an ohm meter.  Taylor and msd wires measured much lower. 

[Bob Gaines]

I stopped using marti plug wires because their resistance is really high measured on an ohm meter.  Taylor and msd wires measured much lower. 

Maybe have a cap with vintage looking/Marti wires and one with modern lower resistance wires. One for show and one for driving. Like many of us have a second set of wheels and tires. I like taylor black wires that you can lacquer thinner wipe off the white printing if using aftermarket.   

[rkm]

People with old V12 Ferraris used to use NGK plugs because their copper cores prevented plug fouling. So do you want show or go?

[Bob Gaines]

People with old V12 Ferraris used to use NGK plugs because their copper cores prevented plug fouling. So do you want show or go?

FYI sparkplugs are hardly noticeable under sparkplug boots so show or go as it relates to sparkplugs is somewhat irrelevant. The Autolite Copper Core Spark Plug - 45 is the OEM and the typical BF32/42 replacement. It looks the same as the factory 428 CJ BF 32 with the exception of the bright finish which can be changed for stealth and the number 45 which is typically hidden under the boot.

[FL SAAC]

Time for new plugs on the KR stock 428CJ driver, asking for recommendations(experiences) for readily available plugs.

Thanks, Joe

Easy peasy

1 platinum plugs
2 petronix system under cap
3 petronix coil
4 stock wires your choice ( but replace them as they will get cooked over time)

Or

5 make your own black wires with no scripts on them and be happy

If you show it, just replace with stock components.

Once done change over,  we dont

[FL SAAC]

One last thing we have not been able to get a BRASS black cap or rotor

Its gray, blue,  red or whatever

But not black

The rotor does not matter once inside the cap you cant see it

The cap we spray it black with a spray bomb  and it comes out looking fantastic

Looking "very original"

Best of luck to you

[shelbydoug]

The only thing that I can add to this discussion is that normally the size and type of plug that was used was the BF32.

That was in the case of the "high performance" plug application that was cold enough for the design of the ignition system, considering the advance curve, etc.

In the case of the 67 GT500 428, they used and recommended the BF42, which is one step hotter and thus less prone to fouling.


That's what I have and I have not looked at what was used originally in the '68 and up?

I am thinking though that the hotter plug was used because the tendency of the 2/4's with an automatic to be "just a little bit big" for a street car in summer traffic and maybe in testing in Arizona in the summer, the decision was, "let's put a step hotter plug in the car just to be sure?"

In any case, a 42 is going to be too hot a plug if you are going to race/track the car and will act as a rpm limiter to and extent. Look to it to be a 5,000 rpm engine with the hotter plug whereas the colder plug is more of a 6,000 rpm plug.

Does the hotter plug run cleaner? That's debateable? You will see white tips on the electrodes with them though. Dark Greyer on the 32's.

[Bob Gaines]

The only thing that I can add to this discussion is that normally the size and type of plug that was used was the BF32.

That was in the case of the "high performance" plug application that was cold enough for the design of the ignition system, considering the advance curve, etc.

In the case of the 67 GT500 428, they used and recommended the BF42, which is one step hotter and thus less prone to fouling.


That's what I have and I have not looked at what was used originally in the '68 and up?

I am thinking though that the hotter plug was used because the tendency of the 2/4's with an automatic to be "just a little bit big" for a street car in summer traffic and maybe in testing in Arizona in the summer, the decision was, "let's put a step hotter plug in the car just to be sure?"

In any case, a 42 is going to be too hot a plug if you are going to race/track the car and will act as a rpm limiter to and extent. Look to it to be a 5,000 rpm engine with the hotter plug whereas the colder plug is more of a 6,000 rpm plug.

Does the hotter plug run cleaner? That's debateable? You will see white tips on the electrodes with them though. Dark Greyer on the 32's.

BF32 is what the 68 and 69 CJ used from the factory. There is not going to be any 6,000 rpm happening with the hydraulic cam in the stock 68,69/70 CJ engine.