NGK XR5 3332's in a stock 78 400 4bbl Fouling

JG71B

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Bone stock internals, just have 1 7/8" Hookers, Weiand intake and Eddy 1406. These plugs seem to be fouling slowly. Slight tan on the strap area, the ceramic is turning black with crud and I occasionally get a shitty idle for a few seconds then back to normally. Not sucking oil into the intake as I just put a new intake and gaskets on ( that was a previous issue, old intake was milled). That's all good now. Sometimes helps revving it and then idle smooths back out. Carb dialed in good, ignition is stock and shows good with a DVM. Idles good when not stumbling, pulls great for what it is in a 71 B body with 3.23's. Would it help to go hotter to the XR4's (5858)? Other than this, the thing runs awesome. Appreciate any help
 

DodgeBoy5150

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Bone stock internals, just have 1 7/8" Hookers, Weiand intake and Eddy 1406. These plugs seem to be fouling slowly. Slight tan on the strap area, the ceramic is turning black with crud and I occasionally get a shitty idle for a few seconds then back to normally. Not sucking oil into the intake as I just put a new intake and gaskets on ( that was a previous issue, old intake was milled). That's all good now. Sometimes helps revving it and then idle smooths back out. Carb dialed in good, ignition is stock and shows good with a DVM. Idles good when not stumbling, pulls great for what it is in a 71 B body with 3.23's. Would it help to go hotter to the XR4's (5858)? Other than this, the thing runs awesome. Appreciate any help

I really like NGK plugs and run them in almost everything! Our '77 Doba has a nearly stock 400 (only changes are Eddy intake and re-curved points dizzy) and I run the NGK XR4's.
I recommend giving the XR4's a try--these plugs are pretty inexpensive if you buy through RockAuto. :thumbsup:
 

JG71B

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I really like NGK plugs and run them in almost everything! Our '77 Doba has a nearly stock 400 (only changes are Eddy intake and re-curved points dizzy) and I run the NGK XR4's.
I recommend giving the XR4's a try--these plugs are pretty inexpensive if you buy through RockAuto. :thumbsup:
Nice! Putting XR4's in now. Then a set of Blue Dot advance springs I got from Halifaxhops this week!
 

kiwigtx

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I used NGK plugs all the time....but are hard to find, and price wise not worth it here at least.

Maybe you need a hotter plug for the combination and fuel you are using.

I recently swapped out to an Iridium plug on my A100, and a hotter range due to fouling. My problems are that converting fuel octane ranges to recommended USA plug specs need adjustment because we run a different octane measurement system here.

Seems to be working out for me so far. :thumbsup:
 

Geoff 2

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Is it points ign? Float level correct [ 7/16"] ? Is the cam std?
 

RJRENTON

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Personally, I prefer Champion Spark plugs. The origional heat range is J-11Y or MOPAR P34P but only available on the internet as NOS. They have been superseded by RJ-12YC which are copper alloy center electrode for a broader heat range. Autolite AP-85 are platinum tipped center electrode and offer a broad heat range as well. Very inexpensive available just about everywhere. I've used AC R43S as well as AC R44S. They work well and are inexpensive also. Presently in my RS23V0A****** GTX, I'm using Champion UJ-11G precious alloy center electrode that is NON PROJECTED. I also use Champion HO-8A a platinum non projected center electrode, with cut back ground electrode. These plugs were developed for HOMLITE 2 cycle racing Go Cart engines running methanol, nitro methane and castor oil fuels mix.
Both types are available on the internet or eBay as NOS. Because these Champion designs are non projected types, i believe that they allow for longer flame front propagation which may result in smoother combustion. My ignition system is a Prestolite dual point distributor and a custom advance curve.....15 degrees initial + 20 degrees mechanical all in by 2400 RPM, NO VACUUM ADVANCE. But this what works for me. NGK plugs are excellent and offer many different configurations and heat ranges....I just prefer Champion....to each their own.....
BOB RENTON
 

kiwigtx

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Bone stock internals, just have 1 7/8" Hookers, Weiand intake and Eddy 1406. These plugs seem to be fouling slowly. Slight tan on the strap area, the ceramic is turning black with crud and I occasionally get a shitty idle for a few seconds then back to normally. Not sucking oil into the intake as I just put a new intake and gaskets on ( that was a previous issue, old intake was milled). That's all good now. Sometimes helps revving it and then idle smooths back out. Carb dialed in good, ignition is stock and shows good with a DVM. Idles good when not stumbling, pulls great for what it is in a 71 B body with 3.23's. Would it help to go hotter to the XR4's (5858)? Other than this, the thing runs awesome. Appreciate any help
What fuel grade are you using....that is a major factor in determining if the plugs are right for you.
 
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