C-1 Spark Plugs

[Robert Willis]

I'm having trouble this year wth the plugs in my 283 fouling.

I know in the past guy's have had trouble with ACs but I'm running the same Champion number that I have since 1998. I just change the fouled plug and it works great for awhile. Something has changed, maybe the fuel blend or a bad box of plugs or a change in the way the plugs are made.

The car has an 891 dist with points and first design dual WCFBs.

What brand and heat range or part number works the best today ?

Bob

[Rob Dame]

Re: C-1 Spark Plugs

I've had AC 46 somethings maybe Rs in my 56 2x4s for about 5,000 miles now still runs fine. When I do change them I think I'll go with the comparable Autolites. Rob

[Mike McKown]

Re: C-1 Spark Plugs

I've never had problems with AC unless I used R44 or R44S. I have used R 45S for quite a few years with no problem.

Any possibility you have a spark plug wire breaking down causing your problem?

[John O.]

Re: C-1 Spark Plugs

Hi Bob

I agree with Mike that you might have a problem with a bad spark plug wire. I don't believe it's the plugs.Also check the distributor cap for carbon tracks that will detour the spark.How is the plug gap? If all that is good, try leaning out your carburaters. Maybe one or both are putting out to much gas.I'm not up on dual quads. Do both carbs feed all 8 cylinders or does each one feed 4 cyl.each? If it's 4 cyl. each, work on the carb that feeds that cyl. It could very well be fuel problem.
I have a pickup truck that did the same thing and it turned out to be a clogged injector.

Good luck...John

[Jack H.]

Re: C-1 Spark Plugs

If the problem of plug fouling is only on one or two cylinders, it's probably prudent fault isolate the ignition (check plug wires & distributor cap, or put 'er up on a diagnostic machine to actually watch the spark waveforms dynamically). If spark itself isn't the issue, it's time for a compression test and follow-on leak down test to understand what's going on in the problem cylinder(s).

This may sound like overkill, but the last thing you want to do with 'baby' is go swallow a valve....

[Robert Willis]

Re: C-1 Spark Plugs

Wires, cap, rotor, points, condenser are all new. The car runs great for awhile then the miss starts and stays. If you pull the plugs one will be wet, so I put an old one in it's place and it runs great again. It's gota be plugs.

Bob

[Michael H.]

Re: C-1 Spark Plugs

Robert,

It sounds more like you have an oil consumption problem on one cylinder than an ignition problem. If the dead plug has just fuel on it, that might be ignition, or a number of other possibilities. However, if it's wet with oil, and fuel, I would look into valve seals or guides. Pretty common on those old motors....

[Robert Willis]

Re: C-1 Spark Plugs

Thanks, but the miss moves from cyl to cyl till I change a plug on the bad cyl. I was just looking for a plug number to get around this. Then again maybe I just got some bad plugs and the plug number is ok.

http://members.kos.net/willisb/

[Mike McKown]

Re: C-1 Spark Plugs

Bob:

Would you care to share with us what heat range plug you are running? If you're running the plugs that came out of that two wheeled Chevelle wagon, they're probably too cold.

[John H.]

Re: C-1 Spark Plugs

I had occasional fouling issues with AC 44's in my '57 270, and switched to AC R45S plugs; that cured it (at least for the five years/5,000 miles I drove it before I sold it). This was a recognized field problem in those days on 2x4's, and the engine plant began installing 46's in 2x4 engines in late '57 - documented in a Service Letter to the dealers, but never picked up in the owner's manuals or the ST-12.

[Clem Z.]

make sure the plug wires are all the way in the

distributor cap,not being held out by the tower boots.

[Robert Willis]

Re: C-1 Spark Plugs

Thanks John,
I thought you would know. I have run Champion RJ12YC since 98 with no problems but this year my new set don't seem to like my engine ( maybe they are made in Taiwan or ??? ).

I will try the ACs

Bob

[Robert Willis]

Re: C-1 Spark Plugs

Thanks to all.... Believe it or not my "new box" of plugs had 7 dud's.