Thread: ZZ502 - fouling plugs

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G'day all
I'm running a ZZ502, and have been fouling plugs in it for years. I've used both Bosch and NGK.
The NGK's I've used are the 5s, 6s and 7s.
I've found other zz502 owners have the same issues, but no one has really solved the problem. Has any one on here fixed it?
Its a stock motor with an Edelbrock 850 - vac Secondarys.

I need to sort out what plugs, but also why they're fouling in the first place.

Cheers

Have you gone through the calibration procedure on the Edelbrock??? The book that comes with the carb is a great diagnostic help for getting the carb right. What is the rest of your ignition system?

I bought the crate motor in piece, and had it assembled, and engine dyno'd by a reputable builder here. It may be that he put in larger jets for a good dyno reading, though I'm aware that other owners are having the same issue, so I do want to run the right plugs

The plugs are a bandaid, Dave is right, you need to get to the source of the fouling. I can't see why that particular engine would be unlike any other engine, if the fuel air mixture is right it should burn clean..........or am I missing something?

Don

the edelbrock 850 ? is this a Q jet or a 800 afb ? if the afb then check the set up springs and look at fuel psi it is in the tune up as for carb setting not the plugs

Yeah, I know it's a bandaid, I want to get to the source and go from there. Will look into those suggestions, thanks.

Have you tried leaning out the mixture at all? I am not sure where the edelbrock air bleeds are, but why not try taking them back a notch, about 1/4 turn at a time on both sides, and see if that fixes the problem. Lean the mixture out a bit, then drive the car for a few days or a few cruises and check the plugs. If they are still black, then turn the mixture screws back another 1/4 of a turn and try again. Just make sure you keep all of the screws turned out the same amount.

Just a side note: I have had some highly recommended tuners mess up pretty bad. Everybody makes mistakes.