All plugs were 'white' and very 'clean'. I understand that means they are burning too hot. Any advice?

I have the Pertronix kit and the Flamethrower Coil, but regular 7mm wires and 'nothing special' plugs about 4mo old. My suspicion is that the Coil sends a lot more juice to the plugs than before.

Most people were suggestion to increase the gap on the plugs with the petronix, which is why i was even looking at the plugs. It was at the original .3 (?mm - sorry?) and I am trying .4 However, wouldn't a larger spark make for a hotter plug?

mmm... before I post, I was looking at those spark plug charts again and its hard to say if it matches 'too hot' or 'carbon deposits':
its a clean, dry, smooth and even white.

As far as 'too hot', i can say this:
- advanced ignition: about 8BTDC, after eliminating pinging under load;
- intake vacuum leaks: no, been working on that all along;
- lean mix: recently gave it about another 1/4 turn richer, even after finding the best mix setting;
- coolant: ok

(just going by the book there...)

thanks - mike

 

Without actually driving over to your place to look at the plugs in person, I would have to guess that the engine may be running a bit lean. Even though you've richened the idle mixture, you need to increase the main jet size. They will have more to do with the color of your plugs than your idle mixture. If I were you, I'd try stepping up a couple sizes on the jets. What engine are you running? Is it stock, or rebuilt? If it's rebuilt, give us some specs such as compression ratio, cam, etc... And what carb are you running?
Jason Kendrick
1970 F100 Custom 390/C6
1978 F150 Ranger Lariat Supercab 460/C6

 

Well, Mr.390 you are absolutely right, I meant to put the basics after my signature...and coincidentally, it is a 390 too.

'68 CS 390 everything stock accept the petronix deal and the Performer 390 manifold. - which is bored for the 4bbl and i have the two barrel autolite on there with the adapter.

Between the petronix and finally sealing the intake very well, it has been running very smooth and starts like a charm. So there were no other symptoms except visually seeing the plug contacts so white.

If you are right about the carb, then it is another reason on my list for switching to a 4 bbl, but as I have stated in some other posts, the 2 bbl is new, runs well, and i need to hold off budgetwise before investing in a new carb for about 6mo to a year. However, if you think bigger jets would help, I can try that.

I never changed the jets before, although I have dismantled an old carb. Are the 'jets' are the two skinny 'tubes'? Is that something you just pick up at a parts store?

I also asked this once before: does an open air element lean out the mix significantly more than the stock big blue air filter encasing? I have both available and can put the stock back on if that would help.

 

Mike, I think 390 is correct in that your carb is too lean. The main jets are the two brass screws (with holes in them) at the bottom of the float bowl. They are easy to change. They will have numbers stamped on them, e.g.; #56, #60, #62, etc. For instance, if you have #60's, then go to #63's or 64's, according to how your sparkplugs look. You should try for a light tan color. The higher the jet number, the richer the mixture will be.

If you decide to change them, be sure to get the right jets. All are not interchangable. Holly jets will not fit Motorcraft carbs, but I'm not sure about Autolite.

 

Thanks! I will try it. - mike

 

For Autolite/Motorcraft jets, forget your friendly parts store and try your local Ford dealership, but I think you'll have more luck at your favorite salvage yard.
Jason Kendrick
1970 F100 Custom 390/C6
1978 F150 Ranger Lariat Supercab 460/C6

 

MLD,
Go to a junkyard. Acquire all stock jets you can get your hands on. Go to your local NAPA store and get a reamer set. I believe welding supply shops sell reamer kits also. You can ream a stock jet to any size you want after that. Remember you can only go up, not down, so take your time. Its the cheap fix. You may be very surprised the amount of power you can get from a factory carb doing this. If you need top end power you can space the carb 1" to 2" from the intake manifold and you'll get better power in the higher RPMs but you'll notice a power loss off the light.
Good luck, Have Fun,
KingFisher