This is bad right? (speckled spar plug, pics inside)

[Zanx]

Just pulled the plugs on my 383 and they ALL look like this on one side, every single one. I'm running 10 degrees of advance at idle, standard Edelbrock 1411 settings apart from the orange spring, stock exhaust, electronic ignition, ED manifold.

It certainly doesn't SOUND like it's detonating but those plugs tell me different.

Whaddya reckon?

[moparmussel]

looks like a case of the clap! add a little penicilin in the fuel!

[1973Swinger]

I wouldnt be admitting to knowing what the clap looks like on this board! LOL

[dave571]

Are you running nitrous on that car?

[Zanx]

Originally Posted by dave571

Are you running nitrous on that car?

Nope.

I've been having a few jetting problems but I didn't think anything this dramatic would happen. All I can thing is that it's got too much advance on cruising RPMs. Also don't know if this happened before I got the car or after. By the shinyness of the globules, I'd say they were recent.

[John Kunkel]

Are you running gas with a high lead content? If so the BB shaped globules could be lead deposits commonly called "dingle balls". A leaner mixture will help keep the deposits to a minimum.

If the gas isn't high in lead, your pistons might be stuck to the plugs.

[Zanx]

Originally Posted by John Kunkel

Are you running gas with a high lead content? If so the BB shaped globules could be lead deposits commonly called "dingle balls". A leaner mixture will help keep the deposits to a minimum.

If the gas isn't high in lead, your pistons might be stuck to the plugs.

John, I'm using unleaded gas with Castrol Valvemaster Plus (with octane booster)

I've just crunched one of the globs between my teeth and it's very crunchy, I was expecting it to be solid.

The lead replacement this is a very good point actually, I am slightly less worried than I was 20 mins ago.

[Zanx]

You know John, the more I think about what you just said, the more it makes sense. The globs are only in one side of each plug, I reckon that would be next to the intake valve. If it was melted piston, then the globs would be solid and not crunchy surely?

[Zanx]

Ok, just been for a spin to induce some pre ignition so I know what it sounds like, foot on the floor from a standstill and I get a slight tinkle for half a second. Now I know what pre-ignition sounds like, it's probably safe to say that it's not something I've heard before from this engine.

[Tarrbabe]

it truned out to be antifreeze.
Hope not.


Just thinking out loud.

[John Kunkel]

You'll often see those globules on aircraft plugs when running 100LL fuel and not leaning properly; it it wasn't for the lead, the aircraft plugs would last a lot longer.

Unleaded auto gas is approved for use in some aircraft and those plugs will never show the globules.

[Zanx]

John, I've gone one stage lean in the cruise now (where the car spends most of it's time) and it doesn't knock so I'll drive it round for a bit and pull a plug to see what's going on. Certainly starts much easier with new (clean) plugs, that's for sure.

Thanks again for your input, turned out to be a gem.

[cageman]

I run 100ll in my race car and I have never seen anything like that.

[Zanx]

Originally Posted by cageman

I run 100ll in my race car and I have never seen anything like that.

I'd imagine your race car runs a little more efficiently than my old slogger

Your fuel is probably mixed a little more accuratley than mine, mine is just a case of throwing in roughly the right amount of additive that's needed for the amount of fuel that's just been pumped in.

[cageman]

Could be, I was just referring to another reply.
As for you, is it possible to put a cylinder tdc and look at the piston thru a sparkplug hole, just to make sure. I am sure by the look of the plug that it is carboned over, but better safe than sorry.