ok so these are my plugs 1-3-5-7 left to right. The wires are 5 years old MSD 8.5mm super conductors, the rotor/cap is 4 years old, and the coil is a 4 year old MSD blaster 2. The car was too hot to pull the other 4 plugs near the DP so this is all I have for now. I did burn a plug wire last month so the wire for #3 is brand new. Plugs are NGK-FR4

The car is making 5lbs of boost, afr's at WOT are 12.8, 32* timing and no detonation. I can't spin the tires in first, power is down across the board. the car can barely get out of it's own way

I have not read many plugs, but as far as I can tell #1 is rich (lots of carbon), #3 is about correct, #5 is a bit rich (lighter carbon), and #7 is ashy (oil or something burning?)

I am thinking new wires since the one new wire looks the best, and new plugs also. Would good spark on #3 and poor spark on the rest cause the plugs to look so different?

 

How old are those plugs?

And that just looks like a big gap but I guess your not up there on the boost so disregard that statment.

For the most part they just look pig rich(almost ready to fowl out) except the #3 but that ones close to it, that plug is what I would exspect to see if you were WOT then just shut if off to look at them, not at idle. But when did you take them out, after a WOT pull or just crusing or idling??

That last on on the right is definitly messed up. Detination?? Or too hot of a plug? And is that a hint of oil I see on the top threads??? Oil burning will cause ashes.

Are those a lower heat range plug then the stockers? Im use to ac delco numbers so I have no idea with NGK.

 

they are stock replacements, and have some miles on them my real concern is the differences between them - they are pretty useless for tuning. I'm hoping I'm having a spark delivery issue and not injector problems or something stupid. I am suspect of the intake gaskets as well... Just trying to get some opinions before I tear the thing down and spend money :haha:

They did run great on 5psi for 3 street pulls before the car stared having issues so they will work better than they are currently

and yeah there is oil on #7, thats part of the reason I'm suspect of the intake gaskets along with oil puddling on the intake and the crankcase getting pressurized

 

Ahh i see, well Id say if you have a tester to do a compression test first, then if you suspect the intake gasket then check that out. But definitly get some fresh plugs on temp range colder and use them so you can sorta read them.

You dont wana see what just happend to my car a few weeks ago, found out today that the piston ring was broken, had blow by and oil slightly on the plug but this was very noticable after a WOT pull. Its been down since that last pull when it enevitably broke. Thankfully I didnt tear up the engine.

 

#1 plug is rich.
#2 plug is a little lean
#3 last plug is fuel/

sounds as though you have a couple other preobel,ms'

 

looks like oil on the last one to me... not good with the boost.

 

fuel injectors ok?. My cars plugs looked like that and was bad injectors.

 

I agree oil is no good, but could hopefully be a simple fix if thats the issue. He doesnt have n20 does he??? I thought just the boost

 

just boost right now. injectors are brand new, hopefully they are not bad

 

lmao pretend i didnt say that.

 

ok well since there is oil on #7, valve cover came off to do valve seals, and then I said screw it and tore the distributor out, intake off and thats as far as I got today. Since it's been deemed an issue beyond spark (oil) and I'm way further into the motor than just ignition components I'll throw the full details in my main build thread with pics.

but here is the cap and rotor - yikes!

 

Aluminum // brass mix of rotor-to-cap
And // Or
Aluminum // brass mix plug-to-cap cause the erosion??

I've *heard* but not seen that a mix of brass & aluminum causes problems.
Just an uneducated thought

 

matching borg warner cap and rotor, cap is brass the rotor may be Al I'm not sure.

 

Wow man, that cap is nasty looking.

 

Those plugs aren't stock replacements for a '91 f-body SBC engine. If the stock iron heads are still on the engine they are the wrong spark plugs.

If the heads have been swapped out for aluminum ones then they are likely the correct form factor spark plug.

RBob.

 

yeah the cap is gross

heads are l98 AL heads, so the plugs should be the correct replacements. I'm going to try a step or two colder plug when i put the motor back togeter

 

Gotcha', y-body L98 heads. The plugs are OK then.

RBob.

 

I think you are running too much timing, at 5psi I would stick around 25* or less on 93 octane. Probably 23* i would start with.

 

thank you for a generic boosted small block timing value, but Al L98 heads require more timing than most, I'm 10* retarded from what I was running NA and am experiencing little to zero knock