7zark7

What do you all think of these?

LT1MAN

iTrader: (6)

throw them ***** away.

Koll

They look a little hot / lean. Also like there is too much timing.
Someone confirm this.

wrd1972

iTrader: (12)

They are lean according to the transition line on the grounding tab. It should be right in the middle of the bend.

dhdenney

iTrader: (53)

Someone go into a little more depth on those pics. I have always wanted some deep explanation on plug reading. I just know a black plug is running rich.

KTM

Touch lean - particularly since they are '42' plugs. That is the coldest plug A/C makes. If you are running that plug lean you can add some more fuel.

Personally I wouldn't throw them away though...you haven't hurt them a bit in my opinion.

Ralls

iTrader: (32)

http://www.centuryperformance.com/spark2.asp
That should help some.

dhdenney

iTrader: (53)

Hey thanks for the link. I had similar pics in my Chilton manual but no explanations. Just titles.

94 F-body

iTrader: (1)

one thing I noticed is there is no antiseize on them, I use it everytime I put plugs in any car, just rember a dab will do ya. and they appear lean with some carbon on the inner wall of the metal, below the electrode.

indirocz28

iTrader: (7)

they look a bit lean, also you have a valve cover leak..- imagine that..

7zark7

So here's the thing, I really can't control the fuelling except for periods when it's running open loop (cold start and high load). These plugs were pulled after some time of normal driving without any high load operation. So other than trimming fuel a bit for cold start there's nothing that I know of that I can do for closed loop operation in terms of fueling. It's running off the O2s right?

I am going to try an even colder plug, an NGK BR7EF, 2 heat ranges colder than stock, which is probably what the motor should have (it makes 500hp). I can't tell what the R42's cross reference to. The only info that I got was from Autolite who said it crossed over to their 103 (one heat range colder than stock)

Overall it does look like it's running hot if I had to guess, but is this from fuel mixture being lean or is it from timing being retarded/advanced?

7zark7

I remember reading somewhere that anti seize on the threads could do some harm. Can't remember why though, so I stopped using it. I usually don't leave the plugs in for long anyways so I don't think it's an issue for me.

7zark7

Funny thing is, the valve cover doesn't leak. That plug was a bit loose. Can't get it tightened down right with the tools I have, the spark plug socket won't fit over it because of the header tube is in the way. It's probably some combustion chamber junk that's blown out from around the threads. I specifically checked for an oil leak above that plug and it's bone dry.

TravisTA

You may be a little lean not much though, But you have way too much timing. Your A/F ratio may be right but the timing could cause your plugs to look a little lean because your combustion tempratures are higher(wich is cleaning the plugs off better). So going to a colder plug probably is not the answer. If it was me I would back off the timing a bit and see if your plugs change at all.

7zark7

Can someone explain how too much timing will make the combustion temperatures higher?

infinitebird

iTrader: (11)

When you advance timing you ignite the mixture earlier on the compression stoke (before the piston reaches TDC). So the engine spends more time compressing explosive gases (as opposed to just air), which results in higher temps.