mdacton

Whats would cause the tips to be slightly green tinted?

The only thing that changed was going from sunoco 110 to torco. Could it be the fuel?

PortMasters

You need a colder plug,
Excessive green oxide indicates overheating the plug. a lot of spark-plug electrodes have an alloy composition that will oxidize green when subjected to high temperatures. The nickel oxide on the center wire and strap would show up first at the tip of the electrode (the hottest part) and progress from there. Try going down a step at a time.

mdacton

What is the next colder plug to a AR103 autolite? Or should I go to NGK's?

PortMasters

Autolite AR94's and no I wouldn't go NGK if 103's are greening up, if you like NGK though go with BR7EFS's (TR7).

mdacton

how much colder is the 94? half or 1 whole step?

I'm going to get a few sets and try them out and get one of the tools to view the plugs with.

Steve in Seattle

1 step cooler.

I belive the AR103's (which is what I run on a high compression stroker) are 1 step cooler than stock. The AR94's are one more step cooler... what you'd normally use for a mildly boosted or juiced application.

mdacton

how high is your compression? mine is a little over 14 static. I have just started to get some runs on it...but keeps having trans problems

PortMasters

Thats plenty of compression to go for the 94's. They have a non intrusive tip, so they will resist blow out better, and help with pre ignition. Yes they are a full step colder than the 103's like steve said

Steve in Seattle

A bit more than 12.5:1 static... 9:1 dynamic. I'm still on the stock PCM (~7000 redline) and a big hydralic roller cam, but she'll run premium... no need for high octane (although with pump gas prices it may be cheaper to get 110 soon :P).

I run a T56 so that helps as well, as does the extra displacement (396)... but stock heat range plugs were HORRIBLLY misfiring. Cooler plugs helped a lot. I have a neat nitrous plate for my monoblade TB, but I want to run it NA for the summer before tinkering on the tune again. When I do, it'll be AR94's for sure, though the AR103's are ok for now.

What do you think your dynamic is at? You have 1.5 points more static, but the larger cam will probably make the dynamic much closer. We're probably seeing similar max pressures, though the 110 octane should help a lot. Seems strange that changing from 110 octane to 110 octane would drive up temps that much (I wonder if this is where the research vs motor octane ratings start to come into play).

Do you know what AFR you're seeing at WOT? In 3rd I see about 12:1, and 4th closer to 12.5:1. Any chance you're running at bit leaner in top gear? (although I thought I was running about as lean as safe, I may be a bit conservative here).

mdacton

I don't think my AFR is right b/c trans was slipping...so with a full load on it I expevt it to need a tad more fuel. I was turning 7500 and doing 113 mph.

The camshaft is way bigger, I don't know the exact dynamic but we are very close. I tried a 106 plug before and got really bad misfires and could not get it started.....also had issues with the 103 so I closed the gap up to .032 and added a MSD box and coil and it made a pretty big different.

The engine really purs good now at 8,000....no misses or anything. I am hoping to have a new trans within a week. I was not able to data log the passes for some reason but I will next time. I have a wideband hooked to my DFI......I was just having problems with my laptop battery saturday.

Steve in Seattle

Hmmm... if the AFR is bouncing around that could explain the coloring your getting. ut it can't be that far off if it'll do 8 grand under load without a miss.

Might be time to add a thermocouple.