BAD-HABIT

No matter what I do I can't seem to get any color on my plugs..I have run AC Delco Rapid Fire and now Champions. Running a 750vaccumn secondary Holley. Motor is a 375 HP SBC. Started with 74 and 82 jets. Went all the way up to 82 and 94 and still no color at all. You could eat off the damn things. To check the plugs I have been running at W.O.T. for about 3-5minutes then put in neutral and shut off. Seems like I should have SOME color on the things....The plugs are not melting but just damn clean. The plugs have about 15hours on them....Last set were the same way...The motor has about 60hours on it. I haven't really had any color on them since the motor was built. What else can I do to make sure Im not leaning this thing out?

BH

HARRISONMIRAGE

I have had similar problems with my 502.Usually if you are lean you can see overheating on the ground strap.If you are getting speed increase by leaning out you are OK.When you stop netting any performance gain go back richer.Of course this only works for full throttle jetting.If you buy a plug magnifier you will be amazed how much more you can see.The colour line is usually deep in the plug at the base of the porcelin.

rmbuilder

Randy,
Try this, good read.
http://www.maxracesoftware.com/spark_plugs.htm
Bob

BAD-HABIT

[QUOTE=HARRISONMIRAGE]I have had similar problems with my 502.Usually if you are lean you can see overheating on the ground strap.

What does "overheating" look like....What should I be looking for??

BH

220BR

If you are reverting a small amount of water, you will steam clean the plugs. Just a thought.

tomcat

rmbuilder: Excellent link, thanks!

BAD-HABIT

WOW......Guess I need to re-think my jetting. I have always thought you looked at the porcellain. I will have to look at the ring.

BH

BadDog

You may try NGK BR6 something in the correct heat range. I have had better luck reading those. They seem to pick up more color due to type of construction.

rmbuilder

BH
The myth of jetting by color is left over from the days of leaded fuels. Certain fuel additives would leave deposits on the insulator that were thought to be an indication of fuel mixture. If you want to check for overheating examine the area where the center electrode meets the porcelain and look for "cement boil".
Tom,
Larry Meaux is the owner of the link. Check out the rest of his site, he's a very talented engine man.
Bob

tomcat

After I read that plug info, you bet I looked at the rest. Good reading in EGT article too. Makes you think, usually a good thing.