spark plugs

**cpop98ws6** · 10-27-2011, 06:13 AM

How can I tell if I need a hotter or colder spark plug? Right now I have ac delco irridiums,not sure of the number but its just the stock plug. I'm running a heads/cam ls1 383 and wondering if I should put a different plug in it.

**Nowhereman** · 10-27-2011, 07:50 AM

You getting any pinging ? NO? then it's not too hot a plug.
Coughing when cold? then the plugs are not too cold.
Should be ok
Your compression ratio is the critical thing here.
Cylinder pressure should be ok.

**pajeff02** · 10-27-2011, 08:15 AM

Coloration and deposits on the electrode tell the story of what is going on. I think it was Firebirdjones who posted some great info on plugs. If I am not mistaken, his work on the dyno lead him to run Autolite AR103's (or something like that). The heat ranges on the NGK's just did not match up from what I remember.

**Nowhereman** · 10-27-2011, 01:55 PM

Originally Posted by pajeff02

Coloration and deposits on the electrode tell the story of what is going on. I think it was Firebirdjones who posted some great info on plugs. If I am not mistaken, his work on the dyno lead him to run Autolite AR103's (or something like that). The heat ranges on the NGK's just did not match up from what I remember.

Actually, with today's fuels it gets harder to do that.
One mistake many make is that they attempt to read the electrode at the top of the insulator.
In reality, you should be reading farther down the ceramic insulator to get a more accurate reading.

**smokestack** · 10-27-2011, 02:35 PM

Originally Posted by Nowhereman

Actually, with today's fuels it gets harder to do that.
One mistake many make is that they attempt to read the electrode at the top of the insulator.
In reality, you should be reading farther down the ceramic insulator to get a more accurate reading.

Kinda like a plug chop for a 2 STROKE? I wonder how we could do that with a car though? Like how many miles under what conditions. Like wot or cruise? And how many miles?. Seems like a good idea. Sorry. Just something i have been thinking about. I it alot with my banshee and makes me think of the cars as well.

**cpop98ws6** · 10-27-2011, 07:35 PM

Originally Posted by pajeff02

Coloration and deposits on the electrode tell the story of what is going on. I think it was Firebirdjones who posted some great info on plugs. If I am not mistaken, his work on the dyno lead him to run Autolite AR103's (or something like that). The heat ranges on the NGK's just did not match up from what I remember.

I was reading thought those posts that FBJ put up, some very interesting stuff in there. I'm gonna look into those copper core auto lights ar103s. Thanks Jeff.

**cpop98ws6** · 10-27-2011, 07:37 PM

Originally Posted by Nowhereman

You getting any pinging ? NO? then it's not too hot a plug.
Coughing when cold? then the plugs are not too cold.
Should be ok
Your compression ratio is the critical thing here.
Cylinder pressure should be ok.

No pinging or coughing, just wondering if I'm running the best plug or not.