Everything there is to know....post it up

I have been searching up and down and need to know more about plug selection and what to look for.

Using Autolite.....tried a few different ones, the colder ones just foul out really easy

http://www.power-21.com/HoneywellPow...gHeatRange.pdf

Been looking around here

 

I ran the Autolite AR-3911's in my L-98 motor. No problems with the heat range. I had problems with the radio and the electronic ignition. Finally went back to resistor spark plugs. Cured all my electrical problems.

 

What are you looking for exactly? Who makes them? heat ranges? plug gaps? Side gap versus regulars?

I've never had luck with Champions, not even in my mowers.

NGK's nice plugs, easy to read, especially for timing and heat ranges.

Denso makes another easy to read plug.

I would stay away from the more exotic (side gaps, etc) plugs especially if you street drive your car to any degree.

 

How do you find the right heat range plug for a race engine?

start cold and work your way up? I have tried 2 cold plugs and they foul very easily so I'm guessing they were not hot enough to burn the deposits off........I will stick with autolites b/c they are readily available local and cheap

 

Cold range plugs are generally a nitrous plug. You can generally tell at the track the cars with really cold plug ranges, they are the ones constantly revving the **** out of thier engines to keep them running after the car has idled for any period of time and you'll see them tweakin the carb or messing around with new fuel maps.

Are you having ignition problems or just looking for something different to try?

I've played aroung with plug gaps alot lately, we had a problem with an ignition miss when the customers car was on the hose, I pulled his plug and asked WTF is this??? He had about a .050 gap, we whittled away at it until about .019 and everyhting was clean and nice. The cylinder pressure was just too much to "keep the candle lit" with the Plug manufacturers recommendation.

Try a NGK plug, you'll see what I mean by easy to read.

Yes, start moderately low and work up from there, exhaust plug gapping areas prior to going up a few ranges.

 

I was running a cold plug with .035 gap. no ignition issues. The car is running lean at idle.....I leaned it way down and it would not idle. So I went to a hotter plug and it ran alot better. I got my idle map like it should have been it will fire up etc.

 

I run NGK race plugs. I pick them up at my local NAPA dealer. they're cheaper than the fancy gimmicky plugs everyone tries to sell.

I normally run a -7 heat range. This year I tried a colder plug and dropped down to a -9. I think it was too cold. I lost a bit of power with the new plugs. I'll pick up some -8's before the start of the season and try them. All my plugs are indexed. If they're not, the piston hits the ground strap.

There's a lot to reading plugs. Normally you want the coldest plug possible before the plug starts to foul up. Plug temperature is the temp at the plug tip and has nothing to do with the temperature of the engine. Too hot and it starts to self ignite the fuel. Too cold and it can't burn off the deposits and starts to foul up.

Google "reading spark plugs".
Main areas to examine a plug are;

Look for a heat ring down inside the insulator. How far it sits on the insulator tells you one thing.

Look for a discoloration line on the ground strap. How far the line is away from the end tells you something else.

Look for discoloration around the bottom ring. That tells you something else.

Anyone who examines a plug by just taking it out and looking at it with the naked eye doesn't know what they're looking for. You need a magnifying glass to properly see what's going on. Preferably with a spark plug flashlight. A spark plug can tell you a lot about how an engine is running. It's not just about the heat range.

The worst part about reading plugs is that they should be new. Trying to read an old plug that's been subjected to the wrong heat range, air/fuel mixture, timing etc won't give to a good reading to what needs to be changed. Plugs are cheap. Change them often after tuning changes are done to see what the results are.

 

I have been looking alot at reading them. For now I guess I will keep trying the AR103's

They don't have NGK at the napa here, thats why I want autolites the next closest place is 40+ miles

 

I asked for a set of NGK plugs at a redneck owned NAPA store in Northwest Florida (needed a set for a jetski motor while I was on vacation) and he looked at me cross-eyed like we were still fighting WWII.

 

I agree, an NGK plug seems to be easier for me to read. Parts stores in this area will carry NGK plugs as direct replacements for regular vehicles, but it's difficult to find anyone that carries the NGK racing plugs, let alone several heat ranges to choose from. I have two alcohol motors that use the same plug so I buy 100 at a time and get a decent price on them. I have found a few internet sites that have a good selection. Running the correct plug is imperative and although they may cost up to $2 each, in the grand scheme of things, that's chump change

 

$2.47 for the ones I have been getting

 

I am not partial to any particular brand. Can't say I ever noticed a rat's *** of difference between them. In a race engine, you need to experiment. A good igniton though should fire almost anything unless it is running too rich or there is oil in the combustion chanber.

Rich

 

I run Autolite AR3923, call Summit or Jegs, delivered to your door.

David

 

Autolite 106 for me

But I don't have a race engine.............

 

I'm using those also...they cross to a AR103. Damn good plug IMO