What color should the spark be with an HEI? I'm chasing down a wierd rough idle thing and I'm thinking possibly bad plug wires - I just used some generic parts store 8mm HEI wires from a 76-81 Chevy something jjust to get it running. I checked each plug by taking it out and grounding it - I get mostly orange but every 3rd or 4th spark is blue. Also on some every 4th spark is a lot brighter than the others. It doesn't sound right to me, that inconsistency in spark intensity and color. Ideas?

Andy

Andy
Some say blue and some say orange I found it doesnt matter,check to see the lenght by taking a plug wire off and check to see btween it and a ground.Do you have the resistor wire taken out of your harness that powers the HEI?

They make a HEI tester that looks like a sparkplug that has a resistance set up if it fires then it is strong enought but I don't think you need it.

Are your plug gaps the same?
what brand plugs?
and how much voltage do you have going to HEI?
IF you have trouble call me 9012898357 I am off till Sunday ,are you going to Super Chevy this weekend.

Andy
Some say blue and some say orange I found it doesnt matter,check to see the lenght by taking a plug wire off and check to see btween it and a ground.Do you have the resistor wire taken out of your harness that powers the HEI?

They make a HEI tester that looks like a sparkplug that has a resistance set up if it fires then it is strong enought but I don't think you need it.

Are your plug gaps the same?
what brand plugs?
and how much voltage do you have going to HEI?
IF you have trouble call me 9012898357 I am off till Sunday ,are you going to Super Chevy this weekend.

Hey Mike

I think I'm going to try to take the kid and the convert up to Arlington for the little show up there on Sat. Her and her mama's patience (mostly her mama) for all things Chevy wears thin rather easily.

I had the gap set at .035 because I didn't know any better, but the car idled fine but had a little higher RPM hesitation. I opened the gap to .047 or so and the high RPM cleared up but the poor idle started around that time. I don't think opening up the gap would cause one or more wires to short to ground, though.

I'm running regular old Champion plugs for a 70s SB V8 (most people here seem to prefer AC, but I quit using those years ago when I had a rash of premature failures). I'd have to look to see exactly which one, but they were off the shelf from Oreilly's.

I've got, or well, I HAD 12 volts to the HEI when I installed it (replaced the resistor wire). Might be something to check although I can't imagine why all of a sudden it owuld be less but stranger things have happened. There is enough juice to jump to ground when I just lay the boot on something metal.

I'm sure everything is OK with the ignition but I just like to be sure.

Andy

Just to update I tested the resistence of the the generic parts store HEI wires I had on the car. They were between 3000-5000 ohms per foot, which is high but it seems well within values quoted here. Just for grins I replaced them with a set of Accel 8mm stranded copper core wires. I tested them as I put them together - pretty close to zero ohms :D I might have some radio problems if I ever hook it back up again but I'll tell ya what the car fired right up and once it warmed up there was no roughness and the stinky exhaust was gone (I thought I smelled it but the Stinky Exhaust Detector in my house said she couldn't smell a thing when I came back in :D )