HEI and OEM ignition interchange-plug gap scenario

[sargentrs]

Just finished installing HEI igntion system and left OEM ignition system intact so I can swap back and forth easily in case something goes wrong with the HEI. Noticed immediate difference in the way she runs even with the old plug gap. I'll be installing new cap/rotor, 8mm plug wires and regapping the plugs to .045 today. My question is, if the HEI craps out and I switch back to the OEM ignition system, will the she still run adequately to get me home with the plugs gapped at .045 or will I be forced to regap them back down as I'm sitting stranded on the side of the road? :banghead: Any and all input is greatly appreciated!

 

[abodyjoe]

i'm sure it will run good enough to get ya home.

 

[tekslk]

You gonna love the hei. Get rid of the old wiring you can get any part you need for hei anywhere. Yes it will get you home if you switch back.

 

[sargentrs]

Thanks guys! I've already noticed a significant improvement. I can also tell my original wiring had issues from watching my aftermarket volt meter I installed. Must've been pulling down the voltage pretty bad because I'd have 14v+ at 1000 rpm but only 12v at idle and less with the lights and heater on. Now I've got 14v+ at idle and still have 13v+ with lights and heater. I'm sure I'll be very happy with her once I get the new cap/rotor/wires on and regap the plugs.

 

[BillGrissom]

No problem. Even a points ignition can throw a spark across a 0.250" gap at 1 atm pressure. Thus you can at least idle. As you go WOT, you will reach a cylinder pressure where the spark can't jump the gap. I had that problem in my 1996 2.4L, it would start missing trying to accelerate on an on ramp. I followed the Chrysler TSB for 2.4L turbos to reduce the gap (0.060 to 0.050" or such) and no more problems. Mine isn't turbo, but perhaps the accident that shoved the engine controller made cracks on the circuit board, or maybe wires start leaking as they age (changed plug wires, coil pack, ... no help).