12volt conversion for Dell

The reason you can't turn yer engine off is because you don't have an "isolating device" scheme between the P-1 "excitation" and the ignition switch "ON" terminal which conviently is connected to the ignition coil. The gutts of the 3-wire Delco 10-SI alternator feedbacks enuff volts to run yer ignition coil iff'n ya donnna "isolate" it.

1) General Motors/Chevy been using their dashboard idiot light to slowdown the backvolts and weaken the sparkies so the engine stops when you turn the ignition key off. You can do the same, many use a trailer clearance light that already have wires attached so its eazy to wire in. You don't have to mount the improvized "idiot-lite" so you can see the bulb iff'n you don't want.

2) Others use a high-tech "diode" to block the back volts. Ya gotts a 50/50 chance to install it correctly, iff'n incorrect engine will continue to run so just re-wire the diode the other way around. Simple, eh?

3) Others use a momentary push-button "excite" switch to gitt the alternator runnin' 'cuz thats all that is necessary, a momentary surge of volts to excite the alternator. Once excited, it will output until engine ignition is turned off.

4) Others use a NEW ignition switch that has a RUN and ACCESSORY outputs screw terminals. RUN for the ignition coil, ACCY for the alternator P-1 "excite" function.

I know of at least 3-other ways to "isolate the excite". The important thing to realize is you can't have both the ignition coil and the alternator excite directly connected together or you'll NEVER gittchur engine to stop runnin'.

Bettcha you don't know that yer alternators P-2 "remote volts sense" is supposted to be directly connected to the alternators BIG BATT STUD output, do you? Iff'n the P-2 sense isn't connected to the battery charge line, it won't know when or how much to charge the battery, so it will by default, charge the max and boil out all your battery acid water.

And I still DONT THINK yer engine sputterin' and backfiring is a function of your 12 volt wiring conversion UNLESS yer runnin' a real 12 volt ignition coil thru a 12 to 6 volt converter resistor from yer ignition switch. You do that and you will diffinately have weak sparkies and sputterin'..... ..respectfully, Dell, a 12 volt advocate for the right reasons

You have a 52 8N, that means a roundcan coil and sidemount 5-nipple distributor. Sputterin' and poppin' when you load yer engine with brushog is a pretty good sign that yer sparkies are miss-wired. Check yer firing order. 1,2,4,3 CCW. (probably gotts 4&3 swapped)

These ol' N-Engines are so good, they'll run at idle on 2-cylinders and you'd think nuttin was wrong.

As for your 12 volt conversion wiring, I don't think there is anyrelationship between it and the "sputtern and backfirin" you report. Unless yer 12 volt battery is so discharged from a bad alternator thats ya gotts weak sparkies. But iff'n yer battery was that weak, you'd be complaining about hard to start..... ....Dell

Sputtering under load could be lotsa things. Could be weak spark.

Have you done the 'standard' tests?

I'm not up on backfireing causes.. or afterfire.. so I'll let one of the other guru's step in and answer.

Soundguy