I converted to hei on my 69 a little while back and havent changed the reistance wire yet.I was thinking of running a #12 wire with an in line fuse fron the fuse block to the dist. What size fuse should it be? There is an unfused terminal marked bat in the center of the fuse block,It has power only when the key is turned,can I use this? I read previous posts on this subject. I'd rather not cut the harnes or mount a relay.I also read that some people couldn't shut off the engine after changing this wire, what's that about? If anyone sees anything wrong with my plan please let me know. Thanks.
I,m running HEI with a msd box on my 327 in my 67. The problem I had running my ignition wire from the fuse block was, older cars tend to generate 4 volts power when the key is turned off (not enough for stock ignition to run the car) however, whith the box it would continue to run. I started to hook up a diode at the voltage regulator (on the brown # 4 wire on my car) which would work in your case but I went with a single wire alternator and used my original ignition wire (the white "fuzzy" one) and everything was hunkedore. Why wouldn't you run the original wire to your ignition?
I think you're on the right track paul, just be sure the terminal is keyed, that is, not on all the time (marked BAT, i think it would be on all the time though) Also keep in mind you don't want it to be lit up when you have the key on the ACCY position (key back, as in engine not running, but radio on) I think a 10A fuse with 12 a wire is adequate... just double check the routing everywhere, make sure nothing is chafing. (keep the fuse as close to powersource as possible!!)
The run on situation is from backfeeding from the regulator back into the ignition circuit, it's an easy fix though... but not necesary if you are running an internally regulated alternator...
Do a search on this subject in the electrical forum..
As I remember my ignition wire only dumped below 12 volts (Around 9 or 10) at intitial key up "start" then a full 12 volts at running. Also, 68ragtop is right, a 12 volt source at acc is not neccessarily powered at "start".
On a 68 Camaro use the terminal on the fuse box that is labeled "IGN". It is switched with the ignition and works fine for me. Do not attach any other power wires (like the old yellow one from the starter) to the ditributor and you will not have to worry about feedback problems.
68 Camaro, 383 small block with TH350 trans. 11.98's at 111mph and never trailered.
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