FrontEngineDragsters.Org Forum
Drag Racing Discussions => Front Engine Dragsters => Topic started by: lake_harley on January 07, 2023, 08:00:59 PM
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I hope to be wiring my FED soon and want to do it right. I've read some on battery cut offs and kill switches and the required/suggested locations for either or both, but remain a bit confused (nothing new there).
I'll be running a GM HEI battery powered distributor, so killing the power to it will kill the engine. Does there need to be a main battery cable run all the way to the rear of the car and then back up to power the starter to disable the entire electrical system? Seems like all of that "hot" battery cable from in front of the engine, where the battery is located, to the back for a main disconnect/emergency kill switch is a danger in itself.
I plan to have my single wire alternator alternator wire going directly to the battery positive. If all of the power for everything else in the car goes to the back of the car with a "Push Off" main switch and goes to a junction block to power the ignition, start button, fuel pump, water pump and taillight is that OK? Pushing it "Off" would kill all power (and the engine) other than the alternator wire and the positive battery cable to the main starter lug. That main power feed (maybe 10 Ga.?) going to the "Kill" switch could be fused in the front so power would be interrupted in case it were to be shorted out on the run to the back of the car. I'm guessing it would need to run through a section of tubing where it passes the flywheel and torque converter.
I hope my rambling isn't too random to understand. Suggestions, or better yet, a wiring diagram would be helpful and appreciated. I'm not totally illiterate when it comes to electric circuits but want to be in line with what's appropriate for a mild, bracket race FED.
As always, thanks, in advance!
Lynn
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we ran a push-pull cable to the back and the switch close to the battery
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Thanks for the suggestion. I have looked into that option as well so the cut-off would be near the battery and the main battery positive cable would be as short as possible. Since I'm using a stock length Powerglide I'd guess the cable would have to be about 80" long to reach from the left rear corner of the chassis to near the battery, since the battery is just ahead of the fuel tank which is just in front of the engine. Some of the remote battery cut-offs I've seen use a rod, but with the distance and obstacles to clear along the way it would have to be a cable.
I can't help but ask though, is my plan just a bad plan in general (if it made any sense as written), or one that wouldn't pass muster in a tech inspection?
Lynn
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we had the pull knob located on a red mounting plate on the right rear part of the cage about the height of the tire the cable just followed the top frame tube
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Thanks again. I guess a push-pull cable would be as easy to route as the extra wiring I had in mind and probably simpler in the end. Typically the rear shut off should be "push off" to kill the power for easier operation in the case of it being needed in an emergency, correct?
Lynn
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Yes, tech requires the engine cutoff switch be "push to disconnect" in the case of a push/pull switch. You can orient the switch or the twist-off lever to get this action. I have had to put a stud in the end of a switch that had a thumb lever to attach the rod. Some levers are hollow. In that case in addition to tapping the lever for the stud I filled the hollow in the switch lever with JB Weld for strength.
BTW, these switches do not last forever. I have had to replace one that was giving an intermittend bad connection. Maybe using isolator grommets would have prolonged it's life?
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Thanks for the clarification and suggestion. This afternoon I abandoned my thoughts of doing some sort of electrically switched cut off and ordered a push/pull cable. I already have a manual battery cut off on hand and after thoughts of using the hollow handle to attach a cable, I decided to fabricate/machine a different steel or aluminum handle with a bit extra length for leverage to lessen the push/pull load on the cable itself.
I appreciate all of you who have offered sound advice when I'm stumped. This FED stuff is all new to me. I am thoroughly enjoying the build process and look forward to the car moving under it's own power!
Lynn
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The other reason for the cutoff switch up by the battery and using a cable is weight, and simplicity.
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Thanks for the clarification and suggestion. This afternoon I abandoned my thoughts of doing some sort of electrically switched cut off and ordered a push/pull cable. I already have a manual battery cut off on hand and after thoughts of using the hollow handle to attach a cable, I decided to fabricate/machine a different steel or aluminum handle with a bit extra length for leverage to lessen the push/pull load on the cable itself.
I appreciate all of you who have offered sound advice when I'm stumped. This FED stuff is all new to me. I am thoroughly enjoying the build process and look forward to the car moving under it's own power!
Lynn
We are rooting for you.
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On my Altered I built I put the battery in the back with a push off mechanical shut off. Then the battery cable goes to electric solenoid for a master kill switch that I can kill all power from inside my car. I turn main power on when I pull it out of trailer and use the inside switch during the day.
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On my Altered I built I put the battery in the back with a push off mechanical shut off. Then the battery cable goes to electric solenoid for a master kill switch that I can kill all power from inside my car. I turn main power on when I pull it out of trailer and use the inside switch during the day.
I do exactly the same thing.
In one instance where I hit the wall, got knocked semi conscious, momentarily lost my vision, and spun around toward the starting line at a high rate of speed the inside switch kept a lot of people standing around the starting line from being hurt. Not to mention myself.
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On my FEd I have a battery in nose, switch just in front of the engine, and push/pull will be at the rear if I get it hooked up.LOL I have got to do it and will need a switch with terminal's for mag also,