Starter Solenoid x 2 SBC ??

[seaduck66]

I'm in the process of putting a new harness in my resto/mod and hope someone can shed some light on this. The vehicle is a 76 40 that I have put a rebuilt SBC in . The PO had a SBC in it as well. Before the tear down and old SBC removal I took lots of pictures and notes. When I was wiring up the motor group this week I ran the IGN (purple wire) and BAT (red wire) to the 2 different small post on the starter and the battery cables to the applicable post on the starter and ALT bracket. To me seems straight forward. When I hooked the battery up the engine stated turning over....Keep in mind I have done nothing with the ignition group yet. So I went back and started looking and remembered that the PO had used a second solenoid mounted to the fender with the battery cables and BAT, IGN wiring. Looks similiar to a Ford set up... Below is a picture of the old set up. Does anybody know why this would be necessary on a SBC set up??? I'm also running EFI Edelbrock and a HEI distributor on the new setup. Thanks for any ideas.

 

[Bret]

Try disconnecting the batt wire from the solenoid. I thought the ignition wire provided 12V to the solenoid to engage the starter. It is possible the 12V you have connected the the small terminal on the solenoid may be grounding through your ignition switch while it is off causing the motor to turn over. The batt connector you have going to the solenoid may actually go the battery side terminal on the large stud to provide power for some other item.

Have you tried putting the IGN on one side of the solenoid and tie the other side to ground? (for the small terminals of course). Do you have a multi-meter?

 

[60fj25]

Are you using the same starter as was on the previous engine? If so it probably has a shunt or wire across the terminals. If you apply 12 volts to the bat terminal on the starter it will spin. When using an external solenoid you hook up the bat wire to it and the ignition wire and only a large wire coming from the fender mounted solenoid to the starter mounted solenoid. It was done because some SBC conversions overheat the starter mounted solenoid.

 

[seaduck66]

Have you tried putting the IGN on one side of the solenoid and tie the other side to ground? (for the small terminals of course). Do you have a multi-meter?

No I have not tried this but will give it a try. Yes to the multi-meter. Thanks for the suggestion!

Are you using the same starter as was on the previous engine? If so it probably has a shunt or wire across the terminals. If you apply 12 volts to the bat terminal on the starter it will spin. When using an external solenoid you hook up the bat wire to it and the ignition wire and only a large wire coming from the fender mounted solenoid to the starter mounted solenoid. It was done because some SBC conversions overheat the starter mounted solenoid

Yes it is the same starter as on the old engine. Thanks also for the ideas. I was not sure why the 2 solenoids. I had not heard aabout the heating problem. Makes since. I'll let you know what I find,
Thanks!!

 

[60fj25]

Run a large guage battery style cable from the output side of the fender mounted solenoid to the bat side of the starter mounted solenoid. There should be a smaller wire or solid piece of shaped metal going betwen that terminal and the smaller terminal on the other side of the starter mounted solenoid.

Run your positive battery cable to the bat side of the fender mounter solenoid and your ignition wire to the other side. (or to test, just jump bat to the other side. the starter should now spin.)

 

[fieldsken1]

we do that on the race cars all the time. you dont need it just bypass it run wire from battery to starter then run ingition wire to starter thats all you need

 

[60fj25]

we do that on the race cars all the time. you dont need it just bypass it run wire from battery to starter then run ingition wire to starter thats all you need

agree, but he needs to remove the wire connecting the bat and ign posts on the starter based solenoid. It sounds like it is still there otherwise just putting bat to the solenoid shouldn't make it spin

 

[Plowboy]

I'm in the process of putting a new harness in my resto/mod and hope someone can shed some light on this. The vehicle is a 76 40 that I have put a rebuilt SBC in . The PO had a SBC in it as well. Before the tear down and old SBC removal I took lots of pictures and notes. When I was wiring up the motor group this week I ran the IGN (purple wire) and BAT (red wire) to the 2 different small post on the starter and the battery cables to the applicable post on the starter and ALT bracket. To me seems straight forward. When I hooked the battery up the engine stated turning over....Keep in mind I have done nothing with the ignition group yet. So I went back and started looking and remembered that the PO had used a second solenoid mounted to the fender with the battery cables and BAT, IGN wiring. Looks similiar to a Ford set up... Below is a picture of the old set up. Does anybody know why this would be necessary on a SBC set up??? I'm also running EFI Edelbrock and a HEI distributor on the new setup. Thanks for any ideas.

When you hooked up the two small posts, according to what you wrote, you have the wires backwards. The ign wire goes on the inside post. The outside post is a coil bypass and only used when the solinoid is engaged. You do not need the outside small post. The "ford" solinoid is used to keep the amps to the starter high. The small ign wire and hot solinoid causes a slow starter. Normally the aux solinoid is a single small post (start). A #6 is run down to the large post on the solinoid. A #10 is run from the large post over to the inside small. Every thing works when you charge the "ford" solinoid.

 

[seaduck66]

Thanks to all for the great input on this. Tonight I got the ignition hooked up and the solenoid issue resolved. I turned the key and the engine turned over for the 1st time in this vehicle. That was a good feeling since I have been working on this restomod for 2 years. After doing some research and going on what some of you said about heat I decided to go with the twin solenoids. Here is the final setup with the maxi fuse mounted next to the remote solenoid.

 

[Chula Vista 71 FJ40]

Just wanted to say thanks to you guys for the wiring diagram pix-

Did this mod yesterday and had the same issue with continuous turnover read this post re-wired and works like a champ.

THANKS-