Crate Motor Wiring Questions

[mikester]

If you want juice: 1/0 wire from the alternator to battery, battery to starter, ground from battery to engine/chassis, chassis to body, etc...

Remember that the electrons flow negative to positive, so grounds should be bigger than the hot leads.

If I do that what happens to the wires feeding the OEM splice ? The 81 had both wires (output wire and the hot wire from the plug) going into the splice. I cant figure out why GM did that. Why not one or the other ?

Someone else told me to run the output to the battery. My plan was to buy the same cables I had made for the 81. Theyre 2 AWG. I did battery ground to block and a ground wire from the block to the frame. Block is grounded to the firewall. No good ?
I dont have anything extra in the system. No fans. The wagon will be the same way.

 

[pagrunt]

So, the 12 AWG is good for the 105 amp alternator output wire ? I used 12 AWG when I remade the splice on my 81 but thats only a 60 amp alternator. I ran it like the original but I took the AC feed out since I switched to heat only. I know I have to redo most of the wiring from the bulkhead to the motor and I know its not a big deal but the whole wire size/alternator/splice thing has really held me up. I only want to do this job one time.
I'll order one of the adaptors on Monday along with a new compressor pigtail.

Thanks for the info !!!

I just at random looked on Rock Auto to get an idea of what amp rated alternators were listed for a '81 MC (which I have), a '81 Caprice/Impala & found nothing near 105. Then I looked up a '86 MC & '86 Caprice since they wire harness's are basicly the same for the Circuit 2 (I parted a '86 MC with same size wires as my '81), finding a 108 amp unit for a 350 Caprice. GM being cheap, the wire used on the '86 Caprice would be the same as the '81 (both list 12 AWG for that circuit) so there shouldn't be any issues using the stocke gauge wire with that 105 amp unit. FYI, 2nd Gen Camaro's started with 10 AWG wire for that circuit with lower rated alternators to 12 AWG wire with higher rated alternators in '80.

 

[mikester]

I just at random looked on Rock Auto to get an idea of what amp rated alternators were listed for a '81 MC (which I have), a '81 Caprice/Impala & found nothing near 105. Then I looked up a '86 MC & '86 Caprice since they wire harness's are basicly the same for the Circuit 2 (I parted a '86 MC with same size wires as my '81), finding a 108 amp unit for a 350 Caprice. GM being cheap, the wire used on the '86 Caprice would be the same as the '81 (both list 12 AWG for that circuit) so there shouldn't be any issues using the stocke gauge wire with that 105 amp unit. FYI, 2nd Gen Camaro's started with 10 AWG wire for that circuit with lower rated alternators to 12 AWG wire with higher rated alternators in '80.

I guess GM uses the 105 amp alternators with the accessory set. The specs are here.

Chevy Small Block Serpentine Accessory drive with A/C

Check out the deal on Chevy Small Block Serpentine Accessory drive with A/C at GM Performance Motor

www.gmperformancemotor.com

 

[mikester]

The whole red Circuit 2 is 12 AWG on our cars. From the fusible links (16 AWG) to the main harness with the one wire, then from the links to the alternator screw post, to the main splice which leads to the alternator plug & A/C blower fan (if an A/C car), then to the main harness. If still quiestioning, check the size wire on a '91-'96 B-body or a '93-'02 F-body to compare what the used. From what I've seen on those adaptor plugs they use a 12 AWG wire for the Circuit 2 wire. If it was me I'd stick with the 12 AWG wire.

So, I ran out to two different yards this morning to find a 91-96 B body. I checked two different cars and they both had a much heavier AWG wire going from the output post directly to the positive cable on the battery. I also looked at a mid 90s CK Chevy pickup. It had the same style alternator thats on the crate motor. Heavy wire from the post to a red junction box. Couldnt tell where the wire went from there since it was a front hit.

If I delete the output wire from the OEM splice and run a piece of 8 AWG from the output directly to the starter will the 12 AWG from the two wire plug power the AC through the OEM splice ?

 

[pagrunt]

So, I ran out to two different yards this morning to find a 91-96 B body. I checked two different cars and they both had a much heavier AWG wire going from the output post directly to the positive cable on the battery. I also looked at a mid 90s CK Chevy pickup. It had the same style alternator thats on the crate motor. Heavy wire from the post to a red junction box. Couldnt tell where the wire went from there since it was a front hit.

If I delete the output wire from the OEM splice and run a piece of 8 AWG from the output directly to the starter will the 12 AWG from the two wire plug power the AC through the OEM splice ?

Just cut that wire & cover the end with something like a shrink tube or good electrical tape, everything else in the splice will be OK. I'd leave just enough of a lead in case you ever need to tap into that circuit. As for the new lead, don't forget a fuible link in the proper size (12 AWG for 8 AWG, 14 AWG for 10 AWG). Did you check the size on the B-bodies & the truck to see if it was a 8 or 10?
On my harness I'll be using a single wire weather pack end on one blower wire with a plugged mate since I'm on the fence with using either the A/C-heater or heater box at this time & want a simple plug & play set up. I'm still working on mine to simplify that circuit for the Alternator, blower, lead to the fuse box & a easy tap in for future needs on top of converting it from a V6 to V8 lenth with trying to eliminate fusible links.

 

[mikester]

Just cut that wire & cover the end with something like a shrink tube or good electrical tape, everything else in the splice will be OK. I'd leave just enough of a lead in case you ever need to tap into that circuit. As for the new lead, don't forget a fuible link in the proper size (12 AWG for 8 AWG, 14 AWG for 10 AWG). Did you check the size on the B-bodies & the truck to see if it was a 8 or 10?
On my harness I'll be using a single wire weather pack end on one blower wire with a plugged mate since I'm on the fence with using either the A/C-heater or heater box at this time & want a simple plug & play set up. I'm still working on mine to simplify that circuit for the Alternator, blower, lead to the fuse box & a easy tap in for future needs on top of converting it from a V6 to V8 lenth with trying to eliminate fusible links.

I wont be cutting the wire and leaving it due to the fact I have to change the harness from the right side to the left. Its all going to be redone with new from the bulkhead connection out. Thats why I only want to do it once.
I have some link wire. I think I have to buy some 12 AWG though. Not a big deal since the auto parts that sells it is only 35 minutes away. To be honest it looked like the wire coming off the output post was even larger. Maybe 6 AWG. I was actually surprised by the thickness. The one on the B body was the same way. The terminal for the side post battery had the two wires stuffed into it.
I appreciate the info. I really didnt think this was going to be such a pain in the butt.

One good thing. I found the small solid AC line that I'll be needing. I might grab the two that they have out in the yard. One is straight and the other has a loop towards the end by the condensor. See which one fits the best. I also found some rally clean copper ground straps. They clean up nice with a SS wire brush.

 

[mikester]

Started messing with the harness today. Made the two fusible link wires. Sandblasted and painted some loom clips. 8AWG from the alternator output and 12AWG to the bulkhead. Tomorrow I might have time to tear into the factory splice. Cant wait. LOL

The old.



And the new.