Author Topic: M unit wiring  (Read 1687 times)

0 Members and 1 Guest are viewing this topic.

Offline Bastaldo

  • Full Member
  • *
  • Posts: 37
M unit wiring
« on: March 13, 2020, 02:49:10 PM »
I searched the forums and tons of great info but still a little confused.

Does the return wire from the R/R (the red one that charges the batter) go back into the m unit’s power supply (the bolt at the bottom right) or does it  bypass the m unit all together and get attached to the wire that goes straight to the batter (with a main fuse).

Also, can the ground wire go to the frame or does that need to be grounded somewhere specific.

Thanks!

Offline calj737

  • Moderator
  • Really Old Timer ...
  • *****
  • Posts: 21,070
  • I refuse...
Re: M unit wiring
« Reply #1 on: March 13, 2020, 02:53:33 PM »
My approach to it.
'74 550 Build http://forums.sohc4.net/index.php?topic=126401.0
'73 500 Build http://forums.sohc4.net/index.php?topic=132935.0

"Of all tyrannies, a tyranny sincerely exercised for the good of it's victim may be the most oppressive. It may be better to live under robber barons than under omnipotent moral busybodies. The robber baron's cruelty may sometimes sleep, his cupidity may at some point be satiated, but those who torment us for our own good will torment us without end for they do so with the approval of their own conscience." - C.S. Lewis

Offline Bastaldo

  • Full Member
  • *
  • Posts: 37
Re: M unit wiring
« Reply #2 on: March 13, 2020, 03:11:49 PM »
Your approach is to bypass the m-unit and splice the return wire into the power wire?

Offline Jnel

  • Hot Shot
  • ***
  • Posts: 296
Re: M unit wiring
« Reply #3 on: April 07, 2020, 04:16:14 PM »
I did this up to help get me thru the Wiring process.   I needed something to keep me keep stuff organized a d i think this is easy to follow compared to some othets I've seen.

Good luck

Jnel

Sent from my SM-N950U using Tapatalk


Offline guamjake

  • Full Member
  • *
  • Posts: 25
Re: M unit wiring
« Reply #4 on: April 12, 2020, 12:08:00 PM »
What is the best way to "piggyback" the wiring, so say if I need a 1 amp fuse for my m lock and also a 1 amp fuse for my gauge and I want to just have both these coming from the same 1 amp fuse, do I take 2 wires coming out of that 1 amp fuse or do I split the 1 wire coming out of the 1 amp fuse somehow into 2 wires?

 Another example of this is from AUX you run 1 wire to both coils, what is the best way to run the wire then have it split?

Offline calj737

  • Moderator
  • Really Old Timer ...
  • *****
  • Posts: 21,070
  • I refuse...
Re: M unit wiring
« Reply #5 on: April 12, 2020, 02:54:27 PM »
You don’t want two devices that each draw 1 amp of protection behind the same fuse. That defeats the purpose.

Run a single wire to one coil, then run a jumper to the other coil.
'74 550 Build http://forums.sohc4.net/index.php?topic=126401.0
'73 500 Build http://forums.sohc4.net/index.php?topic=132935.0

"Of all tyrannies, a tyranny sincerely exercised for the good of it's victim may be the most oppressive. It may be better to live under robber barons than under omnipotent moral busybodies. The robber baron's cruelty may sometimes sleep, his cupidity may at some point be satiated, but those who torment us for our own good will torment us without end for they do so with the approval of their own conscience." - C.S. Lewis

Offline guamjake

  • Full Member
  • *
  • Posts: 25
Re: M unit wiring
« Reply #6 on: April 13, 2020, 07:06:55 AM »
Thanks, calj

I somewhat figured the first example wasn't the best.

I guess the meat of my question is what is the best way to "jumper" these wires? What type of connector?
I found the Tifco 44294 connector seems to be a good option and they make it for several different gauges of wire, what would you recommend?

Offline calj737

  • Moderator
  • Really Old Timer ...
  • *****
  • Posts: 21,070
  • I refuse...
Re: M unit wiring
« Reply #7 on: April 13, 2020, 07:58:48 AM »
Not my preference. I use simple Molex-type self locking connectors. For powering 2 devices from a single run, get a 2-way. From source to one pin, jumper to other side of the same connector. On the mating connector, run 1 separate line to each of the 2 locations.

For the coil jumper, I use a ring terminal and wind the jumper lead to the end of the wire for crimping inside the ring terminal. You only need 18AWG wire here, so you can use a 16AWG ring for the doubled wire, a proper 18 for the jumpered lead to the opposite coil.
« Last Edit: April 13, 2020, 08:00:27 AM by calj737 »
'74 550 Build http://forums.sohc4.net/index.php?topic=126401.0
'73 500 Build http://forums.sohc4.net/index.php?topic=132935.0

"Of all tyrannies, a tyranny sincerely exercised for the good of it's victim may be the most oppressive. It may be better to live under robber barons than under omnipotent moral busybodies. The robber baron's cruelty may sometimes sleep, his cupidity may at some point be satiated, but those who torment us for our own good will torment us without end for they do so with the approval of their own conscience." - C.S. Lewis