Wiring my starter - Ron Francis Harness

[wisel1]

Hello All. I have what may seem like an obvious question. I am wiring the starter (MSD 5090) an noticed a number of connections - I have 5 lines to the starter:

Blue ignition - to solenoid

And 4 to the main terminal

Main Battery cable to Starter (seperate wire from rear)
Red Battery feed to fusebox
Red alternator feed
Red Ignition

I am having a tough time fitting 4 terminals on the starter connector especially with the lock washer. My question is can any of these wires go to the other terminal or directly to the solenoid (prob not) or should I just eliminate the washer. Or is there an alternative routing for any of the wires or other suggestions regarding getting these connected? thanks

[DaveS53]

It's common to install a separate power distribution stud or firewall pass-through stud in a convenient location, so only the main power cable and the alternator feed land at the large terminal on the starter.


http://www.ronfrancis.com/products.asp?dept=37

[edwardb]

Hello All. I have what may seem like an obvious question. I am wiring the starter (MSD 5090) an noticed a number of connections - I have 5 lines to the starter:

Blue ignition - to solenoid

And 4 to the main terminal

Main Battery cable to Starter (seperate wire from rear)
Red Battery feed to fusebox
Red alternator feed
Red Ignition

I am having a tough time fitting 4 terminals on the starter connector especially with the lock washer. My question is can any of these wires go to the other terminal or directly to the solenoid (prob not) or should I just eliminate the washer. Or is there an alternative routing for any of the wires or other suggestions regarding getting these connected? thanks

Amazing how frequently this question comes up. There are several alternatives. All involve not taking all those wires to the starter solenoid. The harness leg label and the schematic in the instruction manual both say "starter solenoid." A much better description would be "firewall solenoid." For many years, and maybe even still (I haven't looked lately) the build instructions showed a separate firewall mounted solenoid and this is where those wires are intended to go. Some still use it, but with the now nearly standard starter with integrated solenoid, no longer necessary. Some type of binding post, bus bar, or even master disconnect on the firewall can be used instead to gather the wires. The only thing you need to your starter are (1) battery connection to the large terminal, (2) blue start solenoid to the small terminal. Also a ground strap through one of the mounting bolts to the frame is highly recommended.

[broku518]

Wow, I am dealing with the same thing. My solenoid screw seems to be very 'busy' :)

I am thinking about installing terminal block somewhere on firewall. Would it be an issue to install one in engine bay? (picture would help)
I am just trying to avoid to install it on other other side and then run it back in engine bay again.

Thanks,
Martin

[phileas_fogg]

This thread http://thefactoryfiveforum.com/showthread.php?26822-Looking-for-a-cleaner-way-to-run-the-starter-and-main-power-leads&p=306323#post306323 has a ton of pictures, and an ingenious solution from Big Blocker.


John

[broku518]

This thread http://thefactoryfiveforum.com/showthread.php?26822-Looking-for-a-cleaner-way-to-run-the-starter-and-main-power-leads&p=306323#post306323 has a ton of pictures, and an ingenious solution from Big Blocker.


John

Thanks John!

[wisel1]

I knew others must be dealing with this - thanks for the feedback. I am going to go with the power junction block from Ron Francis that DaveS53 pointed out. It seems like the easiest solution - main battery line direct to starter (as that's the largest draw), 10g wire from starter up to block mounted on firewall, fuse box supply and ignition to small terminals, and and then out to alternator using the other large terminal. Anyone see any issues with that? BTW, factory five should change the instructions to show a remote hookup.

[phileas_fogg]

Make sure the wire gauge from your junction block to your alternator is sized correctly, and that the junction block is able to handle your alternator's max current. If the run from the junction block to a 100A alternator exceeds 6', you're going to need 4AWG wire!

http://www.allfordmustangs.com/forums/attachments/audio-video-navigation-alarms/62425d1235669252-wire-gauge-ampacity-table-wiringdiagram.jpg


John

[wisel1]

Hi John - thanks for the heads up. I am doing a straight line from the junction block (mounted on the firewall accross the valve cover (nice chrome clip) to the alternator (maybe 3 to 4 ft max). Was going to use the supplied line from the Francis harness (the one that went from Alternator to Starter). My run is shorter than the length of that wire. Also, do you see any issues running the battery supply to the junction block directly and block to starter? Its cleaner than going directly to starter and coming back to the block. thanks.

[phileas_fogg]

If I understand you correctly, at start the full cold cranking amps of the battery would go through your junction box and then to the starter. I have no solid data to say whether this is asking for trouble, but my gut tells me to err on the side of conservativism. IF you used a single terminal on the junction box to connect battery to starter you'd PROBABLY be OK...maybe. On my build, I went from battery to starter, then had a jumper from the starter post to a power stud, and then connected stuff, including the alternator, to the power post.

If anyone with real expertise can shed a dose of cold hard reality, I'm sure we'd both like to hear it.


John

[Papa]

If I understand you correctly, at start the full cold cranking amps of the battery would go through your junction box and then to the starter. I have no solid data to say whether this is asking for trouble, but my gut tells me to err on the side of conservativism. IF you used a single terminal on the junction box to connect battery to starter you'd PROBABLY be OK...maybe. On my build, I went from battery to starter, then had a jumper from the starter post to a power stud, and then connected stuff, including the alternator, to the power post.

If anyone with real expertise can shed a dose of cold hard reality, I'm sure we'd both like to hear it.


John

I did the same and routed all the power leads back inside the car and installed a buss bar to distribute power. It's documented in my build thread starting on post #335. http://thefactoryfiveforum.com/showthread.php?24916-Papa-s-MKIV-Roadster-Build-9115-(We-have-first-start!)&p=306293&viewfull=1#post306293

[DaveS53]

As long as each cable has a properly sized and crimped or soldered terminal end, it should make no difference if the main battery cable goes to a power distribution stud first. All you're doing is bolting together several terminal ends. My car is set up this way. With a fiberglass firewall, I just have a 3/8" brass bolt and washers, routed through the firewall. I have a large 1/0 main cable, terminated inside the firewall, along with an 8 gage wire to a GM fuse box, then a short 1/0 cable on the engine side of the firewall, to the starter. I also routed another 1/0 ground cable directly from the battery to the engine block, rather than using the frame as a ground. To ground the frame, I soldered a brass washer to the frame and bolted another short cable from the battery to the frame. Rust won't be a problem.

The Ron Francis distribution block is rated for 250 amps, if you need to connect more cables.

[wisel1]

I am going to to the same stud on distribution block for cold crank and feed to starter so I think I am good. thanks for all the advice - this forum is a life saver.

Best,

Rob

[Richard Oben]

That and the cables are too short.... We ran the main power from the battery to the starter, we extended the blue wire to the starter. We then ran a battery cable to a power terminal in the engine bay that feeds the RF and other stuff we have, CCRM, ABS etc. This way starter has full power. Just another idea. Richard.