Fusible link questions

[saylor]

they got em at vatozone you coulda already been driving by now lol.

you need th 14ga and 16ga. just throw the book in the corner and trust us heh.

try not to die -

- saylor

 

[Jeff]

That's what I'll do until I can find an original.

 

[Big_John]

Let me repeat, the size of the fusible link is determined by the wire it is protecting. The capacity of the battery or the power of the alternator is NOT RELEVANT!

Ahh... Common sense being applied.

 

[Fury440]

I didn't disagree or ignore what you said. It's just that the NOS parts and the parts manual don't identify the gauge. I think I need a # 14 fusible link, but that information is not given for the parts. How do you know if the one pictured is a 12 or a 14? My guess is part number 2889419 is a 14 and part number 2822692 is a 12. That's why I said I should avoid 2822692.

The Fury one is 2889 419 and it's #14 gauge, red with a white stripe and has male connectors at both ends. If you look at the engine compartment wiring diagrams for the other '70 cars an interesting point pops up.

All except the Fury have a #10 wire from the battery to the B terminal of the starter relay. Also fed from the B terminal is a #16 gauge fusible link with an eyelet on one end and a male connector on the other end into which a #10 gauge wire is connected. This is the main battery feed to the car. Note the #10 gauge between the battery and the starter relay is not protected and any short between the B terminal and the starter solenoid will smoke the wiring back to the battery. The #16 fusible link is dark blue.

The Fury has an upgraded wiring design, the fusible link is between the battery and the starter relay B terminal so that all the wiring is protected. For some reason, possible ease of replacement, thy used plug in connectors at both ends. They also moved from #16 to #14 to handle the extra load added when the starter solenoid is engaged. The #14 fusible link is red with a white stripe.

Does that help?

 

[tbm3fan]

It is 14 gauge as my original had that printed on it. My end connectors probably started out as white plastic and then became yellow and brittle. Never could replicate those when replacing the battery cable that had been amended by the previous owner.

 

[MrMoparCHP]

This is what I have, typical 69 c-body

This is what I need

part number 2926475

Alan

 

[Fury440]

part number 2926475

I see 2889 419, where do you see 2926 475 ??

 

[Fishfan]

A word about fusible links. A fusible link does not protect individual loads, it protects the wire it's wired into. The fusible link is not rated in amps like a fuse, it's rated for the wire gauge being protected. Basically it's a short piece of wire one or two gauge size smaller than the wire being protected. When the amps get high enough to damage or set fire to your wiring harness, the link burns and breaks the circuit. The jacket on the fusible link is rated for high temp so when the link burns out, the jacket still protects the car. Your circuit diagram shows the power feed to be a Red #10 and it shows the fusible link to a #14 which is two gauges smaller than #10. When you buy your fusible link, buy two, one for the car and one for the glove box.

Hope all this makes sense.

Best explanation I have seen on this topic.

 

[Jeff]

This is what I need
View attachment 144431

View attachment 144432

It looks like we are looking for the same thing then. Hiltop Auto Parts has one for $50. I'm not going to pay that much. NOS Mopar Fusible Link Cable 1968-70 C Body With 60 & 65 Amp Alternator - Hiltop Auto Parts

 

[Jeff]

Let me repeat, the size of the fusible link is determined by the wire it is protecting.

It seems a bit more complicated than this (as you've explained in your other postings). It's not completely determined by the wire that is directly connected to the fusible link. For instance, if I upgraded the wire from the battery to the starter relay to 8 gauge, I don't think that would mean I should use a 12 gauge fusible link because the fusible link is protecting more than just the immediate wire.

 

[Fury440]

It seems a bit more complicated than this (as you've explained in your other postings). It's not completely determined by the wire that is directly connected to the fusible link. For instance, if I upgraded the wire from the battery to the starter relay to 8 gauge, I don't think that would mean I should use a 12 gauge fusible link because the fusible link is protecting more than just the immediate wire.

True.
You will find Ma Mopar ran a #10 from the battery, to the starter relay, to the fuse box, and finally to the ammeter. The other side of the ammeter has a #10 connected to the alternator via the bulkhead connector. Everything electric in the car feeds from this #10 bus. The alternator charges the battery via this #10 route. If the bulkhead connector gets dirty, loose or corroded at either of the two terminals used the whole electrical system goes nuts. Mine did years ago, the battery kept going flat and I chased my tail trying to figure it out. It wasn't until I pulled the front sheet metal off that I discovered the bulkhead connector and that I had been very close to a melt down. Note the fusible link didn't see a problem, it was just the bulkhead and fuse box that were close to flames.

That got me curious so I made a simple wiring diagram.

Nothing complicated.

 

[Big_John]

That got me curious so I made a simple wiring diagram.

View attachment 144542

Nothing complicated.

This is great.

I think lots of folks don't understand the basic wiring of our cars. This simplified drawing explains it very well.

Ever think of doing similar simplified drawings of other systems?

 

[MrMoparCHP]

I see 2889 419, where do you see 2926 475 ??

Oops, the red 2889419 is what I need
The blue NOS 2926475 is the one I do not need.

I have the red one in the picture but I'm looking for a near perfect one or NOS


Alan

 

[Fury440]

Ever think of doing similar simplified drawings of other systems?

While figuring out a new system, I generally make a pencil sketch with just the basics as an aid to my understanding. Most of the time I don't keep them since I now understand the circuit and don't need the notes anymore. Sometimes I need to clean a sketch up and scan it for someone else. Those scans live on in my computer.
The simplified diag I posted here was made about 10 years ago when there was a discussion on the drydock about how the power was routed through the bulkhead and where the ammeter lived.

 

[Jeff]

Garden hose gone. Gas tank is out so can't fire it up. It will be interesting to see if it blows on the first charge. Had to be a reason for that hose.

 

[Big_John]

It's time for a new battery cable. There's a smashed spot and the temporary terminal has seen better days.

 

[Jeff]

It's time for a new battery cable. There's a smashed spot and the temporary terminal has seen better days.

Yes, it's on the list. I'm in triage mode ATM. BTW, the terminal is just sitting there for the pic. It fits better than that. It's off right now because of the tank work.

 

[Gerald Morris]

Do as I do. Buy yourself a small SPOOL of fusible link wire in the size(s) you need. I use #12 with my 60A alternator, which I've wired in #8 AWG from the alternator charging post to the fusible link, cut to 6" under insulation, + an additional .5" stripped at each end for termination. I use a split bolt to attach the #8 to the fusible link, which is snugged down firmly to the universal terminal along with the starter wire and the fusible link going to the #8 leading to the starter relay, then the dashboard. Each split bolt connection is first rubber taped, then vinyl taped and finally friction taped over for mechanical strength. This is the standard procedure for taping split bolt terminals BTW. Mine are bronze. I pay about $5.50 for 12 feet of fusuble link #12 AWG for that #8 wire I run the 60A circuit in. This accomodates charging and ALL of Mathilda's electrical loads aside from the starter.

NO NOS ripoff prices!

NO headaches from searching all over Creation for the original termination links!

ALL mine are 7" total length, w 8" insulation. I use 1/4" ring terminals to attach the links to the battery terminal. Its the best spot for them. When I've had short circuits, the links melt nicely, protecting the alternator AND the dashboard circuits, starter and horn relays, et cetera, and I can replace them quickly, easily and be back on my way. After a NASTY fire resulting from my alternator stud shorting when the case cracked last spring, I made damned sure my main power circuits were WELL protected.

Of course, my wiring won't pass muster with purists for being like the original stuff, but Mathilda is a daily driver, NOT a bauble.

 

[Fury440]

Of course, my wiring won't pass muster with purists for being like the original stuff, but Mathilda is a daily driver, NOT a bauble.

Absolutely the way it should be. You ever notice that the purists very seldom own what they judge.

 

[Gerald Morris]

Right on! Yes, the purists mostly would rather snatch up whats left of our Golden Iron Age rides, put 'em in sealed garages filled w inert atmospheres, make them all PURE ORIGINAL and DEPRIVE POOR WORKING FOLK OF THEIR USE. Heaven help us and guard us from the Puristas. Folks LOVE Mathilda, complete w the baby seat in the back, as this shows everyone a WORKING EXAMPLE OF WHAT DETROIT ONCE DID FOR THE COMMON FOLK! Now, they spread eagle us over a barrel, then .....(omitted for decent readers.)