Re: {Chrysler 300} Bulkhead Wires, over heating issues, typical of 1960's MOPAR -Wonky technical discussion.

[John Grady <jkg@xxxxxxxxxxxxxxxxx>]

Hi on this two comments ,
First the problem is not usually the wires , although they would be marginal with a larger alternator on AC car just as Danny says . More in a second on that .
The problem is the 1/4 flag terminals are really 20-25 A devices in the bulkhead connector and they will get warm occasionally under heavy loads and lose their spring tension over the years . Bad design to overload those as they did.  Then resistance goes up , they oxidize and corrode  and then they get really hot and even melt the bulkhead locally . That leads to total failure .
All mopar have this issue through 70’s especially dodge trucks and even Darts. 
Heater / AC fuse clip too does same thing . Jumping that fuse behind fuse block with modern 30 A blade fuse from ACC feed at block to output wire is a good idea . Always solder , crimps are problems on high current , never use those blue insulation cutters . 

So the cure for bulkhead is to cut the 2 (4) wires  flush with the bulkhead connector on each side , solder on one of same gauge under hood and drill firewall for a rubber grommet next to bulkhead pass them thru and solder other side . Insulate joints neatly made with 3/8 shrink tube . 
You can parallel both with another 12 , that is plenty of capacity but don’t go crazy trying to make it look stock . Use black THHN building wire tie neatly with small tie wraps . Using Tape makes a big sticky mess with the  heat under hood . As Dan said you need not run to ammeter just from alt post to starter relay  but that will cause ammeter to read about 1/2 amps . Still reasonable to do . Trying to get #  8 or # 10 wires onto ammeter can be a party . The current will divide equally between two # 12 in parallel if bulkhead thing is fixed  

The second problem is amp gauge . The nuts get loose as there is phenolic insulation in the pile  up where studs go into ammeter . If this nut gets loose as phenolic shrinks it all burns up . So remove all wires and tighten really securely the first nuts against the phenolic , KL lock nuts and small washers to spread out clamp area might be good . Be careful of shorts etc , Ammeters vary . 

On fuses that is not where to fuse . You can add a 50 A super fuse in the heavy lead right at the starter relay , that wire powers the whole car ; —-another way is a fusible link ( Fords have them / napa ) , They come in two gauges , probably Ford AC car or not , or Lincoln . Get the heavier one . One end fits stud other end has crimp ferrule . Critically important to crimp right with tool that crimps a line along the wire , not cheap tool that flattens it ( T and B Tool) usually orange and black . If two 12 you have to solder so only one 12 goes into ferrule or improvise . 

What it is ,is a special thinned wire that  gets a little hot normally , but has special silicone insulation good for maybe 600 F . If a short anywhere in main charge circuit , ignition switch etc ( or rest of car wiring  before the item fuses) it is a thin place , and will melt first protecting main larger wires. 

While on this , twice I have seen destroyed 300 F and G harness where the main feed to power windows seat etc breakers passes though the large  stamped sheet metal hole  at top of drivers kick panel . Wire rests on sharp stamped edge wears through , = horror show . Slit a small rubber hose lengthwise and place over that wire , or use that “wind on “ nylon stuff 
Hope this helps , 
John 

Sent from my iPhone

> On Nov 16, 2022, at 9:51 AM, Dan Plotkin <dplotkin@xxxxxxxxxxxxxxxxxxx> wrote:
> Subject to what John says I say you are chasing far too much complication. Among troubles I’ve seen along these lines is when a high capacity alternator is installed, a fresh healthy battery is installed and allowed to go stone dead after leaving lights on. When the car is jumped and

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