Problem after install new dizzy cap
 

Hey guys, I installed a new cap and rotor (MSD) yesterday, truck ran better than I expected. Well today the company truck broke down on me (powerjoke). I had the wife take me back to the house and got the 75 so I could meet the tow truck driver, fired the truck up idled great backed out to the street, no problem, went about a block and the truck died. Soon as I stopped there was no electrical power in the truck. I could smell something burnt found my in line fuse on the fire wall blown haven't got the cap of yet to look in there, any one have any ideas. Thanks!
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Re: Problem after install new dizzy cap
 

the ones down by the starter u talking about.

Re: Problem after install new dizzy cap
 

make sure nothing is hitting or real close to the exhaust manifolds.. years back i had a truck (f250) that there was a condensor on the back of the distributor that would short out once the truck got hot..once i changed the fusible links it worked fine until it got hot again

Re: Problem after install new dizzy cap
 

Got home and pulled the cap and rotor. Nothing looks like is burn. I can't smell anything burnt either. Coil looks good. Guess tomorrow when I have more time I will put it back together and see what happens
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Re: Problem after install new dizzy cap
 

Got some free time this morning. Looks like the ahole that installed the engine for my grandad got lazy, he didn't put the wires back in the metal tube and left them loose on the back of the block. He had them zip tied to the plug wires. I remember hearing something like a zip tie braking when I was pulling plug wires. It popped both fuse able links and melted most of the wire. Looks like I am going to build a new wire harness for it. Does anyone know what amp the fuse able links are? Thanks!
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Re: Problem after install new dizzy cap
 

All i did was re ran the wires to the fender on the drive side and mounted a fuse box. ran the alt. to it instead of the juntion on the fire wall. those two wires feed the fuse panel. heres a pic of wht mine looks like. my alt. go in to that then down to my battery iso. i have two battery. the i hook up the two wires. i just test the truck with different fuse untill i found one that would work. you can see in the othere pic that the juction box just has two wire, one for my heater and the unhood light.

Re: Problem after install new dizzy cap
 

Fusible links should be 4 wire gauge sizes smaller than the wire they're protecting.

I believe the wires you're dealing with in that area will be either 12 or 10 gauge from the factory. So use a 14 ga fusible link wire if it's 10 ga wire. Or a 16 ga fusible link if it's 12 ga wire.

Note that the location is important too ... don't be tempted to re-locate the fusible links up on the other end of the wire where they'll be easier to reach. They need to be on the "source end" of the wire for best protection. Otherwise it leaves a section of wire unprotected ... a potential fire hazard if it ever shorted out again in that area.

Here's some additional info on fusible links you might find helpful --> http://www.madelectrical.com/catalog/fusible-link.shtml

Re: Problem after install new dizzy cap
 

Thanks for the replies. I'm glad you mentioned the location for the fuse. I was going to put it up top. Didn't even think about putting it close to the source. The link has some good info as well
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Re: Problem after install new dizzy cap
 

The main feed wire is 10AWG red wire running from the Junction block on the firewall to the starter. The burnt Fusible link was 14AWG right at the starter.

You'll need
a solder gun,
electronics wire flux,
electronics grade rosin core solder,
14AWG 3/8"& 10AWG 1/4" uninsulated ring terminals,
approximately 6" of 14AWG fusible link wire (should be the same length as the burnt link),
and several feet of Red 10AWG primary wire.

The studs on the starter and junction block are made of copper, not steel, so tighten them carefully.

This is a really good how-to writeup on building fusible links.

If the Purple start wire is damaged I'd solder and heatshrink a repair. A replacement ring terminal should fit a SAE #8 stud and the Purple wire is 12AWG.

I'll probably get the '75 wiring diagrams posted up this evening.