Bass Ackwards?

R

Relvis P. Johnson

Member
When I put the upper distributor plate into the distributor body it shorts out and blows the main fuse. Why would the whole upper plate be charged? Is there supposed to be an insulated washer on the pigtail connecting to the points?
 
If the car is stock with original wiring a short in the dist shoud not be able to blow a fuse unless the coil is shorted too.
 
Good points...

I've added the fuse down by the starter kit.

An insulated washer was located and installed.

Converted to 12 volts, positive ground, negative side of the coil on the curbside terminal box, positive side connected to the street side.

The aftermarket key switch is connected to the street side terminal on the fire wall box on one side and the other side to the distributor,

The fuse blows.

I'm con-fused...
 
Your switch is hooked up to supply a hot wire to the Nu-rex you had. The stock
distributor need the switch hooked up to a ground. Look at the schematic that
was posted in one of your other threads.

Bob
 
Is there supposed to be an insulated washer on the pigtail connecting to the points? No.
When the points are closed Ground is provided to the Ignition Coil due to the upper plate being grounded to the Distributor Body.
If the fuse blows as you say, there is something wrong with the wiring. Make sure the wiring is exactly as the wiring diagram shows.
Voltage is applied to the Ignition Coil on the (-) terminal and passes through the Primary Coil to the (+) terminal. From there the Voltage is routed to the Ignition Switch. When the Ignition Switch closes Voltage is routed to the Ignition Points on the Movable Contact in the Distributor. If the points are OPEN Voltage stops there, The Stationary Point is at Ground potential because it is attached to the Distributor Plate.. When the points close the Voltage goes to Ground completing the circuit to the coil so that a spark can occur from the output of the Secondary Coil.
So, if wired correctly the Ignition Coil is a Resistor in the circuit and drops the Voltage when the points close. This Resistor is what prevents the fuse from blowing.
Clear as mud!
 
Thanks for your reply.

No way to take pictures currently, I'll see about some help with that.

The nu-rex hot side of the key was on the street side firewall terminal, now its on the curbside...
 
Bob,

You're right. The nu-rex was a hassle and barely would advance. The new motor runs like crap. Better to go back to stock.

There is one distributor wire, connect it to the key switch, then attach the other side of the key switch to?
 
There is one distributor wire, connect it to the key switch, then attach the other side of the key switch to?The coil.

The other coil terminal is connected to the terminal box, the coil is hot all the
time in the stock system, the switch controls the ground.

Bob

 
Relvis P. Johnson said:
Thanks for your reply.

No way to take pictures currently, I'll see about some help with that.

The nu-rex hot side of the key was on the street side firewall terminal, now its on the curbside...
Click to expand...

You corrected the first mistake by making a second mistake. As mentioned the key switch does NOT go to either terminal box post. You mentioned that you have POSITIVE ground at the battery, so the key switch goes to the + on the coil. And the other key switch terminal goes to the points.
 
Thanks Bob & Tom,

I'm rather new to all of this, so I really appriciate your help.

I didn't think it made a diference which side of the coil wire it was connected to, I just thought it was a cleaner installation if I put the lead at the junction box end. Another incorrect correction.

I'll make the change and give it a go.

Thanks again...
 
I made the change and still blow the fuse.

Everything worked fine before except the nu-rex didn't seem like it would advance. All I did was try to re-install the stock distributor, which continues to short out. The schematic in the thread is hard for me to read. The terminal block is sideways. So which way do I rotate the page? it does not show the + or - on the coil. It looks to me like the red and black wire is on the same terminal on the junction block. Is there a simple drawing available?
 
This over simplified schematic may help. Don't worry right now about the coil + -.
I'm almost sure you still have the switch hooked up to a hot wire.

Bob
 

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In Bob C's drawing, IF the coil (primary) has a direct short internally (i.e. between the - terminal and + terminal), with the switch ON, it will blow the fuse when the distributor plate touches ground with the points closed.
 
Now there is a drawing I can comprehend! I'm set up like Bob's drawing, points are closed and the top plate is charged. If I put it in the body, the fuse blows...
 
From my previous post.
"So, if wired correctly the Ignition Coil is a "Resistor" in the circuit and drops the Voltage when the points close. This "Resistor" is what prevents the fuse from blowing."

This is the key element here:
""""This "Resistor" is what prevents the fuse from blowing.""""
In Bob C's circuit the ONLY element that can blow the fuse is the coil. It would have to be shorted internally.
Try another coil.

One other comment is the fuse rated properly, 20 or 30amp?
 
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