nightshiftbbs

72 / 350 / 2bbl coil on top of distributor

I was enjoying a nice time bombing around town and she just up and quit on me. At first I thought I ran out of gas because I occasionally have too much fun and forget to check but... well after a flatbed ride home I found I'm getting no spark to the plugs but I'm not sure of the right place to check the power to/from that coil and distributor. (It's been a long time since I've had to do this!)
There is a 3 connector plug and a single connector plug on the distributor.
Is there an ignition box I need to check too?

Clues and or documents would be helpful?
TIA
TOM

BILL DEMMER

it sounds like you have a retrofitted hei system. check the the wire going into the cap at the terminal marked B+ it's better to use a test light and a meter for this, imo. connect the light and the meter to the B+ wire(red from the meter), and the other side of the light and the black from the meter to a good ground. turn the ignition switch to the "on" position. you should have about 12.6 volts. connect the red from the meter to the battery + terminal, you should have the same reading. if you don't have the same reading as battery voltage, you'll need to start tracing the distributor B+ line back to it's source. if you do have the proper voltage at that B+ wire, you'll need to look inside the distributor. you may have bad connections at the module, or a defective module, or pickup coil.

my guess is somebody did a hack job retrofit of that wire.


bill

MDchanic

The single wire into the distributor cap should be +12V with the ignition on.

If it is, then take off the cap and rotor, remove the module, and bring it to a chain auto parts store where they can test it. The failure mode you describe is common in module failure. If it tests bad, have them test the new one they want to sell you - I recently found a new one bad out of the box.

When installing or reinstalling a module, use fresh, new heat sink paste (white paste, not clear grease - you can get it at Radio Shack).

Other possibilities include poor connections by a previous owner and a blown fuse in the line to the distributor (it shouldn't be fused, but sometimes people put them in)

- Eric

BILL DEMMER

hei wasn't fused from the factory, but a 20 amp fuse would be good. the factory had the hei power source run through a shared fusible link. some kind of circuit protection is a wise idea on a retrofit.


bill

nightshiftbbs

Hack job. This four wire module only had one side plugged in. I dont know where the green and yellow are supposed to go. They are just sitting there inside the distributor

Nasty455

MDchanic

Not sure if that picture will help him much, Nasty.

My memory is a bit hazy on this, but I believe the green and yellow are the Hall effect sensor wires. If so, they have no polarity and can be installed either way.

I believe that you have a four-pin HEI module. If so, then if you hold it like a "U" or a "smile," the two smaller pins on the Right side are the sensor pins for the yellow and green wires, and the two larger pins on the Left side are for the power, with the upper pin being the (+) from the ignition switch (and to the (+) side of the coil), and the lower pin being the trigger lead to the (-) side of the coil.

The best picture I could find is here:



- Eric

Octania

MDChanic- nice graphic but your VA shown is set up for CW rotation like brand C.

If you want protection, I noticed recently that many cars of the 80's have 20 or 30 A BREAKERS in the fuse panel. Seems like a good idea for circuits other than the PW they are usually installed in. Automatically re-set. If it KEEPS tripping, you know you need to fix a problem. Looks like a little metal canister in the fuse area.

I have only had HEI's die in two ways
1) sudden death from the module passing away.
2) intermittent no-spark traced to fatigued wires to the magnet coil, which is moved by the VA [Vacuum Advance] unit, leading to wire fatigue eventually.

MDchanic

True, but we're not talking about vacuum advances here.

Can't a guy just lift a picture from the web without getting his cojones busted?

- Eric

Nasty455

OP wasn't really clear where the wires were actually running.
I know when swapping to HEI the current sensing wire is not used...but I believe mine was brown.
The green wire would be a tach lead.
The red should be 12 volt to the Hei.
The only yellow wire I see is an internal wire inside the HEI.
I'm guessing someone could have spliced an incorrect wire into the system,but without pics we are all just guessing.
Since the car was running,I'm guessing the 12 volt came loose from the hEI.

MDchanic

Agreed, but I think that diagram is for converting some specific non-GM car to HEI.

- Eric

Nasty455

True,but HEI is usually quite simple.
Everything is contained in the dizzy.
Connect the battery and ground lead and go.
Since the car was running,excluding module failure,I'm still guessing the 12 volt lead came loose.

jaunty75

Viagra

nightshiftbbs

nightshiftbbs

Two wires broken off at the pickup coil green and yellow

Nasty455

Why didn't you just say that in the first place? lol

nightshiftbbs

Worded badly in post #5
I should have known right away when those wires came out with the module
DUH

nightshiftbbs

Looks like we have root cause of the failure.

Thanks to everyone who helped out, and those who helped me keep my sense of humor.

So it looks like I want a new distributor.
Any recommendations? Dire warnings?

nightshiftbbs

and another thought...

Those wires must have been getting ready to break off for a long time.
Could that be the source of the occasional backfire through the exhaust?

ctsplicer

Pertronix,great distributor,7 years and still going strong for me,have thgem in 3 of my cars

MDchanic

Definitely.

I'm not clear on why you need a new distributor, though, rather than a couple of wires.

- Eric

nightshiftbbs

The wires are broken off at the pickup coil. Does that part come off the distributor? Its too tight to try and solder them back on in there, and it looks like the shaft has to be removed to get the coil out...

maybe I need a lesson in distributor dis-assembley..

or maybe I am misusing terminology...

Nasty455

A new coil will come with all new wires.
Spend your cash on a tuneup including a cap and module.
If you want a new dizzy,I've bought re manufactured for under $100.
You will still need a cap and rotor and coil.

MDchanic

As Nasty said, all you need is a pickup.

You remove the distributor from the engine, remove the shaft from the distributor, and replace the pickup.

- Eric

BILL DEMMER

a module is not part of a tuneup, unless it fails, it need not be replaced. a new cap and rotor is a good idea since you're going in there. replace the pickup coil and clean and lube up the distributor mechanicals, and you'll be all set.


bill

nightshiftbbs

anyone ever have a problem re-using the pin that holds the gear?
came out kind of easy but i didn't mangle it..

Octania

The wires are broken off at the pickup coil. Does that part come off the distributor?
============
yes, right after you remove the gear and then the shaft. And probably a teensy Jesus Clip. Sounds like my Type 2 failure.



Its too tight to try and solder them back on in there, and it looks like the shaft has to be removed to get the coil out...
========================
Right, and yes, it's tight. At least you have the part available. I am reviving a 1968 W30 UHV, similar pickup/ magnet coil, frayed insulation, not an easy fix, and scrapping it is not an option.


maybe I need a lesson in distributor dis-assembley..
or maybe I am misusing terminology...[/QUOTE]
=============
Don't be miss-using no terminolgy around here mister!


anyone ever have a problem re-using the pin that holds the gear?
came out kind of easy but i didn't mangle it..
===========
New one cannot possibly hurt. I have never had a problem re-using them, but it's not like distributors usually need total dismantling either.




Can't a guy just lift a picture from the web without getting his cojones busted?
===============
Wow, that was SO not busting of cajones. Just striving for perfect correctness in a Brand C world. Never know who will refer to this thread sometime in the future. You're cool.

MDchanic

Define "kind of easy."

It should tap out with firm, but not hard, taps from small to medium sized ball peen hammer.
If you had to really whack it, it was too tight.
If you could basically push it out with a pin punch by hand, to was too loose.

If too loose, as Octania said, it is a standard expanding roll pin, and should be available at any good hardware or auto parts store.

Pin out, gear off (remember orientation), slide shaft out, clean off old grease, examine advance mechanism "up close and personal," and clean, straighten, and lube (with very light oil) as necessary, replace pickup, re-grease shaft, insert, remove again, wipe off excess grease that squeezed out, replace shaft, position gear, replace pin, re-stab into engine (try to get it about where it was, provided that where it was seemed to be working well for you), reassemble, screw down clamp tight enough to rotate distributor with some effort, start engine, and re-time.

- Eric