No spark - Revisited

[vping]

I got a battery in the '74 and turned it over. Sounds very strong & has great compression. No spark.
Horn & lights work as well as wipers & hazzards.

I still need to check most connections to make sure they are not corroded.

When the PO parked the car 10 years ago, she had just replaced Condensor, wires, plugs, cap, rotor & points and it looks like it. I know most of you would recommend changing those which I plan to do but not at this moment.

How do I trace the electrical from A to Z to make sure that I am getting power to where I need it first, second...

 

[DrEntropy]

The "most likely suspect" is FUZZY POINTS! Did you clean 'em with some fine emery cloth? Check for voltage at the coil, put a 12V test light at the CB side of the coil and see if you have "trigger" blink (it won't fire with this)when spun and if not, the points are somehow fouled. Most likely if the coil has voltage and the thing won't light off the points are corroded.

Report back!

 

[startech47]

Might check to see if the washers are stacked up properly on the points and not shoting the power to earth. Phil

 

[Dave Russell]

Just to elaborate on startech47's comment, It's not clear if the car ever ran after the PO replaced the points. Very easy to get the movable point's spring anchor end assembled wrong so that the shouldered insulating washers are not insulating the movable point springs anchor end from ground. This arm which is connected to the coil must only be grounded when the points are closed.

The spring anchor post (threaded) from point plate up should have:
1- A shouldered insulating washer against the plate with it's inner shoulder facing up.
2- The large eye in the point spring fitting over this shoulder.

Above the point spring eye:
3- The eye of a short wire on top of the point spring eye which goes to the side housing insulated block (point connection to the coil).
4- Next the eye of the condenser lead on top of the side connection lead (3) with it's hole centered.
5- A top shouldered insulating washer with it's inner shoulder down & insulating the inside of 2,3, & 4 from the post.
6- A lockwasher & nut over the top insulating washer which secures the stack.
7- A small flexible ground lead from the point plate to one of the point plate to housing hold down screws.

Some points also require a flat insulating washer between the pivoted end of the points & the point plate. This can usually be determined by the point to point vertical alignment, or whether any metal on the point pivot is contacting the mounting plate.

A simple check - Ignition on - points open - should read 12 volts from the coil to distributor connection. Points closed, should read zero volts.
Hope I haven't "over explained"
D

 

[Rick_Stevens]

My 2 cents' worth: Startech47 and Dave's comments are the first place to look. I made this mistake this summer when I replaced the points, in spite of knowing better. Easy to do wrong, easy to fix. (It sounds complicated, but once you see it in action - if that's the problem - you'll go "Doh!")

R.

 

[Bruce74B]

Dave,

I don't think you "over-expained" but gave the best description of the stack that I have ever seen...one to be printed out and saved for future reference! Thanks! /ubbthreads/images/graemlins/cheers.gif

Bruce

 

[DrEntropy]

T'was good.

...and ~I'm~ the one to say "Doh!" I didn't consider the possibility of grounded points... even tho I've DONE it (to) myself. Not just ONCE, either. /ubbthreads/images/graemlins/smirk.gif

 

[dklawson]

Rather than duplicate the comments above or go into a lengthy set of checks, may I direct you to a PDF I put together?
https://home.mindspring.com/~purlawson/files/LucasPointsIgnitions.pdf

Hopefully that will help with tracing your ignition problem.

 

[jlaird]

And that is excellent, it needs to be in the knowledge base if someone can and Doug will give permission.

Someone???

 

[dklawson]

I keep several PDF documents at the link above. They are free to post anywhere they will be of help.

 

[jlaird]

Ok folks, you heard the man. Please add to knowledge base.

 

[Guinn]

Very good advise from all. And just yesterday my neighbor, restoring a 1924 Willis Knight asked for ignition help. I found the spring that activates the movable point was sloppily attached to the insulated post and was grounding out against the base of the distributor. FWIW,

Guinn

 

[dklawson]

Shorting the points to ground is also easy on the Lucas 23/25D and 45D distributors. The little spade lug on the condenser wire can be inserted in a manner that it touches ground. On the 23/25D dizzy's there are also insulating washers that are often put back wrong (or not at all) and that will short the points out.