Question on Hooking Up Dwell Meter

J

jg61hawk

Senior Member
Just for fun I wanted to get a base dwell reading. I have an old meter that says it works with 6 or 12 volts. It says for positive ground just reverse the leads so the black ground goes on the coil and the red hot goes on a ground. Normally a dwell meter goes to the negative side of the coil (my Studebaker 12V negative ground).

Question: On a Model A (stock set up...except modern points) do I connect the meter leads to the positive side of the coil? I tried both sides...I got what I think is a dwell reading when connected to the positive side, but the book says to use the negative side.....I don't completely understand how the system works. I do know on the Studebaker the negative coil side is the distributor side. Is the positive side the distributor side on the Model A?
 
So I went back through my notes and I see the red wire (+ coil side) goes to the ignition switch where it then magically turns into the armored cable and goes to the points. So I'll answer my own question: Jim connect the black ground wire from the dwell meter to the + side of the coil and red hot wire from the dwell meter to a good ground. This should show you a dwell reading. Jim, just set your points correctly and stop being a pest.
 
jg61hawk said:
So I went back through my notes and I see the red wire (+ coil side) goes to the ignition switch where it then magically turns into the armored cable and goes to the points. So I'll answer my own question: Jim connect the black ground wire from the dwell meter to the + side of the coil and red hot wire from the dwell meter to a good ground. This should show you a dwell reading. Jim, just set your points correctly and stop being a pest.
Click to expand...

Who's Jim?? :confused: :confused:
 
I'm a very funny man...well maybe not this time...you know what they say, "if you have to explain a joke ...".

See I said I'll answer my own question...so I talked to myself.... OH well I'll stick to fixing stuff and avoid stand up comedy!
 
One black musician waking out of the club says to the musician walking in..
"Yous too hip for the room".
 
jg61hawk said:
I'm a very funny man...well maybe not this time...you know what they say, "if you have to explain a joke ...".

See I said I'll answer my own question...so I talked to myself.... OH well I'll stick to fixing stuff and avoid stand up comedy!
Click to expand...

My name is Jim and I thought it was funny!:)
 
On four cylinder Fords, just setting the points to proper gap will generally get the dwell time within specs. It certainly doesn't hurt to check it. The early V8 distributor has an extra set of points to improve the dwell on them. Twice as many cylinders made a big difference.
 
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TO ANSWER the original question.

I have 3 or 4 tach-dwell meters which I have used since 1955 on Model As, VWs, Porsches and various other engines with standard points/coil ignition systems.


All of the instruction manuals say they work with 6 or 12 volts, Pos or neg ground.

I always hook the meters ACROSS both terminals of the coil, NOT ground to one side of coil

1. If car is positive ground like Model A the Positive lead goes to the side of coil which goes to the points.

2. If battery is hooked up with negative ground the leads are reversed.
 
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The Master Cylinder said:
What do you set your dwell to?
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31 degrees is what I use.

Note: I am using the new dist cam called "B" profile".

As I remember angle is different with "A" profile.

I do not remember what the "A" number was/is it has been a long time since I found an unworn "A" distributor cam!

I use it to monitor point rubbing block wear.

If dwell changes I know that rubbing block has worn and gap has changed.
 
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