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checking dwell w/ volt meter

32K views 9 replies 6 participants last post by  safety441 
#1 ·
How do you check dwell angle with a voltmeter? Any help would be greatly appreciated.
 
#2 ·
same answer as your other thread..........

I have never heard of checking points with a voltmeter. Can you get your hands on a dwellmeter?

If not, set your point gap at 17 to 19 thou. That should be close enough to get it running. Then use your allen wrench through the little door in the distributer to fine tune it.
 
#4 ·
I have been working on cars since long before the electronic ignitions came out, and never heard of checking the dwell with a volt meter. The measurement that you are wanting has nothing to do with voltage. It is the measurement of how long the points are opened(or closed, can't remember which right now, but know someone will set that straight) in degrees. That has nothing to do with the voltage.
 
#5 ·
Yes, it has to do with the amount of time but it also has to do with voltage (presence of or not perhaps). Here is what's up: I got this new multimeter and it has a setting for ignition points but this is really just the DC Volts <2 setting on the multimeter. The instructions that came with it are worthless as all they do is provide a label for the setting. No details on where to check whatever... hmmm...this intrigues me!!
 
#8 ·
I hear ya...stupid dwell!! Got the dwell adjusted, timing set and the thing idles good, even revvs up good, but when you go to drive, it will drive alright at an idle but if you step on it it cuts and sputters...I suspect either the carb or vacuum advance...too late tonight. Any other thoughts?
 
#10 ·
You are correct, you can set dwell with an analog voltmeter. I worked as a line mechanic for 18 years and got tired of dragging a huge piece of equipment over just to check dwell once a year.

An analog voltmeter shows average voltage. The proper connection is VM positive to battery positive, VM negative to coil negative. When the points are closed the VM receives a 12v (charging system actually, but I will keep it simple) signal. When the points are open, the VM receives a 0v signal. Now comes the math.

If your VM reads 6v, then the points are closed the same time as open. Maximum theoretical dwell is 90 (360deg divided by 4). If the VM is 6v, or 50% of 12v, then the dwell is 50% of 90deg or 45deg. Same with 6 cylinder except max dwell 60deg, and 8 cylinder, max dwell is 45deg. As the voltage increases, the dwell reduces. For example, 8 cylinder engine with VM reading 8.4v. Battery voltage running is 13.6, so the time closed is 8.4/13.6, or 61.8%. Next we take max dwell for 8 cylinder which is 45, then multiply it by the percent closed which is 61.4 with a result of 27.8 deg (45x.618=27.8).

I know the thread is old, but I wanted you to get a correct answer. BTW, I have never tried it with a DVOM
 
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