Dwell Meter and Angle

[pilotnbr1]

I have a dwell meter that I cannot get a reading on. The volts function works and I can't get the rpm to come up either. I hooked one wire to a good ground and the other wire to the negative side of the coil. I get nothing, with the car running great...

Where do you guys hook up your dwell meter specifically?

My instructions say to hook one wire to ground/battery and the other to negative side of coil or tach connection. Isn't the tach connection on the negative side of the coil? BTW I have regular points with an older C.D. system hooked into the coil side.. Wondering if that has something to do with it.

The second part of my question is what would you set the dwell angle to for a desmogged 74 tii with mechanical advance only distributor?

I see an early tii should have a dwell of 59-65 but a 74 tii should have a dwell angle of 66-69.. I am assuming the greater dwell angle is due to all the emissions stuff which I have removed- so I believe that I would go with the lower dwell angles...

Thanks for all the replys! I am just wanting to put in new points using dwell angle.

[Collinster742002]

I attach the red wire on my dwell meter to the negative on the coil; the black I ground to the shock tower. It always gives me an accurate reading attached here. I have also attached the ground to the cylinder head cover nuts.

What kind of tach/dwell meter are you using?

[M3M3]

there should be at least three connections to be made for the tach function to work. power, ground and tach. maybe you were assuming a ground somewhere? my dwell meter also has a fourth for when checking dwell, but i am sorry i don't remember where that goes since i have not used points in so long. i will see if i can find the instructions.

[Collinster742002]

There are many different brands and styles of these meters. I'll post a picture of mine soon... It's OLD

[jimk]

You are trying to set the points dwell and connecting on the CD system side. The points are divorced from the coil curcuit which the dwell meter was designed for.

1. With the use of a CD system, the dwell may not important at all. The points alone used to set the coil charge time when closed. With the CD, the box charges and fires the coil. The CD fires when the points open. And function only as a switch?

2. There is no current to speak of thru the points with a CD. That's one of it's advantages over points alone and the points don't burn. The capacitor (commonly called a condenser for whatever reason I can't imagine) doesn't need to absorb the AC spike. The low current is why your dwell meter doesn't trigger.

3. The timing is most important in the end with a CD.

4. I would set the points gap and reset the timing and you are good to go.

I've been meaning to scan and post up a schematic of a 1970s vintage CD system for anyone who might want it, but haven't had time. I can't help answering questions on how it works, I can hold a soldeering gun and that's about all for electronics.

[R1190]

I fully agree with jimk. In a CD system dwell angle is not a parameter.

For those of you that still keep points, condenser and coil in the original way, here you can find some tips about dwell angle:

1- Dwell angle is the angle during which the points are closed. It can be expressed in degrees or percentage. The dwell angle of a set of points that never close is 0 degrees or 0%. The dwell angle of a set of points that never open is 90 degrees or 100%. Values that are given in degrees can be converted in percentage just dividing by 0.9. Perhaps the values indicated by pilotnbr1 correspond to the same values but with different units (59-65 degrees --> 66-69 %).

2- A dwell multimeter is needed to set the dwell angle. Connect the negative wire of the dwell multimeter to ground and the positive wire to the wire that connects the coil with the points. If you cannot identify the wire that connects the coil with the points then choose one of the two wires of the coil. If the dwell multimeter display shows a dwell angle it means you have selected the right wire. If not, just connect the positive wire of the dwell multimeter to the other wire of the coil.

3- Dwell multimeter is a good invest and not necessarily expensive. Both analogic or digital dwell multimeters are ok to adjust the dwell angle however the accuracy of the digital one cannot compete with the taste of the analogic multimeter. The decision is up to you.

4- Check the dwell angle from time to time. If the value is out of the correct range, adjust it. That way you will prevent innecessary headaches.

Regards from Spain, Pepe.