What's the difference between a mechanical and electronic tachometer?

Question

I have a 1986 Buick Regal with a 307ci engine. Which tach would work for my car?

Answer 1

A mechanical tach works much like a speedometer. It uses a gear drive, usually off the distributor, and a cable. These were used on very early electronic ignition systems in the late 1960s and early 1970s. There may have been other applications that I am not aware of.

An electronic tach uses a signal from the secondary or negative side of an engine coil. There are no moving parts, just wires and the tachometer itself. These are usually very reliable.

For your Regal I would certainly use an electronic tach. There is a Tach lead on the distributor cap that you can use as a signal wire. It is marked Tach on the cap right next to the B+ lead.

Answer 2

1 runs off electric and the other type don,t. if i were you i would get the electronic type, it would be more accurate.

Answer 3

the mechanical ones have not been used in ages. it is a cable driven type, at least the one that i saw was. the electric would do you much better. just three wires to hook up and still very simple.

black to the positive(of the key), black to a good ground(engine block will do) and the green to the negative side of the ignition coil or the tach terminal on the hei system.

Answer 4

Electric uses wires and mechanical I believe uses senders of some sort.