[TBONE1964]

Originally Posted by lolife99

What's the best way to test these tachs?
Anyway to determine a V-8 vs. 6-cylinder tach by testing alone?
(in case the stamping on the back is gone)

Keith,

I have two methods for testing.

The first is I use a tachometer calibration tool made by Kent Moore. It is an old machine but it will tell me if the tachometer matches the setting. For example, there are (3) RPM ranges for each configuration of 4cyl 6 cyl and 8 cyl.

If I hook up an 8 cyl tach, the setting ranges are 1800, 900 and 600. If I have it set on 1800 and the tach reads 2400, then the tach is out of calibration or a 6 cylinder tach.

Once I determine what the tach is, 6 cyl or 8 cyl, I can then do the fine tuning calibration with the small adjuster on the back/top.

It is often misunderstood that moving this adjustment will calibrate a V8 tach to a 6 cyl tach. It is not possible.

After all of that, I hook the tach up to my 72 pick up and make sure that it works well all the way through the RPM range and there is no needle stick or erratic movement.

Hope that helps. It just insures when I sell a tach or a cluster with a tach, I don't get the call saying the tach is off or does not work. It does happen on occasion.

Take care,
Tom