Carl

Is there a way to calibrate the altenator tach? seems like it won't go over 2200 rpm when I first got it it went close to 3000 rpm or is there something wrong with the tach or pickup on the altenator?

BigWaylon

a couple ways to calibrate it...

one...use an optical tach to measure what the engine is actually turning...

two...use a calculator to figure out what the RPM's "should" be at a given speed based on your tire size, transmission, and differential gearing...


maybe some other ways...but those both work...

Greg

wannadiesel

Try moving the probe around a little. Mine read fine at low RPM, but I had to play with the positioning to get it to read accurately at high RPM.

jughead

use one that uses the ac current from the alt. then u wont have that problem as long as the alt. works.

wheelo90

When I got mine, (Autometer) it had a calibration adjustment on the back of it. I calibrated it by letting the motor warm up very nicely and had someone mat the fuel to the floor while I checked to see that I was getting full throttle. I adjusted the tach to read about 2,700 Rpm. At idle, it sat at 750-800 Rpm. Good enough for me!
Wheelo

lowwag64

Carl,u need to put some reflective tape on your crank pulley,grab a laser tach,a buddy,start at idle,calibrate your tach to the laser tach.then go full throttle,then calibrate again.both will read the same when done...

Carl

Thanks I'll try some of the ways you all have suggested, I did find looks like an adjustment on back side with an allen wreanch.

BigWaylon

not sure what brand yours is...

but my AutoMeter had an allen screw on the back, which allowed you to remove the cover of the gauge...

the adjustment was actually a VERY small flat head screw on the back of the gauge (once the cover was pulled off)...it's recessed down into the gauge...

Greg