4104 tach drive question

[John Z]

I decided to try and get my tach working since I was working on the dash. It appears at some time the generator stripped out of the tach drive. The gear that completes the 90 degree turn and drives the generator is gone - long gone!

I tracked down a 0.50 drive which appeared to run the tach twice as fast as it should.

Do I understand it right that the 0.50 means it would drive the generator 1/2 turn for each engine rev? If so, then do I need a 0.25 - 1 drive? Are there both left and right hand drives?

Any other concerns to be aware of?

Thanks.

[luvrbus]

Those drives are 1:1 make no difference right or left John

[John Z]

OK, then I had it backward. The 0.50 refers to the engine - 1/2 rev drives the generator 1 turn. Thanks, I will try and track down a 1-1 drive.

[John Z]

Hey Clifford. My engine has the drive mounted on the casting for the power steering pump. It needs to be .250 to 1 ratio. So this one must be set up differently, or maybe the tach (Autometer) makes a difference. I have been watching ebay with no luck. Anyone have any ideas where i can track one of these down?

[luvrbus]

If it comes from the camshaft front or rear or the balance shaft front or rear it is 1:1 there what your tach requires maybe different,are you running a pulse generator ?

[John Z]

The generator seems to work well. I tried a .5 to 1 drive. The tach worked nice and smooth, but it read twice as fast as it should. Before, I did not know what the 25 on the drive meant. Now I think it stands for .25 - 1 ratio.

[luvrbus]

John a electric tach with a pulse generator should have dip switches on the back of the tach to compensate for the ratio YMMD

good luck

[John Z]

Nary a switch to be found there.