Tachometer calibration

[TrekLawler]

Hello everyone,

   sorry for all the questions as of late, but I'm quickly learning all of the issues with the TC as I try and fix all of the normal things. the thing I tackled tonight was the odometer gears. got all that corrected and the last time I drove it noticed the tach was a little sticky. so i took a close look at it and it appeared the needle was actually dragging a bit on the face, you could even hear it, so I thought I'd try and pull the needle off the pin a bit and it popped all the way off. now I can press it back on and have a little gap for clearance but not sure how to calibrate it so it reads correctly.

 

any neat ideas on how to do this?

 

Thanks,

[Hemi Dude]

You are challenging!  It's late at night here, maybe where you are too. I'll work on that in the morning unless someone else wants to come up with an answer before me. 

[TrekLawler]

Thanks Hemi,

   not challenging, just optimistic to get all of the problems with this car corrected so I can get it on the road before it gets too cold to ride with the top down. I have my idea's how to do it but hate re-inventing the wheel if there is a better way.

 

Thanks again,

Edited September 30, 2017 by TrekLawler (see edit history)

[Reaper1]

I plug the cluster in with the clear face off, key on (engine off)...tach should be "zeroed".  Push the needle on and see how it reads once you start it. If you know the engine runs correctly, then you can just take a glance at the tach to see how close it is. If you have an inductive tach, then you can really make sure it's as close as possible.

[Hemi Dude]

My thinking goes much the same as Reaper1. I would alter the concept a small bit. With an inductive tachometer or any wired one, have the engine idling at it's normal warmed up idle speed. Then, with the clear face off, carefully install the needle at the same RPM as the external tachometer reads. Push it on lightly at first as you may miss by a little. The in dash tachometer does not always rest at (zero) at least mine does not. If it appears to be in the correct position, then press it on fairly firmly. This should get you as close as humanly possible without laboratory facilities.