View Single Post
  #428  
Old 03-09-2025, 04:22 AM
jbtech's Avatar
jbtech jbtech is offline
Yenko Contributing Member
 
Join Date: Apr 2020
Location: CA
Posts: 556
Thanks: 566
Thanked 1,518 Times in 262 Posts
Default

Quote:
Originally Posted by scuncio View Post
How were you able to adjust the tach needle?
Jason's advice and photo from post 270:

Quote:
Originally Posted by SuperNovaSS View Post
There is a potentiometer on the back of the tach behind this sticker to adjust the rpm reading. Just be careful, the potentiometer can be fragile after all these decades.


Jason
I used a very small flathead screwdriver and with the power off I ever so slightly turned the what I'm assuming is the potentiometer screw counter clockwise. I retested and repeated until it was accurate to my liking. I read that it's possible to cause a short if the screwdriver touches the housing during adjustment which is why I did mine with the power off. It was tricky and I couldn't even see inside the opening for the potentiometer but I as I gently turned the screwdriver with the tips of my fingers I waited for it to fall into the slot, Once in the slot I felt a resistance as I turned the screwdriver. Luckily it only needed 2 adjustments. After adjustment I replaced the painters tape that I used to cover the hole.
With all of that said the tach needle itself when the car is off rests about 100-200rpm too high, but since my readings were accurate from 2000-7000rpm after adjustment it was fine by me.
Attached Images
 
__________________
Jose Betancourt

67 Camaro L78
Reply With Quote
The Following 9 Users Say Thank You to jbtech For This Useful Post:
169indy (03-18-2025), 1967 4K (03-09-2025), big gear head (03-10-2025), dykstra (03-09-2025), napa68 (03-10-2025), olredalert (03-09-2025), PeteLeathersac (03-09-2025), ragtop (03-09-2025), scuncio (03-10-2025)