AMGBA website home page or AMGBA Photo Gallery or AMGBA Club Blog
Subscribe in a reader

Join or renew today and receive a free t-shirt or tech CD, see details in the join the club section at!

Author Topic: Tach problem  (Read 8206 times)

0 Members and 1 Guest are viewing this topic.


  • Message Board Member not current AMGBA Club Member
  • **
  • Posts: 8
Tach problem
« on: November 30, 2009, 05:37:44 PM »
My Smiths tach on my '66 MGB indicates too high, and it gets higher when it has run for awhile.  I don't see anything on this in the two tech manuals I have.  Any suggestions?  -  Don


  • chfwrench
  • AMGBA Club Tech Staff
  • ****
  • Posts: 285
  • Membership Number (if known): 91-10014
  • MG information: '73 red B roadster
Re: Tach problem
« Reply #1 on: December 11, 2009, 02:40:04 PM »
Hey Don,

This sounds like an internal resistor problem with the electronic Tach, but I would suggest trying a different external tach to verify. 

The old tune-up multi-meter units that had a tach and dwell meter for the points should do it or hooking-up a Sun or RAC aftermarket external tach, which can often be found cheap at flea markets, swap meets and garage sales

Replacing the tach or brining it to an electronics shop to test components and repair might be the solution.

I hope that helps.  Good luck.

Art Isaacs
AMGBA Tech Staff


   AMGBA website home page or AMGBA Photo Gallery or AMGBA Club Blog