1960 Corvette: Service Bulletin: Correction for Erratic Tachometer Operation

Subject:   Correction for Erratic Tachometer Operation
Model and Year:   1960 Corvette Models
Source:  General Motors of Canada - Service Bulletin
Bulletin No:  NA
Section:   Page 51
Date:  June 15, 1960

With introduction of the new Corvette hood lock assembly, which required re-routing of the tachometer cable assembly, a limit stack condition on the cable length was created.  The problem is one of insufficient length which, while allowing the cable to drive the tachometer at lower R.P.M.’s, permits it to skip at high speed, resulting in erratic operation.

A change is being made in Production to rotate the tachometer drive assembly 180o on the generator, which raises the tachometer drive unit about 2".  This eliminated the basic limit stack problem by reducing the cable length requirement by an inch, and also straightens out the cable routing at the generator end by eliminating a sharp radius where the cable dips down to pick up the tachometer drive.  This should probe to be beneficial on the tachometer noise also.

This re-work can be readily accomplished in the Field in handling "erratic operation" complaints, as follows:

  1. Loosen and remove tachometer cable from the tachometer drive unit at rear of generator.
  2. Remove the two tachometer drive unit attaching screws from the CE frame.
  3. Rotate the drive unit 180o, and re-install the attaching screws.
  4. Re-install the tachometer cable to the drive unit.

Article ID: 952
Created: October 12, 2014
Last Updated: October 12, 2014
Author: Rob Loszewski

Online URL: https://www.corvetteactioncenter.com/tech/knowledgebase/article.php?id=952