Posted on: February 21, 2015

by T.T. Cantwin

Surveys have been made at various UNITEDS to determine the accuracy of electric tachs used in Alpines and Tigers. Tiger Tom uses a tach calibrator which is capable of calibrating tachs for Alpines and Tigers with single and dual point distributors. One survey produced the following results.

Tachs were checked using single or dual point operation as requested by the owner.

Tach #Tach TypePoint TypeError @ 4000 RPM
1TigerDual+200
2TigerSingle+1000
3AlpineSingle+1000
4AlpineSingle+850
5TigerDual+750
6AlpineSingle+400
7TigerDual-1000
8AlpineSingle-800
9TigerSingle+600

Out of the nine tachs tested only one (#1) was within acceptable limits. Generally. they indicated higher than actual RPM. which most likely saved a few engines. It should be noted that an indicated error at 4000 rpm is not necessarily a linear error over the range of the tach. Values shown at 4000 rpm are merely an indication of general tachometer accuracy. Therefore tachs must be checked at other RPM points to determine actual accuracy.