2 tach questions

[hottvr]

Having trouble with the tach in my 72 B. The original one jumped around a lot so I replaced it with another. This one read 1500 rpm fast. Found another one and replaced it today and it reads about 2000 rpm fast. Could there be something wrong with the car or am I just coming across bad tachs? I know I need to find one that I know works but haven't found one yet.
On my 78 B I just picked picked up, the speedo needle is broken off. I have a tach from the same year I took apart, but don't understand how the needle comes off. Can I replace a speedo needle with a tach needle, and how do I do it?
Rick

 

[hottvr]

Tach trouble on the 72 might be related to the electronic ignition

 

[MikeP]

Tach and speedo needles are usually press fit onto the shaft. On other Smiths type gauges I've used a pair of curved needle nose pliers to remove them. Slide them under the needle, 90 degrees from the needle itself, and slowly pop straight up. That should put you under the metal bit on the bottom of the needle that the shaft goes into, if there is one, and keep you from damagin the needle. Installing can be done by gently pressing it on with a finger.

 

[Mickey Richaud]

Having trouble with the tach in my 72 B. The original one jumped around a lot so I replaced it with another. This one read 1500 rpm fast. Found another one and replaced it today and it reads about 2000 rpm fast. Could there be something wrong with the car or am I just coming across bad tachs? Rick

Hey, Rick -

Do you know the condition of your voltage stabilizer? Could be the culprit.

Mickey

 

[hottvr]

Put in a new voltage stableizer and then one I knew worked, still reading fast.
Rick

 

[David_DuBois]

Voltage stabilizer output is not used for powering the tach. There is a calibration potentiometer inside the tach that needs to be adjusted to get the correct readings on the tach.
Cheers,