Lefty's Deceiver

I have a 74 911 and my Tach will go up with throttle application but then bounce around oscillating until it dies out and remains steady. It's like there is no damping of the needle.

Any ideas on what I can do to remedy this?

Thanks

Lefty

emac

Lefty
I have a 81SC and had the same problems. I don't know if the Tach's are the same but the bad news is I had to replace it. I was able to purchase the entire cluster for my car off e-bay for a very reasonable price, and yes they all work.

Lefty's Deceiver

Oh so it's just more $$? Phew, I thought it was more serious than that!

Thanks for the suggestion will look on the 'Bay.

Lefty

Alan Herod

when my tach went berserk, it was the voltage regulator and the alternator rebuild and new voltage regulator cured all for $89.

CDiercks

Check voltage comming from the alternator. If it is not right where it should be it will cause the tach to bounce. As said above it could be the voltage regulator, or the alternator.

Steve Weiner-Rennsport Systems

Lefty:

Erratic tachs on '74 cars are usually indictative of dirty points in the distributor. Clean or replace them and you'll be fine, (better yet, install a Pertronix). You might also make sure that the battery voltage is 13.5 at 2000 RPM. As above, the alternator, voltage regulator, or a battery cable can be bad.

If the tach is truly bad, send it to either North Hollywood Speedo or Palo Alto Speedo and they will fix it. Plus, they can dampen the needle to prevent the excessive bouncing.

Lefty's Deceiver

All,

Thanks for the suggestions. Will try clean the points this weekend. Steve, what is a Petronix if you don't mind me asking?

Thanks
Lefty