1959 Corvette

[Joseph Harrah]

Ihave a 1959 Corvette... All the numbers match.. However when I got the car someone put in a Mallory uilite dist.
When the engine is at 2000 RPM's, the tack is reading 4000 RPM'S...
Can someone tell what I need to do to fix this?

Thanks
Joseph Harrah

[Pat #25912]

Re: 1959 Corvette

Is the tach the original mechanical unit or is it an aftermarket electronic unit? Pat G.

[Ed Jennings]

Re: 1959 Corvette

Unless your car was originally a fuelie, the tach was driven off the generator. It turns at engine speed, while the distributor turns at half engine speed. Suspect you have a wrong combination of parts. The tachs are calibrated differently for each application. A speedometer repair shop can probably recalibrate your mechanical tach.

[Brad K.]

Re: 1959 Corvette

It could be something as simple as someone has put a very small generator drive V-belt pulley on. The correct pulley has a 3 1/2" to 4" diameter. Take a look.
Brad

[John H.]

Re: 1959 Corvette

Or, it was originally a fuelie (distributor-driven tach) and is no longer, and now has an engine-speed generator driving the original half-speed tach head, so it reads double engine rpm. Or, someone changed the tach and installed the wrong one and didn't want to go through the exercise of changing it a second time. Bubba is everywhere

[Michael D.]

Re: 1959 Corvette

send the tach or the guts to roger scott 561 627 9345. he can recalibrate it or totaly refurbish it.