Recalibrate 911 tach?, 6 cylinder tach reads too low Options

[914ltd]

I know there is lots of talent on this sight. Anyone set up to recalibrate a 911 tach?

I am doing a /6 conversion for my customer and this tach reads low, p/n 911.641.301.01. Both Hollywood and Palo Alto are quoting a long turnaround time.

Thanks Brad

[timothy_nd28]

For those recommending a Tach-adapt is simply asinine. It is like adding Sea-Foam to an engine with a dropped valve seat. I'm sure Bob's module does condition the signal but I'm also pretty sure that Brad (being the 914 god that he is) has already got this ignition system well tuned. No module will fix a broken tachometer.

It was stated that the RPM readout was low. These tachometers are pushing 50 years in age, which well exceeds the life of a electrolytic capacitor. After reverse engineering the 911 tachometer and updating some obsolete parts, it is very likely that C4 which is part of the timing circuit of the tachometer has degraded with age and causing the tachometer not to read correctly

[Morrie]

For those recommending a Tach-adapt is simply asinine. It is like adding Sea-Foam to an engine with a dropped valve seat. I'm sure Bob's module does condition the signal but I'm also pretty sure that Brad (being the 914 god that he is) has already got this ignition system well tuned. No module will fix a broken tachometer.

It was stated that the RPM readout was low. These tachometers are pushing 50 years in age, which well exceeds the life of a electrolytic capacitor. After reverse engineering the 911 tachometer and updating some obsolete parts, it is very likely that C4 which is part of the timing circuit of the tachometer has degraded with age and causing the tachometer not to read correctly

Maybe I misunderstood, but I though the issue was the conversion from 4-6 cylinders, not a defective tach.

The Tach-adapt is a good plug and play tool to make some of these parts play together. Are you sure you did not go off half cocked here sir?