[Manchu16]

Has anyone found an alternative for the 3 wire vans tach generator. I want to keep the gauge as the other gauges are all vans. I started to get irregular low readings after 1000 rpm. I know I need 8 PPR. I found a few speedo generators that run 8 ppm with 3 wires (square signaling) and have the male side connector for the engine.

 

[blaplante]

1) be careful with "PPR". You need 8 pulses per Rev. Is that Crank Revs, or Cam Revs? I think the sender runs at camshaft speed.

2) Most speedo generators use a square tang. The Lycoming needs the round shaft with a side tab. Fortunately...
GM made an adapter. I think what I found that works is at https://www.texasindustrialelectric.com/800_Series_Speedometer_Adapter.asp
the HM146 aka GM 25032338 if I recall correctly.

I was researching alternatives to the high prices aircraft tach drives

 

[Manchu16]

1) be careful with "PPR". You need 8 pulses per Rev. Is that Crank Revs, or Cam Revs? I think the sender runs at camshaft speed.

2) Most speedo generators use a square tang. The Lycoming needs the round shaft with a side tab. Fortunately...
GM made an adapter. I think what I found that works is at https://www.texasindustrialelectric.com/800_Series_Speedometer_Adapter.asp
the HM146 aka GM 25032338 if I recall correctly.

I was researching alternatives to the high prices aircraft tach drives

Great catch. Guessing that was autocorrect on my ipad. Definitely 8 pulses per rev. Still looking for options.