260z rev counter adjustment / fine tuning

[AliK]

Does anybody know if this is the adjustment / calibration screw on the back of a 260z rev counter?

Mine is consistently 10% optimistic across the range and I'd like to get it bob on if possible.

 

[jonbills]

Dunno, but I found mine also reads about 10% over at idle.
Twiddle it and see what happens....

 

[Mr Tenno]

Looks like there are adjustment screws on the 240 / 280 so the 260 should have one too: https://www.classiczcars.com/forums/topic/50506-tach-reading-faster-than-tachdwell-meter/

 

[AliK]

Thanks fellas - will have to geek out on that properly when I next have a few quiet moments. When I figure this one out I will post back.

JB - mine is consistently 10% over all around the rev range.

Bizarrely though, my speedo is 15% pessimistic at 30 but gets accurate at 90 (on the track of course)!

That one I defo need to deal with as an indicated 30 is more like 35ish and indicated 50 on the motorway roadworks is closer to 60!