Vitesse Mk2 rev counter

[Puglet1]

During my recent visit to Peter Burgess’s rolling road session it was established that my rev counter was inaccurate.

If I have my unit recalibrated to include the 3.6 diff change is it likely to be accurate or should I be looking for an alternative method of counting the RPM?

 

[johny]

This is the rev counter were talking about because tachos are not at all affected by diff ratio changes? They are connected to the engine and so independant of what ever happens in any of the transmission.... If its that important to you I dont see why after re-calibration it cant be perfectly useable👍

[Pete Lewis]

agree its driven from the distributor drive  it may just need the bezel and glass removing 

take  out the unit , hold the disc drive and just move the needle to give you a better indication of revs 

the guts are pretty much the same as the speedo  they do wear at the needle pivots then the needle 

gets very jerky.  they are all a 3.55:1 ration on 6 cyl cars 

certainly nowt to do with any axle /tyre ratio changes 

often tested at home with a battery drill   with a known rpm

Pete

[Puglet1]

Pete and johny.

How stupid of me linking it with the diff change🤔.

When it was on the rolling road it was reading about 1500 rpm too high .

As always…… Thank you both for your support👍

[johny]

wow long way out! The tuner I take it calculated the correct revs from the back wheel/tyre diameter plus gear and diff ratios? Or did he use an optical instrument on the crank pulley directly?

[Puglet1]

johny. I think he did both because he could also tell me the speedo error.

 

[johny]

yes with a diff ratio change speedo error will be significant and is the important one while rpm is pretty meaningless really unless racing. I suppose as you'll send the speedo away somewhere to be adjusted you can include the tacho with it at the same time?