CRSCRS Posted June 5, 2019 Share Posted June 5, 2019 Hello would anyone know what vehicle this rev counter was fitted too and what type of sender/generator I need to make it work ? Chris Quote Link to comment Share on other sites More sharing options...
attleej Posted June 5, 2019 Share Posted June 5, 2019 Chris, According to a post on this forum ( that I found by googling the patent number) it is a centurion tachometer. The Meteor IVB drive has a small tacho generator connected to the camshaft. John Quote Link to comment Share on other sites More sharing options...
CRSCRS Posted June 5, 2019 Author Share Posted June 5, 2019 Thanks John that’s great. The reason I ask is I’m on with mounting one of these in my Leyland Martian dash panel to replace the original tachometer. It fits correctly with minimal modification to a spare panel I already had, so saving the good one. Just need to find a generator of some sort that I can mount on the Cummins engine. Thanks again Quote Link to comment Share on other sites More sharing options...
sexton Posted October 30, 2019 Share Posted October 30, 2019 Found this late but I can tell you the Centurion tachogenerator which is driven by an idler gear off the cam gear is an AC generator that creates an AC voltage that varies as rpm. So the tachometer is really just an AC voltmeter calibrated in rpm. At 2500 crank rpm the tachogenerator generates about 4V AC. One wrinkle is that the tachogenerator is spun at 0.892 of the crank speed, for reasons that only a British designer would know, so when test spinning the tachogenerator at 2200 rpm, the tach will read 2500 rpm, the redline for a Cent. This doesn't make for an easy conversion to other vehicles. Malcolm Quote Link to comment Share on other sites More sharing options...
CRSCRS Posted October 30, 2019 Author Share Posted October 30, 2019 4 hours ago, sexton said: Found this late but I can tell you the Centurion tachogenerator which is driven by an idler gear off the cam gear is an AC generator that creates an AC voltage that varies as rpm. So the tachometer is really just an AC voltmeter calibrated in rpm. At 2500 crank rpm the tachogenerator generates about 4V AC. One wrinkle is that the tachogenerator is spun at 0.892 of the crank speed, for reasons that only a British designer would know, so when test spinning the tachogenerator at 2200 rpm, the tach will read 2500 rpm, the redline for a Cent. This doesn't make for an easy conversion to other vehicles. Malcolm Thanks Malcolm that’s a great help 👍 Quote Link to comment Share on other sites More sharing options...
Citroman Posted October 30, 2019 Share Posted October 30, 2019 You said 0.892 on the dial it is marked .829 ? Quote Link to comment Share on other sites More sharing options...
attleej Posted October 30, 2019 Share Posted October 30, 2019 Chris, If the vehicle has a B81 you need to take the revs right up to 3750 RPM but the tachometer only goes up to 2500. The engine should not be allowed to labour too much. You can get it to read true, if it is a voltmeter type, by using resistors (a voltage divider) to adjust the voltage going into the meter. I would have thought it would be easier to find another tachometer that either works or can be overhauled by one of the specialist companies. John Quote Link to comment Share on other sites More sharing options...
sexton Posted October 31, 2019 Share Posted October 31, 2019 16 hours ago, Citroman said: You said 0.892 on the dial it is marked .829 ? Well spotted, Citroman! It is indeed 0.829. So that's what the 2500/.829 means on the back of the tach! Malcolm Quote Link to comment Share on other sites More sharing options...
Meteor-Chris Posted November 29, 2020 Share Posted November 29, 2020 Chris, if you can't use the revcounter, I'm interested in buying it. Best regards chris (Switzerland) Quote Link to comment Share on other sites More sharing options...
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