LocostBuilders - powered by XMB

RVC tacho problems

oldmansteptoe - 7/9/15 at 07:24 PM

Hello

I have a Smiths RVC 2415/00AF, 4 cylinder, negative earth tacho in my locust, with 1700 xflow. Ive got a 103 fxys aldon leccy dizzy. Wiring this up seems like it should be easy, bullet connector to negative side of coil, and spade connector to a positive from the ignition, plus earth from the case. At minute im getting nothing. On the back of the tacho someone has wrote by the connectors "ignore" and then has "coil" pointed to the spade connection. Anyone with the same tacho have any ideas? At moment im trying it stationary as car not got front wheels on yet, does the engine need to be cranking, ie car moving for the tacho to work, could this be the reason. Any suggestions at all before I end up buying a new tacho? Many thanks.

Adamirish - 7/9/15 at 07:26 PM

Not sure on the wiring but the tacho should work as soon as you turn the key.

paulf - 7/9/15 at 10:05 PM

There were some smiths tachos that had to be wired in series with the coil feed rather than taking a signal from the coil but not sure if that is one of them , they were used on Mgs and such like.
Paul

MikeRJ - 8/9/15 at 11:10 AM

quote:
Originally posted by paulf
There were some smiths tachos that had to be wired in series with the coil feed rather than taking a signal from the coil but not sure if that is one of them , they were used on Mgs and such like.
Paul

The Smiths RVI tachometer is the model that senses coil current. The RVC (which the OP has) senses voltage on the coil primary.

The RVC tachos usually work fine with electronic ignitions, and the bullet connector is the one that should go to the coil negative side. It's possible someone has been inside and modified it however.

oldmansteptoe - 28/9/15 at 08:27 PM

thanks for the replies fellas and sorry for late reply, been bit busy at work but finally got round to it at weekend. turned out to be simply a duff tacho, tried another smiths tacho and worked no problem. cheers.

think im about ready for MOT now, just in time for Winter!!