ID Smiths Tach please

[IamScotticus]

Could someone ID this Smiths?  Is it worth a restoration service?

 

[Croc]

Have a chat with Nisonger Instruments

https://www.nisonger.com/

 

 

My bet is they tell you to forget about it.  They would not repair my 2004, 2010 or 2018 speedos.  Their unofficial rule is to only repair within the last 4 years of manufacture.  Sad. 

 

If you want to repair then your best bet will then to be send it to a UK specialist. 

[IamScotticus]

I won't bother unless it's a Chronometric. 

[wdb]

It seems like everything you need to know is on the back of the tach. Besides whether or not it works of course! The telltale is a nice thing, never saw one on the Smiths gauges in the BLMC cars I worked on. 

Edited November 18 by wdb

[IamScotticus]

9 minutes ago, wdb said:

It seems like everything you need to know is on the back of the tach. Besides whether or not it works of course! The telltale is a nice thing, never saw one on the Smiths gauges in the BLMC cars I worked on. 

but googling that number isn't getting me anywhere.

Regardless, looking at Chronometrics, I see they usually have it printed on the face, so this may not be one.

[11Budlite]

I'm pretty sure that's not a chronometric tach. I remember seeing a tach just like that advertised in some of the old British car magazines. It looks more like an aftermarket Smiths tach that you would install on a car that didn't come with a tach originally. I don't believe that's a telltale either, but more of an adjustable redline indicator which would make sense if it was to be used on multiple vehicles. Just my two cents.

[IamScotticus]

Ok, I learnt something. 

The model number is on the faceplate.  The sticker is the inspector number.

And yes, the red needle is not a true telltale.

 

What we have here is a generic points or electronic compatible tach.

 

I found this gem from dklawson:

Warning:  Technobabble to follow.

RVI tachs are often called impulse tachs.  They are wired in series with current flowing through the ignition coil.  They do not actually "touch" the ignition system.  A loop of wire (either inside the case or literally looped on the back) inductively couples current pulses flowing through the ignition system wiring to the "counting circuit" inside the tach.  (Failure of an RVI tach means the gauge may not work but your engine will still run).

RVC tachs are a later, more modern design.  They use a single sense wire connection to the "low side" of the ignition coil.  They count the voltage swings between 0V and 12V each time points open and close.  (Failure of an RVC tach MAY result in an engine that won't run if the gauge experiences an internal short).

 

RVI tachs expect the ignition coil current pulse to be on and off for prescribed percentages of time.  Because electronic ignitions don't turn on and off the same way points do, the RVI tachs are typically unhappy and refuse to work when wired with electronic ignitions.  RVC types (because they effectively count voltage pulses) work happily with points and most electronic ignitions.

https://www.theminiforum.co.uk/forums/topic/284095-2-types-of-smiths-rev-counter/

Edited November 18 by IamScotticus

[7Westfield]

Chronometric = mechanical drive

 

Nisonger has been out of the repair business for several years

6 feet of flood water thru the shop and parts inventory

Edited November 18 by 7Westfield

[toldfield]

Try North Hollywood Speedometer Repair 

 

Nhspeedometer.com