[Mgs] Electronic Tach

[james.f.juhas at snet.net]

I would like to retain some semblance of originality and use an MGB tach, but I don't have enough time to find one that's reliable and available.  Next race event is in less than two weeks and I'm repairing engine damage from this weekend.  So I think I need a modern solution.  Thanks for the guide to what numbers mean what.  Good for the future replacemnt.

Jim
MGA #311

-----Original Message-----

From:  "Paul Hunt" <paul.hunt1 at blueyonder.co.uk>
Subj:  Re: [Mgs] Electronic Tach
Date:  Sun May 9, 2010 6:32 am
Size:  1K
To:  "David Breneman" <david_breneman at yahoo.com>; <mgs at autox.team.net>

Indeed.  There are two types though, a current pulse triggered that would 
need you to reroute the coil feed wire from the ignition switch via the tach 
pickup (no other circuits should be fed from this wire), and the later one 
that simply needs a tapping off the coil SW terminal run to it.  The former 
have an RVI number on the dial, and the latter used from 1973 an RVC number. 
Originally 4" which I'm guessing is the same size as your speedo, American 
instruments changed to 80mm in 1967, but back to 4" in 1977, albeit with 
different bezels for 1980, I believe.  UK cars kept the 4" dials until 
rubber bumpers in 1974, then they changed to 80mm and stayed that way. 
There may well have been other British cars that used 4" RVC tachs when the 
MGB had changed to 80mm.

PaulH.

----- Original Message ----- 
> Why not use an MGB electronic tach?  The early ones
> look
> just like an MGA tach except for the trim piece over the
> shaft, and that
> they say "Smiths" instead of "Jaeger".

>> I need to install an electronic tach
>> in my MGA race car.  The cam that's going in has no
>> tach drive and I don't have the luxury of waiting for a cam
>> with a drive.  Recommendations on an aftermarket
>> tach?  What diameter housing? It will go in the
>> dash.
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