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Smith speedos and TR250s

To: alliant!british-cars@EDDIE.MIT.EDU
Subject: Smith speedos and TR250s
From: uunet!sco.COM!banta@EDDIE.MIT.EDU (Beast)
Date: Wed, 14 Feb 90 6:38:20 PST
> Can someone out there with a TR250 give me an idea of what a TR250
> does for mph/1000RPM in top? I can't figure out what my speedo's
> trying to tell me.

Can't help you here.

> Also, a common failure mode for Smiths speedometers seems to be the
> needle jumping around where it's supposed to be. Anybody have any idea
> what causes this? It's happened to both of mine, I took one apart and
> I couldn't immediately see what would cause this.

When I pulled my Jaeger apart for the same problem, this is what I 
encountered.  The shaft the needle is attached to has a needle
bearing at its back end.  Either the needle (point at back end of
shaft) or seat had worn a little or something had loosened up, and 
the shaft had some lateral play.  When in operation, the disc would
rub slightly on the dish. If you've pulled it apart, you understand
what I'm talking about.  I have no good diagrams to work from and
memory is fuzzy on exact placement of bits.

Anyway, the needle bearing seat is threaded into a hole in the
bracket.  There was a dot of glue holding it in place.  Break the
glue off (carefully!), tighten the seat enough that there is no more
lateral play in the shaft, and apply a dot of appropriate adhesive
(I used Dow Household Cement, anything along those lines should do).

My repair has been operational for about 8 months now.  If you don't
feel like tackling it, there are places that will rebuild your
speedo for about $50.  (plug) British Motorsports in the South Bay
(Campbell, CA) does.

Note: Carefully examine how the speedo is assembled before taking
any parts off to perform this task.  In fact, if you have a
polaroid, take pictures of it from several different angles before
starting.  No manual I have ever seen has detailed diagrams of how
these beasties go together.

andy
uunet!sco!banta



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