[TR] TR2-3 electrical melt downs

[Don Hiscock]

As usual, Jonmac's recollections are gold dust.  I hoard every scrap!
(Thanks for 'em, John!)

Does anyone have an Italian TR2-3A wiring diagram?  These must have existed
originally, yes John?

Rdgs,

Don

On Wed, Jun 24, 2020 at 11:01 AM John Macartney <
John.Macartney at ukpips.org.uk> wrote:

> I think Dave Massey is spot on in highlighting the things that can go
> wrong with old looms. He’s also correct in saying the cars were built to a
> budget and I’d add they were never built to last as long as so many have.
> Ten years was the engineered life expectancy. Dave is also prudent to
> comment on the very limited number of fuses for the US market. However,
> it’s worth pointing out that in the days of yore, cars bound for Italy and
> Sweden had completely different looms. IIRC, Italy spec cars had 12 main
> fuses and Sweden a few less. Sweden also banned the plating that was used
> on all hardware and fasteners and insisted on another form of plating.
> Trouble is, I can’t remember what it was now. So, if you’re planning on a
> new loom, get one made in Italy to original spec. Magneti Marelli used to
> have a subsidiary that made them.
>
> Jonmac
>
> At the Battle of Waterloo, 1815:
> Lord Uxbridge:  “By God, Sir - I’ve lost my leg”
> Duke of Wellington: “By God, Sir - so you have!”
>
>
> On 24 Jun 2020, at 15:52, bill beecher <notakitcar at yahoo.com> wrote:
>
> I counted, I only have two(2) fuses on my ‘58 TR3.   Where might the other
> be?
> Thx,
> Bill B
> TS30800L
>
> Serenity Now......
>
> On Jun 24, 2020, at 9:38 AM, DAVID MASSEY <dave1massey at cs.com> wrote:
>
> 
> Keep in mind that these wire harnesses, like the car as a whole, was
> designed to a budget.  These harnesses had three (count 'em, 3) fuses.  As
> such some items were unfused like the headlamps and the coil.  And those
> things that are fused shared a fuse so the fuse had to be sized to carry
> the current for everything on that circuit.  But the wires were sized for
> the particular load.  A thinner wire will have a nigher resistance and
> under  short-circuit conditions the current can be limited to a level that
> will not blow the fuse but the current will cause enough heating to cause
> the insulation to melt.
>
> Another factor against us is the age of the harness.  The connector
> contacts get corroded and will get hot under normal circumstances.  Wire
> strands can fatigue and break within the insulation again resulting in
> overheating under normal use.  The insulation gets stiff and cracks
> exposing the wires within.  Lots of potential failure modes here.
>
> Compare this design to those found in modern cars you will see dozens of
> fuses.  Sure there are a lot more electrical items but most things have
> their own fuses.  This means you can size the fuse more appropriately for
> the wire used to power that device.  Also the connectors used are water
> tight and don't corrode as quickly.  Also, they are, on the whole, a lot
> younger and therefore retain more of their original integrety.
>
> But a fresh works well enough so if you fear a melt-down a new harness may
> be a good investment.
>
> Dave
>
>
>
> -----Original Message-----
> From: bill beecher <notakitcar at yahoo.com>
> To: Tom Householder <trhouse at columbus.rr.com>
> Cc: Triumphs at Autox.team.net daily digest <triumphs at autox.team.net>; FOT
> List <fot at autox.team.net>
> Sent: Tue, Jun 23, 2020 8:52 am
> Subject: Re: [TR] TR2-3 electrical melt downs
>
> Have a friend with a TR6 that had a significant meltdown behind the dash.
> I should think, given the right set of weaknesses, most any section could
> melt.
> Bill B
>
> Serenity Now......
>
> On Jun 23, 2020, at 4:52 AM, Tom Householder <trhouse at columbus.rr.com>
> wrote:
>
> Over the years I have experienced and seen harness melt down in the looms
> to the tail lights .. anyone ever had an under dash melt down?
>
> Trying to answer a question asked of me.
>
> Tom
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