At 01:28 PM 3/16/2005, you wrote:
>Seems to me that the claim that the 'wire' resistance increases with age is
>suspect.
>
>Nice to see that Lucas is close but like his namesake perhaps needs a bit
>better grounding in the materials science area.  I do not know of a derating
>curve for copper vs time.  Not saying that I have all the resources but it
>is likely that if that was the case MOST 20yr old electric motors would
>exhibit the symptoms of copper aging referred to in the article.

Well, without a specific example of exactly how the Bosch starters were
weaker than (for example) the starter on my '79 Dodge van (still on its
original starter, but its 12th or 13th alternator), it's hard to say what
he means by that. Presumably he's referring to corrosion, or perhaps
cumulative mechanical stress of flexion reducing the diameter of the
windings at certain points due to a design weakness, since (as you say)
copper is copper is copper, regardless of age. I wish he'd said how he'd
tested "bad" starters, and how high the resistance was compared to a "good"
one. At any rate, it's not surprising that so many rebuilt starters turn
out to be marginal. The less picky a rebuilder is with cores, the better
the profit margin. Corroded spot on the windings? Wire brush, slap a little
lacquer over it, and if it works, SELL IT!