I have my doubts that the there is a real problem here with Spitfire starters in
general.
Could it be that a loose or partially corroded terminal (internal or external)
resulted in an ohmic contact?. With the very high current load of starting
passing through this small resistance, significant heat will build up.
Components that would not normally melt with clean connections may melt even
after a short 15 to 30 second cranking. Hence as "good" starter can be abused at
times without any damage but a "poor" starter with ohmic connections will
self-destruct earlier than expected.
Vic Whitmore
76 Spitfire
Thornhill, Ontario
Nolan Penney wrote:
>
> 10 seconds on, but how long off? It should be 15-30 minutes to allow
> a good cooling down. Now of course, none of us actually do that.
> We crank and crank and crank, hoping that the motor will act enough
> like a heat sink to allow us to get away with it. Often times you can,
> sometimes you cannot. Most starter motors will allow you to
> get away with upwards of a solid minute of cranking before
> self destructing in a terminal manner. But this does not mean
> that all starter motors will do this.
>
> I will say that my Spitfire has tolerated upwards of 30 seconds
> solid cranking time, with burst after that giving nearly a minute
> of cranking time. Nothing has melted down in the process,
> but I do understand I'm breaking down insulation in the process
> and cutting my motors life short doing this.
>
> To actually melt the plastic housing the hot post sits in, I'd
> speculate that you were cranking...shall we say enthusiastically
> and excessively? :-)
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