>From Kevin:
> I've replaced both ignition relays several times now.
> I can't seem to get them to last more then 2 weeks.
> Anyone have any ideas what would kill a relay?
A 77 MGB has two relays. The one foward of the fuse block is the ignition
relay, the one aft is for the starter. And if I've done any serious work
on the car, there will also be one for the fan mounted way foward. :>
Only two things can kill a Lucas relay, excessive power consumption on the
load leg, or excessive voltage on the windings. By design, the B runs a
fair chunk of power through the ignition relay so that the normal life is
around ten years. This is why I recommend a seperate fan relay. Wired
correctly, this will remove the fan load from the main relay, *and* from
the thermo switch in the radiator.
To kill a relay in two weeks time with load, I would expect fuses to blow,
or wires to melt, first. We are talking on hell of a load to cook the
switch contacts that fast. The more likely possible is winding death due to
excessive voltage. I have seen voltage regulators fail such that they apply
upwards of 24 volts to the system, though it's *rare* with a Lucas ACR
system. If the voltage is high enough to fry the relay windings, it will
also pop light bulbs.
Enough rambling. To directly answer you're implied question, this is not a
normal occurance. Therefore there is no canned answer; rather a bunch of
questions.
Are you sure the relays are dead?
If so, have you ohmed them to see what part died?
What brand/model relay are you using for a replacement?
Is there any unusual car behavior, or any electrical additions, deletions,
or re-engineerings?
And, finally (grin), what are the symptoms when the relay fails?
Randy
randy@taylor.wyvern.com
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