Well it seems my post about where to buy gasoline 'sparked' a very
interesting thread. Lots of info that shows the broad knowledge base
of this group. So, here's another.
We just finished rebuilding the V-12 in an XJS (why, you might
ask). At one point we told the customer that we had driven the car
and were now going to re-torque the cylinder heads. She assumed
that we had done something wrong and needed to correct it. We
explained about heat-cycles and re-torque and she understood, but
asked why she had never had to have the heads re-torqued on her
other (new) cars.
I've rebuild countless engines over the last 30-40 years and
always retorqued the heads after a heat cycle. Sometimes, like with
a Stag, we might re-torque 10 times before things stop moving.
Everybody in the shop (7 guys) agree that you always re-torque after
a rebuild. How come new engines don't need to be re-torqued? I've
never heard of taking a car back for it's 1000 mile re-torque. Maybe
they did this years ago, pre-war?, but I don't know.
Does everybody always retorque? On a race engine? Why don't
new engines need this? Only the cylinder head? Inquiring minds
want to know, plus I'd like to be able to give my client an answer.
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