rebulding head: do I need to replace springs?

[JanDebL at aol.com]

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[ Picked text/plain from multipart/alternative ]
When I was younger and worked as a mechanic we tested all the springs to
insure they met the specifications in the rebuild manual.  Basically, the
tester was a small press with an adjustable height setting and a pressure
scale.  Some springs are designed with a linear rate while others are
designed with a progressive "curve." For a given spring length (or height)
there was a corresponding pressure specification.  Most American industrial
engines had decent springs which were seldom out of spec., even after many
thousands of operating hours.  Most American auto engines had marginal
springs which were seldom reusable - in fact some of the new springs were
barely in spec.  Even some of the aftermarket high performance cam
manufacturers had quality control issues and sold a shim pack which you added
shims under the spring to meet the tension spec.  I suspect the Germans make
decent springs but if the engine has been run excessively hot to the point
where the temper in the springs were effected, there may be a need for some
concern.  I shouldn't cost much to have the springs tested and might be worth
the piece of mind.  Most rebuilders will also verify the new springs are
within specs.
Good luck, Jan