In theory no, since there is no mechanical dependency between the two. But
after doing any work on the engine it is only a moments work to check the
timing and it makes sense to do so.
More of an issue is just what to set the timing to. When the factory
figures were first published they related to brand new engines, whereas ours
now have varying degrees of wear and various replacement parts that may or
may not be to spec, and the fuels we generally have access to these days are
very different to those available originally. Even when new, the
manufacturers figures took account of a range of manufacturing tolerances
which could vary the point at which pinking onset, plus a safety margin, and
it is the maximum amount of advance that can be run without pinking that is
really the objective.On a then new car I found I could run 2 or 3 degrees
more advance without pinking, and that gave me noticeable more performance
and economy than the book figures. Today's lower octane fuels are more
likely to pink than the originals, and so you could well find you can't run
with the original book figures. So the best figure for any engine is the
most advance it will take without pinking at any combination of throttle
opening, revs and load. Of course this will vary depending on factors like
steepness of gradients and possibly altitude, so the same car may need
slightly altered timing in one part of the world from another.
PaulH.
> ------- Start of forwarded message -------
>
> I am thinking about removing all of the EEC systems from my 72 mgb. My
> question is this. Does removal of the air pump require re-timing?
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