Mysterious clicking-broken spring

[Paul Mitchell <paul-m@mweb.co.za>]

I found it! After sending my last email, I nipped back into the garage
for one more look, and spotted it. The valve spring is broken (on the
adjacent valve - I think that was a red herring). So now... I am going
to the UK on boxing day, at which point I can buy all the spares I need.
Until then, I would like to keep running the car. Am I likely to do any
long term damage by running a PI TR6 with a broken valve spring for 3
weeks?

Please say no!

Paul
Cape Town