carboned valve seats
adding starting fluid while running
advancing the timing too far then
flogging the thunder out of it.
you can usually check for carbon by
looking through the window in the
side of the block after your run. :drinkers:
liquids don,t often compress well.
they usually break the ring landing or crack a piston,
lift a head, something along those lines.
if your lucky
i wouldn't chance it.