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The nature of period and amplitude changes in nonradial pulsators ispresently unknown. It is therefore important to examine the correlationsbetween these changes in stars with a large number of simultaneously excitedpulsation modes. However, the small amplitudes require extensive high-precisionphotometry covering many years. We present 702 nights of high-precisionphotometry of the evolved Delta Scuti variable 4 CVn obtained from 2005 - 2012with a dedicated telescope. We detected 64 frequencies, of which 38 can beidentified as combinations and harmonics. The relative amplitudes of thecombination frequencies are similar to those found in 44 Tau and show noevidence for resonant mode coupling. Significant period and amplitude changesare detected for the dominant modes. The known prograde and retrograde modesshow period changes with opposite signs, while the radial mode exhibits onlysmall, cyclical period changes. For each mode, the period changes are constantover the eight years and range from (1/P)dP/dt = -16 to +13 parts per million.On the other hand, the amplitude variations show no systematic behavior betweendifferent pulsation modes. The behavior of the prograde, axisymmetric, andretrograde modes indicates a constant decrease in the rotational splitting overthe eight years.

Nonradial and radial period changes in the Delta Scuti star 4 CVn I. 700+ nights of photometry