Techniques of the folded diagram expansion are used to derive an effective interaction for valence nucleons in the 1p0f shell; differences to the applications in the 1s0d shell are discussed. The effects of folded diagrams are investigated developing a technique which does not require the assumption of a degenerate model space. Two-body as well as three-body folded diagrams are investigated. The folded diagrams, but also using a self-consistent BHF basis of single-particle states, reduce the contribution of higher order terms in the expansion. The convergence with respect to the energy of intermediate states is studied employing the Reid soft-core potential and a modern one-boson-exchange potential. Some simple shell-model calculations demonstrate that the resulting effective interactions yields predictions for excitation energies which are in good agreement with experiment.