Just for your info the Lycoming 0-235 a la C152 has an overhaul life of 2200 hours, although some Lycomings have a life of 2000.
Dependant on compression etc, a top end overhaul may prove necessary before the zero timing by overhauling is required which costs about £7k++ whereas a factory fresh lump is £20k ish. Feed throttle gently!!