toyota 3sge engine wanted 2.0 16valve OR HELP ?

toyota engine wanted will do exchange 1991 h g limited 3sge engine non turbo must be a complete block inc cam belts ect without going into too muchrdetail i changed everything on this engine from oil to clutch when warm it knocks under load i.e driving or reving hard can be reved to the limit when cold before optimum temp and no knocking iv done this for at least 5 times and getting confused im very mechanical and can only think it is the wrong belt but have tried the other 2 belts and there too short i was given 3 options of belt and counted the teeth so made sure the belt i was given was the write one as it is a pain in the ass to do also had new tensioner the car was fine for 2 weeks and the problem a cured any help welcome .