You could be a bit more descriptive, but no amount of forum advice will cure a knocking engine.
Is it knocking, tapping, ticking, clonking, and is it when cold, warm, both. Top of engine, bottom, geabox, when turning, braking, accelerating........?
I should just take it to the garage mate. Diagnosing noises on forums is never eay or accurate.
Good luck, hope you sort it.
I've edited this simply to acknowledge that you posted before I did!
If it is bottom end then you already have your answer. Get a new short engine if you can, don't mess about trying to fix the old one.