d15 and d16
 

I gotta a crx with a d15b6 and the its got rod knock, and click and clack so im wonderin if i just take out the motor itself and replace the motor with a d16, do i need to change the tranny or ecu or any types of conversion, or would it be just bolt and plug and play???

Is it really rod knock, or just the valves? Valve clearance must be adjusted manually to compensate for wear. If the valves are loose, the engine will make a clicking / rattling noise, especially when cold, it will almost sound like a diesel if it is bad enough.

Right, definitely check your valves first... You don't want to replace the whole engine if you don't have to. Valve job much cheaper than a engine swap.