My b18c engine is knocking. Mechanics say its the lower end that needs to be looked at. Should I rebuild or buy a longblock from hmotorsonline?

 

if the engine is knocking, very possibly it's a rod knock so you spun the bearing.

Depending how severe you might be able to get new main and rod bearings installed and it might work fine...but if the rod knock has damaged the crankshaft then you will either need a new crankshaft or your old one repaired.

If you are paying for all this, I would just personally rather get a new longblock and in your spare time take apart your old one and do a rebuild on it