I rebuilt my engine in november, currently breaking it in running Castrol GTX 10w-40. Did the first oil change after the car ran for about 30 mins, will change the oil again with conventional at 1000 kms. Then at 3500 kms I will be switching to Motul 5w-40. Like others said, make sure to keep a close watch on your oil level, and keep in mind that the break in period is very important and will determine how well the engine performs and lasts in the future.
Btw you are getting a new engine as in a used one with lower kms? or building your motor?
Last edited by bg.; 12-06-2012 at 05:31 AM..