new engine rebuilt
 

hi everyone..
im new here and i have a question.
this is the second time that my engine destroyed because main bearing failure.
now im recived my new engine and im thinking to replace the main bearing with king/ acl bearing.
what do you think about this? any suggestion?

I think if you are asking for more problems if you replace the bearings. You are more likely to cause the very problem you seek to avoid.

Figure out what you did wrong with the first motor, and don't do that again. If you don't do something stupid, these motors will last 300k+ miles of enthusiastic use.

Every motor I've had come through my shop that had issues, has had worn mains. I tell everyone I know that gets a used engine "replace the bearings before you put the motor in" It's cheap and can save you a future headache. You just need to make sure the journal bores on the block and the journals on the crank are within spec.
Anyone telling you it's a bad idea to replace bearings is ignorant and does not speak from any experience.

So if your going to replacing them go OEM and fitted by someone who knows how to

Except he doesn't have a motor with issues. His old motor had issues, and now he's getting a 'new' motor (presumably a decent used motor without issues).

Taking it apart to fit aftermarket bearings is not a good idea imo.

So is it an 09MY check end float also, how many miles ?

You don't notice main bearings issues until its too late. Main bearings on these motors wear down. period. and 99.9% of the time the center main. How many of these engines have you taken apart and inspected?

None. But I know there are people with 300k+ miles on their original motor, that is still going strong. So its not like stock bearings fail on all motors.

I maintain that just blindly replacing mains with aftermarket bearings is not a good idea.