do i need to break in my engine?

[RC TTwins]

ok i had a losi 427 and was bashing it around and say i broke the houseing open so i bought a losi parts and used the casing to rebuild the engine do i need to rebreak in my engine?

[roadrashracing]

did you get a new piston sleeve?

[Duster_360]

If you didn't replace the piston and sleeve, I don't see any reason for another breakin. Main purpose of breakin is to get the piston mated or runin to the sleeve.