Outer Limits 4x4 Board

ok i know nothing about these motors but i need some advice so try and take it easy on me if the questions dont make sence. i have read all the info on people cracking there heads on these motors but im wondering if someone can tell me around wat km mark this happens? the car im looking at buying as 210,000kms on it and it hasnt been reconditioned or rebuilt, how long can these motors go without being reconditioned?
hope somone can help me
thanks

mine went at 250k but ive seen em at 300 tho 350 still goin strong