M62 V-8 ENGINES USED IN THE E-39 540 AND E-38 740 ARE NOTORIOUS FOR FAULTY TIMING CHAIN GUIDES. AT AROUND 125,000 THE PLASTIC CAN DISINTEGRATE CAUSING THE CHAIN TO SKIP A TOOTH. ONCE A TOOTH IS SKIPPED THE VALVES ARE CRUSHED AND THE ENGINE IS DESTROYED. THE COST TO REPLACE THE GUIDES IS EXTREMELY EXPENSIVE. I WAS LUCKY IN THAT I REPLACED MINE AT 140,000 MILES