Mercedes Engine MBE 900 Series

Last three weeks we have been working on disassembling a MBE 906. My partner and I began by removing the EGR system followed by the cylinder head cover revealing the rocker arm assembly. After removing the rockers we then pulled the cylinder head by reversing the head bolt torquing sequence. The head was then measured with a straight edge and feeler gauges for warping in addition to measuring its height for excessive wear.

We then dropped the pan to reveal the crank shaft and connecting rods. We dropped the number 1 piston to bottom of the cylinder to gain access to the connecting rod bolts. We found that the connecting rods and bearing caps were a fracture-split style. The rod is etched at the factory by a laser then "snapped" to create a perfect match between the rod and bearing cap. We checked the rod for discoloration and measured the bearing in the small bore after removing the wrist pin to ensure it was within specs. We also re-attached the caps with the bearing bushing installed and torqued it to specs in order to measure for our tolerances. Seeing as this engine has had a long and hard life in addition to playing guinea pig for all of the diesel students, many of the tolerances were out of specification.

 Tolerances for connecting rods

BTC Hours/Shop Hours for past 3 weeks: 96
Running Total Fall Qt.: 156