Engine type classification
All the engines dealt with here are related in terms of their design and make up a family. The type classification, which is made up of a series of letters and numbers, reveals some of the features of the engine in question provided the reader is familiar with the underlying nomenclature. The system is explained here using the type D 2876 LUE 601 as an example:
- D The “D” at the start of the type classification stands for “diesel”.
- 28 The numbers “28” indicates that the power plant in question has a bore of 128 mm.
- 7 The “7” means 170 mm stroke This figure is, however, only approximate for this model. The
- actual stroke is 166 mm.
- 6 The “6” indicates the number of cylinders 6
- L This letter stands for “charge-air cooling” (German: Ladeluftkühlung)
- U The “U” stands for “Underfloor”
- E The “E” stands for “fitted engine” (German: Einbaumotor) and is intended to distinguish MAN vehicle engines
- 601/6.. This is a factory-internal development number.
Removing and installing the cylinder head
General notes
The sealing effect of the cylinder head gasket depends mainly on whether the required initial tension of the cylinder head bolt is actually achieved and retained. Use calibrated torque wrenches to tighten the cylinder head bolts. The specified final torque must be maintained for at least 5 seconds when it is applied. When using snap-type torque wrenches, tighten the bolts gradually as otherwise the torque selected will not be fully transferred to the bolts. Observe the notes on the usability of cylinder-head bolts, tightening sequence, and prescribed tightening method in the chapter “Service Data”.
Tightening
“Tightening” is defined as the initial tightening of newly fitted bolts that have not been tightened following a repair - e.g. after replacement of the cylinder head gasket. Tighten cylinder head bolts while the engine is cold, i.e. the crankcase is warm to the touch or colder. Before inserting the cylinder−head bolts, apply engine oil to the thread (not the threaded hole) and coat the seating surface of the bolt head with installation paste “Optimoly White T”. Do not use oils or oil additives containing MoS2. In the case of unoiled bolts, a significant amount of the tightening torque is converted into friction and is thus lost for bolt pretensioning.