Bukh DV36/48, Workshop Manual

Page: 77 / 196

IJ3
009W2329-R01
Disassembling of Pistons and Connecting Rods
1. Drain off the cooling water and the lubricating oil from the engine.
2. Dismount the cylinder head (see section C).
3. Remove any wear or soot edge which may be at the top of the cylinder liner with a scraper.
4. Turn the engine “upside down”.
5. Remove the oil pan.
6. Unscrew the connecting rod nuts and remove the bearing cap from the connecting rod.
7. Fit the connecting rod bolts with protective caps (soft plastic hose or the like) in order
to avoid the crank being damaged.
8. Turn the piston in top position and press out the piston and the connecting rod of the
cylinder liner. The crank must be in the exact top position.
Note! On later engines the connecting rod nuts have been replaced by unbraco
screws and therefore item 7 can be omitted.
Assembling of Pistons and Connecting Rods
1. Put a slip ring over the cylinder liner.
(The slip ring may be made from a worn out cylinder liner , of which 2/3 should be re-
moved and the remaining 1/3 should be turned weakly conical in the top end wanted.)
2. Place the crank in the top position.
3. Fit the connecting rod bolts with protective caps.
4. Lower the piston and the connecting rod down into the cylinder liner by means of the slip
ring and do observe that the piston ring gaps are staggered. It should further be checked
that the recess in the piston head is turned towards the fuel valve. Before fitting the
pistons and connecting rods lubricate the crank journals abundantly with lubricating oil.
5. Place the engine on the side or turn it “upside down”.
6. Remove the protective caps.
7. Fit the bearing cap with the bottom bearing shells.
8. Tighten the connecting rod nuts with a torque of 69 +/- 3 Nm (7 +/- 0.3 kpm). Use self-
locking nylon nuts for the connecting rod bolts and replace the nuts after each
disassembling of the connecting rod.
Note! The numbers on the connecting rod must be placed as before the disassembling
of the engine and the numbers on the connecting rod and bearing cap must fit.
The bearing cap and the connecting rod are guided by two balls which you must have
in mind when assembling.