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Piston/piston rings
Special tool:
(998) 5423 Piston ring pliers
NOTE!
To prevent damage to the piston cooling nozzles,
they must first be removed before removing piston
and connecting rod.
1.
Remove the piston and connecting rod.
2.
Measure the piston ring clearance.
3.
Remove the piston rings. Clean the piston and pis-
ton ring groove.
Checking piston rings
Check all surfaces for wear. Dark spots indicate
poor contact. Where this is the case, replace the pis-
ton rings.
Replace the piston rings if there is notable wear or
out-of-round, which would make it difficult to fit
the rings in their original positions.
Heavy oil consumption could also be a reason for
replacing piston rings.
4.
Measure the piston ring gap.
Checking pistons
Check for cracks, broken-off sections between the
piston ring grooves and also for groove wear. Pis-
tons with seizure marks on the jackets must be
scrapped.
The piston should also be renewed if there is one or
several cracks in the gudgeon pin seat or in the bot-
tom of the combustion chamber.
Piston renewal also means replacing the gudgeon
pin, piston rings and cylinder liners as a complete
unit.
0.50 mm
0.40 mm
0.50 mm
0.13 mm
0.09 mm
0.05 mm
5.
Use piston ring pliers when fitting the piston rings.
