Marine Installation Manual
2021-08
3-14
3 Engine Installation
3.8 Engine coupling
X72DF
3.8
Engine coupling
3.8.1
Design
The design of coupling bolts and holes for the flange connection of crankshaft/
propulsion shafts as provided by design group 3114 is included in the engine de
-
sign approval by all major classification societies.
3.8.2
Machining and fitting of coupling bolts
•
Before fitting the coupling bolts ensure that the mating flanges are concen
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tric. Close the gap between the flanges completely by means of min. 4 tem
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porary (non-fitted) bolts evenly distributed over the pitch hole diameter.
•
Carry out drilling and reaming of engine and shaft couplings by means of a
computer controlled drilling machine or an accurately centred jig.
•
In the case of non-matching holes or damaged holes apply joint cylindrical
reaming to an oversize hole and then fit an individually machined bolt.
•
The bolts have to be available for inserting in the holes on completion of
reaming. Each bolt is to be stamped with its position in the coupling, with
the same mark stamped adjacent to the hole. The following tolerances have
to be met:
—
bolt hole tolerance: H7
—
bolt tolerance: g6 (clearance fit)
•
If there is any doubt that a fitted bolt is too slack or too tight, refer to the
classification society surveyor and a representative of the engine builder.
3.8.3
Tightening
•
When tightening the coupling bolts it is essential to work methodically. Per
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form crosswise tightening, taking up the threads on opposite bolts to hand-
tight, followed by sequential torque tightening. Finally ensure the same
proper tightening for all bolts.
•
Mark each bolt head in turn (1, 2, 3, etc.) and tighten opposite nuts in turn
according to the Tightening Instructions, making sure that the bolt head is
securely held and unable to rotate with the nut.
•
Lock castellated nuts according to Class requirements with either locking
wires or split pins. Use feeler gauges during the tightening process to ensure
that the coupling faces are properly mated with no clearance.
3.8.4
Installation drawing
The latest version of the drawing relevant for the
Connection Crank/Propeller
Shaft
(DG 3114) is provided on the WinGD webpage under the following link:
