General arrangement and planning
39
Selection of engine
suspension
There are two types of engine suspension; flexible
mounting with rubber mounts and rigid mounting.
Flexible mounting
Flexible engine suspension (rubber mounts) can be
used together with low gear ratios. With higher ratios,
the torsion forces and propeller axial force become
excessive for the rubber mounts.
One condition for rubber mounts to be effective
dampers is that the engine bed is sufficiently rigid.
The bed must also be parallel to engine feet to avoid
tensions being built into the engine suspension. Ten-
sions can increase the vibration level and also short-
en the life span of the mounts.
NOTE! The elasticity of the rubber mounts must nev-
er be utilised to compensate for an inclined bed.
Flexible engine mountings provide good insulation
from vibration between the engine and the bed frame,
thus contributing to a low noise level. Dimensions for
flexible mountings, see chapter Building the engine
bed.
There are two types of rubber mounts: mounts that
are adjustable in the vertical plane, and mounts with
a fixed height that must be shimmed to the correct
height.
Flexible engine suspen-
sion, rubber mount
Flexible engine suspen-
sion, rubber mount
The rubber mounts are compressed during installa-
tion, therefore the engine should rest on the rubber
mounts for 12 hours before the height is adjusted.
Always follow the recommendations of Volvo Penta
when selecting the engine suspension. The use of
incorrect rubber mounts can result in abnormal vi-
brations, which in turn can cause damage to engine
components and also reduce the degree of comfort.
NOTE! When flexible engine suspension is selected,
all the connection of components to the engine must
be flexible.
The propeller shaft must have a flexible stuffing box,
or alternatively a flexible shaft coupling.
The engine’s connections for fuel lines, exhaust and
coolant must be flexible.
To Next Page
Loading...
Need help?
General
