Tightening torque with Protractor tight-
ening (angle tightening)
Tightening using both a torque setting and a protractor
angle requires that first the recommended torque is ap-
plied using a torque wrench and then the recommended
angle is added according to the protractor scale. Ex-
ample: a 90° protractor tightening means that the joint is
tightened a further 1/4 turn in one operation after the
stated tightening torque has been applied.
Lock nuts
Do not re-use lock nuts that have been removed during
dissassembly
operations as these have reduced ser-
vice life when re-used - use new nuts when assem-
bling or reinstalling. For lock nuts with a plastic insert
such as
Nylock®
the tightening torque stated in the ta-
ble is reduced if the
Nylock®
nut has the same head
height as a standard hexagonal nut without plastic in-
sert. Reduce the tightening torque by 25% for bolt size
8 mm or larger. Where
Nylock®
nuts are higher, or of
the same height as a standard hexagonal nut, the
tightening
torques
given in the table apply.
Strength classes
Bolts and nuts are divided up into different classes of
strength; the class is indicated by the number on the
bolt head. A high number indicates stronger material,
for example a bolt marked 10-9 indicates a higher
strength than one marked 8-8. It is therefore important
that bolts removed during the disassembly of a bolted
j
oint must be reinstalled in their original position when
assembling the joint. If a bolt must be replaced check in
the replacement parts catalogue to make sure the cor-
rect bolt is used.
Sealant
A number of
sealants
and locking liquids are used on
the engines. The agents have varying properties and
are used for different types of jointing strengths, oper-
ating temperature ranges, resistance to oil and other
chemicals and for the different materials and gap sizes
i
n the engines.
To ensure service work is correctly carried out it is im-
portant that the correct sealant and locking fluid type is
used on the joint where the agents are required.
I
n this Volvo Penta Workshop Manual the user will find
that each section where these agents are applied in
production states which type was used on the engine.
During service operations use the same agent or an al-
ternative from a different manufacturer.
Make sure that mating surfaces are dry and free from
oil,
grease, paint and anti-corrosion agent before apply-
i
ng sealant or locking fluid. Always follow the manufac-
turer's instructions for use regarding temperature range,
curing time and any other instructions for the product.
Two different basic types of agent are used on the en-
gine and these are:
RTV
agent (Room temperature vulcanizing). Used for
gaskets, sealing gasket joints or coating gaskets.
RTV
i
s visible when a part has been disassembled; old
RTV
must be removed before resealing the joint.
The following
RTV
agents are mentioned in the Service
Manual:
Loctite®574, Volvo Penta P/N 840879-1,
Per-
matex® No. 3, Volvo Penta P/N 1161099-5,
Permatex®
Nr
77. Old sealant can be removed using
methylated
spirits in all cases.
Anaerobic agents. These agents cure in an absence of
air.
They are used when two solid parts, for example
cast components, are installed face-to-face without a
gasket. They are also commonly used to secure plugs,
threads in stud bolts, cocks, oil pressure switches and
so on. The cured material is glass-like and it is therefore
colored to make it visible. Cured anaerobic agents are
extremely resistant to solvents and the old agent cannot
be removed. When reinstalling the part is carefully de-
greased and then new sealant is applied.
The following anaerobic agents are mentioned in the
Workshop Manual:
Loctite®572 (white), Loctite®
241
(blue).
Note:
Loctite®
i
s the registered trademark of
Loctite
Corparation
,
Permatex® the registered trademark of the
Permatex
Corporation.
7
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