Tightening torques-protractor (angle)
tightening
To ensure service work is correctly carried out it is
important that the correct sealant and locking fluid
type is used on the joint where the agents are re-
quired.
Tightening using both a torque
setting and a protractor angle
requires that first the
recommended torque is applied
using a torque wrench and then
the recommended angle is
added according to the
protractor scale. Example: a
9Q0 protractor tightening
means that the joint is
tightened a further 1/4 turn in
one operation after the stated
tightening torque has been
applied.
In this Volvo Penta Service 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
alternative from a different manufacturer.
Make sure that mating surfaces are dry and free from
oil, grease, paint and anti-corrosion agent before ap-
plying sealant or locking fluid.
Always follow the manufacturer’s instructions for use
regarding; temperature range, curing time and any
other instructions for the product.
Locknuts
Two different basic types of agent are used on the
engine and these are:
Do not re-use lock nuts that have been removed dur-
ing dismantling as they have reduced service life
when re-used - use new nuts when assembling or re-
installing. For lock nuts with a plastic insert such as
Nylock® the tightening torque stated in the table is
reduced if the Nylock® nut has the same head height
as a standard hexagonal nut without plastic insert.
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.
RTV agent (Room temperature vulcanizing). Use for
gaskets, sealing gasket joints or coating gaskets.
RTV agent is clearly visible when a component has
been dismantled; old RTV must be removed before
the joint is resealed.
The following RTV agents are mentioned in the Serv-
ice Manual: Loctite® 574, Volvo Penta 840879-1,
Permatex®
No. 3, Volvo Penta P/N 1161099-5, Permatex® No.
77. Old sealant can be removed using methylated
spirits in all cases.
Tolerance classes
Screws and nuts are divided into different strength
classes, 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
tolerance than one marked 8-8. It is therefore
important that bolts removed during the disassembly
of a bolted joint must be reinstalled in their original
position when assembling the joint, It a bolt must be
replaced check in the replacement parts catalogue to
make sure the correct bolt is used.
Anaerobic agents. These agents cure in an absence
of air. They are used when two solid parts, for exam-
ple cast components, are installed face-to-face with-
out a gasket. They are also commonly used to se-
cure 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 degreased and then
new sealant is applied.
Sealants
The following anaerobic agents are mentioned in the
Service Manual: Loctite® 572 (white), Loctite® 241
(blue).
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 siz-
es in the engines.
NOTE! Loctite® is the registered trademark of Loctite Corporation,
Permatex® is the registered trademark of the Permatex
Corporation.
7
| Categories | Volvo Penta Manuals |
|---|---|
| Tags | Volvo Penta MD6A, Volvo Penta MD7A |
| Download File |
|
| Document File Type | |
| Copyright | Attribution Non-commercial |
(2 votes, average: 3.5 out of 4)
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