Tightening torque with Protractor tight- ening (angle tightening) 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. 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. 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. Lock nuts 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.
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. 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. Strength classes The following anaerobic agents are mentioned in the Workshop Manual: Loctite® 572 (white), Loctite® 241 (blue).
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 Note: Loctite® i s the registered trademark of Loctite Corparation , Permatex® the registered trademark of the Permatex Corporation. 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. 7