841279 Volvo.Penta Nut

Measurement of Pressure In Inlet Manifold
Table 1
Tools Needed    
Part Number     Part Name     Quantity    
1U-5470     Engine Pressure Group     1    The efficiency of an engine can be checked by making a comparison of the pressure in the inlet manifold with the information given in the TMI (Technical Marketing Information). The information is also listed on the Fuel Setting And Related Information Microfiche. This test is used when there is a decrease of horsepower from the engine, yet there is no real sign of a problem with the engine.The correct pressure for the inlet manifold is listed in the TMI (Technical Marketing Information). The correct pressure is also on the Fuel Setting And Related Information Microfiche. Development of this information is performed under the following conditions:
99 kPa (29.7 in Hg) dry barometric pressure
29 °C (85 °F) outside air temperature
35 API rated fuelOn a turbocharged engine, a change in the fuel rating will change the horsepower. A change in the fuel rating will change the inlet manifold pressure. If the fuel is rated above 35 API, the inlet manifold pressure can be less than the pressure given in the TMI (Technical Marketing Information). The pressure will be less than the pressure listed on the Fuel Setting And Related Information Microfiche. If the fuel is rated below 35 API, the inlet manifold pressure can be more than the pressure listed in the TMI (Technical Marketing Information). The pressure can be more than the pressure that is listed on the Fuel Setting And Related Information Microfiche. Note: Ensure that the air inlet and the exhaust are not restricted when you are checking the inlet manifold pressure.
Illustration 1 g00434159
Pressure test location on inlet manifold (1) Plug
Illustration 2 g00293196
1U-5470 Engine Pressure Group To measure the inlet manifold pressure, remove plug (1) from the inlet manifold. Use the 1U-5470 Engine Pressure Group in order to check the inlet manifold pressure. The Special Instruction, SEHS8907 contains instructions for the tool.Exhaust Temperature
Table 2
Tools Needed    
Part Number     Part Name     Quantity    
123-6700     Laser Infrared Thermometer     1    Use the 123-6700 Laser Infrared Thermometer to check exhaust temperature. The Operator's Manual, NEHS0630 contains the complete operating and maintenance instructions for the 123-6700 Laser Infrared Thermometer .Crankcase Pressure (Crankshaft Compartment)
Table 3
Tools Needed    
Part Number     Part Name     Quantity    
8T-2700     Blowby/Air Flow Indicator     1    Damaged pistons or rings can cause too much pressure in the crankcase. This condition will cause the engine to run rough. There will be more than the normal amount of fumes (blowby) rising from the crankcase breather. The breather can then become restricted in a very short time. This can cause oil leakage at the gaskets and at the seals that would not normally have leakage. Blowby can also be caused by worn valve guides or by a failed turbocharger seal.
Illustration 3 g00286269
8T-2700 Blowby/Air Flow Indicator The 8T-2700 Blowby/Air Flow Indicator is used to check the amount of blowby. The Special Instruction, SEHS8712 contains the test procedure for checking the blowby.Compression
An engine that runs roughly can have a leak at the valves. An engine that runs roughly can also have valves that need an adjustment. Remove the head and inspect the valves and valve seats. This is necessary to find those small defects that would not normally cause problems. Repairs of these problems are normally performed when you are reconditioning the engine.Valve Lash
To prevent possible injury, do not use the starter to turn the flywheel. Hot engine components can cause burns. Allow additional time for the engine to cool before measuring valve clearance.