Diagnosis of cylinder block malfunctions relative to cooling and lubrication have been discussed in those respective systems. The potential problems with cylinder, the camshaft bore and the crankshaft main journals has also been discussed in this section. Malfunctions of the cylinder block such as leaks, tappet bore wear, etc. require a visual or dimensional inspection… Read More »
Improper maintenance of the lubrication system is also the primary cause of reduced main bearing life. A malfunction of the crankshaft/main bearing will usually be detected by reduced lubricating oil pressure. As with rod bearings, continued operation with low lubricating oil pressure will lead to a rapid deterioration of the bearings and eventually will produce… Read More »
There are a number of power related problems including excessive lubricating oil consumption, smoke, blowby and poor performance that can be caused by inadequate sealing between the piston rings and the cylinder walls. A blowby measurement can help detect the problem. Verification of the damaged or worn component requires visual/dimensional inspection of rings, pistons and… Read More »
Excessive valve lash can indicate a worn valve stem or rocker lever. Loose rocker levers and the need to re-set the valve clearance frequently, can also indicate camshaft lobe or tappetwear. If an inspection of the levers, valve stems and push rods does not show wear, then tappet and/or camshaft lobe wear can be suspected.… Read More »
NOTE: There are two different design vibration dampers used: • Viscous damper (A) for certain marine engines and some automotive applications • Rubber element damper (B) for all other applications As previously discussed in the fuel system, replacement of the gear housing or the timing pin assembly necessi tates a realignment of the pin assembly… Read More »
Troubleshooting the front gear housing and gear train consists of checking for leaks at the gaskets (front cover, timing pin assembly and fuel injection pump) and the front crankshaft lubricating oil seal, inspecting the gears and measuring backlash when required. Refer to Procedure 7-16 to replace the front crankshaft oil seal. Gear noise emitted from… Read More »
Injector protrusion can affect power from the engine. In addition to a single sealing washer (A) on the injector, the thickness (B) of the head gasket controls injector protrusion. Thicker service head gaskets are used when the head surface on the block has been refaced. After machining, the block is identified as follows: After determining… Read More »
Worn valve seals are typically detected by excessive smoke at idle or when the engine is unloaded when the vehicle is going down hill. Verify the condition by removing the valve spring and inspecting the valve seals. Hardening of the material and wear or damage to the sealing surfaces will cause the valve seal to… Read More »
If the air and fuel system are functioning correctly, perform a compression check to determine whether the problem is: • Piston ring sealing • Valve sealing • Cylinder head gasket sealing or a crack in the cylinder head Piston Ring Sealing If the compression is low but can be increased significantly by squirting lubricating oil… Read More »
Verify that the valves are adjusted correctly. Refer to Procedure (7-04).