INSPECTING AND TESTING THE ENGINE FRAME OR BLOCK
Before you begin an inspection or test, make sure the outside of the engine is cleaned thoroughly. This will help you spot cracks, leaks, and other problems more easily than if the engine is dirty. By cleaning the engine, you will also help prevent dirt and other contaminants from entering and damaging parts and accessories of the engine.
Some of the inspections and tests you may perform are listed in the following sections.
VISUAL INSPECTIONS
Inspect the top surface of the cylinder block, the top and bottom crankcase flanges, and the oil pan for warpage. You can use a straightedge, a feeler gauge, and a good light. Figure 3-1 illustrates how to use a straightedge and a feeler gauge to check the top surface of the cylinder block Compare your measurements to the manufacturer’s specifications to determine if the surface is warped.
Visually inspect the cylinder block for cracks, breaks, or other damage.
MEASUREMENTS
Visually inspect the engine block’s bolts to determine if they are bent, broken, or worn.
Figure 3-1.—Checking the top surface of a typical cylinder block.
Measure the bore in the cylinder block, with a dial indicating bore gauge, to determine if wear or an out-of-round condition exceeds the manufacturer’s specification. Figure 3-2 illustrates the use of a bore gauge to measure a cylinder bore. You can use an inside micrometer as well, but a dial indicating bore gauge is easier to use.
Inspect and measure the engine block’s hold-down bolt holes. Use a telescoping snap gauge to determine if wear has caused enlargement of the holes. If a telescoping snap gauge is not available, try to move each bolt from side to side with your fingers. If a bolt moves from side to side, its hole has enlarged and must be repaired. Always follow the manufacturer’s instructions on how to correct a hole enlargement problem.
DYE PENETRANT TEST
Conduct a preliminary dye penetrant test on the engine block’s surface to identify cracks that you cannot see otherwise. Be sure to follow the manufacturer’s instructions on how to conduct this test. Remember that only a certified nondestructive testing technician can perform a dye penetrant test that meets the requirements of quality assurance.
