Analyzing Cylinder Condition By Measuring Air Flow{0651, 1000} Caterpillar

Analyzing Cylinder Condition By Measuring Air Flow{0651, 1000} [GMG00694]
Analyzing Cylinder Condition By Measuring Air Flow{0651, 1000}
1.1. Tool Selection And Assembly
2.1. Testing Procedure

The tools required to analyze cylinder condition consist of parts available from Parts Department and an air pressure regulator which must be obtained from other sources. A Norgen Regulator Model #11-002-013 is shown; however, any suitable air pressure regulator can be used. Air pressure of at least 90 PSI (6,3 kg/cm2) must be available.

Tool Selection And Assembly

(1) Assemble 7S8895 Adapter (1), 6K5875 Hose Assembly (2), 3B7767 Nipple (3), 3B7762 Tee (4), 8M2744 Gauge (5) and air regulator (6). Modify the 3B7767 Nipple by filling it with braze and drilling a .040" (1,01) orifice. This assembly is used to control the air supply on all engines. Use 9S2233 Sealant on all pipe connections.

(2) Assemble 9S7341 Adapter (7) and 7S8890 Adapter (8) to 8S2268 Tube Assembly (9). This assembly is used to connect the air supply to all diesel engines except direct injection.

(3) Screw 7S8888 Adapter (10) into 1P5564 Adapter (11). Install 9L9098 Seal on adapter (11). This assembly is used to test 1100 and 3100 Series direct injection engines.

(4) Screw 7S8888 Adapter (10) into 1P5565 Adapter (12). Install a spark plug washer on adapter (12). This assembly is used to replace spark plugs on natural gas engines.

(5) To test D334, D336, 1674, and 1676 Engines, use 1P5567 Tip (13) in place of the mini-capsule valve, with valve body (14) and standard injection valve retaining nut (15). All other diesel engines use 1P5569 Tip (16) with valve body (17) and standard retaining nut (18).

NOTE: The two pressure gauges should be checked before making this test. For a method of checking gauges see METHODS AND EQUIPMENT BULLETIN FEG00019-12.

(6) A typical testing procedure follows. With the exception of testing equipment as described above, the testing procedure is the same for all engines.

Testing Procedure

(1) Before beginning the actual test, run the engine long enough to warm the oil and build up an oil film on the cylinder walls. On engines with two ring pistons it might be necessary to rotate the engine slightly with the cylinder pressurized in order to force the top ring into the sealing position.

(2) Disconnect the fuel injection tube and remove the fuel injection valve from the cylinder to be tested.

(3) Install the appropriate tip in place of the fuel injection capsule valve. Install the valve body.

(4) Connect the tube adapter assembly to the fuel injection valve body.

(5) Rotate the engine to top dead center (TDC).


It may be necessary to lock the engine in this position. Air pressure in the cylinder can cause the engine to rotate.

(6) Connect the air supply to the regulator and connect the air regulator hose assembly to the tube adapter.

(7) Use the air regulator to adjust the incoming air supply to 80 PSI (5,6 kg/cm2). Record the pressure in the cylinder from the secondary gauge.

(8) If the cylinder pressure is less than 60 PSI (4,2 kg/cm2), and the test was performed correctly, there is excessive leakage. It can often be determined whether the problem is the rings, intake valve or exhaust valve by listening for an excessive amount of air leaking into the crankcase, intake manifold and exhaust manifold. Air can also leak into the engine cooling system.

NOTE: Due to the internal restriction of 8S2268 Tube Assembly, an air pressure reading of 55 PSI will be observed when venting the system to atmosphere. This will not affect the accuracy of the test.

IMPORTANT: This test is not applicable to engines with Keystone piston rings (1674, 94B10014; 1693, 65B10278; and 3406 Engines. Some earlier 1674 and 1693 Engines may have pistons with Keystone rings).