Carrier 69NT40-521, 69NT40-511-199 manual Compressor Reassembly, Compression Rings

6.9 COMPRESSOR REASSEMBLY

To clean compressor parts, use a suitable solvent with proper precautions. Coat all moving parts with the proper compressor oil before assembly. Refer to Table 6-5 for applicable compressor torque values.

1

2

3

1.Suction Valve

2.Suction Valve Positioning Spring

3.Valve Plate Dowel Pin

Figure 6-14. Suction Valve & Positioning Springs a. Suction and Discharge Valves

If the valve seats look damaged or worn, replace valve plate assembly. Always use new valves because it is difficult to reinstall used discharge valves so that they will seat as before removal. Any valve wear will cause leakage for this reason.

Suction valves are positioned by dowel pins (see Figure 6-14) and will assume their original position when reinstalled. No two valves are likely to wear in exactly the same way. Never interchange used valves.

Do not omit the suction valve positioning springs. (See Figure 6-14.) Place the springs so that the ends bear against the cylinder deck (middle bowed away from cylinder deck). Use new gaskets when reinstalling valve plates and cylinder heads.

b. Compression Rings

The compression ring is chamfered on the inside circumference. This ring is installed with the chamfer toward the top. Stagger the ring end gaps so they are not aligned.

The gap between the ends of the piston rings can be checked with a feeler gauge by inserting the ring into the piston bore approximately one inch below the top of the bore. Square the ring in the bore by pushing it slightly with a piston. The maximum and minimum allowable ring gaps are 0.33 and 0.127 mm (0.013 and 0.005 inch) respectively.

Figure 6-15. Piston Rings

c. Installing the Components

1.Push pistons from the inside of the crankcase through the cylinders, being careful not to break the rings. Place chamfered side of connecting rod against radius of crankpins. Install the crankshaft through the pump end of the compressor. Do not damage main bearings. Install matching connecting rod caps through bottom cover plate.

2.The oil screen (located in the bottom of the crankcase), is connected to the inlet of the oil pump. Whenever the compressor crankcase is opened, inspect the screen for holes or an accumulation of dirt. The screen can be cleaned with a suitable solvent.

CAUTION

The set screw on the crankshaft must be removed for the oil pump installation (see Figure 6-8).

3.Install the pump end thrust washer on the two dowel pins located on the bearing head. (See Figure 6-8)

CAUTION

Ensure that thrust washer does not fall off dowel pins while installing oil pump.

4.Install the bearing head assembly with a new gasket on the compressor crankshaft. Carefully push oil pump on by hand, ensuring that the thrust washer remains on the dowel pins. The tang on the end of the drive engages the slot in the crankshaft, and the oil inlet port on the pump is aligned with the oil pickup tube in the crankcase. The pump should mount flush with the crankcase and should be oriented as shown in Figure 6-16.

6-13 T-268-07

SECTION 6