BLACKMER HD172A, Installation, Operation & Maintenance Instructions Manual

CB-9A-040     page 14 

MAINTENANCE

j.  Set the upper distance piece over the piston rods and against the crosshead guide, 

loosely

 install 

upper distance piece capscrews. 

k.  Install each upper packing box O-ring over the piston rods. 

l. 

Install each upper packing box over the piston rods.  (Use the packing installation cone if available.) 

6.  Rotate the crankshaft by hand a few times, then uniformly tighten the crosshead guide capscrews (and 

upper distance piece capscrews on triple-seal models) per the Bolt Torque Table. 

7.

  New packing must be broken in.

  Refer to the end of "Seal Replacement". 

8. 

CYLINDER ASSEMBLY

a.  Install new O-rings in the bottom of the cylinder.  A small amount of grease may be used to hold the 

O-rings in place during assembly. 

b.  Set the cylinder over the piston rods and against the crosshead guide. 

 c.

 Loosely

 install the cylinder capscrews. 

9.  Rotate the flywheel by hand to ensure the compressor turns freely.  

10.

 PISTONS

a. 

If necessary, replace the piston rings and piston ring expanders (see "Piston Ring Replacement"). 

b. 

Rotate the flywheel by hand to bring one piston rod to top dead center of the cylinder assembly. 

c. 

Set one thrust washer and one shim down against the shoulder of the piston rod. 

d. 

Squeeze the piston rings inward, with light pressure, while threading the piston clockwise onto the 
rod.  Tighten with the 3" adjustable spanner wrench. 

e. 

Follow this same procedure for the second piston. 

f. 

Rotate the compressor by hand a number of times to verify that the pistons are centered in the 
cylinder bores.  The pistons must not touch the cylinder walls.  If necessary, adjust the cylinder. 

g. 

Tighten the cylinder capscrews per the Bolt Torque Table in an alternating pattern. 

h. 

It is important that the proper number of shims be installed under the piston.  To check, rotate the 
flywheel by hand to bring one piston to the top.  

1. 

Measure the distance from the top of the piston to the top of the cylinder.  

HD172 

.015" to .010" 
(.381 to 762 mm) 

HD372 
HDL372 

.025" to .040" 
(.635 to 1.016 mm) 

HD612 
HDL612 

.030" to .045" 
(.762 to 1.143 mm) 

HD373 
HDL373 

.050" to .065" 
(1.270 to 1.651 mm) 

HD613 
HDL613 

.060" to .075" 
(1.524 to 1.905 mm) 

2. 

If necessary, remove the piston and add or subtract shims accordingly. 

3. 

Follow this same procedure for the second piston. 

i. 

Replace the nylon locking inserts in the piston retainer nuts. 

j. 

Thread the piston nuts onto the piston rods and tighten with the spanner wrench. 

11.

  CYLINDER HEAD ASSEMBLY

If the valve assemblies have been removed from the cylinder head, it is easiest to reinstall them before 
attaching the cylinder head to the cylinder assembly.  Refer to "Valve Replacement" for instructions. 

a. 

Place the cylinder head O-rings in the grooves located on top of the cylinder. 

b. 

Place the cylinder head assembly on top of the cylinder. 

c. 

Hand tighten the outer capscrews and center capscrews into the cylinder head. 

d. 

Uniformly torque the cylinder head capscrews according to the Bolt Torque Table. 

12.  Rotate the compressor by hand to verify that it turns freely.  Make sure the pistons are not hitting against 

the bottom of the cylinder head assembly. 

13.  Install the intercooler and shroud or water tubing assemblies.  Torque the intercooler flange capscrews to 

20 FT-LBS (27 Nm). 

14.  Attach the return tube and fittings to the cylinder and cylinder head.  (Reconnect water tubing.) 

15.  Refer to the "Pre-Startup Check List", and "Startup Procedure". 

16.  After the compressor has been run for a sufficient enough time to reach operating temperature, allow to 

cool and retighten the valve hold down screws.