Operating instructions
Table Of Contents
- 1 Introduction
- 2 General Description
- 3 Special Tools and Equipment
- 4 Disassembly
- 5 Cleaning, Repair and Replacement
- 6 Inspection
- Definitions
- Magnetic Particle Inspection
- Critical New Part Dimensions
- Fluorescent Particle Inspection
- Dimensional Inspection
- Protective Coatings
- Crankcase Inspection
- Crankshaft Inspection
- Camshaft Inspection
- Connecting Rod Inspection
- Gear Inspection
- Piston Inspection
- Cylinder Inspection
- Inspection Chart
- Crankcase Stud Heights
- Mag Particle Inspection Procedures
- Table of Limits
- Torque Specifications
- General Torques
- Table of Limits Chart
- 7 Assembly of Subassemblies
- 8 Final Assembly and Test
- 9 IO-520-M
- 10 IO-520-BB, CB and MB
8-3
q. Attach right crankcase mount brackets to the
assembly stand and rotate stand until engine is upright
as shown in Figure 8-4.
r. Install generator mount bracket (31) and secure
with attaching parts (24 through 30).
s. Install, but do not tighten support pin attaching
parts (58, 59).
8-7. CRANKCASE, PERMOLD (See Figure 4-
22).
a. Install mounting legs on the left crankcase of the
IO-520-C and attach to assembly stand, supported as
shown in Figure 8-1. Install engine stand bracket to
crankcase with 3/8-16 bolts attached in tapped holes
provided on the IO-520B, BA,M.
b. Lubricate all main bearing inserts and crankshaft
journals. Lubricate both thrust washer halves with
Gredag No. 44 and install. Lift crankshaft assembly
by No.1 connecting rod and propeller flange. With
the aid of an assistant holding Nos. 3 and 5 rods,
carefully lower the assembly into the left crankcase
bearings, making certain the oil seal enters the oil seal
cavity. The connecting rod position numbers will be
toward the upper flange, if properly installed. Lay odd
numbered rods on upper case.
c. Insert governor driven gear (1, Figure 4-23) into its
bearing.
d. After cranJ5shaft has been properly placed in
crankcase, and governor driven gear has been
installed, lay camshaft assembly in. place meshing
spur gear teeth of the cam gear with those of the
crankshaft small gear so that the timing marked tooth
of the cam gear is at the center of the 3/8 inch
observation hole in the web of the crank- shaft large
gear. See Figure 8-3.
e. Measure crankshaft and camshaft end clearance.
See Table of Limits, Section VI for allowable
tolerances.
f. Install idler gear bushing (64, Figure 4-22) in left
crankcase and secure with dowel pin (63). Install idler
gear and idler gear flanged bushing (27).
g. Spread a thin film of No.3 Aviation Permatex on
the left crankcase parting flange. Lay lengths of No.
50 silk thread on the parting flange inside the bolt
holes but not on the edge.
h. Stand up odd numbered connecting rods.
i. Lay right crankcase subassembly on the left case.
Take care not to displace or damage the crankshaft oil
seal.
FIGURE 8-4. LEFT SIDE OF COMPLETED CRANKCASE ON STAND.