TM-9-2815-220-24

AVDS-1790 2CA, 2DA and 2DR Air-Cooled 12-Cylinder Diesel Engines

TECHNICAL MANUAL; UNIT, DIRECT SUPPORT AND GENERAL SUPPORT MAINTENANCE MANUAL FOR AVDS-1790 2CA, 2DA and 2DR Air-Cooled 12-Cylinder Diesel Engines

TM-9-2815-220-24 - Page 124 of 1563

TM 9-2815-220-24

ENGINE NOISY OPERATION

0015 00

MALFUNCTION 1:

(Continued)

Knock or tapping sound.

PROBABLE CAUSE

CORRECTIVE ACTION

a. (Continued)

Rocker arm assembly

defective or out of adjustment.

(1) (Continued)

Locate faulty cylinder as

follows:

PROCEDURE

OBSERVATION

ANALYSIS

Cylinder Compression Test Method:

Perform Cylinder

Compression Test

(WP 0033, Cylinder

Compression Test).

Note cylinder with low pressure

(below 330 psi at 140-180

cranking rpm).

Indicates faulty cylinder,

damaged rings, piston, valve,

connecting rod or tight rocker arm

(no valve clearance).

PROBABLE CAUSE

CORRECTIVE ACTION

(1) Locate faulty cylinder as above.

b. Excessive intake or exhaust valve clearance

or damage.

(2) Adjust valve clearance (WP 0034, Intake

and Exhaust Valve Clearance Adjustment).

(1) Inspect, repair, or replace valve and/or

cylinder (WP 0133, Cylinder Assembly

Replacement).

c. Rocker arm assembly defective.

(2) Replace rocker arm (WP 0104, Rocker Arm

Assembly and Cover Replacement).

(1) Locate faulty cylinder as above.

d. Connecting rod, piston, ring damage, or

loose piston pin.

(2) Check for damage (WP 0143, Connecting

Rod Assembly and Associated Parts Repair

and WP 0142, Pistons, Rings, and

Associated Parts Replace/Repair).

e. Crankshaft bearing damage.

(1) Check for damage (WP 0138, Crankshaft

Main Bearing Inspection).

f.

Worn or damaged gears or bearings.

(1) Check for damage (WP 0178, Disassembly/

Assembly Procedure Sequence for the

AVDS 1790-2 Engine).

WP 0015 00-2