Where would you find guidance for diesel engine operating hour overhaul intervals?
COMDTINST M9000.6 in Table 233-1
WHO is the final authority for determining the timing of overhauls?
MLC Atlantic and Pacific
At approximately 80% of the operating hour overhaul interval, the supervisor shall assess the condition of the engine. What guidance would you reference to accomplish this?
NEM 9000.6, Chapter 233, Paragraph B.2
Who will the supervisor initiate a discussion with to report the condition of the engine and recommend when to conduct the overhaul?
The MLC type desk manager
What additional inspections will MLC complete when deciding whether or not to extend (or shorten) the overhaul based on engine condition?
- OEM Technical Representative Inspection
- MLC ASSIST or NESU/MAT Inspection
- Navy (Fleet Technical Support Command) Inspection
Where would you record adjustments to overhaul intervals?
The cutter’s Naval Engineering Projects List (NEPL)
MLC shall provide specific guidance such as limitations on operating the engine and the plan for monitoring and reassessing the engines condition. Where shall this specific guidance be incorporated?
The cutter’s Long Range Maintenance Plan (LRMP)
MLC may also fund a limited number of OEM technical representative cutter visits and onsite labor hours to assist the ships force with:
- Critical Measurements
- Inspections
When scheduling and planning an overhaul, what items will the supervisor be responsible for ensuring are ordered for the overhaul?
- Flexible hoses
- Valves
- Gauges
- All consumable items required for the overhaul.
What funds will be used for travel cost for MAT assistance to non MAT-supported cutters?
The cutter AFC-30 fund
The ________ shall conduct weekly progress meetings with all key personnel and provide progress reports to MLC type desk.
Supervisor
The ______ shall be responsible for receipt, inventory and inspection of parts and long lead-time material.
Supervisor
The _____ will be responsible for ensuring all post-overhaul test, inspections and break-in procedures are conducted.
Supervisor
Where would you find guidance for documenting the overhaul in the next Cutter Engineer Report?
NEM M9000.6
Who shall document completion of the overhaul in the fleet logistics system, which will be reflected in the cutter’s Naval Engineering Project List (NEPL)?
MLC type desk
Name four things you want to pay particular attention to when preparing to complete an overhaul?
- Installation tolerences
- Wear limits
- Adjustments
- Safety procedures
What must you do before attempting to jack the engine over by hand?
Disable the starter circuit
Remove and upon completion of work, reinstall all interferences in way of work for the main diesel engine overhaul in the engine room IAW _______.
MLCA Standard Specification 0700C0490.STD
Prior to disassembly of the MDE what do you want to check?
Check the face and bore alignment between the engine flywheel and flex coupling.
Cleaning and inspection On the basis of the disassembly and inspection of th engine, submit to the supervisor a condition report of all components with recommendations for _________.
Reuse, repair and/or renewal
Clean, inspect and repair/recondition as specified the following components of each engine per the manufactures tolerances and standards:
- Cylinder block
- Crankshaft
- Pushrods and rocker shafts
- Camshaft and followers
- Cam bearings and bushings
- Gear train
What guidance would you reference for checking alignment after installing a new flexible couple?
CAT special instruction, Form SEH7456-01
The following components for the engine shall be renewed in the after cooler group:
- core assembly
- after core assembly
- packing
- seal
- gasket
The following components for the engine shall be renewed in the crankshaft group:
- thrower
- baffles
- rings
- bearing
What psi would you hydrostatically test a manifold to?
50 psi
Chemically clean the Lubricating Oil Cooler per applicable sections of _________.
Table I of MLC Standard Specification
Visually inspect and hydrostatically test each of the Oil Cooler per _______.
ASTM E1003
When would you take the Crankshaft Deflection Test?
Before starting the overhauled engine, after alignment (cold) and after running the engine for trials (hot).
Upon completion of any major overhaul or repair, as a supevisor, what must you do prior to placing machinery back into operational status?
Test and Operate Machinery
What might you be doing when accomplishing the following task?
- Start ventilation in the main engine room
- charge the pneumatic starting system
- check cooling system valves for porper position
- Ensure MDE fluids are topped off
- Visually check fuel lines/fuel system
Pre-starting check
Check all systems for leaks by turing the MDE in the direction of rotation using the jacking bar to ensure it rotates freely.
PRE-STARTING CHECKS AFTER AN ICE OVERHAUL
Test run the propulsion for a minimum of __ hour at idle.
1 hour
Run-in MDE dockside, for a period of approximately ___ hours, per manufactures instructions.
5 hours
After completion of the final run-in, the following items shall be inspected and corrected as necessary:
- lubricating oil leaks
- water leaks
- F/O leaks all external bolts secure
The test data obtained during the run-in shall be recorded and submitted to appropriate authority within ____ hours after completion of the test.
48 hours
A sea trial for a period of 4 to 6 hours may be required to demonstrate proper operation of the overhauled MDE, in all modes of operation, as per ________.
COMDTINST M9000.6, Chapter 094.1.4
What is piston wear characterized by?
An excessive clearance between the piston and the cylinder
What are symptoms of excessive clearance between a piston and cylinder?
Piston Slap and Excessive Oil Consumption
When does piston slap occur?
After TDC and BDC, as the piston shifts its thrust from one side to the other.
What will accumulation of carbon deposits cause?
Erratic operation and greatly reduce engine efficiency
What is one of the factors controlling piston wear?
Lubrication
What will inadequate lubrication cause?
- Piston wear
- Piston seizure
- Land breakage
- Piston pin bushing wear
What is lack of lubrication caused by?
Lack of L/O pressure or restricted oil passages
There should be _____ on all pistons at all times.
Load Balance
What will cause excessive wear on the piston and piston pin bushing?
An overload or unbalanced load
How is the balance of an engine determined?
By checking the exhaust gas temperature at each cylinder, the rack settings and the firing and compression pressures.
What causes cracking of the lands of a piston?
Insufficient ring groove clearance
Of the causes listed under “Other factors which may cause low compression pressure”, which causes would affect the pressure in only one cylinder assembly of a multicylinder engine?
- A: Leaking cylinder valves
- B: Faulty injector gasket
- C: Faulty head gasket
- D: Leaking after-chamber valves
What causes of “low compression pressure” may effect a group of cylinders or posibly all cylinders.
- Intake air header leakage
- faulty blower
- clogged air filter
What is excessive oil consumption generally associated with?
Worn oil rings
What is caused by excessive operating temperatures?
Oxidation
Name two factors that cause improper ring clearance:
- Abnormal amount of carbon deposits on rings and grooves
- Improper dimensions, new rings must have proper thickness, width, diameter and gap
One cause of undue loads on a ring could be_____.
Insufficient gap clearance
What does a bright spot found on each end of a broken ring indicate?
Insufficient gap clearance
_________ may result from insufficient ring pressure.
Sticking and binding
What indicates the leakage of gases past the rings?
Discoloration (usually appearing as black lines)
What conditions cause piston rings to stick in the grooves, wear excessively or break?
Improper lube oil
What is the greatest factor affecting the wearing of piston rings?
Worn cylinder liner
What must be considered when new piston rings are installed?
- Surface condition
- Amount of taper
- Out-of-roundness of the liner
How should you stagger adjacent rings to reduce gas leakage?
180 degrees
What type of metal are piston pins made of?
Hardened steel alloy
What type of metal is piston sleeve bearings and bushings made of?
Bronze or a similar material
Wear of a pin or bearing is normal, but what factors can increase the rate of wear?
- Inadequate or improper lubrication
- Overloading
- Misalignment of parts
- Failure of adjacent parts
What should you measure piston pins and bushings with to determine if wear is excessive?
Micrometer
What will result of misalignment of connecting rods?
Uneven loading on piston pins and bearings
______ may be caused by improper reaming of the bushing for proper clearance.
Misalignment
Connecting rod troubles usually involve either the ______ or the ________.
connecting rod bearing or the piston pin bearing
Connecting rods must be checked for proper alignment before being installed in an engine and after any derangement involving the _________.
piston, cylinder or crankshaft
Whenever rod bolts are removed, they should be carefully inspected for ___________.
Stripped or damaged threads or elongation
What are some common troubles of crankshafts, camshafts, journal bearings and antifriction bearings?
Metal fatigue, inadequate lubrication and operation of the engine at critical speeds
What are some lubrication difficulties you should watch out for?
- low L/O pressure
- High temperatures
- Lube oil contamination by water, fuel and foreign particles
- Corrosion of bearing materials
- Surface pitting of bearings
- Inadequate bond between bearing material and bearing shell
- Out of round journals
- Rough spots
- Fautly installation
- Poor contact
- Misalignment of parts
- Failure to follow recommended procedures in the care of L/O
What are a few causes of journal bearing failure?
What are a few causes of poor contact between a bearing shell and a connecting rod on journal bearings?
- Foreign particles
- excessive clearance
- rough surface
________ of main bearings can be cause by warped or bent crankshaft.
Misalignment
If there is no manual available to provide guidance on the proper L/O temperature to be maintained, what temperature should you maintain the L/O leaving the engine?
The engine should be mainatined between 160 degrees and 200 degrees fahrenheit if no manual is available.
Dirt in a bearing which has been improperly or insufficiently cleaned may be detected by_______.
- Noise when the bearing is rotated
- Difficulty in rotating
- Visual inspection
Spalled or pitted rollers or races may be first recognized by _______.
The noisy operation of the bearing
Brinelled or dented races are most easily recognized by_____.
Inspection after thorough cleaning
Where does brinelling receive it’s name from?
It’s from the similarity to the BRINNELL HARDNESS TEST.
Can Brinelled Bearings be placed back in service?
NO, they must not be placed back in service!
What is CREEP?
A very gradual rotation of the race.
Cracked races will usually be recognized by a definite _________.
thump or clicking noise in the bearing during operation
The principle type of ______ for timing and accessary drives in most diesel engines is a system of gears.
Power Transmission
What are some causes of gear failure?
- Improper lubrication
- Corrosion
- Misalignment of parts
- Torsional vibration
- Excessive backlash
- Wiped gear bearings and bushings
- Metal obstructions
- Improper manufacturing procedures
_________ of gear trains involve a thorough check of gear shafts, bushings and bearings, and gear teeth during each periodic inspection.
Maintenance and Repair
One of the most important parts of a _______ is the set of gears that drives and sychronize the two rotors.
Root Type Blower
The most direct method for checking gear clearance is by the use of ______.
feeler gauges
What are the principle causes of drive chain failure?
- Improper chain tension
- Lack of lubrication
- Sheared cotter pins or improperly riveted joint pins
- misalignment of parts, especially idler gears
What is used on most engines to adjust chain tension?
An idler sprocket and chain tensioner
During operation, chain increase slightly in length because of ______.
stretch and wear
Turbo chargers used in the CG today may operate with temperatures as high as ______ degrees and speeds up to ______ RPM’s.
1200 degrees Fahrenheit, 75,000 RPM’s
List six supervisor responsibilities associated with planning, scheduling, executing and completing a maintenance or repair task.
- Size up the job before starting
- Check on materials required
- Check on priority of the job
- Consider capabilities and experience of personnel when assigning work
- Keep track of work being done
- Carefully inspect after the job has been completed
Who is responsible for ordering flexible hoses, gauges and all consumable materials required for an internal combustion engine overhaul?
The Supervisor
What four task is the supervisor responsible for during the execution stage of an overhaul?
- Managing
- Supervising all work
- Inspections
- Tests
Upon completion of an overhaul, the supervisor will ensure the completion is documented in what two reporting systems?
- Next Cutter Engineering Report
- CMplus
What two conditons must be maintained in tanks or compartments or when conducting hotwork in an area in conjuction with an overhaul?
- SAFE FOR PERSONNEL
- SAFE FOR HOTWORK
What is the wear criteria and critical dimension data of components based on when cleaning and inspecting a disassembled engine?
Manufactures service/Technical manual
What is a sea trial period intended to demonstrate?
Proper operation of an overhaul MDE
Characterized by presence of abnormal amount of carbon.
Improper piston ring clearance
Characterized by improper functioning of a torsion vibration damper.
Bent or broken crankshaft
Characterized by improper valve tappet adjustment.
Camshaft and bearing trouble
Characterized by fine abrasives in lubricants
Bearing wear causing looseness without apparent surface disintegaration
Characterized by misalignment of idler gears.
Drive chain failure
The lubricating oil temperature shall be maintained at ___________ or below during bearing
checks.
48.9° C (120° F)
Insufficient lubrication to any bearing or bushing, improper installation of bearings or bushings, or defective bearings or bushings normally will be indicated by a noticeable overheating of the affected part by the end of the ____________,
15 minute run at 40 percent speed, no load
Diesel engine log readings shall be recorded every __ minutes during run.
15
