S.07
Engine Overhauling Services
Planned maintenance, overhaul and breakdown recovery for low- and medium-speed diesel, gas and dual-fuel engines in power plants and on ships. Multi-brand, carried out to OEM manuals, limits and torque values, and documented with measurements and photographs.
- 3 levels
- Minor, intermediate and major overhaul
- Since 2012
- Rotating equipment for power and industry
- 24/7
- Emergency breakdown support
Company
About the service
RotoTech Bangladesh Limited is an ISO 9001:2015 and ISO 45001:2018 certified engineering company in Savar, Dhaka. Since 2012 we have serviced turbochargers, turbines, motors and other rotating equipment for Bangladesh's power and industrial sectors, and we hold authorized service status for Napier and Garrett turbochargers.
Our Engine & Mechanical Services Division extends that work to the engine itself. We maintain and overhaul diesel, gas and dual-fuel engines, together with their turbochargers, alternators and auxiliary machinery, across the full maintenance cycle: routine inspection, preventive maintenance, major overhaul and emergency breakdown recovery.
What we focus on
- Reliable operation and less unplanned downtime
- Early detection of abnormal conditions
- Safe work and accurate measurement
- Correct installation, clearances, torque and alignment
- Recommendations backed by evidence, with full technical reporting
- Inspect
- Diagnose
- Plan
- Repair
- Test
- Commission
- Monitor
Target sectors
Power plants & marine
Power generation
IPP, rental and peaking plants running HFO, gas and dual-fuel engine-generator sets. We work within the plant's outage window, coordinate with O&M teams, and hand units back with trial-run records.
- HFO and diesel power plants
- Gas-engine and dual-fuel plants
- EPC contractors and O&M companies
- Industrial utility facilities
Shipping & vessels
Main propulsion engines and auxiliary generator engines on ocean-going, coastal and inland vessels. Work can be done alongside, at anchorage or during dry-dock, with records prepared for class survey where the vessel needs them.
- Low-speed two-stroke main engines
- Medium-speed four-stroke propulsion engines
- Auxiliary diesel generator sets
- Turbochargers, alternators and pumps on board
- Voyage-repair and dry-dock overhaul packages
Multi-brand coverage
Engines in scope
| Make | Speed class | Typical engine families | Applications |
|---|---|---|---|
| Wärtsilä | Medium-speed, 4-stroke | W20 · W26 · W32 · W34SG / DF · W46 · W50DF | Power plants, propulsion, auxiliaries |
| MAN Energy Solutions | Medium-speed, 4-stroke | L/V32/40 · L/V48/60 · L21/31 · L27/38 · L16/24 · L23/30H | Power plants, propulsion, auxiliaries |
| MAN B&W | Low-speed, 2-stroke | MC / MC-C · ME / ME-C | Main propulsion |
| Bergen Engines | Medium-speed, 4-stroke | B32:40 · B35:40 · C25:33 | Power plants, propulsion |
| Other OEMs | Low & medium-speed | MaK · Hyundai HiMSEN · Daihatsu · Yanmar · Niigata · WinGD / Sulzer | Marine and land-based |
Speed classes as used on this page: low-speed below 300 rpm (two-stroke crosshead), medium-speed 300–1,000 rpm (four-stroke trunk piston). Each job follows the engine maker's manual, limits and tightening values for that specific engine.
Scheduled / planned
Planned maintenance
Maintenance is carried out on running hours, following the OEM schedule for the engine, from routine checks through minor and major overhaul.
Running hours. Exact scope at each interval per OEM manual.
Typical activities
- Routine engine inspection and preventive maintenance
- Inspection and measurement of critical components
- Replacement of worn or life-expired parts
- Torque checks and clearance measurement
- Performance monitoring
- Post-maintenance testing and trial operation
Systems inspected
- Lubricating oil
- Fuel system
- Exhaust
- Cooling water
- Starting air
- Charge air
Major components serviced
Fig. 01Cylinder head lifted for overhaul, valve springs and rotators in place
Fig. 02Cylinder liner: collar, sealing area and running surface
Fig. 03Piston: crown, ring pack and skirt
Fig. 04Connecting rod with big-end bearing bore
Fig. 05Bearing shell removed for inspection
Fig. 06Fuel injection pump
Fig. 07Injection pump elements and delivery valves
Unscheduled / unplanned
Unplanned maintenance
When an engine shows abnormal symptoms, our team inspects, troubleshoots and carries out the corrective work. The aim is to find the root cause, return the engine to service safely and keep downtime short.
- S01Abnormal engine noise
- S02High exhaust temperature
- S03Low lube-oil pressure
- S04High cooling-water temperature
- S05Excessive vibration
- S06High bearing temperature
- S07Starting problems
- S08Misfiring
- S09Uneven cylinder performance
- S10Turbocharger abnormality
- S11Oil or water leakage
- S12Exhaust-gas leakage
- S13Abnormal smoke
- S14Sudden loss of power
Breakdown & emergency
Breakdown recovery
After an accident, component failure or sudden trip, we mobilize to site and work through a fixed recovery sequence until the engine is back in safe service.
- 01Breakdown
- 02Site inspection
- 03Damage assessment
- 04Root-cause investigation
- 05Dismantling
- 06Repair / replacement
- 07Reassembly
- 08Alignment
- 09Testing
- 10Trial run
- 11Handover
Typical breakdown cases
- Connecting-rod failure
- Liner damage
- Valve failure
- Crankshaft problems
- Foreign-object damage
- Lubrication failure
- Fire or accident damage
- Piston damage
- Cylinder-head failure
- Main / big-end bearing damage
- Turbocharger damage
- Over-temperature events
- Mechanical seizure
- Component fracture
Emergency recovery stages
Damage assessment
Fig. 08Cylinder-head firing face with valves marked A–D for damage assessment
Fig. 09Crankpin journal: surface condition after bearing distress
Fig. 10Bearing bore and oil-feed holes inspected after failure
Core service
Engine overhauling
We undertake minor, intermediate and major overhauls of heavy-duty diesel, gas and dual-fuel engines. The final scope of each overhaul is set by running hours, OEM requirements and the condition found on inspection.
| Level | Typical scope | Main components |
|---|---|---|
| Minor | Top-end overhaul | Cylinder heads, inlet and exhaust valves, valve train, injectors, gaskets |
| Intermediate | Top-end plus running gear | Pistons, rings, liners, connecting rods, big-end bearings, fuel injection pumps |
| Major | Complete engine overhaul | Main and thrust bearings, crankshaft, camshaft, timing gear, engine block checks, lube-oil, cooling-water and starting-air systems |
Overhaul in progress
Fig. 11Engine top with cylinder head removed, liner bore exposed
Fig. 12Valves withdrawn and laid out against cylinder head A4
Fig. 13Liner withdrawal in progress
Fig. 14Cylinder liner lifted on hydraulic lifting tool
Fig. 15Liner running surface: honing pattern and wear marks
Fig. 16Outside micrometer measurement of a pin
Fig. 17Bore-gauge measurement of the liner
Fig. 18Connecting-rod shank prepared for inspection
Fig. 19Big-end housing with bearing removed
Fig. 20Crankshaft journal with measurement grid marked
Fig. 21Liner measurement at defined heights
Fig. 22Crankshaft deflection reading with digital gauge
Fig. 23Hydraulic tightening: pump pressure reading
Fig. 24Big-end bore measured with inside micrometer
Fig. 25Big-end bore measurement
Fig. 26Valve seats cleaned and marked for measurement
Fig. 27Hydraulic jack set on bearing-cap studs
Component service
Cylinder heads
Inspection & measurement
- Dismantling, visual inspection and carbon removal
- Valve, valve-seat and valve-guide inspection
- Valve clearance and spring checks
- Injector inspection
Testing & reassembly
- Pressure testing and leak checks
- Gasket replacement
- Reassembly
- Torque tightening to OEM values
Cylinder-head workshop
Fig. 28Inlet and exhaust valves removed for inspection
Fig. 29Valve-guide bore measured with dial bore gauge
Fig. 30Valve-stem diameter measured with micrometer
Fig. 31Valve-stem wear check
Fig. 32Valve-seat inspection with dial gauge
Fig. 33Cylinder-head ports after cleaning, head A5
Component service
Cylinder liners
Scope
- Removal and installation
- Wear measurement
- Taper measurement
- Honing condition
- Seating inspection
- Replacement advice
- Visual inspection
- Ovality measurement
- Surface inspection
- O-ring / seal renewal
- Check against OEM limits
Liner bore is measured at set heights and in two planes (fore-aft and athwartship), so wear, ovality and taper are recorded against OEM limits for each cylinder.
Fig. 34Cylinder liner marked 4B5 after removal
Component service
Pistons & connecting rods
Pistons
- Removal and installation
- Piston and piston-ring inspection
- Ring replacement
- Ring-groove measurement
- Piston-pin inspection
Connecting rods
- Connecting-rod inspection
- Big-end bearing inspection and clearance
- Con-rod bolt inspection
- Hydraulic tightening to OEM values
- Component replacement
Running gear
Fig. 35Piston and connecting-rod assembly
Fig. 36Piston pin
Fig. 37Piston ring check
Fig. 38Ring-groove clearance check
Fig. 39Dial-indicator set-up in the crankcase
Fig. 40Connecting rod in crankcase, bolts ready for hydraulic tightening
Component service
Bearings & crankshaft
Bearings covered
- Main bearings
- Thrust bearings
- Turbocharger bearings
- Auxiliary equipment
- Big-end bearings
- Camshaft bearings
- Alternator bearings
Activities
- Dismantling
- Clearance measurement
- Surface inspection
- Replacement
- Final clearance check
- Visual inspection
- Journal inspection
- Wear assessment
- Torque tightening
Bearing work
Fig. 41Big-end bore inspection
Fig. 42Main-bearing shell after removal
Fig. 43Bearing-shell thickness check with vernier
Fig. 44Hydraulic tensioning pressure check
Fig. 45Big-end measurement on the workshop stand
Fig. 46Main-bearing cap lifting fixture inside the engine
Generator side
Alternators & alignment
Mechanical services
- Alternator bearing inspection and replacement
- Shaft and coupling inspection
- Vibration-related mechanical inspection
- Trial run and performance observation
Alignment
- Engine-generator alignment
- Generator alignment
- Soft-foot checking
- Coupling condition checks
- Laser shaft alignment to 0.01 mm
Alternators
Fig. 47Engine-generator sets in a power-plant engine hall
Fig. 48Coupling alignment between engine and alternator
Fig. 49Alternator sleeve-bearing shell
Fig. 50Alternator DE bearing end shield
Fig. 51Alternator shaft journal
Fig. 52Bearing housing on alternator shaft
Fig. 53Alternator rotor removed for inspection
Fig. 54Stator winding inspection
Engineering support
Failure investigation
After a major failure we investigate the probable cause and issue a Failure Investigation / Inspection Report to the customer. The investigation follows these steps:
- 01Site condition assessment
- 02Operating-data review
- 03Visual inspection
- 04Component dismantling
- 05Damage documentation
- 06Dimensional measurement
- 07Photographic record
- 08Component condition assessment
- 09Possible failure mechanism
- 10Root-cause discussion
- 11Corrective action
- 12Preventive recommendation
In-house strength
Turbochargers & workshop
Turbochargers are where RotoTech started. Engine customers get the same specialist team for turbocharger inspection, overhaul and rotor balancing, so the engine and its turbocharger are handled under one contract.
- Napier · authorized
- Garrett · authorized
- ABB
- MAN
- KBB
- Other industrial
Workshop · Savar, Dhaka
At a glance
Capability matrix
Maintenance regimes
- Scheduled
- Planned
- Preventive
- Unscheduled
- Unplanned
- Breakdown
- Emergency recovery
Engine components
- Engine overhauling
- Cylinder head
- Cylinder liner
- Piston & rings
- Connecting rod
- Big-end bearing
- Main bearing
- Thrust bearing
Associated equipment
- Turbocharger service
- Alternator bearing
- Engine-generator alignment
- Pumps & motors
Assessment & reporting
- Engine health check
- Condition assessment
- Failure investigation
- Trial run & commissioning
- Technical inspection report
Track record
Reference sites
100 MW · HFO
BPDB, Chapainawabganj Power Plant
Turbocharger inspection, cleaning, component assessment, nozzle-ring inspection and related technical support.
50 MW · Peaking
BPDB, Titas Peaking Power Plant, Cumilla
ABB TPL67 turbocharger inspection after a high exhaust-temperature and cylinder-valve failure event, with damage assessment and component inspection.
110 MW · HFO
CPRL Power Plant, Rangpur
Maintenance of alternator LSA 58 110-8P-L4; alignment and bearing inspection after high temperature; servicing, installation and commissioning support.
105 MW · HFO
Orion Power Rupsha Limited
Turbocharger inspection, mechanical troubleshooting, bearing work, alignment and breakdown support.
200 MW · HFO
Desh Energy Chandpur Power Company Limited
Turbocharger inspection, mechanical troubleshooting, bearing work, alignment and breakdown support.
Industrial
API Industrial Park Services Limited, CETP Project
Pre-commissioning inspection and condition assessment of pumps and motors, with maintenance, alignment, testing and commissioning support.
Various
Other power plants & industrial facilities
Engine maintenance, turbocharger inspection, mechanical troubleshooting, bearing work, alignment and breakdown support.
- BPDB
- RPCL
- Summit Power
- United Group
- Orion Group
- Desh Energy
- KPCL
- BR Powergen
- BCIC
- Sulzer
Method
Working approach
Deliverables
Service documentation
Depending on scope, the final documentation package can include:
- Service report
- Health-check report
- Dimensional measurement report
- Before / after photographs
- Final service completion report
- Inspection report
- Breakdown investigation report
- Alignment report
- Spare-parts recommendation
- Maintenance report
- Component inspection report
- Turbocharger inspection report
- Maintenance recommendation
Differentiators
Why RotoTech
FAQ
Frequently Asked Questions
Which engines do you work on?
Planned maintenance, overhaul and breakdown recovery for low- and medium-speed diesel, gas and dual-fuel engines in power plants and on ships. Multi-brand, carried out to OEM manuals, limits and torque values, and documented with measurements and photographs.
- Wärtsilä
- MAN Energy Solutions
- MAN B&W
- Bergen Engines
- MaK · Hyundai HiMSEN · Daihatsu · Yanmar · Niigata · WinGD / Sulzer
When is an engine overhauled?
Maintenance is carried out on running hours, following the OEM schedule for the engine, from routine checks through minor and major overhaul.
The final scope of each overhaul is set by running hours, OEM requirements and the condition found on inspection.
What do minor, intermediate and major overhauls include?
- Minor: Top-end overhaul — Cylinder heads, inlet and exhaust valves, valve train, injectors, gaskets
- Intermediate: Top-end plus running gear — Pistons, rings, liners, connecting rods, big-end bearings, fuel injection pumps
- Major: Complete engine overhaul — Main and thrust bearings, crankshaft, camshaft, timing gear, engine block checks, lube-oil, cooling-water and starting-air systems
Can you work on board ships?
Main propulsion engines and auxiliary generator engines on ocean-going, coastal and inland vessels. Work can be done alongside, at anchorage or during dry-dock, with records prepared for class survey where the vessel needs them.
What happens after a breakdown?
After an accident, component failure or sudden trip, we mobilize to site and work through a fixed recovery sequence until the engine is back in safe service.
- Respond: Site inspection and first condition assessment
- Secure: Controlled dismantling and damage assessment
- Solve: Repair or replacement plan based on inspection and measurement
- Restore: Reassembly, alignment and testing
- Return: Trial operation and monitoring after restart
What documentation do we receive?
Depending on scope, the final documentation package can include:
- Service report
- Health-check report
- Dimensional measurement report
- Before / after photographs
- Final service completion report
- Inspection report
- Breakdown investigation report
- Alignment report
- Spare-parts recommendation
- Maintenance report
- Component inspection report
- Turbocharger inspection report
- Maintenance recommendation
Services
Our Core Expertise
24/7 Emergency Support — +880 1730-067280
Call Us
Keeping your engine running.
Keeping your plant producing.
We aim to be a long-term technical service partner for: Power plants · Ship owners & managers · Gas-engine plants · Diesel power plants · Industrial facilities · EPC contractors · O&M companies.
