L’Orange Injection Pump Repair for MWM TBD440 and TBD441 Engines

Specialist Overhaul, Testing and Spare-Parts Support for Historical L’Orange Fuel Injection Systems

Einspritzpumpen Manufaktur NRW is an independent specialist workshop in Germany for the identification, repair, complete overhaul and technical restoration of mechanical L’Orange fuel injection pumps used in MWM and Deutz-MWM large diesel engines of the TBD440 and TBD441 series.

These injection systems were developed for high-output marine, industrial and stationary diesel engines. Many of them have remained in operation for several decades under substantial mechanical and thermal loading.

Professional overhaul requires considerably more than replacing seals. It requires precise identification of the individual pump version, controlled dismantling, dimensional inspection of all functional components, specialist knowledge of the relevant engine configuration and access to replacement parts that are often no longer commercially available.

Our services include:

identification of L’Orange fuel injection pumps
complete dismantling and overhaul
inspection of pumping elements and fuel-delivery components
dimensional inspection of camshafts, rollers, bearings and housings
inspection and overhaul of L’Orange plug-in pumps
identification and supply of replacement components
reverse engineering of obsolete parts
precision reassembly
test-bench operation and calibration
technical support with MWM and Deutz-MWM part numbers
assessment of port and starboard pump versions
and international technical support for marine and industrial operators

Each L’Orange injection pump is assessed individually according to its complete type designation, engine application, direction of rotation, technical configuration and current condition.

Based in North Rhine-Westphalia, Germany – supporting engine operators, shipping companies, power-generation businesses and specialist workshops throughout Europe and worldwide.

Request a Technical Assessment

Please send us clear photographs of the complete injection pump, its nameplate, all visible part numbers and the corresponding engine information before shipping the unit.

Contact Our L’Orange Injection Pump Specialists

L’Orange Injection Pumps for MWM TBD440 and TBD441 Engines

L’Orange fuel injection pumps were produced in different configurations for MWM and Deutz-MWM large diesel engines of the D440, TBD440, D441 and TBD441 families.

Known engine variants include:

MWM TBD440 Engine Family

MWM TBD440L6
MWM TBD440L8
MWM TBD440V12
MWM TBD440V16
MWM TBD440V12K
MWM TBD440V16K

MWM TBD441 Engine Family

MWM TBD441L6
MWM TBD441L8
MWM TBD441V12
MWM TBD441V16
MWM TBD441V12K
MWM TBD441V16K

In historical documentation, spare-parts catalogues and technical enquiries, these engine designations may also appear with spaces, for example:

TBD 440
TBD 441
TBD 440 V12
TBD 440 V16
TBD 441 V12
TBD 441 V16
MWM TBD440
MWM TBD441
Deutz-MWM TBD440
Deutz-MWM TBD441

The engine-family designation alone is not sufficient to identify the correct injection pump.

The actual pump version depends on factors including:

exact engine series
number of cylinders
inline or V-engine configuration
marine or industrial application
port or starboard installation
engine output
rated engine speed
direction of rotation
technical production status
plug-in pump version
pumping-element diameter
fuel-delivery specification
and the original MWM configuration

A binding assignment must therefore be based on the complete injection-pump nameplate, the MWM or Deutz part number and the full engine data.

Port and Starboard L’Orange Injection Pumps

Meaning of the B and S Suffixes

On numerous L’Orange fuel injection pumps used in marine installations, the final letters B and S identify the intended engine side:

B = Backbord, meaning the port-engine version
S = Steuerbord, meaning the starboard-engine version

Examples include:

PYY-G001B and PYY-G001S
PYY-G002B and PYY-G002S
PYY-G005B and PYY-G005S
PYY-G006B and PYY-G006S
PYY-G009B and PYY-G009S
PYY-G012B and PYY-G012S
PYY-G013B and PYY-G013S
PYY-G014B and PYY-G014S
PYY-G015B and PYY-G015S
PYY-G016B and PYY-G016S
PYY-G018B and PYY-G018S
PYY-G019B and PYY-G019S

Port and starboard pumps are configured for their respective installation position, engine direction of rotation and mechanical operating arrangement.

A B-version must therefore not be replaced by an S-version—or vice versa—without a complete technical assessment.

For every enquiry, the full pump designation including the final suffix letter is required.

Why the Engine Side Is Technically Important

In a twin-engine marine installation, apparently similar injection pumps may differ in:

direction of rotation
camshaft configuration
mechanical actuation
plug-in pump orientation
control mechanism
fuel-delivery configuration
drive arrangement
and installation geometry

The port and starboard designations must consequently be retained throughout identification, dismantling, component allocation, reassembly and test-bench assessment.

When both pumps from a vessel are overhauled together, they can be individually identified, inspected separately and compared with one another after reassembly.

Known L’Orange PYY Injection Pump Types

The following L’Orange PYY pump designations are documented in connection with MWM and Deutz-MWM D440, TBD440, D441 and TBD441 engines:

PYY-G001B
PYY-G001S
PYY-G002B
PYY-G002S
PYY-G005B
PYY-G005S
PYY-G006B
PYY-G006S
PYY-G009B
PYY-G009S
PYY-G012B
PYY-G012S
PYY-G013B
PYY-G013S
PYY-G014B
PYY-G014S
PYY-G015B
PYY-G015S
PYY-G016B
PYY-G016S
PYY-G018B
PYY-G018S
PYY-G019B
PYY-G019S

This list represents known pump types and is not necessarily exhaustive.

Pumps with similar external dimensions may differ internally and must not be identified solely from photographs of the housing.

Relevant differences may include:

camshaft and cam-profile design
direction of rotation
pumping-element diameter
delivery specification
plug-in pump version
port or starboard configuration
drive arrangement
engine output
rated speed
and technical production status

Earlier and Later L’Orange PYY Versions

Within the PYY pump family, several earlier versions were superseded by later designations.

Documented successor relationships include:

PYY-G001B / PYY-G001S
later superseded by PYY-G015B / PYY-G015S
PYY-G002B / PYY-G002S
later superseded by PYY-G016B / PYY-G016S
PYY-G005B / PYY-G005S
later superseded by PYY-G013B / PYY-G013S
PYY-G006B / PYY-G006S
later superseded by PYY-G014B / PYY-G014S
PYY-G009B / PYY-G009S
later superseded by PYY-G012B / PYY-G012S

A later pump designation does not automatically mean that the newer pump can be installed in every engine as a direct replacement for the earlier version.

Before any substitution, the following must be verified:

complete pump specification
engine assignment
port or starboard configuration
direction of rotation
mounting arrangement
plug-in pump specification
pumping-element diameter
fuel-delivery characteristics
rated engine output
and original MWM documentation

The terms superseded and replacement version must therefore not be interpreted as confirmation of unrestricted interchangeability.

L’Orange PYO Injection Pumps

Known L’Orange PYO pump versions associated with MWM D440 and D441 engine applications include:

PYO-G018R
PYO-G018L
PYO-G028R
PYO-G028L
PYO-G036aB
PYO-G036aS
PYO-G037aB
PYO-G037aS
PYO-G046B

Depending on the version, these pump assemblies may differ in:

installation position
direction of rotation
pump housing configuration
camshaft design
number and type of plug-in pumps
mechanical actuation
fuel-delivery specification
and engine application

The complete PYO type designation is required for every technical assessment.

L’Orange Plug-In Pumps

Inspection and Overhaul of PYO-U Pump Assemblies

The main pump assemblies use individual L’Orange plug-in pumps—also referred to in German technical documentation as Einsteckpumpen.

Known versions include:

PYO-U081aR
PYO-U081aL
PYO-U091R
PYO-U091L
PYO-U100R
PYO-U100L
PYO-U117R
PYO-U117L

These plug-in pumps may differ in:

plunger and barrel diameter
effective pumping stroke
plunger geometry
barrel configuration
delivery-valve design
control-sleeve design
drive and installation direction
right-hand or left-hand configuration
and assignment to the respective main pump

A plug-in pump with a similar external appearance must not automatically be treated as an identical replacement.

For reliable identification, we require:

the complete L’Orange type number
markings on the plug-in pump
the designation of the main injection pump
the engine type
the installation side
and clear photographs of all components

During overhaul, plug-in pumps are kept assigned to their original pump position unless the technical repair process requires a documented reallocation.

Known MWM and Deutz Reference Numbers

L’Orange injection pumps and their components may also be identified by MWM or Deutz original part numbers.

Known references associated with the 440 engine family include:

12152577
12152581
12152583
12152584
12172044
12172046
12172051
12172064
12172065

Some pump versions are additionally documented under longer MWM NMR numbers, including:

6.440.8.725.008.7
6.440.0.725.069.7
6.440.0.725.318.7
6.440.0.725.916.7

One confirmed identification combination is:

L’Orange pump type: PYY-G014B
MWM NMR number: 6.440.0.725.069.7
MWM/Deutz reference: 12172051

Additional numbers associated with plug-in pumps, pumping elements or individual pump components include:

12152651
12152821
12152823
12152824
12152828
12155916

These reference numbers must not automatically be treated as part numbers for a complete injection-pump assembly.

Before quotation, ordering or overhaul, it must be determined whether the relevant number identifies:

a complete injection pump
a main pump housing
a plug-in pump
a pumping element
an individual fuel-delivery component
a drive component
or another spare part

The physical component, original nameplate and engine documentation must always be considered together.

Correct Spelling of L’Orange Pump Designations

The manufacturer name appears in different forms in older databases, catalogues and online searches.

Common search variants include:

L’Orange
L'Orange
L Orange
LOrange
Lorange injection pump
L’Orange fuel injection pump

For technical documentation, we use the correct spelling:

L’Orange

A frequent error also occurs in PYO designations, where the capital letter O is incorrectly entered as the number zero.

Correct examples are:

PYO-U117R — not PY0-U117R
PYO-U091R — not PY0-U091R
PYO-G018R — not PY0-G018R

Because markings on historical nameplates may be difficult to read, a clear, high-resolution photograph of the original identification plate should always be provided.

Typical Damage to Historical L’Orange Injection Pumps

After long periods of operation, storage or exposure to contaminated fuel, L’Orange injection pumps may exhibit different types of wear and damage.

Typical findings include:

worn plunger-and-barrel assemblies
corrosion on plungers and barrels
seized or restricted plug-in pumps
wear on camshafts and cam profiles
damaged rollers and roller tappets
worn bearings and bushes
defective delivery valves
damaged control sleeves
restricted or seized control racks
hardened or leaking sealing elements
diesel-fuel leakage
lubricating-oil leakage
unequal fuel delivery between pump sections
water damage
contamination of precision components
corrosion after extended periods out of service
incorrect component combinations
damage caused by previous improper repairs
and missing or discontinued spare parts

Even relatively small deviations between individual pumping sections can affect the combustion conditions of the entire engine.

Possible operational consequences include:

uneven engine operation
unequal exhaust-gas temperatures
different cylinder outputs
increased fuel consumption
poor load acceptance
starting difficulties
excessive exhaust smoke
increased thermal loading of individual cylinders
and reduced operational reliability

These symptoms do not automatically prove that the injection pump is the sole cause. Injectors, fuel supply, injection timing, compression, turbocharging and the overall engine condition must also be considered during fault diagnosis.

Our L’Orange Injection Pump Overhaul Process

1. Identification and Incoming Inspection

Before dismantling, the injection pump is documented in the condition in which it arrives.

We record:

complete L’Orange type designation
MWM or Deutz part number
MWM NMR number, where available
port or starboard configuration
engine family
number of cylinders
direction of rotation
main-pump configuration
plug-in pump versions
visible damage
corrosion
leakage
missing components
previous repair work
and information about the previous operating condition

The original condition often provides valuable information about the cause of failure.

2. Controlled Dismantling

The injection pump is dismantled completely or separated into its principal functional assemblies, depending on its construction and technical condition.

The following components are inspected separately:

plug-in pumps
plunger-and-barrel assemblies
delivery valves
camshaft
cam profiles
rollers
roller tappets
bearings
bushes
control sleeves
control rack
shafts
actuating components
springs
housing components
and sealing elements

Installation positions and component relationships are documented during dismantling.

3. Multi-Stage Cleaning

All components are cleaned using suitable workshop processes.

The cleaning procedure removes:

old diesel fuel
lubricating-oil residue
deposits
corrosion products
wear particles
and contamination

Reliable visual inspection and dimensional measurement are possible only after the relevant components have been thoroughly cleaned.

4. Visual and Dimensional Inspection

Depending on the pump version, we inspect and measure:

plungers and barrels
pumping-element diameter
working surfaces
camshaft journals
cam profiles
rollers and roller tappets
bearing positions
bushes
control sleeves
control racks
delivery valves
springs
shafts
sealing surfaces
housing bores
fits and clearances
and mechanical actuating components

The inspection considers:

surface condition
dimensional accuracy
corrosion
scoring
pitting
cracks
distortion
wear limits
and suitability for continued operation

Only components whose technical condition permits reliable reuse are reinstalled.

5. Repair and Replacement of Components

Worn or damaged components are:

replaced with suitable parts
professionally reconditioned
repaired where technically permissible
or reconstructed and reproduced through reverse engineering

The selected repair procedure depends on:

component function
dimensional condition
material
surface specification
mechanical loading
thermal loading
and the availability of suitable replacement parts

6. Precision Reassembly

After completion of all inspection and repair work, the injection pump is reassembled under controlled workshop conditions.

During assembly, we verify:

correct component allocation
port and starboard assignment
plug-in pump position
direction of rotation
mechanical clearances
movement of all control components
camshaft and tappet interaction
sealing surfaces
and the required mechanical basic settings

Port and starboard components remain clearly separated throughout the entire process.

7. Test-Bench Operation and Calibration

Following reassembly, the L’Orange injection pump is operated on suitable fuel injection pump test equipment.

Depending on the pump type and the availability of verified technical data, the following parameters can be inspected or adjusted:

fuel delivery from every pumping section
uniformity of fuel delivery
cylinder-to-cylinder delivery variation
mechanical start of delivery
repeatability
leakage
control-rack operation
plug-in pump function
mechanical actuation
behaviour at different pump speeds
and coordination between multiple pump units

An injection pump is released only after its mechanical operation and relevant delivery characteristics have been technically verified.

Testing Port and Starboard Pump Pairs

For marine installations with separate port and starboard engines, both injection pumps must correspond to their respective engine configuration.

When both pumps are submitted together, they can be:

identified individually
dismantled and inspected separately
assigned to their respective engine side
checked for the correct direction of rotation
calibrated according to their individual specification
compared in terms of fuel-delivery characteristics
and technically matched as a port/starboard pair

The objective is not to make mechanically different pumps artificially identical. The objective is to ensure that each pump operates correctly according to its own verified specification.

For V-engines or installations using multiple pump units, coordinated testing or synchronisation may also be required.

Our workshop has specialist test-bench capability for large injection systems with up to 16 cylinders.

Reverse Engineering of Obsolete L’Orange Components

Original spare parts for many historical L’Orange injection pumps are now available only in limited quantities or have been discontinued completely.

However, the absence of a single component does not necessarily mean that the complete injection pump—or the associated large diesel engine—must be taken permanently out of service.

Where technically and economically feasible, original components can be:

accurately measured
dimensionally documented
analysed according to their function
reconstructed in CAD
assigned an appropriate material specification
manufactured by specialised European production partners
dimensionally inspected
and functionally assessed before installation

Depending on the component, the reverse-engineering process considers:

original function
geometry
dimensional tolerances
fits and clearances
material specification
hardness
heat treatment
surface finish
wear resistance
lubrication conditions
mechanical loading
thermal loading
fatigue behaviour
and long-term operational reliability

The technical and commercial feasibility of reproduction is assessed individually for each component.

Highly loaded components are reproduced only when their functional requirements, material properties and quality-control criteria can be defined with sufficient technical certainty.

Spare Parts and Component Support

Depending on the individual pump version, overhaul may require components including:

plunger-and-barrel assemblies
plug-in pumps
delivery valves
camshaft components
rollers
roller tappets
bearings
bushes
control sleeves
control-rack components
springs
shafts
seals
gaskets
housing components
drive components
and specially reproduced parts

Available components are first identified by:

complete L’Orange type designation
MWM or Deutz reference
dimensions
technical function
installation position
direction of rotation
and physical comparison with the original component

We do not assign replacement parts solely on the basis of an incomplete or visually similar designation.

International L’Orange Injection Pump Service

Einspritzpumpen Manufaktur NRW is located in North Rhine-Westphalia, Germany.

We welcome technical enquiries from:

shipping companies
vessel operators
marine-engine service companies
power-generation businesses
industrial engine operators
engine rebuilders
diesel-injection specialists
spare-parts suppliers
engineering companies
and owners of historical MWM and Deutz-MWM engines

L’Orange pumps and individual components can be sent to our workshop from European and international locations by prior arrangement.

Before shipping, please provide all available identification details and photographs. This allows us to assess:

whether the pump can be accepted
whether it is a port or starboard version
which technical documents are required
whether special transport precautions are necessary
whether additional components should be supplied
and which information is still missing

Please do not dismantle or unnecessarily clean the pump before contacting us.

Its original condition may provide important evidence of leakage, corrosion, contamination, component failure or previous repair work.

Frequently Asked Questions

Do you repair L’Orange fuel injection pumps?

Yes. We inspect, overhaul, repair and test selected mechanical L’Orange injection pumps used in MWM and Deutz-MWM large diesel engines.

The possible overhaul scope depends on the exact pump version, its technical condition and the availability or reproducibility of the required components.

Do you overhaul L’Orange pumps for MWM TBD440 engines?

Yes. L’Orange injection pumps for MWM TBD440 engines can be submitted for individual technical assessment.

Please provide the exact engine version, complete pump designation, MWM or Deutz part number and clear photographs.

Do you overhaul L’Orange pumps for MWM TBD441 engines?

Yes. Pumps used on MWM TBD441 engines can also be assessed.

The engine designation alone is not sufficient; the complete pump identification and engine data are required.

What do B and S mean in a L’Orange pump designation?

For the relevant marine pump designations:

B identifies the Backbord or port-engine version.
S identifies the Steuerbord or starboard-engine version.

The final suffix is an essential part of the complete pump designation.

Can a B-version be replaced by an S-version?

Not without a complete technical assessment.

Port and starboard versions may differ in direction of rotation, camshaft configuration, actuation, installation geometry and other functional details.

Do you repair L’Orange plug-in pumps?

Selected PYO-U plug-in pumps can be inspected and overhauled as part of the complete injection-pump assessment.

The exact capability depends on the plug-in pump type, condition and availability of suitable components.

Can you identify a pump using only an MWM part number?

An MWM or Deutz reference is an important starting point, but it is not always sufficient for a binding identification.

We also require the L’Orange nameplate, photographs of the complete pump and the corresponding engine information.

Can discontinued L’Orange parts be reproduced?

Many obsolete parts can potentially be measured, reconstructed and manufactured through reverse engineering.

Feasibility depends on the component’s function, material, required tolerances, loading and available original sample.

Do you test the pump after overhaul?

Yes. Following reassembly, the pump is operated and tested on suitable test equipment where the pump design and available technical data permit.

Can international customers send pumps to Germany?

Yes, by prior arrangement.

Please send the identification details and photographs before shipping.

Request an Assessment of Your L’Orange Injection Pump

For an initial technical evaluation, please provide:

exact engine manufacturer
complete engine designation
number of cylinders
rated engine output
rated engine speed
marine, industrial or stationary application
port or starboard engine
complete L’Orange pump designation
MWM or Deutz part number
MWM NMR number, where available
direction of rotation, if known
photographs of the complete injection pump
clear photograph of the original nameplate
photographs of the plug-in pumps and connections
description of the fault
information about previous repairs
period of storage, if applicable
and any available spare-parts lists, manuals or test specifications

For marine installations, please state explicitly whether the pump belongs to the port or starboard engine.

A final repair quotation normally requires dismantling and technical inspection because the internal condition of a historical L’Orange injection pump cannot be assessed reliably from photographs alone.

After reviewing the information, we will provide an initial technical assessment and advise you on the next steps.

Contact Our L’Orange Injection Pump Workshop

Name *

Company

Country

Email Address *

Telephone Number

Engine Manufacturer and Model

L’Orange Pump Type

MWM or Deutz Part Number

Port or Starboard Engine

Description of the Fault *

Upload Nameplate and Pump Photographs

Submit Technical Enquiry

Einspritzpumpen Manufaktur NRW

Specialist for Historical L’Orange Fuel Injection Systems

Professional services for:

L’Orange injection pump repair
L’Orange injection pump overhaul
L’Orange pump identification
L’Orange PYY injection pumps
L’Orange PYO injection pumps
L’Orange PYO-U plug-in pumps
port and starboard marine pump versions
MWM TBD440 injection systems
MWM TBD441 injection systems
reverse engineering of obsolete components
spare-parts identification
and specialist test-bench operation

For marine propulsion engines, industrial diesel engines, generator sets, stationary power-generation applications and historical large diesel installations.

Request a L’Orange Injection Pump Assessment