Engine and engine auxiliaries repair

Fuel pump was seized and full of black debris.

Since structural components still were usable it would be possible to repair this pump, but unfortunately, there were no parts available for this model of pump. There was only replacement pump available on the market.

Steering pump was disassembled for inspection and repair.

Intake manifold was brought for inspection and missing components detection.

Throttle was removed for inspection and maintenance.

Cold start valve was disassembled for maintenance.

Injectors were clogged and distributors full with debris – in the best case overhaul at specialist may save those components. It was needed to send this kit to the BOSCH German workshop.

Distributor was completely disassembled for detecting of technical condition and repair of parts.

Throttle valve was completely disassembled and any part was cleaned.

Throttle valve after restoration was assembled and adjusted.

Body and engine compartment components were returned from galvanizing shop.

Missing injection pump installation components were received facilitating assembling of the engine ancillaries.

Restored intake manifold and other renewed components were attached to the engine.

Thermostat was obviously damaged because of slanted plunger and needed replacement.

Received injection pump had several components heavily rusted. We had to disassemble partly this costly unit to check condition of rusted components and decide on possible restoration actions.

Injection pump as it is first was installed onto the engine to check compatibility with other delivered ancillaries. Most of parts fit together, just appropriate for M127 housing for temperature sensors was still missing.

Heat feeler body had numerous rusted through holes, which had to be plugged before any other actions. Some of discovered after cleaning holes are marked below. We used brass soldering to recover this housing.

Restored water pump and thermostat housing were installed onto the engine.

Fuel supply module, including fuel filter and vibration dampers, was assembled from restored components.

Heat feeler housing after repair was galvanized. New seals were used for assembling of the heat feeler unit.

Injection pump was re-assembled using restored components.

Measures were taken for search of missing alternator bracket and belt tensioner.

Available thermo switch housing was modified to fit installation on M127 engine.

Rusted injectors and distributors were cleaned prior to sending for overhaul to BOSCH specialist workshop in Germany.

All existing components were restored and shelved waiting for delivery of missing parts required for further assembling.

Rear gearbox support was still missing. To facilitate installation of the powertrain we self-manufactured missing component.

Waiting for arrival of the ordered parts and overhauled injection components, we installed engine on our test rig.

Order was placed at manufacturer for production of missing engine piping.

Missing fuel lines at the engine were manufactured according to requested measurements.

Distributors and jets were received from overhaul in Germany at BOSCH workshop.

Restored distributors and jets were installed onto the engine facilitating start of the engine tests on the rig.

Unfortunately, overhauling engine in US paintwork has been done on oily surfaces – red paint from the dipstick was getting loose just touching it by hand. This was requiring additional cleaning and painting to achieve acceptable appearance.

Restored alternator and power steering gear were attached to the engine on the rig for operational tests.

Electrical components of the engine were connected to the test bench for operational tests.

Repaired gauges were installed onto the rig for functionality tests. During the test trial, function of all sensors, relays and gauges was tested.

Restored heater unit was attached to the cooling system for tests.

All systems of the engine were tested using specific equipment prior to installation on the car.

Function of the power steering was tested according to manufacturer’s prescriptions.

Need for additional replacement of certain components was detected during tests. Defective unrepairable components were added to the needed parts list. Other components, like injection pump, which was believed as being overhauled, appeared as not tuned, so additional adjustments were needed to this component and whole fuel supply and ignition systems.

Remanufactured in Germany alternator and voltage regulator were tested and adjusted on the test rig.

Fresh galvanized coolant pipe to heater unit had internal corrosion spots and started to leak during the tests, so we had to order new pipe for assembling onto the car.

Work of fuel supply system was not satisfactory and adjustment possibilities of rich running engine were limited, so we had to disassemble system for detailed tests of received from overhaul components.

Pressure test of overhauled injection nozzles received from BOSCH workshop revealed reason for our technical difficulties – two out of six nozzles did not keep pressure. Just two nozzles were keeping pressure according to Mercedes prescriptions. We were forced to start dispute with our supplier. We had to check for possible failure also injection pump.

Un-adjustable injection system was completely removed from the engine and sent to specialist workshop for repeated tests and verification.

Engine was removed off the test rig and immersed into engine compartment.

Arrived cargo with different used components.

Unfortunately, received muffler and silencer were in sorry state – corrosion products spilling out of the pipes were signalling about damaged internal structure of given components.

Even outer shell of main muffler was damaged and we had to look for substitution.

Just front exhaust pipe section seemed usable – we had to clean it for assessment that is more precise.

After cleaning appeared that front pipe had some holes, which we welded before paining.

Front pipe was delivered with some remain in the smashed junction. We carefully extracted unnecessary piece and restored junction end of our pipe.

We acquired new main muffler and intermediate silencer of the appropriate size for re-creation of the exhaust system.

After installation onto the engine, it appeared that injection pump heat feeler housing is again leaking. New housing was self-manufactured and sent for galvanizing.

Renovated exhaust front section was installed onto the engine.

Restored radiator was installed into the place.

New protective shroud was used for installation of new fuel pump.

Since overhaul of worn out injection pump was not accepted, it was not possible to start the engine and complete test drive tasks on restored car. To overcome situation and evaluate possibility to achieve at least some operational capability of the pump and components we put whole injection system on our test rig.

First test revealed that system is completely out of adjustment range.

We flushed with specific agent whole system several times.

First, we made necessary adjustments on both plungers achieving necessary balance.

After flushing all distributors and injectors were accordingly paired.

Necessary adjustments were performed to achieve balanced capacity of all injection ports.