|
|
|
|
|
|
|
MERCEDES-BENZ AND PARTS © 2008 |
|
|
|
|
|
We
offer a reliable and prompt delivery service
OM 636 HISTORY Numerous automotive
applications include the Mercedes-Benz Unimog 411 and 319 series transporter as
well as forklift trucks, farm tractors, combine harvesters and other special
purpose vehicles. The Readily marinised by
fitment of a heat exchanger and sea-water cooling system, the During the 1960s, 70s
and 80s, the In the After the end of
production in OM 636 TECHNICAL DESCRIPTION The cast iron
crankcase has integral cylinders with a standard bore of 75mm. Re-boring is possible up to a maximum bore
of 77mm. Pistons are available in 4
repair sizes. It is also possible to
reline the block back to standard bore. The injection pump and
oil filter are located on the right hand side of the engine (as seen from the
flywheel end). The generator, starter
motor, oil dipstick and breather pipe are on the left. At the front, an alloy timing cover encloses
helical gears driving the camshaft and injection pump off the crankshaft. A side cover seals the valve lifter chamber.
The alloy oil sump is bolted to the
crankcase. The cast iron cylinder
head is fastened to the crankcase by hexagon-head bolts. A composite cylinder head gasket seals the
combustion chambers and water passages between the head and the crankcase. The cylinder head features removable
precombustion chambers into which injectors atomize the diesel fuel for
combustion. Pre-heater plugs are used as a starting aid. An alloy rocker cover with an oil filler
seals the top of the cylinder head. The 3-main bearing,
drop-forged crankshaft has hardened bearing surfaces. The centre bearing serves as the thrust
bearing. Counterweights on the
crankshaft compensate for the rotational inertia in relieving the forces on
the main bearings. The coolant pump is
driven by a 'V' belt pulley fitted to the front of the crankshaft. The forged steel
connecting rods are equipped with bronze bushes at the small end to
accommodate the piston pin and a 2- piece friction bearing at the big
end. The bearing cap is secured to the
connecting rod by 2 special bolts and nuts. The alloy pistons generally
feature 3 compression rings and 2 oil scraper rings. The floating piston pin is retained by
circlips. The piston crown is dished. The drop-forged
camshaft with hardened bearing surfaces and cams is supported by 3 alloy bearings
in the crankcase. Axial movement is
controlled by the front camshaft bearing which together with the 2nd camshaft
bearing is of a split design. Each cylinder features
an overhead exhaust and inlet valve opened and closed by the camshaft by
means of mechanical lifters, pushrods and rocker arms. The fuel lift pump is
mounted on the injection pump and draws fuel from the tank. It incorporates a
hand primer pump that is used the bleed the fuel lines of air (e.g. after
filter replacement). Diesel fuel is
fed to the injection pump after passing through a filter. The injection pump delivers fuel under
pressure to the injectors via rigid injector pipes of equal length. On engines fitted with BOSCH injectors
excess fuel is returned to the fuel tank by a metallic spill pipe
interconnecting the injectors. A
flexible fuel spill hose is used on engines fitted with TDZ injectors. Depending on
application, the injection pump is fitted with a pneumatic or centrifugal
governor that controls the amount of fuel injected according to engine load. On engines producing the maximum 42HP an
automatic timing device advances the timing of the pump with increasing
engine speed. Engine lubrication is
provided by an oil pump driven by the camshaft. Oil is drawn from the sump and directed into
the main oil gallery after being filtered by a fine mesh strainer or
cartridge-type filter. Oil is fed to
the crankshaft and camshaft bearings via small bores. From the front camshaft bearing, oil
continues to the rocker shaft pedestals and cylinder head through external
oil lines. The rocker arm bearings and pushrods are lubricated by oil flowing
through hollow rocker shafts. Cylinder
bores, piston pins and timing gears are splash-lubricated. Two pressure relief valves are fitted to the
oil circuit. The main circuit features
a relief valve that opens at 8 bar, protecting the engine against excessive
oil pressure. The oil filter is
equipped with a valve that opens at 2 bar allowing oil to by-pass the filter
should it be clogged. Most
installations feature an electrical or mechanical gauge to monitor the
engine's oil pressure. The injection pump and
cooling water pumps have their own oil supply and are not connected to the
main engine lube circuit. However,
modern replacement water pumps feature sealed-for-life bearings and require
no maintenance. Engine temperature is
controlled by means of a belt-driven coolant pump, a radiator or heat
exchanger and a thermostat.
Engines to be
reconditioned are completely disassembled and chemically cleaned. The engine
block and cylinder head are pressure-tested and oil galleries cleaned. Any damaged studs on the block or head are
renewed. Cylinders are bored
and honed to accommodate new pistons. Crankshafts are checked, reground and
polished. Matched connecting rods with
improved lubrication grooves for the gudgeon pins are fitted. Crankshaft and camshaft bearings are
systemically replaced. The camshaft
and timing gears are checked and replaced if necessary. A new oil pump is installed before mounting
the sump to the crankcase. Cylinder heads are
refaced within the recommended tolerance or replaced and equipped with valve
guides incorporating valve stem seals. Inlet and exhaust valves are also replaced
and valve seats serviced. Precombustion
chambers of the latest design are fitted. The cylinder head is
fitted to the crankcase and valve lifters installed. Pushrods are checked and replaced if
necessary. The rocker shafts and arms
are carefully examined and any components showing signs of wear are replaced.
New external oil lines and pressure
relief valves are connected to the oil circuit. New gaskets and seals are used throughout
the rebuild. All
engines are test-bench run on a dynamometer for several hours to confirm
power output, oil pressure and exhaust emissions at all operating
temperatures. Engines are supplied
either with or without all external ancillaries according to the application
and customer requirements. The minimum
specification however always includes the diesel fuel injection pump,
injectors and coolant pump allowing engines to be test-run. Customers are
invited to attend whilst their engine is running on the dynamometer after
rebuild. A computer printout
describing all engine operating parameters can be provided on request. In order to protect
the engine from external corrosion, especially important for the alloy
components fitted, completed engines are etch-primed and painted prior to crating.
Although engines are usually supplied
painted with a hammered mid-green finish, customers may specify any colour
preference at the time of order. Fully-dressed rebuilt
engines with new or refurbished marine ancillaries such as BOWMAN heat
exchangers, JABSCO sea water pumps, starter motors, alternators, hoses and
pipe work etc. are available to order. This service provides a
ready-to-fit marine engine. Marinised engines are
fitted with a flywheel but do not include the gearbox or transmission. We can arrange prompt
door-to-door collection and delivery.
Customers can also collect their engine from our workshop. Our reconditioned
engines are fully covered by a 12 months back-to-base warranty. OM 636 SPARE PARTS AND REBUILD KITS Our stocks include: ENGINE CRANKCASE,
FRONT COVER AND OIL SUMP Reconditioned, rebored
crankcases CYLINDER HEAD Bare cylinder heads,
new or reconditioned Complete built-up
cylinder head assemblies, new or reconditioned to include valves,
precombustion chambers and injectors as required. De-coke cylinder head
gasket sets Valve guides CRANKSHAFT AND
PISTONS Reground, polished
crankshafts TIMING EQUIPMENT Camshafts DIESEL FUEL
INJECTION EQUIPMENT Reconditioned BOSCH
PES4A50 fuel injection pumps FUEL FILTER Fuel filter elements MANIFOLDS Inlet manifold casting
ELECTRICAL
EQUIPMENT Pre-resistor for
'series' glow plugs ENGINE LUBRICATION Oil pumps ENGINE COOLING Fresh water pumps with
fitted pulley Coolant vent line kits MARINISATION PARTS Vacuum pipes from
injection pump governor to throttle body Engine oil cooler kits
A copy of the original
operating and service instruction booklets is available. To subscribe to our
mailing list and to receive a compilation of technical and parts bulletins
for this engine, please send a message indicating your email address. So whether you need a
gasket or a replacement engine - contact us to discuss your requirements. Nous parlons français. Wir sprechen deutsch. |
|
|
|
|
|
|
|
|||
|
|
|||
|
Click below to see
an OM 636 engine sitting on our testbed |
|||
|
|
|||
|
|
|||
