load capacity AUDI S4 1998 B5 / 1.G Engine Manual

6
Engine
The crankshaft
The crankshaft is identical to that used in the
2.8-litre V6 engine.
The crankshaft bearing caps are attached to
the central crankcase by 4 bolts.
•
The 4-bolt connection reduces the load on
the bearing caps considerably.
The middle two crankshaft bearing caps are
also bolted to the side of the crankcase.
•
The lateral bolted connection helps to
improve acoustics.The pistons are forged to enable them to
withstand the high loads to which they are
subjected.
Due to the high combustion pressures, a 2-
material bearing shell is installed on the
connecting rod side. The bearing cap has a 3-
material bearing shell.
Advantage:
The bearing shell has a high load-bearing
capacity
SSP 198/11

Lateral bolted connection
4-bolt connection
2-material
bearing shell
3-material
bearing shell

16
Engine
The component parts of the oil circuit
is integrated in the primary flow. By increasing
the capacity and optimising the flow
resistance, the entire oil flow can be routed
through the oil cooler. Unlike the V6 naturally
aspirated engine, a bypass is not required.
The oil cooler ......
contains an oil retention valve, the filter
element, a bypass filter and the filter bypass
valve. The latter has the task of maintaining
engine lubrication via the bypass filter if the
filter element becomes clogged up or if the oil
has a high viscosity.
The oil filter ......
opens up the oil flow to the piston spray jets if
the oil pressure is greater than 1.8 bar.
Reason: at low oil viscosity and low engine
speeds, the oil pressure would otherwise drop
below the minimum permissible level. That
aside, piston cooling is not necessary at low
engine speeds.
The spray jets valve ......
SSP 198/57

Oil pressure control valve
Oil pressure limiting valve
Chain guard

is an internal gear pump. It is attached to the
crankcase as a separate component.
The oil pump is designed in such a way that it
projects deep down into the oil sump and is
immersed completely in the engine oil when
the oil level is correct. This prevents the oil
pump running dry.
The oil pump, in combination with the
extremely short intake path, enables oil
pressure to build up more quickly and safely,
particularly during cold starts.
The oil pump is driven by the crankshaft by
means of a single chain.
A spring-loaded flat plate produces the
necessary tension.
A new feature of the oil pump is the chain
guard made from sheet steel. It encapsulates
both the chain wheel and the chain over a large
area.
This reliably prevents oil frothing and the
problems associated with this.
The oil pump ......