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The V6 came in two basic configurations -- 2.8 liters and 2.6 liters. Both engines share the same block and basic configuration, but had different feature sets. I don't have much information about the 2.6l engine, because it was not offered in the US and I don't have access to European maintenance literature. If you have some factory service documentation on the 2.6l engine, please let me know! I'm also on the lookout for power/torque graphs for the AFC and ACK engines. Thanks as always for any information you can provide!

Common Features of the 2.8l and 2.6l engines:
  • 90o angle V6
  • Gray cast iron cylinder block
  • Split-pin crankshaft with four main bearings
  • Light alloy oil pan
  • Two light alloy cylinder heads
  • Valves operated by single overhead camshafts
  • Self-adjusting hydraulic valve lifters
  • Idle stabilizer with deceleration fuel cutoff
  • Cross-flow cylinder heads
  • Fully electronic fuel injection with cylinder-selective knock control
  • Two three-way catalytic converters with oxygen sensors
  • Self monitoring and diagnosis system


2.8L
2.8 Curves
  • 2.8L / 169in3 / 2771cm3 displacement
  • Maximum output: 174bhp DIN (128kW) @ 5500rpm
  • Maximum torque: 250Nm (184ft. lbs.) @ 3000rpm
  • Maximum engine speed: 6700rpm
  • Bore: 3.25in / 82.5mm
  • Stroke: 3.40in / 86.4mm
  • Compression ratio: 10.3:1
  • Accurate fuel metering by means of a heated-wire
    air mass sensor
  • Dual stage multi-path intake manifold
    • Short intake path: 380mm
    • Long intake path: 780mm
  • Engine code: AAH, AFC, or ACK
  • Weight: 355lbs / 161kg
  • Length: 17in / 432mm
 		 
2.6L
2.6 Curves
  • 2.6L / 158in3 / 2598cm3 displacement
  • Maximum output: 150bhp DIN (110kW) @ 5750rpm
  • Maximum torque: 225Nm (166ft. lbs.) @ 3500rpm
  • Maximum engine speed: 6500rpm
  • Bore: 3.25in / 82.5mm
  • Stroke: 3.19in / 81.0mm
  • Compression ratio: 10.0:1
  • Engine code: ABC or ACZ
  • Weight: ???lbs / ???kg
  • Length: 17in / 432mm


I'm still trying to find some of this info!
I'd love to hear it if you have it.


The AFC revision of the 2.8l V6 implemented many technical improvements over the initial AAH version. Some of the most important changes are as follows:
AAH head AFC head The AAH/AFC and AFC engines had a lighter valve train and different valve timing. Major differences between the original AAH design (left) and the updated AFC design (right) include:

A: The AFC camshaft is lighter and provides different valve timing.
B: The valve spring assembly in the AFC engine has less mass and is a simpler design.
C: Valve stem oil seals are updated in the AFC engine to accomodate changed valve stem diameters.
D: AFC exhaust valves have a smaller stem diameter.
E: AFC intake valves have a smaller stem diameter.


The results from valve timing changes are as follows:
Engine Code
AAH
AAH/AFC
AFC
Dates
11/1991 - 11/1994
8/1994 - 5/1995
12/1994 -
Torque
184 ft-lbs = 250Nm
184 ft-lbs = 250Nm
180 ft-lbs = 250Nm
Compression Ratio
10.3:1
10.3:1
10.0:1
Intake valve opens
4o
10.5o
10.5o
Intake valve closes
42o
45.45o
45.45o
Exhaust valve opens
42o
37.5o
37.5o
Exhaust valve closes
2o
2.55o
2.55o
Min. RON (fuel octane)
95
95
91


The AAH/AFC and AFC engines had an updated oil pan assembly as well. Some of the major differences between the AAH (left) and AFC (right) engines include:

A: The updated engines use a larger oil filter.
B: The oil cooler in the AFC engine has a larger cross-sectional area.
C/D: The pressure relief valve is integrated into a cover assembly on the AFC engines.
E/F: The oil pickup is integrated into the upper oil pan on the AFC engines.
G: The lower oil pan gasket is revised in the AFC engine.
AAH oil pan   AFC oil pan
Updated oil circulation   The AFC engines had a significantly different oil circulation system than the AAH engines. The updated system works as follows:

Intake side:

Oil is drawn into the oil pump (E) through the oil pickup (G).

Pressure side:

Oil pressure comes from the oil pump past the upper part of the oil pan to the 11 bar (160 PSI) pressure relief valve (H), the oil pressure switch (F), the oil cooler (B), and the oil filter (A) to the pressure relief valve (C) and finally the engine (D).

The pressure relief valve (C) controls the oil pressure to the engine. The 11 bar (160 PSI) pressure relief valve (H) is a safety valve that opens only at high RPM and cold engine temperature.

Advantages:

Oil pressure is controlled from the oil filter and oil cooler so that the oil pressure available at those locations is supplied via the pressure relief valve (C) or from the oil pump.
 
 
 
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