Specifications
Engine designation | BAS |
Working volume, cm3 | 4163 |
Power, kW at rpm | 221/6200 |
Power, hp at rpm | 300/6200 |
Maximum torque, Nm at rpm | 380/2600-4700 |
Cylinder diameter, mm | 84,5 |
Piston stroke, mm | 92,8 |
Compression ratio | 11,0 |
The order of operation of the cylinders | 1-5-4-8-6-3-7-2 |
As a power plant on Audi Allroad cars, 8-cylinder gasoline engines with two blocks of four cylinders each are also used. Cylinder blocks are located at an angle of 90°relative to each other, so these engines are designated V8. The cylinder block is made of gray cast iron and the block head is made of light metal alloy. The cylinder head is made according to the so-called transverse principle, when the intake and exhaust channels are located diametrically opposite, across the longitudinal axis of the engine. The air-fuel mixture enters from one side of the cylinder head, and the exhaust gases exit on the opposite side, providing a quick gas exchange.
Each cylinder of the engine in question has three intake and two exhaust valves. Each cylinder block has two camshafts, which are connected by a drive chain to the corresponding exhaust valve shaft. The camshafts are driven by a chain. In addition, the drive of auxiliary units is also performed by a chain.
The intake and exhaust valves are actuated by the camshaft cams via hydraulic tappets, thanks to which the valve clearances are adjusted automatically and remain constant. For this reason, valve clearance adjustment is not required during vehicle maintenance.
The crankshaft rotates in five main bearings. The axial play of the crankshaft is regulated by thrust half rings located on the neck of the fourth main bearing (see illustration 1.0). The connecting rods are attached to the crankshaft by means of connecting rod bearings, and to the pistons by piston pins. The pistons are made of aluminum alloy and are equipped with three piston rings - two compression and one oil scraper (see illustration 1.0b).
Crankshaft dimensions
Main bearing journal diameter, mm | Diameter of the neck of the connecting rod bearing, mm | |
Nominal size | 65,000 | 54,000 |
Repair size | 64,750 | 53,750 |
The engine has a liquid cooling system. It should be remembered that the engine cooling circuit must be filled all year round with coolant, which is a mixture of the appropriate concentrate (antifreeze) with anti-corrosion additives and distilled water.
1.0. Crankshaft:
1 - gaskets
2 - crankshaft oil seal
3 - centering sleeve (3 pcs.)
4 - crankshaft bearing housing bolts
5 - a bolt of fastening of the case of bearings of a cranked shaft
6 - crankshaft bearing housing
7 - lower thrust half ring
8 - the lower loose leaf of the radical bearing
9 - crankshaft
10 - upper thrust half ring
11 - the top loose leaf of the radical bearing
12 - sealing gasket
13 - cylinder block
1.0a. Tightening the crankshaft bearing housing bolts:
1st pass - tighten bolts 1-10 to 30 Nm;
2nd pass - tighten bolts 11-20 with a force of 20 Nm;
3rd pass - tighten bolts 1-10 with a force of 50 Nm;
4th pass - tighten bolts 11-20 with a force of 30 Nm;
5th pass - tighten bolts 1-10 by 90°;
6th pass - tighten bolts 11-20 by 90°.
1.0b. Engine piston and connecting rod:
1 - connecting rod cap bolts. Tightening torque: 1st pass - 30 Nm; 2nd pass - tighten 90°
2 - connecting rod cover. Changing covers is not allowed. When removing, mark B for accessories of the cover to the cylinder. Observe installation position A when installing
3 - upper and lower connecting rod bearing shells
4 - connecting rod
5 - piston pin. When assembling the piston and connecting rod, it is recommended to heat the piston up to 60°C
6 - piston pin circlip
7 - piston
8 - piston rings. The locks of the rings are located at an angle of 120°relative to each other. When installing the inscription «TOR» must face the piston crown
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