Here's a look inside of Audi's V8 engine and how it works!

The Audi V8 engine uses dual overhead camshafts with variable valve timing on the intake camshaft. Those camshafts are driven by a timing chain, located at the rear of the engine behind the transmission. Unfortunately failure prone timing components and the placement of this chain results in expensive failures since repairs are very labour intense.

The rest of the engine however is well built but has unique design elements, such as timing chain powered accessories and a 5 valve design. The oil pump, air conditioning compressor, power steering pump and water pump are driven by an extra accessory drive timing chain setup and shafts leading to the front of the engine to where they reside, as opposed to the alternator which is powered by a traditional belt from the harmonic balancer at the front of the engine.

There are two versions of the 4.2L engine - newer Audi's have timing setups at the front of the engine which weren't nearly as failure prone. The engine in this video (BBK) failed due to a cracked plastic timing chain guide causing timing to skip and errors to be alerted in the computer before complete catastrophic failure. It was out of a 2007 Audi S4 B7. Other failure modes include failed timing chain tensioners, camshaft phasers and stretched chains causing rattle upon cold starts.