They were a flathead design with the valves in the block. At 100K miles I took it to the dealer I know dont shoot me and they charged me a tidy 1400 to change the timing belt and water pump. Here Are The Differences Between Variable Valve Lift And Variable Valve Timing ENGINE 36L VARIABLE VALVE TIMING V6 WITH SIDI SPARK IGNITION DIRECT INJECTION DOHC 288 hp 2147 kW 6300 rpm 270 lb-ft of torque 3645 N-m 3400 rpm STD MOONROOF POWER tilt-sliding with additional skylight. . This system typically activates when. Mechanically variable compression ratio engine. The resulting AC frequency obtained depends on the particular device employed. Each automotive manufacturer has their own unique VVT system but most of them rely on a fully functional variable valve timing solenoid to control the flow of oil to the VVT system as it is engaged. Hands down the best timing beltwater pump kit you can buy for your ToyotaLexus V8 engineI have a ...