Originally Posted By: Doog
Originally Posted By: LeakySeals
Its hard to say in a few words but..The only function oil provides to VVT is the hydraulics to advance/retard/turn the controller/cam gear/actuator which advances and retards the cams which changes the time when the intake and exhaust valves open and close. The oil pressure and flow direction is controlled by the Oil Control Valve which takes commands from the ECU which is making valve timing decisions based on readings from the Camshaft Position Sensor, Engine Coolant Temp. Sensor, Crankshaft Position Sensor, TPS, MAF, and Vehicle Speed Signal.
To answer your question more directly, the VVT is calibrated by sensors throughout the engine, not the oil. However if the oil was too thick, or a deposit problem impacting flow this could impact the ability for the controller to turn, incorrectly setting valve timing.
I am wondering if viscosity could alter the ability of the cam phaser to turn. I am wondering how sensitive the phaser is to viscosity.
8-15cst at 100C is lost in the 40KV range for starters, and then down to whatever crazy starting temperatures those in the Northern hemisphere want to live at (let alone start cars at)