<VV> Interesting quote from "Bob is the oil guy"

[kevin nash]

 I found this at Bob is the oil guy website, somewhere in the frequently asked questions section:


" a. In the valve train between the cam lobe and its follower, the valve spring can push those two pieces together so hard and on such a small area of contact that the local pressures could calculate to 200,000 psi. This is enough to squeeze the oil (conventional or synthetic) out of the way. So oil formulators typically use wear protection additives that form a sacrificial chemical coating on the cam lobes and followers that can withstand those extreme pressures.

b. In variable valve train actuators, detergents and dispersants must keep the actuators clean - the tolerances here are extremely tight and the actuators must precisely alter the cam phasing upon demand from the ECM. Friction modifiers are used to help keep the internal components of the actuators moving freely without stick-slip. To reduce air entrainment in the oil and to ensure the right viscosity at the right temperature, oil formulators carefully select quality base stocks and incorporate anti-foaming or air release additives.

c. For timing chains, in addition to the need for correct wear protection additives and friction modifiers, the oil formulators also watch the dispersants in the oil quite closely. The fear is that without a suitable dispersant, soot and carbon in the oil could collect inside the pins of the chain and create wear or limit movement that would result in the chain's effective length changing. If the chain's effective length changes even slightly, it can be sensed by the ECM and create problems"


Kevin Nash

63 Turbo EFI daily driver

Friday Harbor Wa