Smoke coming out of the intakes.

[epapp]

What causes the engines to have the highest load on the valve train at idle???? I don't buy that for a second. you're telling me my 5 timing chains, IMS shaft/bearing and cams/valves are under less stress and load when I'm WOT going through all gears at 5k rpm? The only thing I can think of is the chain tensioners and variocam. Still doesn't make any sense.

The second sentence of Jakes is inherently true of any moving part requiring oil, and mostly just a statement. If I'm not mistaken, the moving parts DO get a constant flow of oil, EVEN at idle...unless the oil pump just decides to take a break < 1000rpm...

I know Jake has a lot more experience than myself with these engines, but this doesn't make sense to me.

[jaykay]

As I recall the Vario cam solenoids actuate at 3000 rpm to phase the cam shafts into the proper position for low rpm operation. The actuators extend tensioning the chains in order to effect rotation of the cam shafts. This increased cam drive chain tension is what accelerates wear of cam drive components.

Above 3000 rpm this tension is relived as the cams change phase for high rpm operation. There are other loads associated with wot but it appears the cam drive is the most dominant point of vulerabilty. Oil film strength on cylinder walls seem to be better at higher rpm.