Quote:
Originally Posted by thstone
Aha! I found the exact conditions:
When the ignition is switched on, the electromagnetic valves of the camshaft adjusters are supplied with positive potential. If the engine is started, the control unit applies ground to terminal 25 (camshaft adjuster for cylinder line 4 - 6) and to terminal 52 (camshaft adjuster for cylinder line 1 - 3) if the following conditions are fulfilled (VarioCam activated);
1 - Engine oil temperature between -3°C and 133°C
2 - Engine speed > 1,300 rpm
3 - Throttle opening > 5%
or
1 - Engine oil temperature > 133°C
2 - Engine speed > 1,480 rpm
3 - Throttle opening > 3.9%
Variocam is deactivated by the DME control unit if: engine speed > 5,120 rpm"
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This sounds like the 2003 & up VarioCam which has infinitely adjustable cam timing & 3 timing chains.
My previous post was about VarioCam actuation for 1997-02 engines with 5 timing chains which I believe is what the OP has. This actuation has 1 step cam adjustment that occurs between 2200-2600rpm depending mainly on oil viscosity & wear of the parts involved.
To illustrate the inevitable wear problem, I think of the parts as a brake shoe against a dull chainsaw, hydraulically activated. Each time you force the brake shoe against the chainsaw it wears. If you cruise in the activation rpm range, you risk multiple activations & deactivations, leading to accelerated wear.
The updated wear pads seem far superior in wear resistance. On a good dyno graph it's easy to see which pads the engine has due to the smoother cam adjustment transition.
My apologies to Meathead for not answering your question more directly. I type slow & try to address multiple issues simultaneously.