VP D2 55/75 Turbo Wate-Gate Opening

[Dave100456]

Hi
I've researched various threads on the Volvo Penta D2 waste-gate seizing issues.

My D2 waste-gate opens and snaps shuts by the return "spring" action. However, when its fully open, its travel is limited by the exhaust elbow (as my dented 0.01mm feeler gauge indicates).

My Question is how much should the waste-gate open? I know other owners have ground the exhaust elbow casting to allow more clearance.

Mine moves the actuator rod by 3-4mm is that enough? My guess on the waste gate arm rotational movement would be that it moves more than 10 but less than 30 degrees. Is this correct???

Thanks

 

[Skylark]

A waste gate is a bypass arrangement and is used to limit the speed of the turbine wheel. Exhaust gas bypasses the turbine wheel, hence the energy is wasted, when open. It takes very little movement of the valve arrangement to do this.

In its simplest form, boost pressure, taken from one of the ports around the compressor housing or from the inlet / plenum chamber, will be connected to an actuator. This is a spring over a diaphragm and connects directly to the waste gate valve mechanism. More boost equals more movement equals more bypass to limit boost until equilibrium.

The valve should not hit the elbow at max boost.

Your measurement of 3-4 mm sounds about right. If you really wanted to know, you should measure max boost pressure and compare this to the engine spec.

Find an unused port in the induction anywhere upstream of compressor outlet or Tee the hose into the actuator. Insert pressure gauge and measure at high engine load. Don’t know without looking but it’s probably around 7-10 psi.

 

[Dave100456]

Thanks Skylark.

 

[Ring of fire]

We are now in the habit as part of our winter laying-up of taking off the exhaust elbow and cleaning the wastegate. We don’t touch the turbine vanes though. We then apply a little fogging oil to the wastegate to ensure it doesn’t stick over the winter. Volvos recommendation of NOT turning the spindle more than 15 degrees looks spot on. It doesn’t take much movement of the spindle for the wastegate to open and as Skylark has said it doesn’t need to open more than a couple of mm to do it’s work. I think perhaps the notion of the spindle having to move laterally