Oil pressure relief fitted upside down

When I eventually look at the old case for a rebuild is it likely the shop just wanted to sell me a new case or is it very probable the case is warped. They did send a pic of light shone through the case mating halves, but the case had not been cleaned up and maybe not even got any engine case nuts on so could be made to look out by slight misalignment. Or maybe I am too much of a cynic !

 

You may be a cynic Clean the mating faces, bolt it together, torque it up and see for yourself?

 

As far as I know VW didn’t fit slotted valves to any dual release Type 1 cases although I’ve heard that engines destined for hot climates may have had them. Type 4 have the slotted piston on the pressure relief valve (pulley end of the engine). There is no point in fitting a slotted piston in the control valve (flywheel end), all that valve does is dump oil back to the sump.

If you look at a drawing of the oil system, you’ll see what the relief valve (pulley end) and the control valve (flywheel end) do. http://www.vw-resource.com/oiling_system.html

 

This. As I recall, both pistons on my type 1 are plain.

 

No doubt after market ones have "go faster" slots. Honestly I think manufacturers do stuff like this for the selling point with little regard to practicality, in most cases rightly assuming the buyer won't really know and will buy into "extra features" with a "must be better" mentality.