87 MM 4x4 2.6 ltr.

Started suddenly having oil, smoke blow back through my rocker-valve cover breather vent.

Checked under cover and found number 2 intake jet valve stuck in it's holder and the rocker arm adjuster snapped off.

Got all the parts, pieces for the jet valve and left jet valve shaft in place which is stuck in place.

Checked compression,,all 4 cylinders at 150 and above. Checked piston tops seems all is well. Starts and has good power

but oil and minor steam like smoke comes out valve cover breather vent.

Also checked coolant no leaks, brand new radiator also. and oil for coolant leaks no signs. It does not over heat either.

No holes in pistons and good compression...I'm baffled. Anyone have any idea or have had this happen to you with these engines?

Thankx for any answers or ideas!