Never heard of that happening, but if it did it would indicate very badly worn valve-guides.
warped valve cover. bad gasket. cracked valve cover cracked block
look at the head with the valve cover off find where the exhaust manifold goes in tha is the exhaust valve or looking at the valves the first one is exhaust then intake then intake ,exhaust,exhaust,intake,intake,exhaust if you have the head off i think the intake valves are bigger than the exhaust
The exhaust lifters will line up with the exhaust manifolds,Remove the valve cover if your working on a V8 and the valve that lines up with the exhaust port will be the exhaust valve,If it is a Chevy V8 they will be from standing in front of the car exhaust,intake,intake,exhaust,exhaust,intake,intake,exhaust.
Replace the PCV Valve.
Valve cover gasket
The oil leak is coming from the valve cover gasket and leaking onto the exhaust manifold, the rubber valve cover gaskets get hard from the engine heat and start to leak, you will have to replace the rubber valve cover gaskets to stop the oil leak
The Exhaust Gas Recirculation Valve on a 1989 S10 is located in the valve cover. It is toward the front of the motor.
Need to replace the valve cover gasket.
No, it will not cause smoke from the exhaust pipe. However the leaking oil can drip on the exhaust manifold where it will be burnt and smoke.
The EGR valve is located on the back side of the valve cover on driver's side. It is connected from the rear of the valve cover into the intake manifold's plenum chamber, again on the drivers side.
The exhaust valve is always smaller.
The combustion chamber has an exhaust valve and an intake valve. The power stroke is ignited just before TDC, in timing with the spark plug to ignite the fuel/air mixture. Hence, this forces the piston down with both valves closed. NOTE:Intake stroke (valve open to receive the f/a mixture), Compression stroke, both valves closed, Power stoke (see above), Exhaust stroke (piston upwards, with only exhaust valve open.