Hydraulic locking will usually bend a con rod. If you're lucky, the engine will fail there and then. If you're not, it will fail some time later, in flight. Happened to a guy in the US in a Yak 14T - he didn't survive.
Pulling the prop through on a Vendeneyev (like what Yaks have) won't get all the oil out if it's not run for quite a while as the inlet pipes from the supercharger have a low point which is lower than the valve seats. You have to remove the drain plugs in the inlet pipes of the lower 3 cylinders. The Vendeneyev has a pneumatic start system - compressed air is admitted to the cylinders via an air distributer to turn the engine while a 'shower of sparks' magneto is operating.
The Gipsy Major engine in our Chippy is primed by flooding fuel into the inlet manifold and pulling the prop through 4 compressions.