Always check your timing marks, its free and bent valves can be expensive. Just to add to this thread, about the crank seal leaking on our 4e engines, Ive seen on two engines where the crank seal has actually marked the crank so when you are fitting a new seal, do it carefully, lube it nicely and then rotate engine and check it has a good contact. Plus I wonder if excess crankcase pressure causes the seals to leak? Most vauxhalls leak at the crank because the pvc valve gets blocked and it seems a shame to spend so much to fix the seal when a £5 pvc was the cause. Glad I have a Toyota