98% for me !!!!
yeah the the engine drawing air, or atmos pushing it in, was a tough one. i decided to go with the suck it in. as if you took the inlet chamber, to be sealed. ( after all the test case world is all that was shown ), then it would have been sucked from the reduction of pressure netted by the dropping piston.
of course we know its actually in real world helped by the atmos pushing... but hey didnt want to get 100%. oh the mechanical engineering a-level alone would have got me 94%.

the only two based on oil/fuel and that one ambiguous one.
