Intake burnt, oil gasket leak.

[Moggy]

Well the thing you have to remember is...we still have fuel injection today so it was far from a bad engine. I also like the whine it makes from it's supercharger...for me it harks back to the late twenties and the races between the Mercedes and Bentleys. I just believe the Merlin was a better engine, it's problems were identified and fixed...partly by Miss Shilling and later by the diaphragm carburetor. As Bader and Stanford-Tuck say in the video, they could catch the 109 after it had dived because they believed word had got round the Luftwaffe that an ace pilot had ripped the wings off a 109 in a dive and pilots would pull out of dive early. Wasn't the 109 tested pre-war with an earlier Rolls Royce engine, the Kestrel?
Also, 1 last thing to consider...the Spitfire and Hurricane were never really designed to go up against 109s. They were at heart bomber interceptors kind of like 109s later in the war.