After looking at all your guys with you clean engines I just had to do something about mine. Went out and bought some Autoglym engine and machine cleaner and got to work.
Took some plastic bags to cover the electrics first, then took out the pressure washer and set it to wide spray so there is not too much force and wet the engine compartment. I then sprayed the engine cleaner on. With an alloy wheel bristle brush I gave the grime a quick scrub and then rinsed it off with the pressure washer again. A quick wipe down then and let the rest of the remaining water evaporate.
Came out pretty ok for 10 minutes work I think. Nothing compared to your spotless engines but look at what it was like before...
Before
 | After
 | Before
 | After
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p.s. That is my very drunk flatmate in the picture... he is going to kill me when he finds out I posted that picture.
-Kin