go to halfrauds and get engine de-greaser and engine laquer
both products are made from a company called gunk
do what it says on the tin (ha ha)
thats the easy part
things to cover when power washing off the degreaser
induction kit (if you have 1, normal airbox can be exposed)
fuse boxes
distributor cap
ecu if its in the bay (silver box)
the rest is ok, but dont power wash directly on to a altonator
what i do is,
get black refuse bags and wrap around the above parts well
electric wires in the bay are usally covered and even connected by scart connections
if you have bare wires showing, cover them too