Sorry to hijack, but how much would it cost to completely rebuild an engine, yourself? or is there maching work involved?
That depends on what you consider as being part of a rebuild, what tools you own, where you buy the parts and ultimately, who you know

A rebuild could just be the essentials, rings, shells, valve guides and seals.
... Or it could be crank lightening, knife-edging and balancing, flywheel lightening and balancing, bore re-hone, rings, shells, big ends, crank seal, head gasket, head bolts, oil pump, water pump, thermostat, crank seal, valve guides, stem seals, valves, tappets, valve springs, spring seats, valve grind, head skim, rocker seal, sump seal, oil pump pickup, timing belt, tensioner .... yada yada yada.
The rebuild cost is what you want it to be, £10 - £100,000
