Back in the day we'd change the cylinder head on old cars, whack a gasket in, don't worry about stripping the replacement head if it looked ok, often as not it wouldn't fire on the starter or handle if it was old enough, so stick it in 3rd and tow it, always worked.
When rebuilding an engine from scratch always assemble EVERYTHING with liberal amounts of fresh oil or you will have the same problem.
Brand new rebore, new piston, new rings and new valves and new ground seats in the head assembled dry, will achieve two things.
1/ cause massive wear on all parts
2/ flatten your starting battery in short order
compression dry like this will be, to use a technical term, "bugger all"
Anything left standing for several months will dry out like this, and any condensation formed diurnally through open valves or breathers just makes it worse......
ALWAYS oil anything that has been left stood, eg add oil through plug hole or injector hole, then crank once with plug / injector still out, then leave to sit 24 hours.
A teaspoon full of oil is too much, one or two squirts from an oil can per cylinder, tops, add too much oil and you get hydraulic damage.
"oil" means heavy weight engine oil, NOTHING lighter.
Anything light enough to detonate inside the ring spaces is early death for the engine, so everything that comes out of a spray can is verboten, as is diesel in a petrol car, unless you like broken rings and scored bores and even lower compression.
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Remember, ALL engine lose or leak some compression, no seal is perfect, but, the faster the engine is cranking, the less the leaks.
A lazy starter that gives 45 crank rpm may not be enough to start, spot 24 volts on a 12 volt starter and crank at 75 rpm and away she goes.
Adding oil does the same thing, reduces the leakage per stroke
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Cold engine also has more leakage than a hot one, coefficient of thermal expansion etc
worb bores, esp torque reaction wear (ovality) also does this...
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hence the old diesel adage
"if it starts easy from cold, there ain't much wrong with it"
never buy a warm engine, like, never buy a car at night or in the rain, same deal.
