Either a warped head and blown headgasket or a cracked head.
An intake gaslet will also blow and let it in on a 4.3. I had it happen.
Cracked injector cups.
Car engines burn fuel in cylinders. When the fuel burns the air in the cylinders expands. The expanding air pushes down on a piston. The piston pushes down on a crankshaft. Then the piston comes back up. The piston going down and up makes the crankshaft rotate. This rotating motion is transferred to the wheels of the car. That pushes the car along. Thus the fuel burning in the cylinders pushes the pistons. Without Petrol to burn in the cylinders, the pistons would not push the crankshaft. It would not make the wheels move.
one side piston is broken
A great big YES!!! The cylinders must be bored-out to the next size.
One or more of your cylinders are not holding their seal. Worn out piston rings, worn/damaged piston, worn/damaged cylinder wall are the most likely problem areas.
Assuming that you are referring to the engine's piston cylinders, either your engine has been submerged in water, someone is playing a nasty (and expensive) joke on you, or you have a serious head gasket leak.
Most pistons are attached to the connecting rod with piston pin. These are either pressed into the side of the pistion using a hydaulic press or held in with clips. (Or both) You can compress the piston rings to fit in the cylinders by hand, or with a special ring compressor. I would suggest that someone who has done it before helps you.
Depends on the smoke. White smoke from burning antifreeze would be a crack in the cylinder head or bad head gasket. Dark smoke would be burning oil from bad piston rings.
no, why would it have antifreeze?
do you seriously think that theres a hole in the piston in all the cylinders? or the rings are gone in all the cylinders.. highly unlikely.. the main cause of loss of compression is the rings are burnt gone. the rings are stuck, the valves are stuck, hole in the piston and/or head, bent valves, or the timing chain/belt came off, or broke. with all the cylinders being down, i'd look into the last one. that's the only thing that would be logical to effect all the cylinders evenly.
If all cylinders fired at once, power distribution would be very jerky, so the engine is set up to have the cylinders firing in sequence for a smoother power delivery instead. And if the pistons move in a certain rhythm, then they have to receive their sparks in a certain rhythm too, as the engine will only run well if the cylinders fire when the piston is in a certain position.
Presumably they would be cylinders.