Suzuki Repair: 92 Geo Metro LSI w/ 1.0L suzuki eng. 1st Cylinder, piston ring, head gasket

Question
Hi, I have a geo metro, it has a Suzuki 1.0L 3cyl. engine (Same as suzuki swift).  The cylinder that is most furthest from the timing belt is having problems(1st cyl I think).  It does not produce alot of power at all, it has a compression of 60psi, compared to the other two which have 150psi each.  I found this out because my car is really shaky, it dosn't want to start when its cold out, and i have to rev it to warm it up or it will stall.  I did a tune-up recently but this did not help (spark plugs, wires, distributor cap, good gas, fuel injector cleaner, oil supplement).  By unplugging the spark plug from each cylinder and seeing the result, turning off the 1st cylinder did not make much of a differance in the engines running, but if I unplugged the other two that produce 150psi, the car would get more shaky and stall.  So I knew that cylinder was a problem, and after running a compression test, that cylinder had 60psi, now I knew this was the problem. There is spark that goes to the cylinder, and if I rev the engine past 3000rpms, I think the cylinder starts to work as the pressure inside builds up.  So I am pretty sure there is gas and air getting into it.  So now what I think it is, is the valves are malfunctioning and letting the pressure out of the combustion chamber, or its the walls in the cylinder itself, or perhaps the piston ring.  The car has 148,000km's and this problem has been ongoing since I bought it at 130,000km's.  So it took me almost 20000kms just to notice this problem.  I also took off the valve cover and it looked like the valves do open and close when the engine turns, maybe they are burnt and do not provide a good seal.  I did not want to take off the head, because I would have to buy the head gasket just yet, because my problem could be something else.  What do you think it is, and what should I do about it?

Answer
At this mileage, it could be a valve or a piston/ring problem.  There's an easy way to find out.  Go back to the low compression cylinder, and put a couple of teaspoons of engine oil in it, and then do a compression test.  If the compression raises, the oil temporarily sealed the rings and raised the compression.  If not, there is a valve problem.  At this mileage, if you intend to keep the vehicle, consider an overhaul, another motor, or the like.