Pressure will not build up in the tank and the silver tubing gets extremely hot.

most likely a problem reed /poppet valve in the compressor heads

If it were the check valve, (safety release valve), you would hear the air escaping from the safety release valve. You have an air leak somewhere. A small leak in the system will keep the compressor from building pressure. If you turn the compressor on and feel around the ends of the tube that leads from the compressor cylinder head to the tank (be careful... it will be HOT) you may feel air escaping from the tube connector at the tank or the connector at the compressor cylinder head. If that is the case, tighten the connectors at the compressor head and the tank. If the connectors still leak, you will need to remove the tube and replace the packings (gaskets) at each end of the tube. Also check all of the hose connectors for leaks, and check the hose for damage that may cause an air leak. If you remove the air hose from the compressor and run the compressor you will be able to tell if your problem is in the hose or hose connectors or the compressor-to-head air tube.

Bill:

I would remove the pressure gauge and check the bottom of the air gauge fitting. The small hole at the bottom of the gauge fitting may be clogged. Sometimes when the pressure gauge is installed a piece of Teflon tape (used to seal the threads) can get lodged over the pressure gauge air port.

Cbillgreene:

Your compressor is leaking air somewhere between the compressor head and the tank. With the compressor running, feel carefully around the ends of the tube that leads from the compressor head to the air tank. You will probably feel some air leaking around one end or the other. If so... remove the tube and find out which packing has failed.

This sounds like the compression release valve is leaking. This valve bleeds the cylinder pressure to allow the motor to start without having the load on it. On this size compressor the valve is often built into the pressure switch. It is a little "pintle" type valve and you will hear hissing while unit is running but the opressure will not build up very much. When the pressure switch calls for the unit to run, the little valve closes with the switch. COntamination or other stiction keeping the valve form closing will cause the problem. You will find this near a tube that goes to the pressure switch. The switch itself hooks into the tank, but this little tube will connect to the cylinder head or the main tube from the compressor. Yours may look similar to ones at this site:
http://www.generalairproducts.com/Fire-Protection-Products/accessories-pressure-switch-a-switches-check-drain-a-pressure-relief-valves.html
The valve is also commonly called the "unloader" valve.

Very rare to have problems with rings. Blow-by would produce high pulsating pressure in the crankcase causing oil to blow out the oil filler plug/ dipstick. If normal crank pressure, suspect problem with valves or gaskets. Remove air filter cover and check for air blowing out of intake or very hot head or air discharge tube. Leaking valves or blown gasket will cause low volume/ low pressure and hot discharge air. Remove the in-tank checkvalve and look for carbon deposits /debris build-up. If the checkvalve and the interior or discharge hose are coated with oil deposits /carbon, most likely problem is valve plate/ gaskets /head. Good luck with your repair.

Bad check valve. But I would check the regulator, by turning it down to about 10 PSI and running it and see if it builds again, if that works then it is the check valve. But from what you are saying I would replace the check valve anyways.

when i turn it on motor runs but it will not build up air pressure

THE COPPER LINE IS SUPPOSED TO GET HOT, SCALDING HOT ACTUALLY. THE MOST COMMON REASON FOR COMPRESSORS NOT BUILDING PRESSURE IS CLOGGED AIR FILTER OR THE VALVES IN THE HEAD ARE BROKEN OR NOT OPENING AND CLOSING CORRECTLY. YOU MAY POSSIBLY HAVE A BAD AIR LEAK DOWNSTREAM BUT YOU CAN CLOSE THE DISCHARGE VALVE ON THE TANK TO ELIMINATE THAT PROBLEM. HOPE THIS HELPS OR GET YOU STARTED.

sounds like you need a new check valve which should be somewhere between the compressor outlet piping,tubing,etc and the tank which prevents the air in tank to back feed to the compressor which would cause hard starting and could damage the motor easy way to check is when you shut off the compressor with some air in the tank if the check valve is bad it would continue to bleed air out out the unloader valve .the unloader valve on your unit is most likely part of the pressure switch when the unit shuts of it should only bleed down the pressure in the pump so it would make it easy to start when needed hope i didn't confuse you