motivation of lossless image compression
No you don't need compression to get spark but you do need compression for it to run.
Depends on why there is no compression.
The higher compression the engine the more power it can theoretically produce. The compression ratio is mainly determined by the type of fuel being used.
If engine is losing compression it is likely the rings are worn and need replacing. The valves are likely leaking too and need replacing.
a diesel engine uses compression and has no need of spark plugs
Compression pumps are used depending on the need for it. Compression pumps can be used in water pipes to regulate the water pressure. Compression pumps can also be used in air pipes and ducts to regulate the pressure in the air.
You will have an improvement in engine performance and an increase in compression unless the compression rings on the pistons need replacement .
"600 psi" is not a compression ratio; it's a pressure. For a RATIO, you need to compare TWO different numbers.
compression
you need: fuel compression and spark
You can go to auto zone and borrow one of their compression tools, it screws into where the spark plug goes and reads compression as the motor turns over. You will need the specs for that particular motor which i am sure they can provide for you.
Loss of compression is caused by bad internal engine wear or internal engine failure. Both mean the engine will need serious repair