When checking the compression on each individual cylinder what is a normal number to achieve? What is too low? How long does the compression need to stay about 3 minutes? or just check it and move onto the next one?

Example, between 180 and 210 on compression in each cylinder?

 

anyone?

 

It varies with camshaft design. Usually you check all of the cylinders, and see if they all read within 5 to 10 % of each other. One thats a lot lower than all the others is suspect.