The compression can be different from one engine to the next depending on mileage and maintenance. What is important is that all cylinders are within 10/15 lbs of each other.
If it's in good shape, Then all cylinders should read about 150 LBS. Less is okay as long as all of them have no more then 10 LBS. difference between them. If the compression is less then 120 LBS. then the engine has valve or pistion ring problems.
150 LBS. per cylinder. If you hace more then 15 LBS. difference between any cylinders the engine will idle rough and not run good.
any where from 120 lbs to 180 lbs
Anything above 125 LBS. is fine as long as there is no more then 15 LBS difference in any of the cylinders.
That number can vary, what you want to see is the compression reading on all of the cylinders within 10 - 15 lbs of each other.
You will have to do a compression test yourself to know that. A engine that is in good shape should have at least 150 LBS. per cylinder. There can not be more then 20 LBS. difference in any cylinders. It has to have at least 100 LBS. for the cylinder to fire at an Idle.
There are a lot of variables when checking compression...basically the idea is to have all cylinders within 15 lbs of each other. Double check your readings.
120 kg is equal to 264.5547146 lbs 120 kg* 2.2046 lbs 1 kg = 264.5547146 lbs
Sounds a little low to me. Check to see if all cylinders measure about the same. ANOTHER ANSWER That would be good for most engines. What you're looking for is any kind of serious fluctuation in the pressure between cylinders. If you're getting 90 psi consistently, you're in good shape.
120 pounds = 120 lbs.
120 kilograms is equal to approximately 264.55 pounds.