Compression Check: How many PSI?
 

What should the PSI be at for a LT1? I have decked heads so the first cylinder checked out at 200 PSI and holding. Im about to do the others, what is the area I am looking for?

Re: Compression Check: How many PSI?
 

about 180 or higher.

Re: Compression Check: How many PSI?
 

Ok I just read the directions and figured out the equation that you have to do. The other 2 I just tested were about 220, gonna do the rest in the morning.

Re: Compression Check: How many PSI?
 

When doing a compression test it isn't the pressure that matters, it's the consistency. You want all cylinders to be close to each other. Static compression ratio, valve timing, etc. all effect the pressure of a compression test.

A better method of determining the health of a cylinder is to do a leakdown test. This accurately measures the sealing ability of the valves and rings.

As long as the rest of the cylinders are around 200 psi I'd say you have a healthy engine :)

Re: Compression Check: How many PSI?
 

Ya, what technically is different on a leak down compared to a compression test? Wouldnt the compression check leak down too once full?

Re: Compression Check: How many PSI?
 

A compression tester usually has a valve in it to keep the pressure in. You release it, once the pressure is read. Pressure normally bleeds off even in a healthy engine. The valve in the compression tester gives you time to observe the reading.

A leakdown tester injects air pressure into the cylinder. One gauge of the tester shows what pressure is going in and the other tells you how much [how rapidly] air is leaking out.

Re: Compression Check: How many PSI?
 

Thanks Shoebox

Re: Compression Check: How many PSI?
 

My recent compression test on my stock engine yielded 200-210 psi on all 8 cylinders.