Does anyone have Leak Down specs for a newly rebuilt L28 engine versus a well used one?

I am starting a rebuild on an old engine and wanted to know how what I currently have would compare to an engine that will have new rings, valves, cylinder honed, etc....

The rebuild engine is not really showing signs of being worn out, and the previous owner indicated that it ran fairly well. It was pulled before I got it so I haven't seen it run.

Here are the Leak Down Test results for my project engine for comparison:

These are all in the green band on the gauge.

1: 15%

2: 27%

3: 30%

4: 15%

5: 17%

6: 15%

 

You should see less then 5% on each cylinder.

On 1/9/2016 at 2:23 PM, txvepr said:

The rebuild engine is not really showing signs of being worn out, and the previous owner indicated that it ran fairly well. It was pulled before I got it so I haven't seen it run.

How long has it been since it last ran?  Results from cold dry cylinders may not be very representative.

So, I am guessing that a new clean engine with clean valves would have almost sealed cylinders? And as time goes on, carbon, etc.. buildup will cause those valves to not seal completely plus any wear on piston rings would also have effect also.

 

9 hours ago, txvepr said:

So, I am guessing that a new clean engine with clean valves would have almost sealed cylinders? And as time goes on, carbon, etc.. buildup will cause those valves to not seal completely plus any wear on piston rings would also have effect also.

 

I learned what the term "lapping valves" means the hard way by not having the foresight you have. 

Carbon builds up on the valve seats and the valves causing them not to seal off, just like you said.

9 hours ago, txvepr said:

So, I am guessing that a new clean engine with clean valves would have almost sealed cylinders? And as time goes on, carbon, etc.. buildup will cause those valves to not seal completely plus any wear on piston rings would also have effect also.

I was thinking more along the lines that an engine that sits will get a small amount of surface rust on the cylinder walls, maybe a valve seat or two (two or three of the valves will be open while sitting), and the oil will drain from the rings and cylinder walls.  Even in brand new engines.  If you just went straight to a leak-down test on an en engine that's been sitting, without spinning the engine or running it, results would be expectedly iffy.