http://www.peachparts.com/shopforum/showthread.php?t=105144
The above link is a discussion about blow by and its relation to the engine condition.
Here is what my diesel MB mechanic said about blow by specs:
Acceptable new engine specs are 24 liters per minute.
50 liters per minute is a caution
He has had cars with 70 liters per minute that will still start.
Go find a used home gas meter, plumb it up and measure.