Today I completed another cylinder leak down test after I got the engine up to operating temperature. I ran the engine for about eight minutes at a variety of RPMs and temperature stabilized at 190°.
Shut her down.
Plugs were removed.
Valve covers were removed.
All rockers were loosened so that all valves were simultaneously closed. Valve covers were replaced so that I could listen for air leaking through the oil fill cap, intake manifold, and exhaust systems. The PCV and fresh air intake tubing was also disconnected from the intake.
All cylinders were tested with 100 psi. Leak down test video.
The photo shows a chart of my results. I have blow by in cylinders #2, #5, #8. I also seem to have intake valves that are not sealing properly. I heard some air through the intake on cylinders #5, #7, #8.
Here is a result I DIDN’T EXPECT!
Cylinder #6 tested in the low 60s TWICE on prior leak down tests. It’s now at 93%.
I now have a dilemma.
1. Do I run the engine on the run stand and see if the other cylinders improve, like #6 improved? If I choose this option, I will probably swap the oil for some break in oil. Perhaps a straight 30 weight oil would be best.
2. Do I approach the engine builder with the results I have?
3. Should I remove the oil pan and look for pieces of broken rings?