Thanks Jimkola. The procedural steps you provided are very similar to the first leak down test I performed but I do want to try this again just to make sure. And just to make sure I am doing this right, perhaps you can provide more clarity on:

1) I can pull the valve cover and check to see if the valves are at compression but wouldn't turning the crank TDC where the distributor rotor points to cylinder #1 do the same thing and be just as accurate?
2) Once I determine TDC for cylinder #1 and perform the leak down test, I then go to cylinder #3 and do the same test. After that, I rotate the crankshaft 360 degrees to TDC again in order to do cylinders 2 and 4, right?

Thanks,
JAREDL

 

If you test #1 at TDC with rockers loose, piston at top of rise, you rotate the crankshaft 180 degrees and test #3. Removing the distributer cap and watching the rotor rotate might be the easiest..
As you pressurize the cylinder the air pressure may move the piston, so you might need to hold the crank pulley if it does.

 

Cool. I'll give this another shot. I wonder if the pistons moved when I tested cylinders #2, #3 thus giving them the poor reading. I'll try it again and post results

Thanks

 

Yeah. Those 20 psi would indicate something went wrong with the test.
post both left/right gauge readings at each cylinder.👍🏻

 

Hi Jimkola, I was able to re-do the leak down and received the same results as before:

Cylinder 1: 4% leakdown (100psi/96)
Cylinder 2: 80% leakdown (100psi/20)
Cylinder 3: 80% leakdown (100psi/20)
Cylinder 4: 3% leakdown (100psi/97)

I took video of the tests and the sound of the air escaping somewhere near the exhaust manifold but apparently I can't upload the file due to yotatech limitations. Anyway, the engine just purrs and runs fine. I would think with these numbers that it would run like crud. While doing this work, I rechecked the valve leash and changed out plugs, wires, distributor cap, and pcv valve. Probably didn't need to do it but I figured I might as well while everything was torn apart. I'm totally at a loss and maybe I should run it until something more major fails besides the oil loss mystery.

 

Are you sure you're testing 2 & 3 at the top of their compression stroke?(piston all the way up)
Not to beat you up on this, but 1&4 with stellar readings, and 2&3 with abysmal readings doesn't make sense

 

I think so. I turn the crank to TDC and the distributor pointing to cyl #1. I test cylinders 1 & 3 turn the crank 360 degrees and test cylinders 2 & 4.

 

Get the cylinder to Tdc, and pull the distributer cap to make sure the rotor is pointing at 1#1. Do the Leakdown test for #1 cylinder.
after that, rotate the crank pulley 180 degrees. Look at the rotor to verify. Now test #3 cylinder.
now, rotate the crank pulley 180 degrees. Your timing Mark on the crank pulley should now be back to 0 degrees. Now test #4 cylinder.
After completing #4, rotate the crank pulley 180 degrees and test #2

lmk what you get👍🏻

 

Will do. Thanks.....it looks like I have been doing the leak down test incorrectly.

 

Ok, I have new numbers and something odd to note that may help figure out the issue....first the numbers:

cyl 1: 4% leakdown (100/96)
cyl 2: 7% leakdown (100/93)
cyl 3: 6% leakdown (100/94)
cyl 4: 4% leakdown (100/96)

I'm assuming these numbers are pretty good and thanks for the new direction on how to do the leakdown test. What do you think? So, the odd thing that I noted is that I mentioned earlier that I just changed out spark plugs, wires, distributor cap and PCV valve and after doing so, I had to readjust my idle - no big deal as I figured this is normal. But I checked my oil with the truck warm (it had cooled down about an hour but still warm) and I'll be danged if now my oil level is about a half quart over the fill level. So, I'm not sure what this indicates. I'll check the level again tomorrow when the engine is cold and I'm going to go for a drive and see if anything changes but I thought this was odd - maybe in a good way.

 

That’s fantastic results! Congrats. Takes a LOT off the table.
If the engine is overfilled by only half a qt you have two choices. Drain some out, or let the engine get rid of the extra. If it were more than that I’d encourage draining some, you don’t want to have the crankshaft churning through oil sitting in the pan

 

Yep. I'll drive it some more and see how it goes. Thanks again!