AQ131A Cylinder Leak Down Test

[shawnn82]

SO while i wait on my distributor to arrive, i figured id do a leak down test. The engine hasnt been run in 2 - 3 weeks. Did a compression test while I did my last test run of the boat about 2 weeks ago and all 4 cylinders were in th 165 - 168psi range. So today, i get #1 at TDC and with as soon as i let the air in, i can almost hear it flow out right away even at 10 psi through the valve cover filler cap. Is this a symptom of performing test while engine is cold? I doubt i should be hearing any air leak at 10psi. I jus did a timing belt change as well and all the marks line up.

 

[Don S]

Re: AQ131A Cylinder Leak Down Test

You have to get it on #1 TDC on the compression stroke, not just the timing marks lining up on the belt.

 

[shawnn82]

Re: AQ131A Cylinder Leak Down Test

You have to get it on #1 TDC on the compression stroke, not just the timing marks lining up on the belt.

Yes #1 was at TDC when i ran the test. I just mentioned the timing belt to help diagnose what i was doing wrong if i was doing anytihng wrong, given its the last thing i worked on.

 

[bruceb58]

Re: AQ131A Cylinder Leak Down Test

Like Don said, just because had it at TDC does not meant its TDC on the compression stroke, you had it likely on the exhaust stroke. Rotate the engine another 360 degrees and try again. Once you do that, you rotate the engine 180 degrees and test the next cylinder in the firing order....and so on.