Cylinder leak down test results

89supracrazy

New Member
Oct 31, 2009
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wise
I performed the leak down test and here are my results. Cylinders 1-6 all leak out steady threw the oil cap and cylinder 6 exhaust valve is leaking also. I have read no more than 15 percent tolerance but shit mine will just keep leaking. I need some input on what to do. Is it rebuild time for me. I guess this is my smoking issue I have been having on deceleration.
 

CyFi6

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Oct 11, 2007
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Are you sure you did the test properly? Plug in air supply, turn the knob until the gauge reads 0% leakage, then connect your spark plug tube and pressurize the cylinder and read the % leakage. Air is always going to escape out of the crankcase, its just a matter of how much, and you cant tell just by listening.
 

gottadiesel

Flyin Low
Feb 16, 2009
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^^
I am with CyFi6 - Make sure you are following the proper steps to do a leak down test. IIRC 15% is the maximum you want to see on loss, but I 1-10% is normal, my tests netted 8-9% loss across the board on a fresh re-build, but not broke-in yet...

Here are some links that may be helpful to make sure the equipment and process is correct... These are not articles with a supra, but the process applies to most motors...

http://en.wikipedia.org/wiki/Leak-down_tester

http://www.meyerracingonline.com/leak.html

http://www.team-integra.net/forum/d...5&TopicID=156270&PageMsg=Viewing+Common+Topic
 

metaphysico

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Jan 2, 2008
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Also you can do a wet test to check if its the rings, put a small amount of oil in the cyl before doing the test, if the values are a lot better with the oil in it its ring wear. As for the exhaust valve make sure you had the #6 piston at tdc on compression stroke. So the crank will be 180 out.
 

89supracrazy

New Member
Oct 31, 2009
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Ok. Thanks for all the replies. I have never did a leak down test before this is my first one. I did not leave the guage on to see how much it drop down. I took for granted that the rings were bad because of air that was coming out. What I did was after the leak down test I did a compression test to see what the numbers were, and here they are.


Cylinder 1- 163
Cylinder 2- 164
Cylinder 3- 166
Cylinder 4- 165
Cylinder 5- 163
Cylinder 6- 168


The exhaust valve on the number 6 cylinder probably is good if it builds that kind of compression. I'm I right on this.
 

89supracrazy

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Oct 31, 2009
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Suprapowaz!(2);1604130 said:
Was this a dry test. Those are very good numbers. Looks healthy to me. Smoke on decceleration is usually a valve stem seal leaking.


Yes. It was a dry test. I probably did not perform the leak down test correct. It was my first one. If it was a bad valve stem seal wouldn't it smoke on first startup also. I was thinking if it is bad enough to smoke on deceleration that it would smoke on startup. Maybe I am wrong. Has anyone else experience bad valve stem seals symptoms.