Engine Compression and Leak Down Test
03-11-2010, 05:20 PM
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Engine Compression and Leak Down Test
Got some new spark plugs recently. Wanted to put them in today but I figured if I was going to go that far why not go a little further and see how good my motor is holding up and do a compression test and leak down test at the same time. I've always wondered how much compression I've lost over 10 years and 66,500 miles. My hopes were high. So with a lot of help from my buddy Mike we tore into it and put my motor to the test.
Getting started. Got the plugs out.
Finding top dead center. Move that crankshaft.
Hooking up the leak down tester.
Picture of some results on cylinder 2 I believe. Pressure going to the cylinder on the left and loss of pressure shown on the right. Looks like about a 3% loss.
Disabled the fuel and ignition and hooked up the compression tester. Crank it.
Here are some shots of my spark plugs. Put in the same Laser Platinum NGK plugs. PFR7G-11S. Stock No. 7772. Gotta smoking deal on them.
Final results.
The motor was cold because I wanted pretty much the worst case numbers. Numbers of course would of been better on a completely warm engine but why make it easy on the car. Thats just cheating.
Cylinder 1
Leak Down: 2% Pressure Loss
Compression: 230 psi
Cylinder 2
Leak Down: 3% Pressure Loss
Compression: 230 psi
Cylinder 3
Leak Down: 1% Pressure Loss
Compression: 230 psi
Cylinder 4
Leak Down: 7% Pressure Loss
Compression: 225 psi
All and all I'm pretty happy with those numbers. Cylinder 4 is a little weak but I was expecting a 7-8% loss across the board and 200-210 psi of compression in each cylinder. And I would of been happy with that but the results are even better.
Cant wait to dyno it and see how much she puts to the ground.
Getting started. Got the plugs out.
Finding top dead center. Move that crankshaft.
Hooking up the leak down tester.
Picture of some results on cylinder 2 I believe. Pressure going to the cylinder on the left and loss of pressure shown on the right. Looks like about a 3% loss.
Disabled the fuel and ignition and hooked up the compression tester. Crank it.
Here are some shots of my spark plugs. Put in the same Laser Platinum NGK plugs. PFR7G-11S. Stock No. 7772. Gotta smoking deal on them.
Final results.
The motor was cold because I wanted pretty much the worst case numbers. Numbers of course would of been better on a completely warm engine but why make it easy on the car. Thats just cheating.
Cylinder 1
Leak Down: 2% Pressure Loss
Compression: 230 psi
Cylinder 2
Leak Down: 3% Pressure Loss
Compression: 230 psi
Cylinder 3
Leak Down: 1% Pressure Loss
Compression: 230 psi
Cylinder 4
Leak Down: 7% Pressure Loss
Compression: 225 psi
All and all I'm pretty happy with those numbers. Cylinder 4 is a little weak but I was expecting a 7-8% loss across the board and 200-210 psi of compression in each cylinder. And I would of been happy with that but the results are even better.
Cant wait to dyno it and see how much she puts to the ground.
03-12-2010, 09:27 AM
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Originally Posted by boostftw,Mar 11 2010, 10:00 PM
Hey not bad at all. Its pretty much even across the line. 
03-13-2010, 07:17 AM
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Originally Posted by ileventhal86,Mar 12 2010, 10:39 AM
Roger those are good numbers! Good job taking care of her.
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