Leak down test procedure??
Leak down test procedure?? Would anyone be willing to outline the procedure for doing a leak down test??
I have a compression tester and am going to do that tonight.
When I installed my new springs during my cam swap last year I heard air leaking when the cylinder was pressurized. Tapping on the valves helped, but did not stop it completely.
Should I just pressurize the cylinder and listen??
Thanks in advance for the input!!
I have a compression tester and am going to do that tonight.
When I installed my new springs during my cam swap last year I heard air leaking when the cylinder was pressurized. Tapping on the valves helped, but did not stop it completely.
Should I just pressurize the cylinder and listen??
Thanks in advance for the input!!
You use the tool you used to pressure up the cylinders for the spring swap. You'll need a psi gauge on it. Check a service manual for how much psi to fill the cylinders with. Fill each cylinder and watch for any loss in pressure.
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Joined: Aug 2004
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From: Portland Oregon
A Compression tester is used by turning the motor over with the starter and reading the gauge. A leak down is used with the cylinder that you want to test at TDC, then add air pressure (100 psi is good), and read the gauge. The leak down tester has 2 gauges. One for incoming air pressure, the second measures the air pressure in the cylinder. The leak = the difference of the two. EG 100 psi in, other gauge reads 96 = 4% leak down.
Leak down is easy, the hard part is getting the piston right at TDC so it doesn't turn over when you apply the air.
Leak down is easy, the hard part is getting the piston right at TDC so it doesn't turn over when you apply the air.
Originally Posted by racecar
A Compression tester is used by turning the motor over with the starter and reading the gauge. A leak down is used with the cylinder that you want to test at TDC, then add air pressure (100 psi is good), and read the gauge. The leak down tester has 2 gauges. One for incoming air pressure, the second measures the air pressure in the cylinder. The leak = the difference of the two. EG 100 psi in, other gauge reads 96 = 4% leak down.
Leak down is easy, the hard part is getting the piston right at TDC so it doesn't turn over when you apply the air.
Leak down is easy, the hard part is getting the piston right at TDC so it doesn't turn over when you apply the air.
As an example go here: http://www.racerpartswholesale.com/
click on leak down tester, and follow the link to a "how to"
click on leak down tester, and follow the link to a "how to"
Originally Posted by racecar
Leak down is easy, the hard part is getting the piston right at TDC so it doesn't turn over when you apply the air.
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I know this should be very obvious...but make sure its at TDC on the compression stroke. Also the guages i use, have a hand valve on them that adjusts the pressure, i get the cylinder at TDC compression,thread the hose with the sparkplug adapter into the head, than hook the line to the leakdown tester, i than slowly turn the hand valve to slowly build the pressure until it is at specification. If you turn the guage and adjust the pressure first, as soon as you hook the hose to the adapter, all that pressure rushing into the cylinder can cause the motor to turn.
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I took my rockers off and all of the spark plugs out when i did the leak down test. It wont matter where the piston is when you pressure it up it will go to the bottom. with the rockers off you know the valves are closed.
