leak down tester issues? - Team Camaro Tech
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post #1 of 8 (permalink) Old Feb 13th, 08, 07:08 AM Thread Starter
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leak down tester issues?

So I tried last night to perform a leak down test on my #2 cylinder to see why my plug keeps getting oil on it. This is a Harbor Freight (US General) leak down tester.

My setup went like this: I had the cylinder at TDC, both valves closed. My air compressor has 100 psi in it. I hooked up the air line to the tester and turned the regulator on the tester all the way out or closed. I hooked up the other end to the cylinder.

The instructions read like this:

7. Turn the regulator knob clockwise until the Leakage Gauge reads "0" at the end of the yellow band.

8. You can know read the amount of leakage on the Leakage Gauge as a percentage loss.

The instructions say to slowly open the regulator until the leakage gauge reads 0. I did that and the other PSI gauge read 11 PSI.

I assume the instructions have a typo of some kind, how can I set the Leakage Gauge to "0' and read the same gauge as a percentage loss? Also, I barely opened the regulator valve to get to the "0" reading as well. I am talking not even enough to blow up a balloon.

What am I doing wrong or is the gauge messed up.

Erik

67 Camaro Pro Street, 540 Bill Mitchell Merlin big block, Merlin Aluminum heads, Holley 870, hydraulic camshaft, 2" Hooker Super Comp headers, Mallory and Crane ignition system, TH400, 2600 stahl, Ford 9" w/ 4:10 gears and posi.
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post #2 of 8 (permalink) Old Feb 13th, 08, 07:12 AM
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Re: leak down tester issues?

You would normally set the upstream gauge to 100 psi and read the pressure on the downstream gauge. You are basically reading the pressure drop across an orifice. The percent leakdown is some arbitrary number associated with your tester.
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post #3 of 8 (permalink) Old Feb 13th, 08, 07:19 AM Thread Starter
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Re: leak down tester issues?

Thats what I assumed as well. When I tried to do that the Leakage Gauge went off the chart to the bottom of the gauge where there is no readings at all.

I am not sure what to think. I can say I never heard any air escaping anywhere on the motor assuming air was making it into the cylinder.

Erik

67 Camaro Pro Street, 540 Bill Mitchell Merlin big block, Merlin Aluminum heads, Holley 870, hydraulic camshaft, 2" Hooker Super Comp headers, Mallory and Crane ignition system, TH400, 2600 stahl, Ford 9" w/ 4:10 gears and posi.
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post #4 of 8 (permalink) Old Feb 13th, 08, 07:26 AM
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Re: leak down tester issues?



If you cap the output of the tester with a pipe plug, your gauges should follow each other up and down. The minimum leakage point seems to be on the high side of the gauge.
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post #5 of 8 (permalink) Old Feb 13th, 08, 07:30 AM Thread Starter
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Re: leak down tester issues?

onovakind67, Thanks for the replies. I am new to this have never used a leak down tester before so bear with me. Why would I want to cap the end of the tester, just to see if it works or something? Sorry, but I am not sure what your saying.

I followed the instructions and they just don't seem to make sense.

Erik

67 Camaro Pro Street, 540 Bill Mitchell Merlin big block, Merlin Aluminum heads, Holley 870, hydraulic camshaft, 2" Hooker Super Comp headers, Mallory and Crane ignition system, TH400, 2600 stahl, Ford 9" w/ 4:10 gears and posi.
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post #6 of 8 (permalink) Old Feb 13th, 08, 07:37 AM
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Re: leak down tester issues?

If you cap the end, you will have no leakage. The leakage gauge should be in the zero leakage position, which I would assume to be the clockwise end of the green area. If you remove the cap and have a large leak, the leakage gauge should indicate a very high leakage, which I would assume to be the most CCW position of the leakage gauge.
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post #7 of 8 (permalink) Old Feb 13th, 08, 07:43 AM Thread Starter
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Re: leak down tester issues?

thats what I assume as well, but like I said. When I tried to apply 100 psi to the left gauge the right went all the way down to about 7 o'clock and off the chart. And when I did it like the instructions say and set the right gauge at "0", that meant I only ran like 10lbs into the cylinder I guess. i barely cracked open the regulator.

Erik

67 Camaro Pro Street, 540 Bill Mitchell Merlin big block, Merlin Aluminum heads, Holley 870, hydraulic camshaft, 2" Hooker Super Comp headers, Mallory and Crane ignition system, TH400, 2600 stahl, Ford 9" w/ 4:10 gears and posi.
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post #8 of 8 (permalink) Old Feb 13th, 08, 07:44 AM
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Re: leak down tester issues?

Sounds like a faulty setup to me.
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