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Thread: Orifice change E-2A compression tester

  1. #1
    frequent_flyer's Avatar
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    Orifice change E-2A compression tester

    I have an ETC E-2A differential compression tester that was manufactured with a 0.040 inch orifice.

    Does this tester have a removable orifice? If not, can the fixed orifice to opened to 0.060? I emailed ETC but have not received a reply yet.

    Thanks.
    Last edited by frequent_flyer; 11-12-2021 at 10:15 AM. Reason: deleted "Testing of Lycoming O-360 requires a 0.060 orifice."

  2. #2
    behindpropellers's Avatar
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    Quote Originally Posted by frequent_flyer View Post
    I have an ETC E-2A differential compression tester that was manufactured with a 0.040 inch orifice. Testing of Lycoming O-360 requires a 0.060 orifice.

    Does this tester have a removable orifice? If not, can the fixed orifice to opened to 0.060? I emailed ETC but have not received a reply yet.

    Thanks.
    I need an .040 compression tester, will trade for your .060 if you want.

    Tim

  3. #3
    stewartb's Avatar
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    This SI says .040 orifice and applies to all Lycoming engines.

    https://www.lycoming.com/sites/defau...ompression.pdf

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    frequent_flyer's Avatar
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    What was bothering me was - why did I buy an 0.040 tester when FAA says I should be using an 0.060 tester. This only came up because my IA forgot his tester and we used mine for the compression test. He has always used an 0.060 tester so the results with my 0.040 tester were, as expected, lower.

    I dug through my document library and found Lycoming Service Instruction SI 1191. This specifies that an 0.040 orifice should be used which explains my purchase decision. My IA has been performing compression tests in a way that is not in compliance with Lycoming recommendations. I suppose the best resolution will be to always document in the the log what orifice size was used.

    I'm going to keep the 0.040 tester and make sure my IA uses it for the next inspection.

  5. #5
    stewartb's Avatar
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    The .060 for bores of 5” and greater comes from AC43.13-1B chapter 8. My tester is .040 per Lycoming.

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    frequent_flyer's Avatar
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    Quote Originally Posted by stewartb View Post
    The .060 for bores of 5” and greater comes from AC43.13-1B chapter 8. My tester is .040 per Lycoming.
    Yes, understand that. You sent your earlier reply while I was composing mine. I had simply forgotten about SI 1191 in the years my 0.040 tester has been stored away unused.

    I do wonder how many IA are using 0.060 testers on Lycomings though.

  7. #7
    hotrod180's Avatar
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    TCM also came out with a service bulletin on compression testing, SB03-3.
    Recommended procedure for all continental engines is to use an Eastern Technology Corp E2M tester, which has a .040" orifice.
    So apparently both Continental & Lycoming recommend a .040" orifice.
    Cessna Skywagon-- accept no substitute!

  8. #8
    hotrod180's Avatar
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    Quote Originally Posted by frequent_flyer View Post
    ..... He has always used an 0.060 tester so the results with my 0.040 tester were, as expected, lower.....
    So a cylinder that came up as lets say 60/80 using a .040 tester,
    would come up as maybe 65/80 using a .060 ?
    Cessna Skywagon-- accept no substitute!

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    I have no idea why, but FAA changed AC 43.13-1 to read .060 for bores greater than 5". For the past 75 years it was .040 for any engine less than 1000 cubic inches and .060 for engines of 1000 or greater cubic inches. I think when Continental had all the cylinder issues and started with the master oriface that would allow cylinders as low as 40 psid, they made the change based on cylinder bore. It is only a relative indication of cylinder condition. use the tester you have, and if it indicates an issue, grab a borescope and look inside. The Continental SB actually says you are supposed to use a bore scope every time. Part 43 Appendix D paragrqaph (b) (3) Internal engine--for cylinder compression and for metal particles or foreign matter on screens and sump drain plugs. If there is weak cylinder compression, for improper internal condition and improper internal tolerances. Doesn't say what type of compression test to use, you can use a direct cylinder compression test and still meet the regulatory requirement.
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  10. #10
    Steve Pierce's Avatar
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    I see a 2-3 psi difference between the two orifice sizes.
    Steve Pierce

    Everybody is ignorant, only on different subjects.
    Will Rogers

  11. #11
    hotrod180's Avatar
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    Quote Originally Posted by Steve Pierce View Post
    I see a 2-3 psi difference between the two orifice sizes.
    With the larger orifice gauge reading higher?
    Cessna Skywagon-- accept no substitute!

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    Quote Originally Posted by dgapilot View Post
    I have no idea why, but FAA changed AC 43.13-1 to read .060 for bores greater than 5". For the past 75 years it was .040 for any engine less than 1000 cubic inches and .060 for engines of 1000 or greater cubic inches......
    It makes sense now why the ETC tester with the .060 orifice is designated the E2M-1000.
    Cessna Skywagon-- accept no substitute!

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    Orifice change E-2A compression tester

    Used the one with the .040 orifice on my R985 for years!


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    Built this because:1. I’m cheap. 2. Wanted more accurate gauges. 3. Easier to see while holding a prop in one hand and turning a regulator in another.
    Does help to have a brother-in-law with his own high precision machine shop with full anodizing capabilities.
    Click image for larger version. 

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    Steve Pierce's Avatar
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    Quote Originally Posted by Techteach View Post
    Built this because:1. I’m cheap. 2. Wanted more accurate gauges. 3. Easier to see while holding a prop in one hand and turning a regulator in another.
    Does help to have a brother-in-law with his own high precision machine shop with full anodizing capabilities.
    Click image for larger version. 

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    Do you have a source for the gauges. I have not had a pleasant experience with Eastern customer service over the years and have got gauges elsewhere and like the looks of those. Have a set that evidently got damaged on the last airline flight for pre-purchase regardless of packing them well. TSA doesn't seem to put things back they way they found them after searching my tool bag.
    Steve Pierce

    Everybody is ignorant, only on different subjects.
    Will Rogers
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    Quote Originally Posted by Steve Pierce View Post
    Do you have a source for the gauges. I have not had a pleasant experience with Eastern customer service over the years and have got gauges elsewhere and like the looks of those. Have a set that evidently got damaged on the last airline flight for pre-purchase regardless of packing them well. TSA doesn't seem to put things back they way they found them after searching my tool bag.
    On mine, I have a shut off valve on the outlet. Saves running the regulator up and down for each cylinder. Just don’t open it quickly!


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    Bought these off of Amazon. I would have run JACO gauges, but going off their descriptions I had the bar machined for 1/4 NPT…. and they were actually 1/8” NPT… and the bar was already done.
    The gauges are just tire pressure gauges. The JACO ones would even be more accurate.
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  18. #18
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    I had a problem with one set , the hose that goes from the gauge to the cyl. Was closing off when hanging down on a plane with Amph. Floats and held 80/80 or close to that.I noticed a problem when two cyl.’s were much higher than the others. I called ATS and they sent me a new one right away and I sent the old one back so they could inspect it. It didn’t take much pressure to close it off.

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    hotrod180's Avatar
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    Quote Originally Posted by algonquin View Post
    I had a problem with one set , the hose that goes from the gauge to the cyl. Was closing off when hanging down on a plane with Amph. Floats and held 80/80 or close to that.I noticed a problem when two cyl.’s were much higher than the others. I called ATS and they sent me a new one right away and I sent the old one back so they could inspect it. It didn’t take much pressure to close it off.
    That was the special tester they manufacture for airplane salesmen.
    Cessna Skywagon-- accept no substitute!

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    Quote Originally Posted by hotrod180 View Post
    So a cylinder that came up as lets say 60/80 using a .040 tester,
    would come up as maybe 65/80 using a .060 ?
    No, both testers would show the same reading. The different orifice sizes are only to provide you with the lowest acceptable leakdown values. For example, the .040 orifice might indicate that 45psi is the lowest acceptable value (ie 45/80) where the .060 might indicate 40psi as the lowest acceptable value.

    The orifice built into these gauges are not used during the test; they are only used prior to the test to get the days lowest acceptable leakdown number.

    Chris


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  21. #21
    frequent_flyer's Avatar
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    Quote Originally Posted by airChris View Post
    No, both testers would show the same reading. The different orifice sizes are only to provide you with the lowest acceptable leakdown values. For example, the .040 orifice might indicate that 45psi is the lowest acceptable value (ie 45/80) where the .060 might indicate 40psi as the lowest acceptable value.

    The orifice built into these gauges are not used during the test; they are only used prior to the test to get the days lowest acceptable leakdown number.
    You seem to be confusing an optional built in calibration orifice with the differential orifice. The differential orifice flow rate, and resulting pressure drop, is what determines the cylinder pressure reading. The orifice size has direct impact on the measured cylinder pressure.
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  22. #22

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    Quote Originally Posted by frequent_flyer View Post
    You seem to be confusing an optional built in calibration orifice with the differential orifice. The differential orifice flow rate, and resulting pressure drop, is what determines the cylinder pressure reading. The orifice size has direct impact on the measured cylinder pressure.
    Yes, there is a restrictor orifice between the two pressure gauges, but the .040 and .060 orifices that are being referenced in this thread are the “master orifices” (to use Continental’s terminology) which are to set the lowest acceptable leakage value.

    Chris


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    Steve Pierce's Avatar
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    Quote Originally Posted by airChris View Post
    Yes, there is a restrictor orifice between the two pressure gauges, but the .040 and .060 orifices that are being referenced in this thread are the “master orifices” (to use Continental’s terminology) which are to set the lowest acceptable leakage value.

    Chris


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    The orifice I am talking about is between the two gauges and the .040" reads lower on the same cylinder as the .060".
    Steve Pierce

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    Will Rogers

  24. #24
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    Quote Originally Posted by airChris View Post
    but the .040 and .060 orifices that are being referenced in this thread are the “master orifices” (to use Continental’s terminology) which are to set the lowest acceptable leakage value.
    No, you have misunderstood the discussion. Gauges are manufactured with 0.040 or 0.060 orifices between the input pressure gauge and the cylinder pressure gauge. This is the orifice size that was being discussed. The master orifice, or calibration orifice, is not provided with many testers and would have to be purchased separately.
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