I have my Powerplant O&P tomorrow and I’ve spent the whole day looking for a compression test video that’ll help me and this is the best one I’ve seen so far
Thanks for you observation. One spark plug was removed from each cylinder prior to beginning the test. Thus, inadvertent ignition is impossible. That fact was omitted from the presentation, but now everybody knows. Thanks again.
This is SUCH a well done video, EXCEPT for the low video quality. I wish you'd consider re-doing this at better resolution. VERY VERY well explained. I'm not AP, just autos, outboards, small engines, made my own tester, modified Horrid Freight which turns out not to use standard orifice or pressures. Found a .040 jet which I used instead and some refrigeration gauges.
While you may be technically correct, the expression "Compression Test" is commonly used. This test not only measures compressed air past the rings, but also the integrity of the valves. More valve problems are diagnosed than ring problems, in my experience. Thanks for your comment.
I omitted to mention valves to be brief,but compression is terminology that has filtered down over the years from a careless understanding of what is being done. Quite honestly TH-cam is not the forum to learn aircraft maintenance.Professionalism has been degrading for years and the quality of the A&P is suffering due to it!
You do know this is not a compression test.This is a leak down test,determining how much compressed air is passing the rings.It's called a differential test because you compare the static pressure to the pressure the cylinder can maintain.We dont do compression tests on aircraft engines,and whenever I hear an aircraft mechanic use that term I cringe,because that was not what you were taught by a reputable mechanic or school.I dont know how or why the compression wording ever came into use on aircraft but it is incorrect terminology.
A year later, but I learned that this is indeed a leak down test, you have limits that each cylinder cannot leak past, and no more than a 15 PSI differential between cylinders, etc. However, the school mentioned that it was a leak down test initially and after that its always been referred to as "compression test" at school.
Gentleman that is Not a Compression test. ,that is A differential Cylindet test, you also have to mention, the size of the orfice that this engine require
The master orifice refers to an internal orifice in the differential tester. TCM bulletin SB03-3 Service Bulletin refers to a .040 orifice be used and required on testers on ALL Teledyne Continental engines in accordance with the aforementioned bulletin unless specified differently by tester manufacture. For all other makes of engines, consult FAA AC43.13 REV 1B for guidance in selecting the proper instrument for your engine.
From SB03-3, I have a cyl at 58. My IA wants to pull the cyl. SB says boroscope, if nothing wrong - good too go. As long as it's above the min master "o" reading, good to go. The AC143-xx etc, had this "60" minimum, which is wants he want to go by. I can't believe he is not up on the SB.
That comes under the heading of personnel opinion and experience. 58 is pretty low if the other cylinders are showing something greater than a 10 psi difference.TCM is pretty adamant that the cylinder be at full operating temp for one hour before testing if you have a low cylinder. Lycoming doesn't find a 58 psi reading acceptable for any of their engines that I know of.
That mag. impulse click isn't reliable. Like on my engine it has Bendix shower of sparks mags. There is no click. I use a bamboo stick in the spark plug hole to determine when it's close to TDC. Then put the connector in the spark plug hole and shoot the air to it.
You never addressed the importance and safety of disconnecting the magneto P leads to prevent engine starts when pulling the prop through. This should be the very first thing you do when performing a compression check! VERY VERY IMPORTANT!
You have that backwards! Removing the P lead would allow the mag to fire. P leads ground the magneto points through the mag switch so the mag cant fire! Removing P leads renders the mag "HOT" Please people if you are not an A&P dont give unwarranted advice on aircraft maintenance without verifying your advice first.
Please tell me you are joking??? Disconnecting the P-leads puts your magnetos into a "hot" position. Taking the leads off will only remove your ability to use the key to ground out the magneto, but the magneto is still fully capable of running that engine P-lead or not. Been plenty an inspection i have come to find a broken P-lead on a mag, poor guy had no idea he had hot mags til we took off the cowling. Please tell me you aren't taking them off in the false belief that it wont fire the engine!
I have my Powerplant O&P tomorrow and I’ve spent the whole day looking for a compression test video that’ll help me and this is the best one I’ve seen so far
THIS IS ME RIGHT NOW!!! Literally 18 hours from my O&P and I'm panic-watching videos for the practicals
@@wadeallman452 how did it all go?
Just found out an a and p can do the conditions inspection without an IA
THAT WAS A GREAT description of the compression test thanks so much
This is great! Explained well. Thanks
Thanks for you observation. One spark plug was removed from each cylinder prior to beginning the test. Thus, inadvertent ignition is impossible. That fact was omitted from the presentation, but now everybody knows. Thanks again.
This is SUCH a well done video, EXCEPT for the low video quality. I wish you'd consider re-doing this at better resolution. VERY VERY well explained. I'm not AP, just autos, outboards, small engines, made my own tester, modified Horrid Freight which turns out not to use standard orifice or pressures. Found a .040 jet which I used instead and some refrigeration gauges.
While you may be technically correct, the expression "Compression Test" is commonly used. This test not only measures compressed air past the rings, but also the integrity of the valves. More valve problems are diagnosed than ring problems, in my experience. Thanks for your comment.
I omitted to mention valves to be brief,but compression is terminology that has
filtered down over the years from a careless understanding of what is being done.
Quite honestly TH-cam is not the forum to learn aircraft maintenance.Professionalism has been degrading for years and the quality of the A&P is suffering due to it!
Nice video 👍🏻helpful. I’ve learned to do most of my own maintenance from TH-cam videos. Very informative
Well explained. Now I understand. Great short video. Thanks!!!
Just looking at the comments to see how many arguments there are 😂
Mr that is Not a Compressio. Tester, that is Cylinders differential testing
You do know this is not a compression test.This is a leak down test,determining how much compressed air is passing the rings.It's called a differential test because you compare the static pressure to the pressure the cylinder can maintain.We dont do compression tests on aircraft engines,and whenever I hear an aircraft mechanic use that term I cringe,because that was not what you were taught by a reputable mechanic or school.I dont know how or why the compression wording ever came into use on aircraft but it is incorrect terminology.
A year later, but I learned that this is indeed a leak down test, you have limits that each cylinder cannot leak past, and no more than a 15 PSI differential between cylinders, etc. However, the school mentioned that it was a leak down test initially and after that its always been referred to as "compression test" at school.
Gentleman that is Not a Compression test. ,that is A differential Cylindet test, you also have to mention, the size of the orfice that this engine require
Explain the Master orifice and in use with TCM engines
This is best explained by reading Continental Motors Service Bulletin SB03-3. www.tcmlink.com/pdf2/SB03-4.pdf.
The master orifice refers to an internal orifice in the differential tester.
TCM bulletin SB03-3 Service Bulletin refers to a .040 orifice be used and required on testers on ALL Teledyne Continental engines in accordance with the aforementioned bulletin unless specified differently by tester manufacture.
For all other makes of engines, consult FAA AC43.13 REV 1B for guidance in selecting the proper instrument for your engine.
From SB03-3, I have a cyl at 58. My IA wants to pull the cyl. SB says boroscope, if nothing wrong - good too go. As long as it's above the min master "o" reading, good to go. The AC143-xx etc, had this "60" minimum, which is wants he want to go by. I can't believe he is not up on the SB.
That comes under the heading of personnel opinion and experience.
58 is pretty low if the other cylinders are showing something greater than a 10 psi difference.TCM is pretty adamant that the cylinder be at full operating temp for one hour before testing if you have a low cylinder.
Lycoming doesn't find a 58 psi reading acceptable for any of their engines that I know of.
Gentleman ,,Remember That-it is No Compression test ,,that is A Differential cilíndrelo Teste you are Misleading some people,please make it Correction
That mag. impulse click isn't reliable. Like on my engine it has Bendix shower of sparks mags. There is no click. I use a bamboo stick in the spark plug hole to determine when it's close to TDC. Then put the connector in the spark plug hole and shoot the air to it.
You never addressed the importance and safety of disconnecting the magneto P leads to prevent engine starts when pulling the prop through. This should be the very first thing you do when performing a compression check! VERY VERY IMPORTANT!
You have that backwards! Removing the P lead would allow the mag to fire. P leads ground the magneto points through the mag switch so the mag cant fire!
Removing P leads renders the mag "HOT"
Please people if you are not an A&P dont give unwarranted advice on aircraft maintenance without verifying your advice first.
Please tell me you are joking??? Disconnecting the P-leads puts your magnetos into a "hot" position. Taking the leads off will only remove your ability to use the key to ground out the magneto, but the magneto is still fully capable of running that engine P-lead or not. Been plenty an inspection i have come to find a broken P-lead on a mag, poor guy had no idea he had hot mags til we took off the cowling. Please tell me you aren't taking them off in the false belief that it wont fire the engine!