Selecting a compres...
 
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Selecting a compression gauge

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Bret
 Bret
Posts: 61
Trusted Member
Topic starter
 

Group - I am obtaining the necessary tools and equipment to conduct an owner assisted annual. In anticipation of the annual inspection I an searching for a compression gauge. I am a little confused by the various options at Aircraft Spruce. Can some of you please recommend the best one for our 108-2 with Franklin 165?

Below is a link to the various compression gauges available at Aircraft Spruce:

https://www.aircraftspruce.com/search/search.php?s=COMPRESSION+TESTER+franklin&x=0&y=0

Thank you for your help!

Bret C
N190C
Neodesha, KS

 
Posted : 16/10/2016 3:36 am
truckerloyd
Posts: 57
Trusted Member
 

New member here. Sorry you haven't gotten a reply since 2016. Since we operate Franklin engines and there is no minimum pressure differential allowed, we must go with the FAA stated 80/60 rule. But don't, there are many new disclosures that allow continued operations. Some are below, some are interpretations. I would not, as an A&P, arbitrarily remove a cylinder without "bore-scope" as some Continental procedures dictate. Common sense is good. The one link below gives good discussions. The one gauge from spruce is all you need for now.

Hope this helps

DIFFERENTIAL CYLINDER PRESSURE TESTER MODEL E2A
$92.75

When an owner asks me whether to be concerned about low compression readings, one of my very first questions are "How's the oil consumption?" and "What do the top plugs look like?" If a cylinder isn't burning oil or pressurizing the crankcase or leaking past the valves, it's probably just fine regardless of what the compression test numbers are.

https://www.avweb.com/news/savvyaviator/188758-1.html

 
Posted : 03/05/2017 5:42 pm
truckerloyd
Posts: 57
Trusted Member
 

New member here. Sorry you haven't gotten a reply since 2016. Since we operate Franklin engines and there is no minimum pressure differential allowed, we must go with the FAA stated 80/60 rule. But don't, there are many new disclosures that allow continued operations. Some are below, some are interpretations. I would not, as an A&P, arbitrarily remove a cylinder without "bore-scope" as some Continental procedures dictate. Common sense is good. The one link below gives good discussions. The one gauge from spruce is all you need for now.

Hope this helps

DIFFERENTIAL CYLINDER PRESSURE TESTER MODEL E2A
$92.75

When an owner asks me whether to be concerned about low compression readings, one of my very first questions are "How's the oil consumption?" and "What do the top plugs look like?" If a cylinder isn't burning oil or pressurizing the crankcase or leaking past the valves, it's probably just fine regardless of what the compression test numbers are.

https://www.avweb.com/news/savvyaviator/188758-1.html

 
Posted : 03/05/2017 5:44 pm
lawheelock
Posts: 774
Prominent Member
 

I am sorry that I had not seen this post requesting information on what "compression" gauge to purchase.

In reality the differential test is not a compression test, but rather a cylinder leak test. A true compression test uses the testers like have been used on automotive engines for years as it is more of a dynamic test while the differential test is a static test.

If you have not already purchased a tester, I recommend the E2M Spruce P/N 12-01015. It is a little more expensive, but it has the built in Master orfice for calibrating in accordance with the Continental SB03-3. While that SB technically pertains to Continental Engines only, I have found over the past 49 years of experience with Franklin engines is that the ring sealing and leak test results and parameters are much more like Continentals than Lycomings. That SB requires the use of a Master Orfice for calibrating the leak tester which on Continentals provided you follow the other checks like with a borescope, allows leak tests as low as in the 40s/80. When I first became aware of the Continental Service bulletinl. I purchased a Master Orfice that met Continentals requirements at more than $120 so getting a leak tester with it attached for the price Spruce shows is a bargain.
You will also need to purchase the separate 14mm adapter to use in our Frankllin150/165 engines. Remember, a 165 is simply a hopped up 150.

Don't pull a cylinder that is below 60/80 until you find out if it has valve problems or broken ring problems. If none of those problems found using a borescope, it can pass with leak readings as low as in the low to mid 40s. Probably 75% or more of the cylinders that get pulled did not need to be.

Larry Wheelock, A&P/IAStinson 108 N584LW 180 LycTexas in Winter; Indiana in Summer

 
Posted : 04/05/2017 4:50 am
lawheelock
Posts: 774
Prominent Member
 

I am sorry that I had not seen this post requesting information on what "compression" gauge to purchase.

In reality the differential test is not a compression test, but rather a cylinder leak test. A true compression test uses the testers like have been used on automotive engines for years as it is more of a dynamic test while the differential test is a static test.

If you have not already purchased a tester, I recommend the E2M Spruce P/N 12-01015. It is a little more expensive, but it has the built in Master orfice for calibrating in accordance with the Continental SB03-3. While that SB technically pertains to Continental Engines only, I have found over the past 49 years of experience with Franklin engines is that the ring sealing and leak test results and parameters are much more like Continentals than Lycomings. That SB requires the use of a Master Orfice for calibrating the leak tester which on Continentals provided you follow the other checks like with a borescope, allows leak tests as low as in the 40s/80. When I first became aware of the Continental Service bulletinl. I purchased a Master Orfice that met Continentals requirements at more than $120 so getting a leak tester with it attached for the price Spruce shows is a bargain.
You will also need to purchase the separate 14mm adapter to use in our Frankllin150/165 engines. Remember, a 165 is simply a hopped up 150.

Don't pull a cylinder that is below 60/80 until you find out if it has valve problems or broken ring problems. If none of those problems found using a borescope, it can pass with leak readings as low as in the low to mid 40s. Probably 75% or more of the cylinders that get pulled did not need to be.

Larry Wheelock, A&P/IAStinson 108 N584LW 180 LycTexas in Winter; Indiana in Summer

 
Posted : 04/05/2017 4:52 am
truckerloyd
Posts: 57
Trusted Member
 

Very good information reply. Thanks. It is good to know that the Franklin is close to continental clearances as I would prefer to follow the SB that Continental put out (Now in their MO manual). Thanks again.

Lloyd

 
Posted : 07/05/2017 11:48 am
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