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  #11  
Old 11-20-2016, 08:13 PM
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Bubblehead Bubblehead is offline
 
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Quote:
Originally Posted by AttackPilot64 View Post
I still had all my horsepower,fuel flow, my CHT and EGT's were all normal.
So the cylinder was still making normal power and CHT and EGT was normal with almost no compression?
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  #12  
Old 11-21-2016, 11:49 PM
Captain Avgas Captain Avgas is offline
 
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Quote:
Originally Posted by Bubblehead View Post
So the cylinder was still making normal power and CHT and EGT was normal with almost no compression?
I was thinking the same thing. Maybe the OP doesn't have CHT and EGT monitoring of all 4 cylinders.
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  #13  
Old 11-22-2016, 12:06 AM
gasman gasman is offline
 
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Or maybe he landed just in time...............................
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  #14  
Old 11-22-2016, 08:12 AM
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Quote:
Originally Posted by Bubblehead View Post
So the cylinder was still making normal power and CHT and EGT was normal with almost no compression?
That is certainly possible as I too had the same experience a few years ago. I have an IO-360A1A in my -8 and during a routine compression check I found my #3 cylinder at 10/80. And just like the OP, I had no indication of power loss, CHT, or EGT changes. If there were, it certainly wasn't obvious. In my case, the cause of the compression loss was a crack starting at both sides of the top spark plug hole and continuing halfway around the circumference of the cylinder! I don't know how many hours or minutes it could have gone before blowing the top off. After putting on a freshly overhauled cylinder, I did notice a very slight power increase, but no real changes in CHT and EGT. Takes a lickin' and keeps on tickin'!
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  #15  
Old 11-22-2016, 08:42 AM
cardinalflier cardinalflier is offline
 
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Attackpilot: I think Emag has two ignition advance curves available. How much timing advance did you have? Also, what do you have for an engine monitor?
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  #16  
Old 11-22-2016, 09:18 AM
lr172 lr172 is offline
 
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Quote:
Originally Posted by Bubblehead View Post
So the cylinder was still making normal power and CHT and EGT was normal with almost no compression?
You shouldn't closely correlate leak-down results with compression. A leak-down test (mistakenly referred to as a compression test in the aviation industry) only measures static leakage and can only be used as a guideline for cylinder health. 10/80 doesn't mean no compression. If you put a real compression gauge (measuring dynamic compression levels) on the cylinder and crank it over, you'll find plenty of pressure to fire the charge. Power level will be reduced somewhat, however, due to the lower pressure produced.

The 80 point scale is set to provide diagnostic guidance and is not an absolute compression range. 10/80 correlates to a low enough compression level that the cylinder is in need of repair, but not necessarily that it is not functioning.

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Last edited by lr172 : 11-22-2016 at 09:29 AM.
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  #17  
Old 11-22-2016, 09:18 AM
David-aviator David-aviator is offline
 
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Engines wear out, nothing lasts forever.
Sounds like yours is due an overhaul.
What is total time on engine?
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  #18  
Old 11-22-2016, 09:47 AM
AttackPilot64 AttackPilot64 is offline
 
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Default Engine

That's correct I have a dynon skyview system and of course Cht and EGT probes in every cylnder/exhaust. The only thing abnormal was mabye a 15 degree rise in CHT. Mabye I landed just in time but even after I landed I pulled my cowling and wiped the engine down and we did another run up to try and identify the leak. No abnormal sounds Cht or EGT on the ground run. The only reason I even elected to do a compression test was because it looked as if the engine was leaking out of the base of the other 3 cylnders. I figured the case was over pressurized.
I have already torn the engine completely down ( fearing the worst) but everything looks to be in great condition.no metal in the Sump or anything! I plan on cleaning everything up and inspecting evething to ensure everything is within limits.
My next questions is I have 500 hrs on the engine SMOH I went ahead and ordered new Cylnders pistons ect I planned on ordering new bearings for the bottom end but do you guys think I should send the crankshaft and cam off for inspections. They have 500hrs since last time they were sent off. All the gears were replaced last overhaul and they look to be in great condition. I plan on spending next day or 2 mic ing and cleaning parts. If Ishould send them off who do you guys recommend ? I want to get her back together as soon as I can
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  #19  
Old 11-22-2016, 09:56 AM
AttackPilot64 AttackPilot64 is offline
 
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Location: SPring lake NC
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Default Mag question

Cardinal flyer , I currently had the A jumper wire on my P-Mag. With the V40 software the give you up to 34 degrees.
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  #20  
Old 11-22-2016, 10:01 AM
guccidude1 guccidude1 is offline
 
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Location: Reno NV
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Default Lycoming IO-360 Engine leak escalated quickly

Two lines of thought here. One, the "might as well, we're this close anyway", go ahead and send the items to be inspected. Number two, if you were buying this engine for your plane, which engine would you prefer, xxxx hours total time, 500 hours SMOH, 0 hours STOH with new cylinders or this engine, xxxx Total Time, 0 hours SMOH with new cylinders. Dan from Reno
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