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  #1  
Unread 02-04-18, 02:15 PM
rmorris rmorris is offline
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Turbo overhaul

First the why....after annual last October, my T337C front engine went from a qt oil about every 8-9 hours to a qt about every 1.5hrs....pretty drastic. All indications (other than high oil consumption) show normal, on the EDM960, and otherwise. Have taken it to 4 mechanics before last week (now a 5th), and the first 4 checked for leaks, compressions, breather tube, borescope for health/oil burn indications, and even did the airspeed indicator to the oil filler neck to see case pressures during run up on ground. No definitive answers, but one cylinder was really low, and others low...about 800 hrs on engine. SO they recommended I fly it 10 more hours and track oil consumption religously, and suggested it was low cylinder compressions or turbo most likely.
So I took the plane to a 5th shop and just put in work order to pull the one really low cylinders, the other two on that side, and replace with new cylinders. Not by coincidence, that is same side as turbo, so asked them to remove all turbo sys so I can send off for overhaul.

So....had my wife look through TAP on last flgiht towards mechanic, and dig out ads on turbo overhauls. I have used one on the list, but looking for any input others have, positive or negative on pricing, customer service, turnaround, etc...
in no particular order):
Mike's Tulsa, OK
Martin Induction Systems Enid, OK
Main Turbo CA
Approved Turbo (ATC) CA & FL
Airmark FL
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  #2  
Unread 02-04-18, 07:20 PM
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Red Air Rambo Red Air Rambo is offline
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I used ATC in FL to do mine last time and have no complaints.
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  #3  
Unread 02-04-18, 09:13 PM
Kim Geyer Kim Geyer is offline
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We use Main Turbo. Not sure how their prices are compared to others, but have not had any problems. Also check the scavange line on the turbo (the bottom line) and see if it's loose where it connects to the starter drive. If it's loose it could cause your oil consumption problem.
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  #4  
Unread 02-05-18, 11:03 AM
rmorris rmorris is offline
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Quote:
Originally Posted by Kim Geyer View Post
We use Main Turbo. Not sure how their prices are compared to others, but have not had any problems. Also check the scavange line on the turbo (the bottom line) and see if it's loose where it connects to the starter drive. If it's loose it could cause your oil consumption problem.
I'll have them check that connection, thanks.
The airspeed indicator to oil filler tube showed high case pressure during run up on ground. I've akready committed to turbo overhaul and 3 cyl replacement, so will be frustrated if it was a hose connection...esoecially after 4 diff mechanics looked at issue. But I guess you live and learn
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  #5  
Unread 02-05-18, 05:57 PM
JAG JAG is offline
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What oil level were you running?

I hate to see 3 cylinders being pulled...
If I read correctly, 4 out of 5 mechanics said to monitor - what was the result? How many hours did you monitor? What were the compression's? If you lowered your oil level a little, did this change your oil consumption?

A friend of mine who used to have his own engine overhaul shop (and whom I respect his knowledge) told me on the IO 360 not to get my underwear in a bunch if I have a low compression on a single cylinder. He said the engines were known to have the rings turn and line up, causing compression loss. He indicated that if it was blow-by into the crank, just keep running it and check again in 20 hours (if all other indications were good of course). He said he would often see the compression go back up as the rings turn a little. Not saying this is what happened to you, but if you do have blow-by past the rings, it pressurizes the case and can push oil out the breather. Did you have more than usual oil on the belly? Did you have the turbo boroscoped to look for any evidence of oil leakage?

It just seems weird that this all of sudden happened after the annual as you indicated.
Food for thought for the future. I don't mind changing cylinders...I just don't like paying for them.

Jeff
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  #6  
Unread 02-08-18, 05:58 AM
AV8ing AV8ing is offline
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+1 for Main Turbo in CA !

(and -1,000 for ATC in FL: NEVER AGAIN - CRIMINALS ! )
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  #7  
Unread 02-12-18, 07:32 PM
rmorris rmorris is offline
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ATC doing overhaul

Quote:
Originally Posted by JAG View Post
I hate to see 3 cylinders being pulled...
If I read correctly, 4 out of 5 mechanics said to monitor - what was the result? How many hours did you monitor? What were the compression's? If you lowered your oil level a little, did this change your oil consumption?

A friend of mine who used to have his own engine overhaul shop (and whom I respect his knowledge) told me on the IO 360 not to get my underwear in a bunch if I have a low compression on a single cylinder. He said the engines were known to have the rings turn and line up, causing compression loss. He indicated that if it was blow-by into the crank, just keep running it and check again in 20 hours (if all other indications were good of course). He said he would often see the compression go back up as the rings turn a little. Not saying this is what happened to you, but if you do have blow-by past the rings, it pressurizes the case and can push oil out the breather. Did you have more than usual oil on the belly? Did you have the turbo boroscoped to look for any evidence of oil leakage?

It just seems weird that this all of sudden happened after the annual as you indicated.
Food for thought for the future. I don't mind changing cylinders...I just don't like paying for them.

Jeff
Yep, more than usual oil on belly, had all cylinders borescoped.
I was told same thing about the rings might have turned...but it had been going on for months. Despite that, they asked me to fly it another 10 hours, record oil, and return...I said enough is enough, after the 4th mechanic failed to find anything conclusive.
but my wife did ask a couple of hours ago if all this work wil solve the problem....I sure hope so
in the end I had the mags pulled as well for 500hr inspection, and they both failed resistance check, so overhauling them. Replacing 3 cylinders on one side, and new push rode tubes as well to make it all fancy new. all new hardware on anything that was taken off, especially turbo system. Overhauling both turbo controller, wastegate, and turbo itself.
so almost half a top overhaul anyway, ATC in CA has the system and is doing thr overhaul now. I will let you all know with an update post how it goes.
Main responded with aggressive pricing, and good pitch, but they were literally an hour after I had already shipped to Mary at ATC.
So far, having good vibes from Mary....stay tuned.
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  #8  
Unread 02-13-18, 02:57 AM
AV8ing AV8ing is offline
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"ATC in CA has the system and is doing thr overhaul now"

'Shoulda gone to Main ...
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