by intoaircooled » Mon Sep 19, 2016 9:09 am
Bill,
First I'm going to start off by saying I'm sorry for your troubles, it sounds very frustrating, for sure.
Just a couple of thoughts on my part. I don't see how your turbo would take out two of your cylinders unless there was an extended over boost issue or overheating problem, but most likely if that was the case it would more then likely cause damage in the heads. And I'm sure that wouldn't be the case, simply because you would be keeping a close eye on that. And you indicated that your not making boost pressure anyway. So I don't see how the turbo would cause you to loose compression on those two cylinders. It would have to be something else that caused the cylinders to fail.
Have you removed the exhaust pipe to expose the hot side of the turbo to see if it's freely spinning? You would have to be careful with the gasket (most likely it will get damaged and have to be replaced). How many hours do you have on the turbo? Do you have a cool down at idle procedure you followed.
When I installed my kit I clocked it at the time of the install, just because it didn't seem right to have the line on the side. Top feed and bottom drain just made more since to me just so oil couldn't collect at the bearing at shut down. I also had a spin on oil filter that was already in use. I tied it into the system to filter the oil from the turbo but mostly to add more volume and to help in cooling the oil before it was returned to the oil sump. I didn't do the valve cover return from the turbo just because the spin on filter was already in place and my oil/air separator was already using that valve cover. This works very well and I have just over 40 hours on it now. The only issues I have had was my # 2 cylinder exhaust flang bolts coming loose and my turbo dropping offline during a flight. It was unnerving but once I realized it was just a normal non turbo engine performance, I flew it home and figured out what was wrong and haven't had an issue since. I also had some oil coming out the prop hub. That we fixed by up sizing the breather to a 5/8" ID line and the rings breaking in, still see a very small amount of oil but that is expected as it just a slinger and not a "seal".
The sump filter would catch anything and filter it before it would be pumped back into the engine. It's very unlikely that any coking oil contaminates from the turbo (if any) would make it into the engine as it's filtered before hand.
If you can check the free spin of the hot side of you turbo and it's good, I would be looking at the waste gate valve. It may be out of calibration and opening way to soon and not allowing you to make pressure. The turbo system is very simplistic in it's design and shouldn't be very hard to troubleshoot a problem with.
Carl Benda
A&P
Intoaircooled Engines
Barn find Sonex 048 AeroVee 2.1 Turbo