Turbo rebuild

[T41pilot]

Has anyone out in Aerovee turbo land rebuilt or refurbished their turbo? My Turbo only has 8 hours on it and it is seized to the point it is unusable. I got the vanes to break loose, but it feels terrible with no spin capability. No amount of fogging or rust spray has freed it up further. My guess it is coked up inside. I have the turbo cooling system plumbed in and used it after each flight. I only have 5 flights on the plane so far. There is a turbo shop within a 45 minute drive from me that can probably get it refurbished but average cost is 400 to 500 bucks. Don't know if this turbo falls in that range. Haven't talked to to them yet. Very frustrating to have to keep shelling out money for extra parts plumbing etc for such low time in service. I probably have the skills to get the turbo apart but in the brief reading on turbos I have done so far,it is indicated that it has to be balanced after servicing. I certainly don't have the skills or tools for that. So what are my options here?

[Onex107]

Turbos are balanced at different harmonic frequencies by removing metal from the blades. It should not be necessary to rebalance after cleaning and replacing the bearings. My 2 cents. I witnessed a rebuild by a hangar neighbor. From what I read on turbo coking it occurs in the temp range of 400 to 800 degrees. Your cooling system should prevent temps that high. Check out your lube and cooling systems. Another friend has attached a thermocouple to the bearing housing and never sees temps over 300.

[T41pilot]

Thanks onex107. My Turbo freed up overnight with left over fluid that I had not realized was still in it. I was convinced that I was going to take it in for service but now I may just let it soak some more for good measure. It doesn't spin like when it was new but spins about the same as the amount of my last flight that was successful. This is the second time it has acted up. The first time it failed, it freed up on its own during a run up when I had the plane tied down. There is a bearing kit that I can buy from speedyracer.com that is about 30 bucks. It is my understanding that this turbo is a TB2568 that fits a 4bd2 Isuzu engine. Let me know if I'm wrong. I'll soak some more and may try it and in the meantime order the bearing kit if it looks correct to a person in the know. Google tb2568 turbo repair kit for info.

[pfhoeycfi]

Did you determine why the turbo was binding up? I'll just throw this out there in case it's cooling system related, but I couldn't get the cooling pump to prime by filling the system via the catch can...so even tho the catch can and system appeared full, it was not, and therefore not pumping. I put a fill tee in the pump suction line and that worked great for the initial fill.

Peter

[Brett]

When I needed bearing replaced in mine a few years ago I had the local turbo shop replace them. Cost me $80.

[Onex107]

My friend's Onex turbo cooling system had problems. He has had three water pump failures for different reasons. He found that the pump had to be at the bottom of the system, or it would not prime. When the radiator fan was running, he could not hear the water pump and did not know it had failed. If you lower the water level in the catch can below the return line you should be able to see the pump flow. His thermocouple attached to the top of the bearing housing does not show the actual temp at the shaft and bearings, but it is relative and will show you that the cooling system is working after shutoff. It seems that after shutoff the temp jumps about 50 degrees before the cooling system takes over and starts to reduce the temp.
Is your cooling system able to be turned on manually? It might be a good idea to turn it on while taxiing. The other thing I noticed on another Onex was a screened opening next to the cooling fan to admit outside air. The only air available behind the baffles is hot engine air.

[T41pilot]

I found that my pump was intermittent during the course of the first 3 flights. The suggested connector didn't fit well and I modified it to work. So maybe I gunked the Turbo up to the point where it started to fail right off the bat. Plus a week sometimes 2 or more between flights as well as I troubleshot various problems probably didn't help. I didn't see rust caked on anything though. I install the coolant the same as you would bleed brakes by forcing it through with a squeeze bulb and exiting out the radiator into a bottle until no air shows. That seems to work well. I can turn it on manual to verify flow when done. I reinstalled the Turbo today as it loosened up nicely with some soaking and multiple shots of oil. I have to add the coolant yet. I have no doubt it will work for the next flight but for how long is what I'm interested in. If it fails again soon, I will have to consider other options.