Turbo or waste gate issue?

[PilotX]

My partner is stuck in KMTJ. Can't get more than 23" of manifold pressure. Did a quick search but nothing definitive on MS or the net.

TTSMO is around 350, just out of annual, third flight of the day so while not definitive, not near 1000 hour expected turbo overhaul.

Probably not interested in flying at 23" over the mountains, if that is even partially safe. Our mechanic suggested tapping the waste gate controller, I am going to try to find a local A&P. Any initial thoughts?

 

[PilotX]

Well looks like the turbo has a chipped blade fin and isn't spinning smooth. 

[kortopates]

pull it off and send it to Gary at Mainturbo


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[PilotX]

9 minutes ago, kortopates said:

pull it off and send it to Gary at Mainturbo


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Think that is what we will need to do. Sunday is not the best day for this to happen. Thanks.

[kortopates]

If you want to expedite he can have an exchange or new unit ship out monday but sending in yours for repair is usually a lot cheaper but more than double the time.


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[Rick Junkin]

Careful with the v-band during removal!

[PilotX]

I just looked through the logs, no indication of the age of the turbo (new/overhauled/swapped) from when the engine was installed in 2019. Is the turbo part of a factory overhaul? The governor is listed, the prop (belly landing) oil hoses, oil cooler, overhauled alternators, vac pump, starter.

[Fritz1]

put a wrench on the waste gates shaft and make sure it moves freely, lube waste gate shaft with mouse milk at every oil change, find out what was done during annual that might have anything to do with what you are experiencing, and while you are at it inspect turbo transition weld in exhaust with mirror from backside

[exM20K]

I would want to know where that piece of metal and the shavings from the blades rubbing the housing went. 

-dan

[PilotX]

Lot of questions. Plane is a couple hours away, by plane, so I will get somebody to pull it and overhaul it. It will either go to Main Turbo or Western Skyways, which is on the field. Certainly have to make sure there isn't any metal floating around, could be too late either way as it was run a couple of times after the issue was discovered but wouldn't get above ambient MP. I'll let everybody know.

[Steve Dietrich]

I think it really depends on where the engine came from .  

My recollection is that a reman engine 

 

- Where did the missing piece go   

- Is there other turbo damage 

- What caused the damage - stray metal in the intake ? 

If the piece can not be found in the intake system then probably borescope engine 

[Steve Dietrich]

second look at the photo - scoring apparent on the turbo housing potentially creating more metal in the intake. 

[N201MKTurbo]

8 hours ago, PilotX said:

Well looks like the turbo has a chipped blade fin and isn't spinning smooth. 

What makes you think it has a chipped blade?

[enginenerd]

A few things

The notch on the center hub is from balancing. 

It's a journal bearing turbo, without oil pressure don't expect it to spin like a top. It should have little to no axial play, but radially it should wiggle quite a bit but not contact the housing. 

If the turbo seems ok, it may be wg stuck open, failed spring, etc. 

[kortopates]

19 minutes ago, N201MKTurbo said:

What makes you think it has a chipped blade?

agreed it merely looks like blade scrape from excessive shaft free play. One should try wiggling the shaft of the compressor, as i bet you'll see it that's why its contacting the side wall.  Its a common way they can wear out.

[N201MKTurbo]

9 hours ago, kortopates said:

agreed it merely looks like blade scrape from excessive shaft free play. One should try wiggling the shaft of the compressor, as i bet you'll see it that's why its contacting the side wall.  Its a common way they can wear out.

It could also be some debris that got past the air filter, but feeling for bearing play is the first check. If there is bearing play, I would check the oil system.

[PilotX]

1 hour ago, N201MKTurbo said:

If there is bearing play, I would check the oil system.

It is wobbly, didn't post a video, but my partner popped off the hose and was able to wiggle it. Sourcing v-band, Textron has some but.

What do we need to consider with oil system?

[exM20K]

10 hours ago, enginenerd said:

The notch on the center hub is from balancing.

Wow. That is an astonishing mass of metal to remove for balancing something that is spinning so fast. Thanks for pointing this out.

I’ve never seen a cut like that on mine, but it does look machined.

props, spinning at a fraction of the rate a turbo does, get balanced with washers.

-dan

[PilotX]

Good news, Gary at Main Turbo said around 3-4 day turnaround on an overhaul. Now to get it pulled and shipped.

video of the turbo:

https://www.dropbox.com/scl/fi/yw6nzz18n8felkpol1dtb/IMG_4433.mov?rlkey=1sv01x126mbx2sjuydg1w9ork&st=9qc3qxl8&dl=0

 

[Schllc]

wow, that has to be a bearing, or a bearing race.

[N201MKTurbo]

That is a crazy amount of slop.  You have a dead turbo.

I would remove your top plugs so you can spin the engine with the starter, disconnect the drain line from the turbo and place a container under it and spin the engine and make sure you are getting oil through the turbo.

[exM20K]

On 11/17/2024 at 12:53 PM, PilotX said:

Probably not interested in flying at 23" over the mountains

This, in retrospect, was a very good choice.

[PilotX]

Western Airways is going to manage the R&R with the turbo overhaul quote range $6-10,5 AU. Reviewed the logs. No indication of pending failure. We fly LOP but TIT below 1650. 

[Fritz1]

wow, sounds like you got it under control now, I got my cowl off and will give the turbo a good wiggle and will see how it spins, your video was scary, 1650 dF is still a tad high for TIT and the probes tend to read up to 100 dF low before they fail completely, might be a good idea to test the probe while the turbo is out, I had a KS probe and that failed within 300h, got about 80h on the Alkor now and that still looks good, think going above 1600 dF really burns these probes up fast

[exM20K]

1 hour ago, Fritz1 said:

1650 dF is still a tad high for TIT and the probes tend to read up to 100 dF low before they fail completely, might be a good idea to test the probe while the turbo is out,

This for sure.  my TSIO550 goes through them like they're free, which they are definitely not.  erratic readings is also another failure mode, but I agree, TIT and EGT will read colder and colder before they croak.

-dan