Bravo TBO and beyond

[Schllc]

I’m looking at a bravo to purchase. Great history, good maintenance, flown regularly. It’s about 250 hours from tbo with good compressions. I’m wondering if anyone has experience beyond tbo. Engine was pulled about 200 hours ago for an SB and some accessory work that hasnt been clarified yet (no prop strike),just don’t have the rest of the logs, but the crank was inspected and engine was reinstalled. 
I understand the expense that is imminent, but the airframe is in really good shape, tanks all just stripped and resealed, and it’s kind of a blank slate at this point, ready to be turned into all of my preferences. Just wanted to know how soon that engine will become due.. would love to get another three years two flying and one waiting on the engine..

thoughts?

[LANCECASPER]

This is a lame answer . . . but it just depends. Bravo cylinders do pretty well, if the TIT was kept conservative (+/-1600), but Lycoming has had their problems with crankshaft SBs and camshaft and lifter corrosion.  Every Bravo I had I used Camguard.

If it was flown regularly and has made it to 1750 chances are good it will go 2000 and beyond. (Sort of like if you make it to 75 without cancer or heart problems you have a 50/50 chance of making it to 100 ) Just keep a really close eye on the exhaust on this airplane, especially the weld on the "Y" on the tailpipe. 

On most "blank slate" Bravos though, by the time you do everything you want to do you'll be in Acclaim territory.

[Rick Junkin]

I don’t have beyond TBO experience with my Bravo yet, but I plan to.

Do you have access to engine monitor data to get an idea of how it’s been flown? That would be a good place to start. That, and a borescope check of the cylinder walls. But if it has good compressions and isn’t making metal you may be able to execute your three year plan if the exhaust and the turbo components are also in good shape. You may also want to get a peek at the lower engine innards to get an idea of the general condition. I was able to get a borescope in through the oil filler neck to look at a few lobes on the cam on mine. You may also want to look at doing the cylinder health check that @PT20J described using a pressure gauge to measure peak pressure in each cylinder while turning the engine over with the top plugs removed. I’ll link the post if I can find it.

I’m interested in knowing what SB was recently accomplished. Good luck!

Cheers,
Junkman

 

[LANCECASPER]

15 minutes ago, Rick Junkin said:

I’m interested in knowing what SB was recently accomplished.

Exactly. The last one I can think of was the crankshaft SB (569A). If they've only flown 200 hours in the last 15 years that's not good. Or if they just did that SB recently they were about 12+ years late.

[Schllc]

It was an AD and a few SB’s. 
see below

[Schllc]

1 hour ago, LANCECASPER said:

On most "blank slate" Bravos though, by the time you do everything you want to do you'll be in Acclaim territory.

It will have the same engine in the bravo as the Aerostar.
The lycoming engine really enjoys the low rpm’s which significantly reduces noise for me. I loved my acclaim but the noise of the continental was something I didn’t enjoy.  
the noise reduction down at 2200 is dramatic.  hot starts are the same, Different turbo system, 30 less hp but same power stroke.
Plus even though I will spend close to the same, it will all be exactly how I want it, I will do a panel first, then a sports car type interior, then paint after the engine is done. It has long range tanks that were just all stripped and resealed, the newer style interior, decent paint.  I’ve always wanted to do a project. No rush on this on, just want to milk the engine to the finish line. 

[LANCECASPER]

10 hours ago, Schllc said:

It will have the same engine in the bravo as the Aerostar.

Unfortunately the only thing the Bravo's TIO-540 engine shares with the TIO-540 on the Aerostars is 540 cu. inches.

The two engines are completely different and don't share any parts, except maybe the dipstick. The TIO-540s used in the Aerostars and the big Piper twins (ex. Piper Navajo Chieftains) all used heavier cases and heavier crankshafts. The TIO-540-AF1B used in the 270hp Bravo is what some refer to as a "lightweight" Lycoming 6 cylinder engine. The closest engine Lycoming makes to the Bravo engine would be a 260hp version that's in the Commander 114TC or the 235hp version that's in the Turbo 182.  Winding it up to 270hp on the Bravo is pushing its limits*.

Bravos are great airplanes but you'll be disappointed if you expect a smooth, quiet engine. 

 

* Early on when aviation writers were talking about the M20M engine they made the mistake of thinking it was a de-rated "heavy" engine. An AOPA article in the 90's corrected that mistake. (https://www.aopa.org/news-and-media/all-news/1998/january/pilot/mooney-bravo) 4th paragraph

[Boilermonkey]

I purchased a run out Bravo 5 years ago.  Not only was the engine over time, the O2 system was INOP and the TKS stem was broken. Otherwise she was solid.  We fixed the O2 and TKS and ran the engine to ~2300 hours.  We did not have anything elevated in the oil analysis, but with the original analog engine gauges we didn't have a view of what the engine was really doing.   Starts started to take longer even with new plugs and mags.  Power was good, but I did not have a reference of what it should be.  So, we pulled the trigger and ordered a factory reman.   Aside from the shop installing the new engine making some huge errors, everything has been great.  The new engine is stronger and smoother, so something was starting to go at 2300 hrs.

My only challenge with the new engine is keeping CHTs below 400.  #1 and #6 hover at or just below that with the cowl closed in cruise and 75% power 100F ROP.   Played around with baffles to no end.  200hours on it now.

[Schllc]

5 hours ago, LANCECASPER said:

Bravos are great airplanes but you'll be disappointed if you expect a smooth, quiet engine. 

To qualify my statement, I don’t expect quiet, I’m hoping for “quieter”.

when I pull back the rpm’s in the A, you can take off your headset comfortably.  I don’t anticipate that kind of reduction, but was hoping for some!

2200rpm in the continental didn’t seem to make a lot of difference in the noise and the performance drop was unacceptable. 
do you find the noise in the two the same, or the bravo louder?

[slowflyin]

I purchased mine at TBO.  Ran it another 400 hours before OH.  Only did it then because the timing was right financially.  Oil analysis and compressions were still great.  It had the original jugs from the Bravo conversion.  I'd have to look but I estimate 2200 hours on the top end.   

[LANCECASPER]

6 hours ago, Schllc said:

To qualify my statement, I don’t expect quiet, I’m hoping for “quieter”.

when I pull back the rpm’s in the A, you can take off your headset comfortably.  I don’t anticipate that kind of reduction, but was hoping for some!

2200rpm in the continental didn’t seem to make a lot of difference in the noise and the performance drop was unacceptable. 
do you find the noise in the two the same, or the bravo louder?

The props on the two airplanes do produce much different sounds, but as far as engine/prop combinations in the Bravo and Acclaim, I don't notice one being quieter and one being louder -  they are both loud. I will be wearing Bose headsets with either.

Also I think it's hard to compare the noise of an engine sitting a couple feet in front of you with ones mounted out on the wing in a twin. But I do find the TSIO-550 in the Acclaim much smoother and more balanced than any of the three Lycoming TIO-540s I've had (At least the Platinum engine option in the TSIO-550 which I have). Having a dynamically balanced prop and Tempest fine wires in either is a must. The biggest noise reduction in the last Bravo I owned (serial number -0150) and something I'll eventually do on the Acclaim, was the installation of the Bob Fields Inflatable Door Seal. When I got it aligned right and inflated it the first time it was a night and day difference. I could have a conversation without the headset on if I wanted. 

Early Bravos (serial number 27-0180 and before) were louder than later Bravos for a different reason. The newer fiberglass panel interior, covered in Ultraleather, which started with -0181 replaced the Royalite used earlier. That along with the insulation they added made it noticeably quieter. It cut down on the vibration of those Royalite panels.

They are both good airplanes, but there were many improvements made along the way from the Bravo to the Acclaim.  For me personally, the biggest upgrade was the engine. I like the performance, how smooth it is, and the way that it is laid out makes it much easier to maintain. Also there are so many oil fittings on the wet-head Lycoming on the Bravo it seems as if you are always chasing down a small oil leak.

[Schllc]

This is of the newer variety, and i would be interested to see the difference the inflatable seal makes.  Maybe a good door seal and thicker windows would do more than anything else.  There is a distinct advantage to doing the work as refurbishment, rather than buying and depreciating.  I would have liked to keep the acclaim, but couldnt justify that number on the balance sheet as a depreciable, with the twin.   I am probably foolish thinking about a second aircraft at all...

This is very discouraging.  I do understand that riding next to an engine is not the same as riding on top of an engine.  I never expected the noise reduction of a pressurized twin, but the noise is exhausting to me in the single.  After four hours I am wiped out and hoped to ameliorate that some what....

 

[Fritz1]

got about 850 h on factory reman, so far so good, previous owner put it in after about 1100h on original engine for reasons known to him, biggest improvement were Tempest fine wire plugs and replacing dead baffle pieces and sealing all nooks and crannies with RTV, cruise 29" 2400 or 30" 2300, balanced prop at 2300 but seems to run smoother at 2400, flow typically 18-18.5 gph 100 dF rich, hottest CHT in cruise typically 360-380 dF, max TIT 1580 dF, run Phillips XC Victory, change 25h, check mag timing every 100h, only unscheduled maintenance in 650h was replacing turbo waste gate with leaking actuator shaft last year, weakest spot on engine is weld on Y-turbo transition I think, check every oil change, backside with mirror, very happy with the airplane, she ain't perfect but can't think of a better piston single for 2 people on long xc trips year round from the mountains to the prairies 

[Airterrys]

Bought my 94 with about 1450tt and planned to run it 400-500 till overhaul. At first annual it did not pass shop recommended lycoming SI-1650 and was grounded. At over 100k and 9 months later I have an overhauled engine being reinstalled as I write and will be waiting another 4 months for a turbo v-band clamp. Last I heard the wait for a factory reman was 1.5-2years. Just posting so that you can hear what happens when you loose the gamble. Do your research and hope for the best, best of luck! I love the airplane but would rather be flying. If anyone has a lead on the v-band clamp, I would love to hear about it.

[LANCECASPER]

8 hours ago, Airterrys said:

Bought my 94 with about 1450tt and planned to run it 400-500 till overhaul. At first annual it did not pass shop recommended lycoming SI-1650 and was grounded. At over 100k and 9 months later I have an overhauled engine being reinstalled as I write and will be waiting another 4 months for a turbo v-band clamp. Last I heard the wait for a factory reman was 1.5-2years. Just posting so that you can hear what happens when you loose the gamble. Do your research and hope for the best, best of luck! I love the airplane but would rather be flying. If anyone has a lead on the v-band clamp, I would love to hear about it.

Which Service Instruction is 1650?

[Airterrys]

It requests a test of the prop governor shaft which is anchored by a set screw accessible from inside the case. I will try to find a copy of the instruction and put it up here.

[EricJ]

On 6/25/2024 at 7:33 PM, Schllc said:

It was an AD and a few SB’s. 
see below

Not sure what they Eddy-current inspected in the crank just by pulling the accessory case, as very little of the crankshaft is exposed without splitting the case.   Eddy-current inspection is not specified in either of those SBs or the AD, all of which address prop strikes or sudden stoppage.   Something significant must have happened that they bothered with the eddy-current inspection of the crank tail, which is all that's exposed, unless they just happened to have somebody there with a machine that is NDI qualified with it.   It sounds like whatever happened that it all went back together okay, but I don't think anybody would go to all that work for no reason.   Bit of a smoking gun there, but it doesn't mean there's an issue, just a question.

[LANCECASPER]

11 hours ago, Airterrys said:

It requests a test of the prop governor shaft which is anchored by a set screw accessible from inside the case. I will try to find a copy of the instruction and put it up here.

Definitely not familiar with that one.

[Rick Junkin]

19 hours ago, Airterrys said:

It requests a test of the prop governor shaft which is anchored by a set screw accessible from inside the case. I will try to find a copy of the instruction and put it up here.

@LANCECASPER That’s actually SI 1560 vs 1650. I wasn’t familiar either. I’m wondering how many engines have been torn down because of this loose/missing set screw.

I’m also wondering why it’s an SI vs an SB or AD, what is the impact/risk of not doing it? Loose governor drive? Set screw floating around somewhere? Is the SI referenced by a later SB or AD? Time of compliance is “at the owner’s discretion”.

Here ya go. https://www.lycoming.com/sites/default/files/attachments/SI1560%20Set%20Screw%20Inspection.pdf

Cheers,
Junkman

[Schllc]

On 6/28/2024 at 11:53 PM, EricJ said:

Bit of a smoking gun there, but it doesn't mean there's an issue, just a question.

I think the cryptic log entry, when it was apparently a nose gear collapse, is less than inspiring. From the log entry it doesn’t appear they split the case, and not sure how thorough an eddy current is for a sudden stoppage. But as little is know about the event, was it running or being towed, it’s a roll of the dice. 
cracking the case and replacing all the bearings at 1600 hours with a thorough cam and lifter inspection could be a good thing. Just don’t understand why it’s logged that way. 
was this just sloppy documenting or a shortcut on proper repairs?

[EricJ]

3 hours ago, Schllc said:

was this just sloppy documenting or a shortcut on proper repairs?

It may be neither.    It appears that they complied with the AD and the cited SBs, and then also did an eddy-current inspection on the tail of the crankshaft where the gear attaches, and sufficiently documented all of that.   Splitting the case is really just a thing that insurance companies tend to insist on for some reason, it isn't required by the AD or SBs.    Splitting the case is probably often unecessary and overkill, especially if the engine wasn't making power or wasn't make much power during whatever event led to the inspection.  

[philiplane]

They complied with the AD due to some sort of prop strike. That's the only reason to do it. If it was a result of a non-running prop strike, where the nose gear collapsed while towing for example, the engine is probably fine. No damage to rotating parts under power in that case.

The exhaust system is the biggest concern. Especially the turbo transition piece.