NEW BRAVO ENGINE BREAK IN

[rocketman]

Thought I would start a new post on breaking in my new TIO-520-AF1B engine. So I have now about 14 hours on factory rebuilt. Engine consumption has stabilized (1 quart in 13 hours) and the temps have come down as well. But not quite where I would like them. I have flown mostly 75% power at 24/34 while always maintaining CHT below 400, usually around 375 on the hottest cylinder which is #3. But to do this requires 24 GPH and half trailing cowl flaps. At lower power settings it still runs nearly 400 CHT on #3 when I lean it to TIT of 550 or shut the cowl flaps. I have always flown at 8000 MSL or below usually between 4000 - 6000. Baffling is in good shape, the intercylinder baffling springs are all installed,  and everything else seems about right including oil temps etc. I am in Tennessee where the break in is usually around 50-60 degree F OAT. I have never let the CHT go above 4000 in any break in flights. I usually fly for 1 1/2 to 2 hour trips. I am using AD oil (Phillips XC 20-50) as mandated by Lycoming.

Is this about right, Am I impatient to get the break in over with so I don't have to limit myself to 8000 MSL or below? Should I be looking at anything else like engine timing (doubt it would be off since it was set at the factory). Thanks for your help. 

[DVA]

Hi!

Breakin is always a mystery it seems. You'll find all kinds of advise, even from the shops and manufacturers that often contradict each other. My experience and opinion is that you should always do five things, during Breakin, with any piston engine unless otherwise advised with a good reason: 1) keep ground time short, and run ups quick; 2) fly above 65% power (75 is fine) so that the compression pressures are high enough to effectively seat the rings; 3) CHT at or below 400, lean or rich of peak doesn't matter; 4) vary the power settings every 30 minutes in cruise during the first 25 hours; and 5) change the oil and filter every 10 hours. 

The engine doesn't care what altitude you're at, especially a turbocharged engine. Fly where you want to, just keep the temps in order. 

The af1b should have its oil changed every 25 hours after Breakin - some skip a filter change but I don't. I use W100 mineral oil during Breakin, and then Aeroshell 100 plus in summer. 1 qt in 13 hours on a new engine seems way low to me? But if the engine is happy, and it seems to be, that's fine  

I love that engine, but it must be treated kindly. No quick throttle changes, slowly let the turbo come up to speed. Make sure the baffling is correct and that everything is sealed and there are no air leaks around the top baffling. 

I have GAMIs in mine, helped a lot with saving fuel, but that engine is tough to tune for LOP. I do it, but I need to be running around 65% power, above that i run ROP, never peak TIT. (Separate discussion)

Here's a handy chart I put together from the Lycoming graphs that help with % of power for a few settings. They're interpolated and averaged and are based on std temp - you can use the graphs in the engine manual to get exact, but these are close enough. 

HP - AT LEAN LIMIT

100%      270    2575        27.5GPH
75%        201    2400        17.1GPH
70%        189    2400        15.5GPH
65%        175    2400        13.5GPH
60%        160    2200        13.0GPH

REAL HP corrected for RPM/MP/ALT (Std Day (+/- 1% per 10F from Std)
TIT ROP -125 Max power  

%power    HP            RPM        MAP  ALT 

93%          250          2400        34"    0-FL220
87%          235          2400        32"    0-FL230
80-85%    215-225    2400        30"    0-8K 8K-FL250
75-80%    200-220    2400        28"    0-8K 8K-FL250
65-70%    180-195    2400        26"    0-8K 8K-FL250
60-65%    160-180    2400        24"    0-8K 8K-FL250
55-60%    145-165    2400        22"    0-8K 8K-FL250

85%        230        2200        34"    0-FL250
80%        215        2200        32"    0-FL250
75%        203        2200        30"    0-FL250
65%        175        2200        28"    0-FL250
60%        165        2200        26"    0-FL250
55%        150        2200        24"    0-FL250
50%        135        2200        22"    0-FL250

 

Edited May 12, 2016 by DVA
formatting

[carusoam]

Question for the OP: TIO520?  I have TIO540 on the mind for the Bravo... ( did I miss something?)

Nice post, DVA. (Quality vs. Quantity)

Best regards,

-a-

[rocketman]

Sorry - TIO-540. I keep getting it confused with my Rocket Continental TSIO-520 engine.

[aviatoreb]

3 hours ago, rocketman said:

Thought I would start a new post on breaking in my new TIO-520-AF1B engine. So I have now about 14 hours on factory rebuilt. Engine consumption has stabilized (1 quart in 13 hours) and the temps have come down as well. But not quite where I would like them. I have flown mostly 75% power at 24/34 while always maintaining CHT below 400, usually around 375 on the hottest cylinder which is #3. But to do this requires 24 GPH and half trailing cowl flaps. At lower power settings it still runs nearly 400 CHT on #3 when I lean it to TIT of 550 or shut the cowl flaps. I have always flown at 8000 MSL or below usually between 4000 - 6000. Baffling is in good shape, the intercylinder baffling springs are all installed,  and everything else seems about right including oil temps etc. I am in Tennessee where the break in is usually around 50-60 degree F OAT. I have never let the CHT go above 4000 in any break in flights. I usually fly for 1 1/2 to 2 hour trips. I am using AD oil (Phillips XC 20-50) as mandated by Lycoming.

Is this about right, Am I impatient to get the break in over with so I don't have to limit myself to 8000 MSL or below? Should I be looking at anything else like engine timing (doubt it would be off since it was set at the factory). Thanks for your help. 

Isn't 24/34 more like 80% on the rocket-tsio520?  Also called out as max continuous. Nothing wrong with that setting for break in though if you keep it cool enough which it sounds like you are.

http://www.rocketengineering.com/sites/all/docs/305Rocket.pdf

POH calls for 25-26 at that setting.

[DVA]

It’s important to look at the Engine Manual for clues on power and settings.  Normally aspirated engines can be easily calibrated for a %power because most of the variables like pressure altitude, intake temp, etc. can be surmised. A turbocharged engine like the TIO-540-AFxx is more difficult to call out a percentage easily and accurately as it changes rather significantly with those previous factors.  That said, the manual has the power percentage charts and you can see the % power when you graph it for your current conditions. (I added a power chart above that is a rough averagejust to get someone in the ball park, and more so to illustrate that there is a general misconception with Bravo drivers on the real amount of power you are running with that engine.

I’ve heard (too many) people say that they are running "about 75% power" on the Bravo when they fly at the “common” 32/2400. That’s just wrong, they are closer to 90% power, and at those levels you have to treat that engine with great care and finesse or you’ll be seeing new top end and turbo bills piling up fast.

If you look at the engine manual, you get clues as to what Lycoming really is doing concerning power in that engine. For instance, you set the density controller at 35”MP (not 38”) at 2575 given a certain compressor discharge temp for 100% power.  This means, according to the the engine experts I have spoken with, that the AF1x makes more than 270 HP for that brief period of time during the take off and initial climb. That makes sense to me, and it is why you pull back to 34” after clear of obstacles; at that point you are close to 100% max continuous power for the high performance cruise climb. ( I don’t stay there long, I’m back at 32” 2400 pretty quickly cuz things get hot fast)

Mooney’s marketing department wants us to go fast and they, by design, don’t care much about engine longevity. And Lycoming rates this power plant for a very high percentage of continuous power so you can go fast, and they only care a little more about engine longevity. Us as pilots, should care about engine longevity and that’s why we all have these great discussions. 

But make no mistake, by running this engine at 34 / 2400 you are making over 90% power on most days. Cruising along at 30-32 / 2400  you’re well over 80%. If you want to run at 75% power, then you have to about run 2400 / 28 (or 2200 / 30) and the good news is you’ll still be going pretty fast!

That explanation also helps some people realize why the Bravo is hard to run LOP - it’s because you are trying to run it LOP at a much higher power setting than you thought. My Bravo with GAMI’s now runs fine LOP at 28/2400 at 30F lean of peak TIT (yes, I loose about 10 knots, but gain 5.5GPH and have sparkling clean plugs, valves and piston tops and low CHTs). If I am running a higher power, such as 32/2400, I **always** run it 125 ROP TIT to stay out of the high pressure, hot cylinder, might detonate, cost me money “Red Fin” zone.

[Bravoman]

 I have about seven hours on my new engine in my bravo. Seems to be running excellent. My experience is very similar to Ron's, and my oil consumption since the inception has been very low. The temps is the  main thing. But I understand that that really starts to stabilize somewhere in the 25 to 50 hour timeframe. With regard to altitude, I have kept it under 7000 feet, but  my MSC, Joey Cole tells me that I can start to take it higher given that it is a turbocharged bird and it is all about keeping the manifold pressure up so that the power level can be maintained for break-in.  The lower altitude for break-in is obviously critical for non-turbo charged set ups. 

Regards, Frank

[mike_elliott]

2 hours ago, DVA said:

That explanation also helps some people realize why the Bravo is hard to run LOP - it’s because you are trying to run it LOP at a much higher power setting than you thought. My Bravo with GAMI’s now runs fine LOP at 28/2400 at 30F lean of peak TIT (yes, I loose about 10 knots, but gain 5.5GPH and have sparkling clean plugs, valves and piston tops and low CHTs). If I am running a higher power, such as 32/2400, I **always** run it 125 ROP TIT to stay out of the high pressure, hot cylinder, might detonate, cost me money “Red Fin” zone.

I am curious, DVA, what your TIT is at 30 LOP.

[DVA]

Hi Mike,

Depends on altitude, but I’m generally at 1600ish. Hottest cyl 380 (#3) cowl flaps closed or mostly closed.

[Bravoman]

4 hours ago, DVA said:

Hi Mike,

Depends on altitude, but I’m generally at 1600ish. Hottest cyl 380 (#3) cowl flaps closed or mostly closed.

It is interesting that both you and Ron's hottest cylinder is #3. That is my coolest. My two hottest are 1 and 6.

[FlyDave]

13 minutes ago, Bravoman said:

It is interesting that both you and Ron's hottest cylinder is #3. That is my coolest. My two hottest are 1 and 6.

My coldest indicated CHT is #3 also. But I think this is because the probe is a gasket type for the original CHT, not the bayonet type in the other cylinders.

My hottest are #4 and #6.

[carqwik]

Doesn't the Bravo require the Lycoming "additive" in the oil?  I thought the Phillips oil doesn't have it and thus is not for use in the Bravo engine?  The Aeroshell 15W-50 and W100+ have the additive...

http://www.lycoming.com/Portals/0/techpublications/serviceinstructions/SI%201409C%20%2802-20-2009%29/Lycoming%20Engine%20PN%20LW-16702,%20Oil%20Additive.pdf

I don't know whether this applies to break in but when my engine was rebuilt (crank replacement AD), I recall using the Aeroshell 15W-50.

My #6 runs hottest....have to open the cowl flaps in cruise a bit to keep it under 400 in the summer...

[aviatoreb]

1 hour ago, Bravoman said:

It is interesting that both you and Ron's hottest cylinder is #3. That is my coolest. My two hottest are 1 and 6.

Are they numbered the same way front to back in Lycoming vs Continental?

[Bravoman]

2 hours ago, aviatoreb said:

Are they numbered the same way front to back in Lycoming vs Continental?

I am certainly no expert in this area, but I believe the continentals are essentially numbered  the opposite way.

[Bravoman]

2 hours ago, carqwik said:

Doesn't the Bravo require the Lycoming "additive" in the oil?  I thought the Phillips oil doesn't have it and thus is not for use in the Bravo engine?  The Aeroshell 15W-50 and W100+ have the additive...

http://www.lycoming.com/Portals/0/techpublications/serviceinstructions/SI%201409C%20%2802-20-2009%29/Lycoming%20Engine%20PN%20LW-16702,%20Oil%20Additive.pdf

I don't know whether this applies to break in but when my engine was rebuilt (crank replacement AD), I recall using the Aeroshell 15W-50.

My #6 runs hottest....have to open the cowl flaps in cruise a bit to keep it under 400 in the summer...

No anti-scuff type additive should be used at all during break in. That includes cam guard and the like. Again, I am no expert, but I understand that it prevents things like rings from properly seating. I have also learned through the process of getting a new engine in that mineral oil is to be used in non turbo break in and AD in turbo    ( per Lycoming directive).

[rocketman]

As a follow up question, I am comparing the CHT on my 14 hour factory rebuilt engine to the engine I replaced it with which was a 2200 SNEW. The CHT's seemed to run much cooler with the older engine at comparable engine settings. Is this a normal process where a 14 hour engine which is probably 95% broken in to run warmer CHT's than a run out engine on the same airframe?

[aviatoreb]

1 hour ago, rocketman said:

As a follow up question, I am comparing the CHT on my 14 hour factory rebuilt engine to the engine I replaced it with which was a 2200 SNEW. The CHT's seemed to run much cooler with the older engine at comparable engine settings. Is this a normal process where a 14 hour engine which is probably 95% broken in to run warmer CHT's than a run out engine on the same airframe?

Broken in just means the rings become seated.  This can happen in just a few hours. But it will loosen up just a bit so the termps will come down gradually over the next hundred hours or so.