Engine Break In

[rubixcube2k3]

So I'm looking to get some feedback from anyone here experienced with breaking in an engine after a top overhaul. We installed 4 new cylinders, pistons, etc this annual, and of course being the OCD SOB that I am, I have tried following the lycoming instructions to the letter regarding breaking in. The first problem I encountered is that the recommended numbers by the PoH don't line up anywhere near what my MVP 50 is reflecting for power output. My cylinders were surprisingly cool throughout the takeoff, climb, and cruise. Even so cool at points that I had to run it harder to get them into the lower end of the temperature green range. (at times we were below 350* CHT on cylinders 1 and 2). I will be attaching a few pictures of the MVP-50 at various cruise phases. At the PoH recommended 17"/23 I was still showing in excess of 79% HP on the MVP at 5000' with an OAT of 58*. Can anyone advise if I am doing something wrong? I just want to  make sure I'm doing what I should be doing-  I'm terrified of glazing a cylinder or causing some inadvertent damage due to not properly breaking in the new cylinders. We flew for 2 hours today, and never at the same RPM and MP setting for more than 45 minutes, but for the life of me I could not get anywhere near the 75% and 65% numbers on the MVP-50 without feeling like we were going to drop out of the sky or fly backwards in a stiff wind. I took three pics all together, one at 17"/2300, and two reflecting the only "safe" power settings I could choose to get 65% and 75% reflected.  At no point under 85% indicated HP on the MVP could I get Cylinders 1 and 2 into the green zone for CHT Temps. 

 

Thanks!

Abe

[N601RX]

I'm not familiar with the MV50, but all the JPI units requires some configuration before the %HP is correct.  It doesn't look like yours has been set up yet.

Based on your MP and Fuel flow you we're likely below 50% power.

[carusoam]

Use the MAPA addition rules:  MP + RPM/100 for the C =65% hp

Let me know if you need this looked up.  Most IR'd C drivers probably know this number, and one for 75%.

Break-in flights are usually done at high power settings.  This gives good ICPs for cylinder/ring seal and the Pistons travel the fullest extent in the cylinder.  Essentially avoiding building a step in the cylinder wall at the end of their travel in a place short of their maximum travel.

My engine break-in (IO550) was done at 75 and 65% power.  Changing MP and or rpm every 15 minutes.  Mixture was all in for deep ROP cooling.

This is from old memory.  If it doesn't make sense, I can look up the details...

Keep the following in mind.  When avoiding the red box, an NA engine can be kept safe by flying at altitudes above 8k' (or so).  MP for 65% is going to be a bit higher than 17.7"

Does your POH give %HP in the power settings chart? If it does, it should match the MVP/JPI pretty closely.  Where the MVP/JPI falls down is in the area of ROP vs LOP.  When running LOP, 100% of the FF is being used for HP. When running ROP, it is more of a charted combination of MP, RPM and possibly FF...

As 601RX points out MVP/JPI needs to be set up properly.  It will probably need to know ROP vs LOP.  It will need to know this for leaning as well.  During leaning the JPI will want to track the first or last to peak depending on ROP or LOP.

I'm not a mechanic.  I used to love this level of detail...

Best regards,

-a-

[aaronk25]

Take a look at your book and find what settings get you 75% and run it there. After 2 hours of flying your probably all broke in. Keep the Chts under 380 and above 300 and have fun. I broke mine in running lop and at peak egt.

I ignore the %of hp as reported by the computer as its only accurate if calibrated and its NOT accurate when lean of peak.

Sent from my iPhone using Tapatalk

[Andy95W]

17" and 2300 rpm is about 50-54% HP.  At that point, there is a good chance you are not breaking in your cylinders and possibly glazing them.  I doubt you've successfully seated the rings at such low power settings.

Definitely use the book settings for horsepower until you get your MVP properly setup and calibrated.

23-25" and 2400-2500 rpm for 2-3 hours will do it, just keep an eye on CHTs.

[rubixcube2k3]

Thanks everyone, I guess I'll pay southern avionics a visit and ask about the calibration. I also have a dome light issue for them to look at so I need to drop in and pay them a visit. Is it fairly safe to say that flying by the book numbers I can be fairly confident that I am breaking in properly? I should have stated initially that I didn't linger very long at the posted  HP combinations. the better part of the 2 hours flown today was spent at 24"/23 and 21"/21-22. I didn't think flying that slow was correct or safe. I went to the lower power settings between flying the book numbers, only to find that it felt really really weird. 

It definitely helps to hear from other's experiences. I just wanted to make sure that I was correct in following the book, over the latest and greatest instrumentation. 

 

Thanks, 

Abe

[carusoam]

Abe,

Did you get specific instructions from your mechanic to follow for Break-in?

The process has evolved pretty well over the last decade or so.  More science, less mystery, real data collection, that kind of stuff.

Continental gave some pretty straight forward procedures to follow and things to avoid from the first start into the first few hours.

Break-in flights are typically high powered, low altitude flying.  Some people, like Aaron, include high power LOP into the regimen.

just wondering,

-a-

[Guest]

Does your airplane still have the old tach and MAP gauges?  If so use them and Lycoming SI1427 for break in. There is something wrong with your MVP50

http://www.lycoming.com/Portals/0/techpublications/serviceinstructions/SI%201427C%20(12-29-2010)/Lycoming%20Reciprocating%20engine%20Break-In%20and%20Oil%20Consumption.pdf

The engine need higher MAP to push the rings out against the cylinder walls, otherwise they will never break in and result in glazed cylinder and high oil consumption.

Clarence

[Browncbr1]

Some of you mentioned %HP as displayed by jpi is wrong when LOP.  When setting up cruise, I reduce rpm to catch 65%, then go lean of peak.  I see the %hp drop to around 50-55%.  Does this mean I can increase rpm or map to get back up to 60-65%hp?   I had understood that around 60-65% power is ok to go LOP.  But, I had assumed that power level is for when ROP before pulling ff back. 

[Andy95W]

9 hours ago, rubixcube2k3 said:

 I should have stated initially that I didn't linger very long at the posted  HP combinations. the better part of the 2 hours flown today was spent at 24"/23 and 21"/21-22.

You're probably just fine.  Keep running it hard, keep your CHTs below 400° (380° is better), and change the oil and inspect the filter when Lycoming says.

[rubixcube2k3]

10 hours ago, carusoam said:

 

Did you get specific instructions from your mechanic to follow for Break-in?

The process has evolved pretty well over the last decade or so.  More science, less mystery, real data collection, that kind of stuff.

Continental gave some pretty straight forward procedures to follow and things to avoid from the first start into the first few hours.

-a-

He actually recommended following the Lycoming Break-In SI without variation. The problem was that it referenced HP, and not MP/RPM. The PoH suggested one thing but the MVP reflected differently. Referring back to the Lycoming Break-In SI, it plainly states to use the PoH Published power settings for best results. That being said, I'm glad that was what I did for the most part. Now just to get another few hours in it running it at those numbers, and hopefully all will be fine. I'll keep checking the oil and the plugs between flights just to be sure. 

 

[FBCK]

I'm going though the same process as well, so I'm running my engine at 75%.  I also purchased a new car recently and the car manual tells me not to operate the engine above 3000 rpm for the first 2000km.  This actually makes more sense to me then running an engine at 75% when new, and I do understand the concept of glazing, but why would I not get glazing in my car engine.

[carusoam]

Abe,

The 76 C's POH gives a chart in the performance section for cruise and range at various altitudes, MP, RPM and %BHP.

Lower Altitude gives higher MP, the biggest factor...

RPM is a smaller adder to the power equation.  But, adds to the piston's potential to travel to extremes in the cylinder.

ROP or LOP for this process is mostly CHT control.

I think somebody posted a C's POH in the site here somewhere under documents.

If all four cylinders are behaving well from a CHT and EGT point of view.  That is a good sign. 

Break-in requires some force through the full range that the engine is going to operate in.  Cruising around at low MP and low rpm will probably just delay the break-in period.  It's an engine, not fine china.  Get the procedure from the guy that is responsible for the Break-in's success.  Follow it.  If for some reason it doesn't work, you have a guy to go back to to help get it right the second time.

I had my mechanic do the first engine runs and two flights.  The high risk, stay near the airport ones.

From my C's POH and the photos above....

17" 2350rpm=54%BHP

20" 1950rpm=48%BHP

19.6 1850rpm = Elvis has left the building on the low side of performance data

Best regards,

-a-

[carusoam]

FBCK,

Three things come to mind...

Cars have the benefit of mass production.

Car engines are water cooled.

car people are not as capable.

The break-in period for a car is to mostly to wear in some sharp corners.

Did you get a particular oil that the engine came with that was different from the long term use oil?

I am only a PP, not a mechanic...

Best regards,

-a-

 

[PTK]

19 hours ago, aaronk25 said:

...I ignore the %of hp as reported by the computer as its only accurate if calibrated and its NOT accurate when lean of peak.

This is an erroneous assumption and incorrect advice.

Going by my EDM800 which I'm intimately familiar with, the %HP algorithm needs HPC (HP Constant), EC (engine constant) and aircraft HP setting to be properly configured. It uses these three parameters and it looks at RPM, FF, OAT, and MP.  The resulting %HP is dead on whether LOP or ROP.

EI does it differently. I believe they require configuration of POH cruise RPM and MP and then they look at RPM, MP and EGT. It doesn't look at ff. The instrument doesn't "know" and can't distinguish if it's LOP or ROP as far as the %HP parameter goes.

 

[carusoam]

It took both JPI and MVP many updates to get their algorithms up to par.  The LOP algorithm was the easy one...

The MAPA method is pretty well trusted by the MAPA training pilots.

My IO550 was broken in this way with a MAPA pilot on board.

Because, when you can only afford to do it once.  It needs to be done right.

Periods of 15 minutes for power changes were roughly determined by crossing boundaries on the ground. Going down the Jersey Shore has plenty of natural markers that can be verified with a watch.

there are so many things to try and pay attention to.  Time can slip by very quickly.  Flying Around 1,000 feet agl doesn't leave much time to look at the time and navigate too...

more ideas on break-in,

-a-

[Guest]

A new engine or an newly overhauled engine will be run on a test stand for several hours, with at least one of those hours at maximum rated continuous power.  If it doesn't blow itself to pieces on the test stand, you running it at 75% for a few hours during break in won't harm it.

Clarence

[Shadrach]

10 hours ago, Browncbr1 said:

Some of you mentioned %HP as displayed by jpi is wrong when LOP.  When setting up cruise, I reduce rpm to catch 65%, then go lean of peak.  I see the %hp drop to around 50-55%.  Does this mean I can increase rpm or map to get back up to 60-65%hp?   I had understood that around 60-65% power is ok to go LOP.  But, I had assumed that power level is for when ROP before pulling ff back. 

I run LOP at 80% plus at 2500 in the winter time. It's as cool or cooler than any ROP setting. At 65% even an absolute moron would not be able to hurt an IO360 with the mixture knob. 65% is put the mixture anywhere power, one can run LOP at almost any power level if they know what they are doing. Here's a good rule of thumb for folks still getting comfortable with LOP: Any POH MP and RPM that suggests a mixture setting of peak to 100ROP is going to be cooler and kinder to the engine if leaned past peak.

I have been running my engine LOP for a long time at all altitudes. I run at MPs as high as 29" LOP with a very happy engine.  I read a Cafe foundation race report from the early 80s and was surprised to learn that Roy Lopresti set his engine the same way for low altitude operations during the race.

[rubixcube2k3]

Figured I'd share the actual flight info from the MVP as Charted by SavvyAnalysis. May as well take advantage of it's data recording capability, right? No point in having it to not use the post-operational flight analysis features.  

Top chart is EGT & CHT vs. Flight Time, while the bottom Chart is RPM & MAP vs. Flight Time. 

 I placed a call to EI and Southern Avionics today to get some more information about the calibration error. No answers yet, but honestly,  it's backseat to everything else, considering that I can complete the break-in without looking at the HP Output field.  Going to do some 1-2 hour flights over the next few good weather days to well known territory.

I pulled the lower plugs today and while the rear plugs were dry, the front plugs had a fairly light oil coating on them. It appears as though the engine used just shy of 1/3 quart of oil in the 2 hours of flight yesterday. I'll keep sharing data through the break-in if anyone is interested. 

 

[carusoam]

Keep posting, Abe.

We all get to go through this at least once.

Not all of us are able to share data as well as you have.

best regards,

-a-

[aaronk25]

Abe, just remember that it may take a day to 5 days for the 1/3 (more likely 1/2) qt to drain back to the sump after operation depending on OAT and viscosity of oil used. If you wait a week the oil level very well may be the same as prior to engine start. There is a lot of places for the oil to cling to and takes a bit for gravity to work its magic. You might already be accounting for this. If your not it sounds like your engine may be broke in and oil consumption stabilized. The wet spark plugs make me question that a bit but these engines are far from precise.

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[mike_elliott]

18 hours ago, rubixcube2k3 said:

Figured I'd share the actual flight info from the MVP as Charted by SavvyAnalysis. May as well take advantage of it's data recording capability, right? No point in having it to not use the post-operational flight analysis features.  

Top chart is EGT & CHT vs. Flight Time, while the bottom Chart is RPM & MAP vs. Flight Time. 

 I placed a call to EI and Southern Avionics today to get some more information about the calibration error. No answers yet, but honestly,  it's backseat to everything else, considering that I can complete the break-in without looking at the HP Output field.  Going to do some 1-2 hour flights over the next few good weather days to well known territory.

I pulled the lower plugs today and while the rear plugs were dry, the front plugs had a fairly light oil coating on them. It appears as though the engine used just shy of 1/3 quart of oil in the 2 hours of flight yesterday. I'll keep sharing data through the break-in if anyone is interested. 

 

The CHT's show the rings may have seated. I would run the next couple of hours no less than 25" MAP and vary RPM from 2400-2550 some. MAP sub 25 isn't optimal on break in from what the Engine guru's tell me.

[rubixcube2k3]

So today, I had some fun, ran the engine hard, got a fairly cost effective upgrade to a 2015 Corvette Stingray, and  got to see two of my favorite people. 

 

Mike, I did take your advice and run as much MAP as possible while varying RPM between 2300 and 2480ish.  Seemed to keep all of the cylinders CHT in the green zone for the duration and under 390 for the most part. Thanks for that advice. 

The logs are attached and labeled accordingly, I had a lengthy descent into KECP since Tyndall decided to keep me at  altitude until I was directly over the airport.  In both directions, I noticed that CHT and EGT on cylinder 3 seemed to exceed that of Cylinder 4. Not in a large amount, but basics of understanding would make me think that cylinder 4 would be marginally hotter since it is further to the rear in the baffling. Am I correct that it's not the norm, or am I hyper-analyzing? The higher EGTs make me wonder if there isn't a plug fouling, perhaps. 

I'm currently running champion massives, but I am contemplating returning to the fine wire plugs that I installed and pulled out right after the mags were installed last year due to fouling. (I now believe the fouling to be a result of the failing cylinder, rather than just bad luck with the plugs. 

 

Anyway, as always, I welcome any thoughts and recommendations from the community. 

KECP to 1R8

 

1R8 to KECP

 

[mike_elliott]

flew just a bit north of you guys today on the way to Longview. Glad it is all working out abe. give Ron and Ron my best!

[carusoam]

Vettes and Mooneys..!

Great combinations of speed and efficiency.

Best regards,

-a-