Engine breakin

[RobertGary1]

Took my F out for its first flight on the 0 time A3B6 engine. A couple things I noticed that I"m not sure they are common...

 

1) Fuel pressure on the mechanical pump was running 29 psi at 75% power. That's much higher than the old pump ran. Maybe this is normal for a new pump? Its within the green arch. I don't recall seeing a limiter on the old servo to the sensor line but maybe there was and I returned it with the old engine???

 

2) CHTs were fine. They were pretty flat across the 4 and were in the low 300's.

 

3) EGTs were uneven. At 75% power, pulling 12 gal/hr (slightly rich) I was seeing around 1180/1349/1460/1195. In my old engine the EGTs were very even. Is this common at break in? I did notice that while the EGTs were very uneven at idle before the flight they were level at idle after the flight.

 

4) Oil pressure was nicely in the middle of the green. An improvement over my last engine where its last 30 seconds of life were with oil pressure at 0.

 

I had previously ran the engine for 15 minutes to position the plane after I finished the engine install so I could get a hanger to work on the annual. So I guess this was 15-1:15 of its young life.

 

-Robert

[FloridaMan]

Is it the factory fuel pressure gauge? Does it read the same with the boost pump on and off? If it is the factory gauge, what does it read with the engine off? 

[carusoam]

What instructions are you following for the break-in?

The IO 550 instructions for break in are something like running full rich while switching between 65% and 75% power settings every 15 minutes....

CHTs are expected to vary with the break-in exercise as friction can be quite high while breaking down surfaces...

EGTs I would expect to be pretty level. Friction doesn't seem to be part of exhaust gasses...

Of course, it has been a while since I read these instructions....

Best regards,

-a-

[aaronk25]

Regards to egt.....did you do a GAMI check on them to see if there close?? Also did you reuse the same injectors and keep them in the same positions relative to cylinder #?

[RobertGary1]

This is the factory gauge. This is the instructions from Lycoming. Not GAMI. New injectors installed by Lycoming. I didn't do anything with the injection system other than install the servo they gave me to the engine. The spider and injectors were all installed by Lycoming.

-Robert

[carusoam]

Was there a fuel system set-up performed with the new install?

Idle setting and full throttle fuel flow are typically set at this time...

Best regards,

-a-

[RobertGary1]

Nothing in the instructions I have to test fuel flow other than adjusting idle and mixture. I'm sure Lycoming did more when they bench ran the engine.

It's likely this is normal and my old pump was just weaker.

-Robert

[carusoam]

Those EGTs look whacky...(as they often can, sensitive to install location)

As Aaron pointed out a good GAMI spread test is in order...

Is the exhaust system unchanged from the old engine?

Do you have exhaust temp data from before?

There is a fuel injector test (four jars) to perform if the Gami spread is wide...

Best regards,

-a-

[RobertGary1]

The exhaust temps were very even on the old engine. Same egt sensors and same exhaust pipes.

-Robert

[N601RX]

Is it possible that the cylinder with an egt of 1460 is only running on one plug?

[RobertGary1]

Is it possible that the cylinder with an egt of 1460 is only running on one plug?

I did wonder that but I did a msg check back on the ground. Maybe it's only funcky at power though.

Mags and plugs are new, also provided by Lycoming.

-Robert

[N601RX]

I would try cleaning the two high injectors and if that didn't help look at the plug/mag.

[kmyfm20s]

Oil passing by the rings will have an effect on the EGT's. If CHT's are good it could be they just haven't seated yet.

[Cruiser]

Before you start doing any troubleshooting. Do the break-in.

 

Follow a proven procedure but most of all, run it hard. I say again, run it hard. 

Don't baby it. 

 

Be certain:

1. timing is set correctly

2. double check the timing

3. keep CHTs below 400°F better if below 380°F, but no higher than 400°F

4. keep it below 4,000 MSL and run it hard.

5. Did I say to run it hard? Min. 75% power.

6. Watch the oil consumption, when it stabilzes the cylinders/rings should be broke in. What ever the hours it takes.

7. Don't forget to run it hard.

 

p.s. don't worry about EGTs now. unless there is a sudden change in value or higher than 1550°F

[philiplane]

Run it hard.

 

Forget a GAMI spread, you can't do one until you can lean the engine anyway. That won't happen until you have at least 10 hours on the engine.

[RobertGary1]

Good points on holding off. I'll check the oil level in the next couple of days. Maybe the first hour is too soon to worry about non-flat EGT spreads.

 

-Robert

[FloridaMan]

This is the factory gauge. This is the instructions from Lycoming. Not GAMI. New injectors installed by Lycoming. I didn't do anything with the injection system other than install the servo they gave me to the engine. The spider and injectors were all installed by Lycoming.

-Robert

 

The reason I asked is if it is the factory gauge is that when mine failed, the indicated fuel pressure started to creep up until it exceeded the redline eventually and would indicate in the middle of the green with the engine off. 

[RobertGary1]

The reason I asked is if it is the factory gauge is that when mine failed, the indicated fuel pressure started to creep up until it exceeded the redline eventually and would indicate in the middle of the green with the engine off. 

 

Your gauge failed or your engine failed? The pressure seems to otherwise be reasonable when pressurizing for start up. However, the pressure from the mechanical pump is so high now that turning on the electric pump in flight doesn't change anything.

 

-Robert

[Shadrach]

Run it hard.

 

Forget a GAMI spread, you can't do one until you can lean the engine anyway. That won't happen until you have at least 10 hours on the engine.

This is not true, but to each their own. I have broken in jugs LOP and it works beautifully.

[Shadrach]

Do run it hard. Lean or rich, you need to be pulling ~70% horsepower or more. While I normally wouldn't worry about raw CHT numbers, yours are a bit odd. 1180-1200 is what I like to see full rich, not leaned for best power.

[FloridaMan]

Your gauge failed or your engine failed? The pressure seems to otherwise be reasonable when pressurizing for start up. However, the pressure from the mechanical pump is so high now that turning on the electric pump in flight doesn't change anything.

 

-Robert

 

The gauge When I bought the plane, it read at the top of the green. About a year and a half later it started to creep past the red. 

[jetdriven]

This is the factory gauge. This is the instructions from Lycoming. Not GAMI. New injectors installed by Lycoming. I didn't do anything with the injection system other than install the servo they gave me to the engine. The spider and injectors were all installed by Lycoming.

-Robert

My factoy A3B6 required GAMI injectors to run anywhere near peak EGT. Current Injector configuration is C-F-H-D. And even then, #2 goes right off a cliff past peak, and it has the richest injecor you can buy.

[RobertGary1]

My factoy A3B6 required GAMI injectors to run anywhere near peak EGT. Current Injector configuration is C-F-H-D. And even then, #2 goes right off a cliff past peak, and it has the richest injecor you can buy.

 

That would be unfortunate. As long as I cleaned/soaked my injectors every year I was able to run LOP in my old engine with the Lycoming injectors. I hope I didn't take a step backwards with a 0 time engine.

 

-Robert

[jetdriven]

My old engine, also didn't require GAMIs but the A3B6 needs them, and in fact, it still doesn't cure the mixture distribution problem.

[RobertGary1]

A3B6 is the only game in town. Lycoming doesn't make the A1A any longer. This is my second, my previous engine was an A3B6 as well. They idle smoother due to counter weights. The tapets last longer as well with the rollers. My first A3B6 was installed under an STC from ModWorks. I didn't do anything faa special with this one since it was just a replacement of the same. I did verify that my stc wasn't specific to the engine s/n though.

-Robert