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Rebuilt engine break in question


jkarch

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I’m eventually getting a rebuilt IO-360 for my J. (August) After the initial 5-10 hours where I run the engine full bore at 2600-2700 RPMs and full manifold pressure, when can I start climbing above 7-8 k and go below 75  percent power so I can fly over the mountains and cross the country?

Also anyone know how if overhauling a mechanical tach is a bad idea?

-J

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I installed a Lycoming rebuilt IO-360-A3B6 last October. Lycoming sent a bunch of service instructions and bulletins with the engine as well as a DVD. I found the break in procedure a bit confusing. Most of the information supplied is for a field overhaul. But with a rebuilt, Lycoming runs it in a test cell for an hour. Attached is a copy of the test report for my engine. That run takes a lot of the concern out of the first run after installation. I never noticed any big changes in temps or performance during my break in flights. All were done at about 75% power ROP using 25"/2500 at 2500' MSL. I never had high CHTs and I never saw them decrease. It burned about 7 hours/qt of oil for the first 30 hours and is now burning about 8 hrs/qt. Talking to other owners and Lycoming the oil consumption is a bit of a crap shoot. Some burn more some less - no one seems able to predict or explain the variation. I changed the oil at 10 hours (some Lycoming docs say ten, some say five). I figured ten was reasonable since the oil had been removed and replaced with preservative, and a new filter installed, after the test cell run. There was very little metal in the filter at ten hours. I changed the oil again after another 30 hours and switched from Aeroshell 100 to Aeroshell W100. The filter had only half a dozen small flecks of metal. I also did an oil analysis (Blackstone) at 30 hours and the metals were normal. Compressions at this time were 1-79/80, 2-79/80, 3-78/80, 4-79/80. My conclusion is that the most critical part of the break-in is done during the test cell run. After the first ten hours, I flew normal missions at 75% and just didn't do any stalls, slow flight, touch and goes, long low power descents and such. 

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Test Report.pdf

 

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+1 for following the manufacturer guidelines...

The misery/mystery of engine break-in have all been broken...

Break-in of an NA engine typically includes

a set of flights... the first ones orbit the airfield looking for leaks and other tests...

The Long XCs typically include... the Jersey Shore runs...1k’ AGL

  • High power
  • Cold running, cold air, maximum cooling
  • Full mixture
  • alternating rpms every 15 minutes
  • Keep an eye on CHTs, you might see the break-in actually occur...

If the engine was run on a test stand, most of the Break-in may have occurred already...

PP thoughts only, not a mechanic...

Best regards,

-a-

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So it sounds like with a pre tested engine for 30 hours total don’t go above 5k ft altitude ( 1k-2500 preferred ) or 75 percent power unless cycling between 65 and 75 even if temperatures and oil consumption stabilize? Also sounds like cowl flaps should be open the whole time, full rich operation, and keep 75 percent power on descent. Occasionally run at full power? Oil change at 10 then another 20-30?

what about traffic pattern? Cowl flaps open or closed? What power settings?

When can I finally climb above 5k?

-J

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Collecting CHT data will probably give you the insight...

Raw cylinder / piston ring clearances are tight... they generate a lot of heat... the result is higher than normal CHTs.

If you are not seeing higher than normal CHTs the rings have nicely worn in...

I followed the Continental guidelines for the break-in of my IO550... a few hours of flying each time for a few days...

The reasons for full power...

  • Break-in is not a gentle exercise... with gentle, There is no break-in...
  • Max pressure in the cylinders helps to seat things properly...
  • Max rpm has a way to push the piston all the way to the extreme end of the travel...
  • Altering rpms on a schedule... keeps from wearing a small region by spreading out the wear intentionally...

It helps to bring your engineer with you so you can fly the low / fast runs... and have somebody else be watching the gauges and helping keep an eye out for traffic down low...

I brought some high powered Mooney specific CFII (John Pallante) when I did mine... they were familiar with engine break-in, and Mooneys, and I can always use the training... :)

Primarily, I didn’t want to be alone if something fell off the engine, like a fuel line... i’d Be on the ground before I could figure out what happened...

The low altitude flight is for best MP... over the ground we were probably at around 2k’, over the ocean, 1k’... during the descending transition, Vne was a limitation that was observed.   We were supposed to change rpm every 15minutes or so... conveniently, my CFII pointed out some really obvious land marks on the ground instead of watching a clock too...

WOT, full RPM, down low at 190 kts... things come up quickly while in a descent... it is good to have support close by when questions come up...

Break-in is not an exact science. More of a good guideline that captures all of the steps needed, and things to avoid...

No need to fly 10’ msl...

PP thoughts only, not a mechanic or a CFI...

Best regards,

-a-

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You should also make sure that your maintainer has a pressure pot to pre oil the engine before the first start. This ensures that your new engine gets oil pressure quickly and minimize damage.

Clarence

 

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Run it hard and not above 4000ft until oil consumption stablizes. Then you are good to go. But I wouldn't fly it over the mountainous range before 100hours plus oil analysis and filters all chekced out. 

Edited by Tommy
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2 hours ago, M20Doc said:

You should also make sure that your maintainer has a pressure pot to pre oil the engine before the first start. This ensures that your new engine gets oil pressure quickly and minimize damage.

Clarence

 

I’ve heard basically spray some corrosion-x in to all four cylinders and run with ignition disconnected and plugs off until oil pressure starts to go yellow, then go.

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3 hours ago, jkarch said:

100 hours before flying over mountains? Seems like a lot! How does it work with the bathtub curve? 30 - 40 plus oil analysis perhaps, but my last three samples showed a happy engine, and the cam was shot!

 

That shows the real value of oil analysis, smoke and mirrors in my experience.

Clarence

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3 hours ago, jkarch said:

I’ve heard basically spray some corrosion-x in to all four cylinders and run with ignition disconnected and plugs off until oil pressure starts to go yellow, then go.

With an engine worth 10’s of thousands and a pressure pot being worth a 100, it’s a cheap investment.  I do the pressure pot for all newly repaired or overhauled engines.

Clarence

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You should also make sure that your maintainer has a pressure pot to pre oil the engine before the first start. This ensures that your new engine gets oil pressure quickly and minimize damage.
Clarence
 

I assume the engine shop would’ve test run the engine, so no pre oiling is necessary?


Tom
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2 hours ago, M20Doc said:

That shows the real value of oil analysis, smoke and mirrors in my experience.

Clarence

Everybody says that but elevated iron is always present when the cam and lifters spall.  Also, washing out the filter in mineral spirits into A quart plastic bucket and then placing a magnet under the bucket and pouring the solvent off you can tell very quickly if it’s making metal or not. That metal goes somewhere when it spalls.  If you didn’t catch it it means you weren’t looking hard enough.  But the signs are there .

One of our engines had high iron since it was rebuilt, and you know three or four years of this trend was enough to keep the warranty claim open. Eventually they took it back and went through it again for free. But it was some data to stand on. 

That engine came back after an extensive rework by the overhauler,  and due to work and weather timing and other considerations we only had about 17 hours on it before flying it through IFR half across the country and then over to the Bahamas and back. I was a little bit nervous. But everything worked out fine. But do pull that Cowl off every few hours and look at everything

Edited by jetdriven
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19 minutes ago, jetdriven said:

Everybody says that but elevated iron is always present when the cam and lifters spall.  Also, washing out the filter in mineral spirits into A quart plastic bucket and then placing a magnet under the bucket and pouring the solvent off you can tell very quickly if it’s making metal or not. That metal goes somewhere when it spalls.  If you didn’t catch it it means you weren’t looking hard enough.  But the signs are there .

One of our engines had high iron since it was rebuilt, and you know three or four years of this trend was enough to keep the warranty claim open. Eventually they took it back and went through it again for free. But it was some data to stand on. 

That engine came back after an extensive rework by the overhauler,  and due to work and weather timing and other considerations we only had about 17 hours on it before flying it through IFR half across the country and then over to the Bahamas and back. I was a little bit nervous. But everything worked out fine. But do pull that Cowl off every few hours and look at everything

AFAIK, oil analysis will miss particles that are too large for chemical or spectroscopic analysis, so it should be used in conjunction with checking the oil filter and screen.

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9 hours ago, ArtVandelay said:


I assume the engine shop would’ve test run the engine, so no pre oiling is necessary?


Tom

That may be true, but they didn't run it with your propeller, propeller governor, oil cooler, oil cooler transfer hoses etc.  All of these things need to be filled with oil before the engine can raise pressure in the bearings.  Now you're hoping that the oil in the bearings from the last run at the overhauler is going to be protect the crankshaft and bearings while the oil pump fills the rest of the empty parts.

A gamble I can’t take with my customers engines.

Clarence

 

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1 hour ago, jetdriven said:

Everybody says that but elevated iron is always present when the cam and lifters spall.  Also, washing out the filter in mineral spirits into A quart plastic bucket and then placing a magnet under the bucket and pouring the solvent off you can tell very quickly if it’s making metal or not. That metal goes somewhere when it spalls.  If you didn’t catch it it means you weren’t looking hard enough.  But the signs are there .

One of our engines had high iron since it was rebuilt, and you know three or four years of this trend was enough to keep the warranty claim open. Eventually they took it back and went through it again for free. But it was some data to stand on. 

That engine came back after an extensive rework by the overhauler,  and due to work and weather timing and other considerations we only had about 17 hours on it before flying it through IFR half across the country and then over to the Bahamas and back. I was a little bit nervous. But everything worked out fine. But do pull that Cowl off every few hours and look at everything

I do all of those items as well, but there are times when I've got a magnet full of metal and the oil sample(Blackstone) report says that all is good with the engine and oil.  Filter examination in my experience is the most important.

Clarence

 

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That may be true, but they didn't run it with your propeller, propeller governor, oil cooler, oil cooler transfer hoses etc.  All of these things need to be filled with oil before the engine can raise pressure in the bearings. 

How’s that different than any start? I assume oil drains from all the above back into the oil pan?


Tom
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32 minutes ago, ArtVandelay said:


How’s that different than any start? I assume oil drains from all the above back into the oil pan?


Tom

The difference is after a recent run, the oil pressure will come up pretty much instantaneously. Contrast that to starting it up after it been sitting for several weeks or longer and the oil has back drained to the sump sufficiently that even the oil pump has drained. You'll be running for several second at least at idle rpm before the oil pressure come up to safe levels. Add in the risk of poor start with high engine RPM at startup and not only is excessive un-needed wear a concern but risk of real damage from high rpm without oil pressure.

This is so easily avoided by turning the engine over without the plugs which anyone can do or even better if you or your maintainer has access, using a pre-oiler. The later is a bit invasive as one has to be careful to re-attach the oil hoses and properly torque the connections but it avoids all engine revolutions  without oil pressure.

Edited by kortopates
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4 hours ago, M20Doc said:

I do all of those items as well, but there are times when I've got a magnet full of metal and the oil sample(Blackstone) report says that all is good with the engine and oil.  Filter examination in my experience is the most important.

Clarence

 

That’s exactly what I got with this: dead cam and good oil analysis!

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53 minutes ago, jkarch said:

How do you get/make a preoiler?

 

Also I have an old UBG-16. Is this good enough or is there a reason to upgrade to a CGR30P?

Here’s an example from Summit Racing, but there are many sources.  I think I paid about 150$ Canadian for mine.  Buy one for your new engine and donate it to your maintainer when your engine is finished, he’ll be quite happy.

There is no mystery to using one, remove a convenient oil gallery plug, install the adapter fitting, connect the hose, fill the reservoir, pressurize with shop air, open the valve and wait for a pressure indication on the ship gauge.  

Bleed the air pressure out of the tank, remove the hose and fitting and reinstall the gallery plug with thread sealant and torque the plug per the manual.

Clarence

 

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663AAD7A-67E9-4C9A-AC46-18BCD46CDA39.jpeg

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