Engine run-in requirements

[sfGnome]

I was under the impression from previous reading (that I can’t lay my hands on readily) that engine run-in should be done in the air so that temperatures can be kept within limits wile running at the required speeds for the required period. This, of course, implies little engine running before an aircraft’s first flight. However, I was just reading the Europa owners handbook and found the following statement. “Before first flight, you will have needed to run the engine for a minimum of 2 hours without any problems”.

 

Am I mixing up different requirements for air and water cooled engines (the Europa is water cooled), or am I mistaken about running in in the air, or what? Can anyone shed light on this issue?

[skippydiesel]

1 hour ago, sfGnome said:

I was under the impression from previous reading (that I can’t lay my hands on readily) that engine run-in should be done in the air so that temperatures can be kept within limits wile running at the required speeds for the required period. This, of course, implies little engine running before an aircraft’s first flight. However, I was just reading the Europa owners handbook and found the following statement. “Before first flight, you will have needed to run the engine for a minimum of 2 hours without any problems”.

 

Am I mixing up different requirements for air and water cooled engines (the Europa is water cooled), or am I mistaken about running in in the air, or what? Can anyone shed light on this issue?

I am unware of any Rotax instructions for "running in" however believe there can be no harm in following Rotax minimum load RPM of 5200 for all operations (no lugging) and although not specified doing a few extra oil changes on the new engine. I changed my oil & filter at 5 hrs, oil again at 25 hrs and will do a full 100hr service at 50 hrs.

 

I believe that Ly/Cons have a recommendation for "running in" along the lines of full power/ hrs?

[old man emu]

A complex question that will have two teams battling it out til Doomsday. One team says to run the engine at lower power settings for the specified period. The other says fire it up and give it full power. That was effected by towing a plane to the start of the runway, starting it and taking off. But that was for WWII radials.

 

With your Europa engine, you have the advantage of temperature and pressure gauges to help you monitor those factors. So you won't be worrying about cooling.

 

However, I can see a bit of poor communication in this:  you will have needed to run the engine for a minimum of 2 hours without any problems . What exactly did the writer mean?

 

I see that as good advice, simply because by running the engine while on the ground, you can check that everything required for proper combustion, and hence power development, is set correctly, and that nothing has been left loose or has come loose. In that sentence I cannot detect any reference to things that happen when we first run an engine, such as bedding in bearings and rings and valves. Perhaps Europa bench runs the engine before signing it off for sale. In some engines the manufacturer specifies that non-detergent mineral oil is used for the first few hours. One idea here is that the oil will burn and soot will fill those minute surface unevennesses. After that period, you can switch over to detergent  mineral oil, or synthetic if specified.

[facthunter]

They used to have engine testing structures at Essendon where engines were test run with Wooden Prop slugs. Once in  service they use the ordinary Power settings.  The engine HAS to be able to take full power as normal for take off. IF the clearances are correct that should not present any problems. In the tropics some VH engines have experienced some tight piston fits causing burnishing of the pistons. The allowable fit range is quite substantial. That goes from initial ( relatively Tight) to on the wear limit.. The looser fit are less risk. A few hours of running would hardly make any measurable difference. No one runs cars in any more but running them full bore straight away would not be the best treatment but so is nursing them as well. Nev

[skippydiesel]

4 hours ago, sfGnome said:

I

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Am I mixing up different requirements for air and water cooled engines (the Europa is water cooled),.............................

Pedantic I know BUT the Europa is neither liquid or air cooled, its an airframe. The engine can be a liquid cooled eg Rotax 9 range or air cooled eg Jabiru - I have assumed that your enquiry is about a Rotax 9 motivated Europa😀

[sfGnome]

11 minutes ago, skippydiesel said:

3 hours ago, skippydiesel said:

I believe that Ly/Cons have a recommendation for "running in" along the lines of full power/ hrs?

That’s possibly where my confusion arose. I read Kitplanes a lot, and they tend to be Ly/Cons focussed.

3 hours ago, old man emu said:

A complex question that will have two teams battling it out til Doomsday.

I’ll admit to being a bit worried about that before I asked the question. 🤨

11 minutes ago, skippydiesel said:

Pedantic I know BUT the Europa is neither liquid or air cooled, its an airframe. The engine can be a liquid cooled eg Rotax 9 range or air cooled eg Jabiru - I have assumed that your enquiry is about a Rotax 9 motivated Europa😀

Yep, you’re right. I should have said Rotax. Perhaps I should have just looked at what Rotax say about it…

Edited May 26, 2023 by sfGnome

[facthunter]

You don't nurse motors like one used to. If this is done the rings may not seal as well as they should and  the motor will fume and likely use more oil.  Nev

[old man emu]

19 minutes ago, facthunter said:

You don't nurse motors like one used to

That would put you into the team that advocates full power, straight out of the box.  I'm not commenting on which team you are in, just noting that we have one in that team and no one has nominated for the opposition.

 

The US Army instructions for running in the engine of a WLA Harley are given below. I've left out the bits about checking for loose nuts and bolts on the frame and that the chain oiler is working. Those engines were designed in 1937 and made using the metallurgical knowledge of the time. As Nev said, modern motors don't have to be nursed like this.

 

RUNNING‐IN NEW ENGINE (OR VEHICLE).

a. A new motorcycle engine or newly overhauled engine must be given proper “break‐in” consideration for at least the first 1,000 to 1,200 miles of service. 

b. At first 500 miles, drain oil tank and refill with fresh oil. Check front and rear chains (step b above). Thereafter, follow instructions in Maintenance Operation section.

e. Following pointers must be observed when running‐in new engine or newly overhauled engine:

(1) Do not exceed 30 miles per hour during first 100 miles.

(2) Do not exceed 35 miles per hour during next 200 miles.

(3) Do not exceed 40 miles per hour during next 400 miles.

(4) Do not exceed 50 miles per hour during next 500 miles.

(5) Avoid use of low gears during break‐in operation as much as possible.

[sfGnome]

2 minutes ago, old man emu said:

(1) Do not exceed 30 miles per hour during first 100 miles.

I remember my dad treating his new Holden that way. Bit tough to replicate in an aircraft through. Thanks a lot to taxiing! 😝

[sfGnome]

Well, I did what I should have done in the first place and looked at the Rotax doco. The installation manual says to do the test run accordance with the operators manual, and that says nothing about first runs, just the normal preflight test. So, it appears that Rotax doesn’t require any specific run-in. I guess that Europa’s 2 hour test run instruction is just to find all the normal infant-mortality problems (like poorly fitted pipes and chaffed cables, etc) while you’re still on the ground.

[pmccarthy]

Don’t honk, new donk.

[kgwilson]

When my A3300 engine was new the instructions were to avoid prolonged ground running mainly due to reduced airflow & possible overheating. Of course testing required slow speed taxiing, the high speed taxiing etc. This gave me time to adjust things like idle speed etc. Of course first flight meant full power at takeoff and instructions were not to baby the engine and fly at normal to high cruise of 2850 -2950 RPM & obviously monitor Ts&Ps. This was to ensure rings were bedded in properly and avoid bore glazing. Well my engine has only done just uner 450 hours but leakdowns are excellent, I don't top oil up between changes & always use 98 premium ULP.

[facthunter]

I'd agree with that and don't lug the motor. Climb at a higher airspeed when you can and avoid very hot days That's just practical common sense. Don't run for long with the cowl off either. Your rings should seal in under an hour. You'd probably help that by doing a few short up to full throttle bursts before you do the first take off.. Let the motor cool a bit and repeat till you're happy. I wouldn't  knowingly put  any motor in the air with a "soft" compression. Rotax's have good compression usually from scratch and you'll notice that when you "burp" it.  Nev

[old man emu]

35 minutes ago, facthunter said:

Don't run for long with the cowl off either.

It is a misconception that ground running without the cowls on is Okay. The cowls don't simply take care of the aerodynamics of the airflow on the outside of the aircraft. Those cowls and baffles have been designed to direct cooling air over the cylinders, especially the rear ones. It's usually OK to have the cowls off when doing something like tweaking the ignition timing as the engine is only running for a few minutes at low revs. But to taxi an aircraft out to a runup bay for full power testing without the cowls shows a lack of care for an engine. 

[facthunter]

It can render the engine severely damaged. A surprising number of people are unaware of it.  Nev

[Marty_d]

On 26/05/2023 at 6:36 PM, old man emu said:

That would put you into the team that advocates full power, straight out of the box.  I'm not commenting on which team you are in, just noting that we have one in that team and no one has nominated for the opposition.

 

The US Army instructions for running in the engine of a WLA Harley are given below. I've left out the bits about checking for loose nuts and bolts on the frame and that the chain oiler is working. Those engines were designed in 1937 and made using the metallurgical knowledge of the time. As Nev said, modern motors don't have to be nursed like this.

 

RUNNING‐IN NEW ENGINE (OR VEHICLE).

a. A new motorcycle engine or newly overhauled engine must be given proper “break‐in” consideration for at least the first 1,000 to 1,200 miles of service. 

b. At first 500 miles, drain oil tank and refill with fresh oil. Check front and rear chains (step b above). Thereafter, follow instructions in Maintenance Operation section.

e. Following pointers must be observed when running‐in new engine or newly overhauled engine:

(1) Do not exceed 30 miles per hour during first 100 miles.

(2) Do not exceed 35 miles per hour during next 200 miles.

(3) Do not exceed 40 miles per hour during next 400 miles.

(4) Do not exceed 50 miles per hour during next 500 miles.

(5) Avoid use of low gears during break‐in operation as much as possible.

"Do not exceed 30mph during first 100 miles", yet "Avoid use of low gears"??

[onetrack]

The old engines had tight clearances when factory new, or freshly overhauled. If you gave them curry from new, the heat buildup from the tight clearances could easily see them seize up - thus the explicit instructions for "running in".

 

Todays engine technologies means engines can produce full power and be loaded up from new, because new engines are not "tight" to allow for "break-in". Current engine designs and materials means wear levels are very low in engines today.

[Carbon Canary]

The quality of lubricants has changed as well.

[kgwilson]

Back in the 50s & 60s 160k was about the most you could expect from an engine. Now 300-400k is not uncommon before anything has to be done. My current Mitsubishi has just over 220k on the clock & nothing has had to be replaced. It just gets serviced every 15k. Of course fuel and lubricants are much better as is the engineering and metallurgy, not to mention much better roads. 

[old man emu]

45 minutes ago, Marty_d said:

"Do not exceed 30mph during first 100 miles", yet "Avoid use of low gears"??

3-speed gearbox. 0 to 14 mph in first. 15 to 30 in second, then 30 to 64 mph in third. We are talking about a 45 cu in engine  4.75:1 compression ratio producing 25  HP at 4600 RPM. The bike will happily chug along in second gear. with 30 lb-ft torque at 2400 RPM

[facthunter]

A race car engine cannot be run in before service nor can an aero one They have to have the necessary clearances to cope. Good air and oil filtration are a big part in extending engine life, and quick engine warm up.   Also a lot of turbocharged engines run at low RPMs.  Nev

[skippydiesel]

2 hours ago, facthunter said:

.................   Also a lot of turbocharged engines run at low RPMs.  Nev

Depends on application Nev. These days even little 3 cylinder buzz boxes can be turbo charged and man they rev!

[facthunter]

Only if you tramp on them and keep your foot to the floor. They Don't Need to and highway work is seeing just over 2,000 RPM on  them. They get good torque as low as 1400.   Nev

[spacesailor]

Surprisingly, newer car's, seem to be prone to multiple problems. 

My neighbours  CX7 and his brother same model car , have had $ thousands spent trying to find " engine warning light " ON problems. 

Just google the dozens of people trying to fix their faults. 

'  spark-plugs- coils-O2 sensor's ( two )-fuels-caps- catalytic converter ,' the list of parts that the mechanic's replaced is endless .

This problem ' damaged battery terminal ' that gave intermittent fault signals. 

I hope they  ( the neighbour's ) are HAPPY with the " backyard " mechanic two, hour repair job !. LoL

PS ' I do have a " engine diagnosis tool '' .

spacesailor

 

 

 

[Kyle Communications]

Lets face it Rotax specify 2000 hr TBO....a bad run in wouldnt show up until after 2000 hr of ops