cylinder break in power settings

[NewMoon]

breaking in New cylinders on an Acclaim. Says run 65% and 75% power. Can't find in the POH where it says what those settings should be. MP, RPM and FF. Any help thx

[A64Pilot]

Way I have always done it is to climb at full power to say 5,000 ft or whatever will give you 75% with prop pulled back a couple of hundred RPM and cruise at full throttle. I’ve never had a cyl head temp issue, but I run rich too. As your a Turbo full throttle ain’t going to work of course, you will have to pull it back or I guess go very high, I’d pull it back.

I keep it very rich the first couple of hours, wasting fuel to keep temps down.

I want decent altitude just in case, and I don’t like cruising at T/O RPM. I think high MP is what breaks in a cylinder more than RPM, cylinder pressure forces the rings against the cylinder wall and high MP of course creates high cylinder pressure.

Note, I have NO turbo experience so I can’t help you with MP settings.

I don’t go LOP until I think it’s broken in, in my case that’s always been 10 hours or less. I’ve been lucky I guess. Stupid rich is fuel wasteful but it does keep temps down.

I also avoid long warm-ups, especially at first. You can glaze a cylinder pretty quick before it’s broken in, I think that is one reason why some take so long to break in and why maybe some never do, so pre-heat real good so you don’t need a warm up.

I like to change oil and filter in a couple of hours too as almost break in metal occurs very quickly and I don’t want metal in my oil, but concede I’ve never heard of it killing a motor.

Another opinion of mine is that temp cycles are important in the break in process, that overnight cool downs and flying again the next day help as opposed to one long flight.

Plus I don’t want to be away from home if an oil leak or something pops up.

Your charts don’t have a % power?

Seems not

 

[A64Pilot]

I think 75% isn’t a magic number, I think they want you at the max continuous allowable power, and for most engines that’s 75%. 

In other words I’m going to guess that using the max power in your cruise charts is max continuous power and what I’d shoot for assuming you can’t answer your question. Because surely only continuous power settings are in cruise charts

[Shadrach]

The reason for varied RPM and power settings during break is to ensure even ring/cylinder seating through out the piston’s stroke. 

I would call Continental and see if they will send you charts specific to your engine. The TSIO550G info that I found on line was spec’d for 310hp and was not comprehensive. I am sure that Continental has the numbers. Hopefully hey will make hem available.

[jlunseth]

Here is a great piece on engine break-in, don’t remember where I found it, it might have been on this site: https://pceonline.com/wp-content/uploads/2017/04/ECI-BreakInInstructions.pdf

As it happens I am breaking in my new Continental TSIO360LB right now. They want you rich of peak, which makes sense. They are looking for high pressure that will keep the rings seated against the cylinder walls, plus temperature moderation. I agree with the advice to run very rich, that’s what will keep the temps down. 

I would be very surprised if your Acclaim POH does not have settings for 65 and 75% HP rich of peak. Every POH I has tables with those settings.

The TCM break-in instructions say to try to keep the CHTs between 300 and 380. They suggest that for low power regimes like descent to landing you should pull the RPM knob way out. I was reluctant to do that at first, but do it routinely now and it allows you to keep power up without gaining too much speed. Also helps to create drag, i.e. throw out the speed brakes and drop the gear.

Mine are breaking in fine with this advice, just had them borescoped.

PS: I thought I might have found the pceonline article on Moonespace. Actually, I found it on the Pilot’s of America forum.

Edited January 19, 2024 by jlunseth

[Danb]

2 hours ago, jlunseth said:

Here is a great piece on engine break-in, don’t remember where I found it, it might have been on this site: https://pceonline.com/wp-content/uploads/2017/04/ECI-BreakInInstructions.pdf

As it happens I am breaking in my new Continental TSIO360LB right now. They want you rich of peak, which makes sense. They are looking for high pressure that will keep the rings seated against the cylinder walls, plus temperature moderation. I agree with the advice to run very rich, that’s what will keep the temps down. 

I would be very surprised if your Acclaim POH does not have settings for 65 and 75% HP rich of peak. Every POH I has tables with those settings.

The TCM break-in instructions say to try to keep the CHTs between 300 and 380. They suggest that for low power regimes like descent to landing you should pull the RPM knob way out. I was reluctant to do that at first, but do it routinely now and it allows you to keep power up without gaining too much speed. Also helps to create drag, i.e. throw out the speed brakes and drop the gear.

Mine are breaking in fine with this advice, just had them borescoped.

I recently broke in new cylinders in my acclaim. Here’s Mike Busch article 

2021-07-28 0830 F7 Cylinder Break-In Do it Right.pdf

[toto]

Kind of OT, but I’ll mention that all of Mike Busch’s books (a three-volume set) are available for free on Kindle Unlimited. Not a reason to subscribe by itself, but if you’re already a Kindle Unlimited subscriber it’s pretty nice. I look at his books all the time for one thing or another. 

[Shadrach]

2 hours ago, toto said:

Kind of OT, but I’ll mention that all of Mike Busch’s books (a three-volume set) are available for free on Kindle Unlimited. Not a reason to subscribe by itself, but if you’re already a Kindle Unlimited subscriber it’s pretty nice. I look at his books all the time for one thing or another. 

They are on audible (Amazon) as well.

[NewMoon]

14 hours ago, Danb said:

I recently broke in new cylinders in my acclaim. Here’s Mike Busch article 

2021-07-28 0830 F7 Cylinder Break-In Do it Right.pdf 2.27 MB · 13 downloads

Thx, how did it go?

[Danb]

2 hours ago, NewMoon said:

Thx, how did it go?

Pretty good, my temps are nice low and consistent. Never know if I did it totally correct don’t have a handle on if my oil consumption is really stabilized. With the flying weather in the NE and Mid Atlantic plus Biden occupying our airport I haven’t flown much in last two months. The plane is smooth and generates good power, this spring I’ll have a better idea when we start our long trips. Basically I followed the procedures in the Continental engine manual which is really good. I think the first couple hours are the most important hopefully I did it ok in that period. I had 5-6 long, over 1000 mile trips, since like mentioned the temps are awesome.

[BDPetersen]

I recall a break-in discussion by a GAMI expert making the case for LOP break-in. The assertion was that the slower “burn” yielded a protracted power stroke that kept the pressure up on the rings for a longer travel in the cylinder, spreading the wear (break-in)over a bit more of the cylinder walls. I believe I used this method a time or two.

Please don’t shoot the messenger.

[A64Pilot]

Many methods work, to include just flying the thing.

For example flight schools and rental aircraft aren’t taken out of service and flown through long protracted break in procedures, they would go broke. They are taken around the pattern once or twice to ensure smooth running and no oil leaks then placed into service. As with most things I think as pilots we make more of this than is necessary.

In my opinion pattern work is an excellent break in, repeated burst of full throttle followed by short cooling periods, repeat.

I think however that following the procedure recommended by whoever is going to warranty the thing if all doesn’t go well is smart. Example I think using mineral oil is a silly hold over from my Grandfathers times, but If the manufacturer of the cylinder requires it, I’m running the stuff.

[Shadrach]

4 hours ago, BDPetersen said:

I recall a break-in discussion by a GAMI expert making the case for LOP break-in. The assertion was that the slower “burn” yielded a protracted power stroke that kept the pressure up on the rings for a longer travel in the cylinder, spreading the wear (break-in)over a bit more of the cylinder walls. I believe I used this method a time or two.

Please don’t shoot the messenger.

Indeed there was a discussion on the Mooney mailing list back in the early aughts about LOP break in. Walter Atkinson was involved and made a very good case for why it is superior if done correctly. When I broke in my last set of cylinders, I did the most of the break in at high power LOP. We established good oil control inside of 5hrs and the oil was reasonably clean when changed at 10 hours. Temps were 360 or less during all phases of break in.. That was over 600hrs ago and it’s been running strong ever since. Compressions at last annual we’re 79,80,80,80 and borescope images are healthy with minimal deposits. It’s been a very healthy power plant since IRAN.