Bad news - free advice sought

How to keep the Cessna 170 flying and airworthy.

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hilltop170
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Re: Bad news - free advice sought

Post by hilltop170 »

Jim-
There are as many opinions on how to break in a new engine as there are people who are willing to give an opinion.

After overhaul, the bottom line is the whole engine is in as good shape as it will ever be with the exception of the piston rings are not seated-in to the cylinder walls. If the rings don't seat properly during break-in, the engine will use excessive oil the rest of its life, there will be excessive blow-by fouling spark plugs, and the cylinder compressions will likely be sub-par.

The way aircraft cylinders are prepared for break-in is the cylinder walls are intentionally left roughed up microscopically so the rings can wear down the high spots and lap themselves in giving a good seal. The only way to seat the rings is for the engine to produce enough internal combustion pressure to force the rings against the cylinder walls long enough to wear down the jagged peaks to the point where they are smooth and not generating excess heat due to the friction of the lapping process.

The only way for the engine to produce maximum internal combustion chamber pressure required to seat the rings is to run the engine hard, at the highest allowable continuous power setting until the rings are seated making sure the cylinder head temps do not exceed max allowable. The CHTs will run hotter than normal due to the obvious higher friction between the rings and cylinder walls as they seat-in together and that is to be expected. This cannot be done on the ground so any ground run time should be absolutely minimized, only long enough to check for proper mag function, oil leaks, and oil pressure. NO PROLONGED GROUND RUNNING!

The first flights should be made at as low altitude as possible to make highest manifold pressure. Cooler ambient is better than warmer as well. Each flight should be about an hour to let everything stabilize. Circling the field in the pattern at pattern altitude is a good way to spend the first hours in case you need to make a quick landing. This also eliminates having to fly low over folks who might not want to see you there. Then land quickly as possible with the least possible low power operation and check for leaks, etc after shut down.

You can use a prescribed break-in procedure from the cylinder manufacturer or you can use max power for takeoff and max continuous for the rest of the break-in. I have broken in several new engines and top overhauls using max power for takeoff and max continuous until break-in is achieved with excellent results and never have had a problem.

Being able to see how the engine is behaving in real-time with a fuel flow computer and all-cylinder CHT/EGT instrumentation is another key ingredient in achieving a good break-in. Not required but very helpful. Cylinders will all be running at different CHTs and the hottest cylinder will be the controlling factor no matter which one it is and might change positions inflight. Power settings and mixture will have to be set so the hottest cylinder will not exceed max allowable.

What I have observed is each cylinder will break-in at different times, new cylinders usually take around 3 to 3-1/2 hours if everything is right. Chrome cylinders might take longer. CHTs will make a noticable drop of 20-50°F over a ten minute timeframe when the rings seat-in on each cylinder. Watching for that drop is important and why I use max continuous power instead of varying power as some procedures specify. Its difficult to see the drop when other factors are changing at the same time.

Once all cylinders have seated-in, I use at least 75% power until the cylinders have at least 10 hours on them before returning to normal operations, ensuring good break-in. If done properly you have a good chance of making TBO on the cylinders. If not done correctly, persistent problems can be expected.

A few key points:
-You only have one chance to seat-in the rings correctly, you don't get a do-over
-Don't "baby" the engine thinking you should be easy on it to break it in slowly, poor results will be your reward
-Don't exceed CHT limits, that is very important!
-Break-in the new engine at as low altitude and high power as possible
-Continuous power settings allow you to see when CHT drop occurs
-If all-cylinder CHTs are not available, run max continuous power at low altitude for at least 10 hours

And of course, since we have ambulance chasing lawyers and bleeding heart juries without any common sense, everything you just read is my own personal opinion and not a directive on how you should operate your airplane, but it is how I have done break-ins for over 45 years with good results.
Last edited by hilltop170 on Fri Nov 18, 2016 4:08 am, edited 2 times in total.
Richard Pulley
2014-2016 TIC170A Past President
1951 170A, N1715D, s/n 20158, O-300D
Owned from 1973 to 1984.
Bought again in 2006 after 22 years.
It's not for sale!
hilltop170
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Re: Bad news - free advice sought

Post by hilltop170 »

Yes, Arash, we are saying the same thing, I'm just a little more long-winded. It's hard to know how much a person understands about engine break-in so I just tried to cover all the bases.
Richard Pulley
2014-2016 TIC170A Past President
1951 170A, N1715D, s/n 20158, O-300D
Owned from 1973 to 1984.
Bought again in 2006 after 22 years.
It's not for sale!
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GAHorn
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Re: Bad news - free advice sought

Post by GAHorn »

Don't deliberately rust-up the cylinders, however. :wink:
Use straight mineral (non-dispersant) oil for initial break-in. (I realize some will say it's OK to use the dispersant oils but almost 50 years of experience have shown me that sometimes the dispersant oil break ins did not go well and I"ve never had a problem with mineral/non-dispersant oil.)
'53 B-model N146YS SN:25713
50th Anniversary of Flight Model. Winner-Best Original 170B, 100th Anniversary of Flight Convention.
An originality nut (mostly) for the right reasons. ;)
flyboy122
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Re: Bad news - free advice sought

Post by flyboy122 »

hilltop170 wrote:Jim-
There are as many opinions on how to break in a new engine as there are people who are willing to give an opinion.

.
No truer words have ever been spoken! First and foremost I would ask the shop that built the engine what they recommend. That way if the engine has troubles, they can't blame it on you. That being said I would question a procedure that deviates significantly from OEM recommendation. Lots of people think they know more than the OEM. Very few probably do. I don't. The bonus of going with an OEM is you are covered from a liability standpoint. In my case I'm an A&P and usually sign off my own work. Doing it per the book saves a lot of uneasy questions should there be an incident. I note the procedure in the log, including the Service Letter number and revision level.

The last engine I did used Superior cylinders, so even though it was a Lycoming I used Superior's procedure. I guess I could have used Lycoming's as well, but figured the highest likelihood of trouble on break in was the cylinders so I used their OEM. The procedures were almost identical anyway, and very close to Richard's procedure.

DEM
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cessna170bdriver
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Re: Bad news - free advice sought

Post by cessna170bdriver »

On my overhaul in 2006 I installed 6 new ECI cerminil cylinders and their recommendation was Phillips 20W50 oil cradle to grave. The cylinders measured in the mid 70s/80 even before being run, and after the first flight, 5 were 80/80 and one at 79/80. I wouldn't have believed it had I not been standing there when the compression check was done. From then through the 300+ hours until impact from a runaway hand-propped Cherokee 140 necessitated a teardown, there was never a cylinder below 75/80, even after one 13-month period the engine didn't run at all. From now on I will ALWAYS follow the manufacturer's recommendations for cylinder break-in no matter what they are.
Last edited by cessna170bdriver on Sun Nov 06, 2016 2:27 pm, edited 1 time in total.
Miles

“I envy no man that knows more than myself, but pity them that know less.”
— Thomas Browne
hilltop170
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Re: Bad news - free advice sought

Post by hilltop170 »

I agree with Miles on using the recommended oil for break-in. I too bought new ECI Nickle-Carbide cylinders for the O-300D in my 170 in 2006 because it has to sit for periods of a few months every year. Phillips 20-50 was specified TO BE USED FOR BREAK-IN or the warranty would be void. Like Miles, I had great results. The cylinder rings all seated-in around 3 to 3-1/2 hours and have consistently been in the high 70s/80 in the 300+ hours since.

Last year I had to put a new P-Ponk O-520 in my C-180 due to the old Millenium cylinders being condemned by a BOGUS AD (in my opinion perpetrated by Continental against Superior) which required all Millenium cylinders to be removed after 17 years time in service no matter what condition they were in. Mine had 1100 hours since new, had never been off the engine, and were all in the mid 70s/80.

I used Phillips 20-50 for break-in on the factory reman and again, all rings seated-in in 3 to 3-1/2 hours. All cylinders are high70s/80 after 100 hours. One thing I discovered after break-in, when I changed to Aeroshell 15-50 for the winter, the starter would spin the engine much faster with AS 15-50 than Phillips 20-50. That is intuitive but I didn't think it would make as much difference as it did.
Richard Pulley
2014-2016 TIC170A Past President
1951 170A, N1715D, s/n 20158, O-300D
Owned from 1973 to 1984.
Bought again in 2006 after 22 years.
It's not for sale!
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jimnh20
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Re: Bad news - free advice sought

Post by jimnh20 »

Thank you gentlemen for the thoughtful replies. I have been using the procedures that several of you have proffered and George, I am using straight mineral oil for break in. So far the cylinder temps are behaving well (have a egt/cht gage). But of course there is always the "next" issue. Prior to the overhaul my temps would border on redline. I have the original gage with just red and green. I also have the spin-on oil filter STC. With any significant climb (say 2000 feet) on a warm (say 85F) day it basically pegs the gage. I'm trying to fly in cooler temps with little climb but this does naturally have me concerned. I've read the threads that the older gages redlined at 225, but I'd like to hear from experienced folk here what they think and would do in like circumstances.
Jim Norman
1952 C170B
1982 TR182
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ghostflyer
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Re: Bad news - free advice sought

Post by ghostflyer »

Well one thing i have done on a number of occasions before pulling the cylinders for overhaul of them etc,etc is pull the sump off and clean it . This is especially for an engine that have done a thousand hours in the last twenty years . Things you find in sumps is totally amazing also . The grey sludge and water you find is beyond belief. Plus it allows a check on the corrosion that's happening. I know of a process that where the area prone to corrosion is soda blasted clean and then cleaned with MEK and then painted with an poxy paint .[ipad will not let me put in the correct spelling ] . This stops the corrosion factor in the critical areas. Recently we pulled a sump off that was done 5 years ago and it was good as the day it was put in except the paint had yellowed a bit . Besides sludge we have found in sumps has been a very large split pin , smaller split pins ,washers , and a very old car key. The key had been originally chromed but the brass ??? Had started to break down . All these had been placed in a photo frame and hung on the office wall until it disappeared one day.
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GAHorn
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Re: Bad news - free advice sought

Post by GAHorn »

Well, allow me to back-pedal a bit on my previous posting...

I did not mean to imply it was OK to disregard any mfr's break-in recommendation. That comment was generically intended for OEM steel-cylinder and channel-chrome cylinders...not the newer processes which undoubtedly have special considerations by their mfr's. (And I posted that not having read Richard's pre-existing post that he used the X-country oil...it may have appeared I was disagreeing with him on that matter and I was not. My own rebuilds and engine work performed in my past have all been either new steel or channel-chrome....never an ECI or Ni-Ch cylinder, as those have not been my preference.)

I guess I should have specified that better.
'53 B-model N146YS SN:25713
50th Anniversary of Flight Model. Winner-Best Original 170B, 100th Anniversary of Flight Convention.
An originality nut (mostly) for the right reasons. ;)
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JSwift
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Re: Bad news - free advice sought

Post by JSwift »

Gents,

As it turns out I’m picking up my trusty steed this week after a post prop-strike incident in which I opted to pay the over and above for a full overhaul with Millennium cylinders. Amongst many options over the ensuing five months I did not choose to install a full engine monitor. I will have to rely on my oil pressure, oil temperature and EGT gauges to deduce how my break in is proceeding. I did install an EI fuel flow gauge.

My plan is to follow Hilltop’s advice for the first ten hours to include the use of OEM recommended break in oil.

Any other words of wisdom in the next few days are welcome. Thanks for the tips so far.
N2594D, 1952 170B #20746
Near Enfield, CT
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Bruce Fenstermacher
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Re: Bad news - free advice sought

Post by Bruce Fenstermacher »

Jack,

No full engine monitor? 8O :D

My words of wisdom. Savor the experience. You will be joining the ranks of tens of thousands of pilots who broke in their overhauled engine with no full engine monitor. And you can then tell the story to those young aviators just before leading into that other story about walking to school up hill both ways with no shoes.

Mid 2017 we overhauled our C-145 and used Superior cylinders. We used a secret formula of 4qt 40w and 4qt 50w Shell mineral oil. The secret is, is is what we had on hand.
We did nothing out of the ordinary other than running it harder than the normal hard running we usually do. This means we only pulled the throttle back to about 2600 except to land and we only did that to ensure we wouldn't exceed 2700. We did not exceed 3000 msl and most of our break-in was under 2000 msl.

Of course we monitored engine oil pressure and temps but saw nothing different than any other normal operation. About the only thing we did different besides 2600 rpm rather than 245-2500, is we checked our oil level religiously. And there is the rub. In 18 hrs of operation we lost a total of 1 qt of that special mix. 8O

Normally oil consumption on break-in is high. Engines push out oil at a higher rate till broken in. Something in the rate of 2-3 quarts over 10-15 hrs. One just keeps replenishing it till the rate slows down to normal rates and then one proclaims the engine broken in.

So our engine only pushed out 1 qt and between 15-18 hrs my partner and I proclaimed the engine broken in.

As for the special sauce of half 40 and half 50w, I can only recommend it to those who find themselves in the pickle I was. I probably would have waited and bought more 50w but my partner Leroy, who has been breaking in engines for about 70 of his 80 years, was looking cross eye'd at me. What a pickle. I did at least insist we only use the same oil manufacturer, Shell, rather than a mix of Shell, Exxon/Model and BP he first pulled from the storage locker.
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JSwift
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Re: Bad news - free advice sought

Post by JSwift »

Thanks Bruce!

Weather looks good and we are off to Chatham to pick up 94D in the morning. I'll let you know how it went in about 10 hours or so. Now if I can only convince the better half that flying 10-20 hours on my bird is my JOB for the next week! ... :D
N2594D, 1952 170B #20746
Near Enfield, CT
Let's go fly!
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GAHorn
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Re: Bad news - free advice sought

Post by GAHorn »

For the life of me I cannot figure out why page 2 and page 3 of this thread are identical. (Perhaps a moderator has inadvertently manipulated this thread? ...or there's a glitch in the software... whatever...)
Anyway.... Bruce, I'm curious about the reluctance to mix different brands of mineral/non-additive engine oil. Does Shell, Exxon-Model, and BP avoid adding the same non-additives to mineral oil..??? or do they not add different non-additives..? :lol:
'53 B-model N146YS SN:25713
50th Anniversary of Flight Model. Winner-Best Original 170B, 100th Anniversary of Flight Convention.
An originality nut (mostly) for the right reasons. ;)
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Bruce Fenstermacher
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Re: Bad news - free advice sought

Post by Bruce Fenstermacher »

Actually on very close examination you will find page 2 and page are not exactly the same. There are however many duplicate post on each and I think a few that only appear on one or the other page. For example the first post at the top of each page is different.

I have no idea how it could have gotten this way.

As to the oil, I have no idea if Shell, Exxon-Model, and BP mineral oil is exactly the same or different. That is where I drew the line. We would mix weight but not manufacture.
CAUTION - My forum posts may be worth what you paid for them!

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ghostflyer
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Re: Bad news - free advice sought

Post by ghostflyer »

Over the years in our shop we have had all the brands of engine oil on the shelves. The oil reps leave a 5 gal drum as a sample in hope we will buy the oil in 44 gal drums. The oils we have used is shell, BP, Exxon, Total , Phillips , Castrol and about 3 other brands that I can’t remember [old age] . It’s my opinion that the very high time engines are telling the story on what to use in oils. Engines that use Exxon exclusively [cheap cost] have bearing issues [eg pitting]. While the best oil is Phillips . It has some corrosion inhibiter in it and a very stabile oil at high temperature . It does a very good job.
NOTE.. please Mr rep from Phillips , I need another sample .
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