The International Cessna^® 170 Association

Has anyone had difficulty of ring seating on new millenium cylinders?
I have 40 hr and rings did not seat.
thanks
Dave

Did you use mineral oil and run it hard?

In response to Gahorn:

yes I used mineral oil, but I did not run it hard due to the instructions I had from the overhauler.

I have been told that I should have done that, now all cylinders have to come off and re hatch and new rings and do it again.

My $ at this point, I was trying to find if others had the problem it might be a manufacture problem.

So far no such luck
Thanks for the response.
Dave

My goodness! How things do change.
Back in the BIG WAR when engines were round and ran on Avgas instead of kerosene, engines used to be "Slow Timed" after installation and before normal operations. Many's the time I flew around for three or four hours at the softest power setting that would keep the airplane flying just to "break in" the new or overhauled engine. Of course, most radial engines drink copious quantities of oil all of their lives anyway, so we were never trying to "seat" the rings. I think we were just trying to see if the SOB was going to blow up anyway. Some of them did!

doakes wrote:In response to Gahorn:

yes I used mineral oil, but I did not run it hard due to the instructions I had from the overhauler.

I have been told that I should have done that, now all cylinders have to come off and re hatch and new rings and do it again.

My $ at this point, I was trying to find if others had the problem it might be a manufacture problem.

So far no such luck
Thanks for the response.
Dave

When you pull the cylinders, have real Continental rings put in it..if you e-mail me I can show you the difference..
ias#whidbey.net

One thing that you may want to try before pulling off cylinders is a chemical cleaning.
GM makes a “Top Engine Cleaner” part number 1050002. It cost $6 for a 15 oz can.
If you warm up the engine and pull the top plugs you can position the piston at bottom dead center on the compression stroke then dump about 6 oz into cylinder. Work the prop to move the piston back and forth. Some of the fluid may boil out of the plug hole.
Go back to your break in procedure. Use break in oil as recommended. If you are a mmo fan use it also. Reassemble the engine; tow the plane out to the runway, do a run up and fly. Prolong idling will put you back in the same condition that you started with. The top ring needs pressure to seal and with the low cr that we have to deal it’s hard to break it in
I have seen this work. It does clean the carbon out, results may vary. Let me know what results you get.

Dave, I am in the tenth hour of my break-in on ECI cylinders. At the sixth hour I watched the CHT drop from 300 degrees to 200 degrees in just a couple of minutes. Yesterday the CHTs were well less than 200. I believe this means that the rings seated (at least on the #1 cylinder). I highly recommend going to the ECI website and printing their engine break-in procedures manual. I followed the instructions to the letter with the exception of using Aeroshell straight mineral oil as opposed to the Phillip's that they recommend (it is only a recommendation). They only recommend cruise power for the initial flight, then varying power. I mostly ran cruise or a little higher. I think the thing is to avoid the high temps that might be experienced at wide-open at least for the first flight. Good luck!
David

ECI has a chrome-moly compression ring that can seat before the engine starts. You may have this kind of ring in your engine. You need pressure to seat the standard rings that comes with high power settings. That makes heat, hard to have one with out the other. When you feel that things have stabilized a leak down test would make a good data point for you new engine

Babying a new engine is not good for it. Remember that these engines turn less than 2700 rpm....not exactly high-performance. High manifold pressures (open throttles) are necessary to spread the rings against the cylinder walls to seat them quickly...before the cylinder walls glaze. Once those cyl walls glaze.... then the rings will no longer match up to them and you'll have an oil burner.
As long as red lines/limits are not exceeded, (good forward speeds will aid cooling),... the engine will not be hurt by high power settings. It will actually be broken in much better. (Mineral oil should be used, makes no difference as to brand.)

gahorn wrote:Did you use mineral oil and run it hard?

GA go to this address and read "oil definations"


http://www.eci2fly.com/Tech_Ref/bi/BIOiltalk.htm

Tom Downey wrote:

gahorn wrote:Did you use mineral oil and run it hard?

GA go to this address and read "oil definations"


http://www.eci2fly.com/Tech_Ref/bi/BIOiltalk.htm

Common useage of the term means "non-additive" or "non ashless dispersant" oil. (Mineral oil technically means oil refined from crude as opposed to other sources like vegetable, synthetic, etc.
By definition it also means "pure" ....meaning no additives.) I'll bet you knew that as well. Heh?

In any case, I did go to the site you suggested, and guess what they did? In their own words:
"Approved Aviation Oil: Approved Aviation Oil any brand name oil produced under the following specifications:

MIL-L-6082 or SAE J1966 for Mineral Grades
MIL-L-22851 or SAE J1899 for Ashless Dispersant Grades"

In any case, they also seem to agree with my former statement. Mineral grades seem to do better for break in than other types. And... they also use the term "mineral" to designate non-additive oils.

(But one of their other statements is completely wrong or at the least misleading. "NOTE: The advantage is quick pumping at start-up, performance identical to a higher viscosity oil at moderate temperatures and a thicker film at high temperature."
The incorrect/misleading part of that statement is that: Multiviscosity oils will NOT provide a "thicker film at high temperature" ...than the SAE grade indicated on the can/bottle.
Multiviscosity oils are tested at 100 degrees C. A 15W50 oil is actually a SAE 15 oil with viscosity improvers (additives) to make it behave at 100C similar to SAE 50 oil at 100C. As long as those VI's are not worn out/evaporated/broken down....it's fine. But when that breakdown inevitably occurs.... oil consumption will increase because the user is left with SAE 15 oil in the crankcase.) Most folks who have used multiviscosity oils have noticed that immediately after the oil change their oil consumption is rather low, but after several hours of operation.....Hey!...it's using oil again! And now you know why. The additives are history. (Another reason I generally prefer single-grade oils.)

"Mineral Oil: Oil separated from crude oil according to boiling points."

That is what wanted you to see..

Most folks think that mineral oil is some thing special.

It is any oil that is refind from crude.

Now let us discuss why we want a NON AD oil for brake in?

most old engines like my WARNER radial, has no oil filter, I want a NON AD oil because I want the hard particulate contamination to fall out of the oil as soon as it can..rather than be pumped back thru the bearings..

BUT

If your engine is equipped with an oil filter, you need the hard particulate contamination to be carried to the filter, and that is what AD oils do..

So it is an old wives tale that all engines need a NON detergent oil for brake in. AD oils do not lubricate any better than a NON detergent oil.

They just have the ability to carry dirt in suspension, and that is not good if you don't have a filter.

I had my engine OH'd about 4 years ago, both the cylinder mfr (ECI) & the OH'er recommended using Phillips XC20-50 for break-in. Since I normally used that stuff anyway, I did so-- broke in just fine. I do have the steel cylinders, I understand that the chrome (& other specially treated?) cylinders are often more of a problem to break in. BTW, I do have a spin-on filter.

Eric

hey Tom, that is the best explanation I have heard regarding the reason to either use or not use certain oil for break-in - thanks for some new brain cells.

as far as breaking in regimes - we have had good luck running Phillips 20W50 regular oil that we run in everything (not the break in mineral oil version), and running the engine hard. that means keep the ground time to a minimum (yes, you're going to have a couple of ground runs to check functions and leaks, keep them short), get it into the air and get cooling air over it. some guys I know even tape over the oil coolers on their ag planes to get the temps up, I don't go to such extremes. once you're up, run it at high cruise for 20-30 minutes, then start varying the power settings for 15-20 min at a time (add a couple inches, change rpm by 100, etc). Run it hard, keep angle of attack low for cooling air and enjoy the flight. After the first flight if all is well then run high cruise for the next few, but you should be Ok to go after the critical first flight.

if you have good enough instrumentation to see a change in the CHT, then once it comes down you probably have seated things. Change the oil after 10 hrs or so (filter too), since there are lots of things besides rings getting seated to one another in there and that means metal floating around in your oil.

I've used this method with success in our twins as well as the singles I used to work on when I was a mech first. If you're running some fancy stuff like 15W50 or Exxon, I'd run straight mineral oil for the break in just because it isn't as "good", you need some wear to occur.

my .02, works for us.

I disagree, Tom. While there are engine mfr's who state that non AD mineral oil is not required for break in,... the best way to break in an engine is to use exactly that: non-AD mineral oil. Non AD mineral oil is the old-standby for break in because it allows rapid wear/matching up of rings to cylinder walls. If that mating surface is not achieved early in the engine's operation, then when the cylinder walls take on their inevitable "glaze", then the opportunity is lost and you're left with an oil burner and/or re-attempt, usually by partial disassembly, re-honing, and new rings.
The reason it's "best" in my opinion is because 1- it does not contain any anti-wear additives and allows rapid wear to occur thereby quickly seating rings/cylinders and 2- it does not promote the re-circulation of break-in particulates during break-in. Filters do not remove all harmful break-in particulates. In fact, the most common filters are only partially successful in catching particulate smaller than 40 microns, and they allow most particles smaller than that to continue to circulate, just exactly like an oil-screen-only engine does. (Filters are good at catching/holding dirt, but not break in particulates. Don't believe? Then take a look at any filter that's been used in conjunction with magnets, after it's been cut open.)
If I agreed with your theory, Tom, then I'd have to wonder why so many round engine guys then switch to AD oils after break in. Don't they realize they're about to pick up all those particles and send them thru their new engine? (Anyway, while the new engine is being broken in, and while that non-AD oil is being furiously stirred by all the thrashing parts,... all the particulates are being kept in suspension and they are being circulated thru that engine as it breaks in....just like AD oil would. AD oil only keeps the stuff suspended for longer periods between engine runs. (And the stuff the AD was intended for is primarily lead from the fuel anyway....not metal shavings.)

The likely reason the Phillips 20W50 oil makes a successful break-in oil is because it's base is a thin SAE20 wt oil which, in a new engine, will not be as successful in keeping unpolished rings off of unpolished cylinder walls and therefore will allow breakin to occur. But it isn't the best viscosity for other new parts such as gears, bearings, etc. (BTW, Phillips also markets a multigrade mineral break-in oil as well, designates with a capital "M" in the grade nomenclature.)

Most engine rebuilders I know still insist on non AD mineral oil for break-in, despite the approval of other oils by the mfr's. They do it for a reason: It's more dependable as a break in oil. Just my opinion, too.