Subjective Cylinder Comparison ? Lycoming vs. ECI

Let me be clear - I have been a huge ECI fan ever since they began making replacement parts that challenged the design technology and quality of the Lycoming monopoly. Way back in the days before ECI and Superior, you bought your parts from Lycoming, and that was that ? and many of us complained about poor cylinder and valve cooling due to lousy parts finishing and antique metallurgy. With the advent of competition came, well?competition! And quality on all counts improved. Let?s forget, BTW, that they have ALL had AD?s, SB?s, recalls, and failures?.yes, they all have those?.).

Because I was an ECI fan, I was pleased when Mattituck built my RV-8 engine from ECI components, and the Cerminil Cylinders were, in my mind, a big plus due to their non-corrosive properties. Of course, I never dreamed I?d be flying the airplane five days a week so that corrosion just wasn?t going to be an issue, but I liked the idea. Mattituck did their usual excellent job of matching the various components for the engine, and it was a very smooth runner, even LOP (with a carb!). I was never, however, very satisfied with the oil consumption on the jugs ? the best ever was about 8.5 hours/quart, and I averaged about 5 - 6 hours per quart. I talked with Mattituck frequently over the years, and was told this was well within spec, and that we could re-ring and hone, but might very well end up at the same place.

Well time went on, and I kept using oil ? eventually, it got to a quart in four, just about the time I had 1400 hours on the engine, and I decided it was time to do the top. I have recounted this here earlier this year, so let?s just say that I went with Lycomings this time due to a number of reports of problems honing nickel cylinders, and customer service mis-steps on ECI?s part. The four new Lycoming (standard nitride) cylinders came from A.E.R.O. and have broken in nicely. With fifty hours on them, I can draw a few interesting (and somewhat subjective) observations between the old and the new:

1. Oil Consumption: Clearly, even though it is still stabilizing, the Lycomings are doing far better ? on the order of a quart in 9 or 10 hours right now.

2. Balance: The four ?random? jugs and pistons from Lycoming don?t seem to have changed the dynamic balance by any perceptible amount ? the engine is wonderfully smooth (except when I get it excessively lean and jugs start mis-firing of course).

3. CHT?s: The Lycomings are running about 20 degrees WARMER all the way around, and seem to heat up and cool down more quickly than the ECI?s. All are within normal limits, and the baffling is identical. (I had no cracks or damage to the baffling in 1400 hours ? simply amazing!)

4. Leaning: The carefully matched ECI?s from Mattituck did better than the random replacements from Lycoming. The four EGT?s don?t come together as nicely as I lean, and the engine won?t run quite as smooth when I get to peak or beyond ? therefore, I am not able to get as low of fuel flow numbers - probably on the order of .5 gph average at lower altitudes (better up high).

5. Oil temperatures: Seem to be running just a little bit cooler with the new jugs, now that the initial break-in has occurred.


Overall, I am happy with the new jugs, but a little sad to lose that beautiful smooth LOP capability ? we?re still getting LOP (as evidenced by the significant drop in CHT?s when you go over peak), just not as deep. I am curious to see how the engine will do on its first long cross-country to Oshkosh and back in a couple of weeks. I expect to see the oil consumption improve a little bit more, but we?ll see.


Paul

Oil consumption really has very little to do with how the engine is broken in and more to do with how the honing process is done at the factory. The RV-6 I fly has about 100 hours on ECI cylinders and it goes about 30 hours before a quart needs to be added. Lycoming and most engine shops use only one grit of honing stones for roughing and finishing which in my opinion is pretty stupid. No other engines have cylinders that are honed in this fashion anymore.

Very interesting comparison Paul!

honing

Rocketbob has hit the nail square on the head. Sometimes I just don't understand why things have to drag along in the aviation world.

Excellent info for comparison but it seems that the differences are two fold, different companies, and different cylinder finishes. I would be interested to see the comparison between different companies for similar cylinders (ECI vs Superior w/through hardened steel) or the same company with different cylinders (Through hardened steel vs Cermanil from ECI). Thanks for providing the data!

Very interesting! I wonder what all of the factors are in oil consumption. My Mattituck built ECI engine (delivered late 2007) uses about 1 qt in 30 hours. That value has been unchanged since break in. I've got about 350 hours on it now.

One thing that I forgot to include in this post is that it turns out I had delaminating rings - it was an issue that ECI knew about, but it apparently wasn't well publicized. When we took the jugs off, it was apparent that about half the ring/cylinder contact areas had delaminated, and I blame that for the high oil consumption over the years. What I find interesting is that the ECI's ran cooler CHT's than the Lycomings - consistently. All are within limits, just ... different.

Can you comment on the relative quality of the fins?

Dave

Makes sense. More heat transferred to the oil yielding lower CHT and higher OAT than the new jugs which may be shedding more heat through the head and less into the oil. If so, that should be kinder to your oil.

David Paule said:

Can you comment on the relative quality of the fins?

Dave

Click to expand...

The fin quality was good on both - it was something I checked as soon as I got the Lycomings because the reason I went with ECI "way back when " was Lycoming's reputation for lots of flashing between the fins around the spark plugs. Clearly, competition forced them to clean up their act - they are far better than what I had on my old Lycoming-powered Grumman in the late 90's.

Paul

Paul,
Did you say how many hours you have on the lycoming cylinders? I could infer 90 hours from your signature but this may not be so.
You are certainly in a unique position to make such a comparison but I suspect it may still be early days and at best you are seeing some trends. I will be interested in your ongoing observations.

My own cylinders (std) on my new Lycoming O-320 are at 90 hours right now.

I change the oil at 25 hours and have seen a small but progressive reduction in oil consumption throughout the 90 hours. (first 50 hours on mineral oil). The last 25 hours has less than a quart consumed - I fill with 7 quarts at oil change and now at the 25 hour mark the level is about .25" above the 6 quart mark. Previous 25 hours saw it drop to 6 quarts.

I have also observed what seems to have been a steady and continuing reduction in CHTs over the 90 hours - this is difficult to pin down precisely because the data is very variable. Initially I had great difficulty keeping temps below 400 climbing out, and 380s in cruise. Now it is better, perhaps by 20-25 degrees across the board. I record and compare CHTs over time normalizing the temps against the OAT. They seem to trend down over time.

Oil temperatures barely leave the minimums in winter.

Judging from comments I have read here my experience may not be so typical. My conclusion for now is that the cylinders continue to loosen progressively beyond the initial break in. Perhaps the choke on the Lycoming cylinders creates significant thermal transfer to the cylinders. Do the ECI cylinders have such a similar choke.

This one engine is my only experience and I find some of the observations I make a little confusing at times. It is very interesting to hear your experience especially with reference to the ECI cylinders.

Oops....somehow, my own editing removed the fact that I am at about 50 hours on the new jugs. Changes from here on out are slow and asymptotic to where I expect them to end up.

I agree with you Doug - I expect to see a little improvement as time goes on - and it might be that temps end up finishing about where they wee. What seems more noticeable is the rate at which the new jugs heat up and cool down - it's just interesting. After a period of loaded-up Acro (which keeps speeds down), temps rise to where I want to cool them down a bit, and this seems quicker with the Lycs. But as titled this - it is "subjective".

It will be interesting to see how things change on the trip to Oshkosh and back.

Paul

The oil consumption part of this discussion was a point I watched.

Back when Paul detailed the cylinder change in his prior thread, I have been accustom to oild burn in the "qt per 8-10hrs" range. I had not thought much of it with my O320 until Paul mentioned his high oil burn. I just had to call the builder of my RV-8. To confirm and he did - I burn less than a qt in 50 hours. I hope it stays that way.

Ironflight said:

4. Leaning: The carefully matched ECI?s from Mattituck did better than the random replacements from Lycoming. The four EGT?s don?t come together as nicely as I lean, and the engine won?t run quite as smooth when I get to peak or beyond ? therefore, I am not able to get as low of fuel flow numbers - probably on the order of .5 gph average at lower altitudes (better up high).

Click to expand...

Paul, interesting observations on leaning. Maybe incorrectly, I thought that these engines didn't respond significantly to flow balancing, but rather the lousy fuel distribution was a fundamental problem of an updraft intake system and the higher boiling fuel components condensing in the intake tracts, then the liquids randomly feeding. I've heard rumors of this phenomenon on tape, but haven't been able to track it down.
In any case, why this is so interesting to me, it seems to show there is hope for running carburated engines efficiently, rather than having cylinders all over the board. A before and after GAMI flow would bolster the argument. If matching cylinders lets me save gasoline, I'll pay extra. There are times- not infrequent when a pilot can't get lean enough to keep CHT's below 400F (due to flow imbalance) and we end up burning an extra 2-3 gallons an hour to get all the cylinders very rich. Those dollars add up fast with $6 a gallon juice.

Was anything changed on the ignition system? Just curious, since a good spark seems to be another large factor in our ability to run these cylinders on the lean side.

We changed to P-Mags several moths before the cylinder changes - the engine still ran quite smooth deeply LOP with the old cylinders, so that really doesn't factor into this subjective comparison. But I do lean towards the belief - with a very small sample size for data - that matching the components for flow DOES make a good bit of difference in how deeply you can get LOP.

Paul

Oil in cylinder can lower combustion temps

Paul-

Since you have a difference in oil consumption, the minor difference in temps may be related to oil lowering combustion temperatures.

This is something i learned from Jim Cavalero at Diamond Racing Products. They had their own proprietary piston ring package for just that reason. Diamond is a supplier to NASCAR engine builders.

Larry Tompkins
544WB RV-6A
W52 Battle Ground, WA

ECI cylinders

One thing that I would like others to know, ECI makes two different cylinders. The Cerminil that Paul used and a through hardened steel like Superior uses. Lycoming advertises that their nitrite cylinders are harder than the through hardened steel of their competitors.

I am presently running ECI through hardened steel cylinders on my O-320 RV-6. I now have 400 hours on those cylinders. After changing to AD oil, I would do an oil change and filter, add 7-quarts. After running the engine, it would read 6.25 quarts on the stick. I do not add any oil till it gets to 4 quarts on the stick. I have not added any oil between changes of 40 to 45 hour oil changes. Since the last oil change (~370 hours, I added a quart) I added a quart at 30 hours since change. That was the first quart that I have added between changes in the past 400 hours of operation. I am running 9:1 pistons.

The Superior cylinders started out using a quart every 25-hours and eventually went to 1 quart every 6-hours but there was 2,200 hours on them and the exhaust guides were worn out. The Superior through hardened steel cylinder at 2,200 hours still had the cross-hatch in the cylinder walls and they all measured standard new size including the choke. I was using 10:1 pistons with the Superior cylinders for last 1,900 hours. IMHO, the nitrite may be harder but the through hardened steel is hard enough for my flying.

IF I live in Huston where the humidity is high instead of California where there is almost no humidity, I would lean toward the Cerminil cylinders like he did unless I flew a lot.

I like Paul, will more than likely put NEW Lycoming cylinders from AERO on my 360 project engine that I have in my shop. I also would not hesitate to use ECI or Superior through hardened cylinders. I do not like CHROME cylinders.

Just my opinion and yes I know that the info may only be worth what you paid for it.