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Piston Ring Differences

scubber

scubber

SPONSOR
Delevan,NY
Looking for your experience & is this normal ? New ECI rings going on Nickel jugs-standard, 0290D2 eng., from ECI kit CN201, provided by cylinder overhaul facility. Puzzled over the difference in size ("open" end gap) between the top ring ECI #AEL13883CCA, and 2nd compression ring LW-13883 (Lycoming no.). Concern centered on LW ring. The no. matches parts book as well as ring nos. match list on ring set. LW ring was a bear to get in cylinder to end gap. When rings put on piston (#69841-match manual), LW ring almost falls off. About 20 thousands taken off each ring for proper end gap. ECI contacted and shown ring overlay pic (hopefully attached to this thread). They said all parts are proper. The concern is that if rings can fail from stress, i.e. being opened too much during installation, that LW will be under extreme stress when compressed in the cylinder. Have 2 jugs on, going no further until some additional info, and past experiences from others. My IA has never seen such a difference. Thanks, as always. Larry Ciszak
 

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Don't rely too much on what ECI tells you, They sent me a 0-200 case back where the two sides did not match. The bearing surfaces did not even line up. They said that was impossible and that it couldn't happen. I sent the case back and received what looked like a new case, but they said there was no problem with the one I sent back. The ring in the pict is for a bigger piston.
 
The nickel cylinders should have a moly top ring, but every set I have ever seen were exactly the same size out of the box. If a ring has a different diameter out of the box, I would be very suspicious as well. Something looks really wrong to me. I know O-290 pistons and rings are hard to find. Makes me wonder if they aren't trying to substitute with something else.

-CubBuilder
 
The ring is NOT a bigger diameter; just has the gap open way too much.

My thought is it IS actually the correct Lycoming ring.

However; somewhere in the manufacturing process the " Static Ring Gap"

was formed too large.

Cast Iron doesn't bend so possibly if the ring was cut while hot to create the

gap it may have become distorted.
 
Thanks for your replys. Mikes' report will be on hold until I get a little more info (Thanks Mike). Was hoping someone recently had used ECI's ring kit on nickel cylinders. I have learned that the ring in question is a Lycoming ring. ("LW" is their part designation). The parts manual shows that number as both #1 & #2 rings for standard steel cylinders. Spoke with Lycoming today and they concurred that is their ring, but couldn't comment on the fact in nearly falls of the proper piston. I mentioned that they should have ring design specs in the archives to compare to, as well as inventory. They do not make a ring kit for nickel cyls. Sent them the above pic as well as several showing different actual measurements. I will keep you posted. Larry C.
 
I agree with the above post in that SOMEBODY must have put rings on an 0290D, or 0290D2, (D2B, D2C). For standard steel cylinders, the parts book lists the same Lycoming Nos. for all those models as my rings in question (LW13883). If anyone has access to the "Short Wing Site", it would be great if you could post there. Should be several Pacers and unmodified Tri-Pacers out there still running these engines. Still awaiting a reply from Lycoming. I presume someone is running the reply past The Legal Dept., in recognition of the current "legal environment". Thanks again. Larry C.
 
scubber said:
I agree with the above post in that SOMEBODY must have put rings on an 0290D, or 0290D2, (D2B, D2C). For standard steel cylinders, the parts book lists the same Lycoming Nos. for all those models as my rings in question (LW13883). If anyone has access to the "Short Wing Site", it would be great if you could post there. Should be several Pacers and unmodified Tri-Pacers out there still running these engines. Still awaiting a reply from Lycoming. I presume someone is running the reply past The Legal Dept., in recognition of the current "legal environment". Thanks again. Larry C.
Click to expand...

Here is a picture of a new O290-D2 piston with rings from an engine I did a few years ago. Note that the properly fitted rings are not about to fall off the piston, which is why I referred to the diameter of the ring in question as being larger in my previous post. When I have installed rings in an ECI nickel cylinder, the moly and iron ring sizes were identical in diameter in their uncompressed state.

-CubBuilder

O290 Piston.webp
 

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Ibuilt an O-290-D2 several years ago and don't remember any problems other than the center main wasn't bored to proper size. Never did figure out how the case shop managed that one. I can't remember if it had chrome or steel cylinders.

I would be inclined to get another set of rings and see if they are the same.

You can sign up on ShortWingPipers.org and post. Just hit Forum Registration here: http://www.shortwingpipers.org/join.html
Doesn't cost anything. there was a recent problem with a fresh overhaul using excessive oil and low compression. Turned out a ring broke.
 
Larry,
The Free Gap should be the same for all the rings. If this one is the same size as the others when compressed, and the others are the correct size, then this one was most likely "sprung" in handling, packaging or something. While I doubt the ring would fail in use, it would put extra inherent pressure on the cylinder walls than the other rings. I would suggest replacing the ring for peace of mind. It'll be interesting to see what Lycoming has to say. You could also check with Hastings and question them about free gap and such (might not want to mention anything about airplanes and aviation in your conversation). The people at Hastings have always been very friendly and helpful to me when I called.
Tom
 
Check Six

Note this is not 1 ring but it is 1 ring in EACH Blister Pack. Total 4.

My opinion is Cast Iron doesn't stretch much but will break.

This is the way it is made.
 
Copy P.o.P. Thanks.
It'll be interesting to see what Lycoming has to say, if they reply. Might have something to do with inherent pressure on the scraper ring, but as I recall, both rings on my -D2 pistons had the same free gap.
Tom
 
It took a while to get someone to look into my situation. But, I would like you all to know what they said. They confirmed the "LW" ring was indeed their ring. Each of the -2- people I spoke with had no idea ECI was including their ring in the ECI kit. Lycoming confirmed that the part no and measurements (static) that I provided were consistent with spec as well as present ring inventory (144 rings in stock). I was told this ring is cast iron and has a larger free gap due to the very hard cylinder bore (chrome/nickel) to aide "break-in". Confirmed Lycoming does NOT make a complete ring set for Nickel Cylinders. Was told that the "free gap" of a ring for standard steel cylinder would be more like what is shown in my pic of the ECI top ring. Rings for std. steel are harder than the bore and don't require extra pressure for break-in. Thus the reason rings as in pic above, and other of your experience, are smaller in free end gap. And, they don't look like they are going to fall off the piston. In summary, I was told all appeared satisfactory, and to install per manual. I asked for this in a confirming email . .and am still awaiting the same, after a week. Keep me posted folks of anything you experience to the same, or contrary. Here's hoping . .. Thanks. Larry C.
 
Thanks for the update, Larry. Understand they want more inherent pressure to aid "break in". Was wondering if that might've had something to do with it. Standing by to see if they'll actually send you an email confirmation.:pop:

Tom
 
That's really interesting. I built an O-470 with ECI Nickel Cylinders 3 or 4 years ago. I didn't note any difference in spring pressure or open end gap between the Moly top ring and the iron second compression ring. Not to say that what they are telling you is wrong. Only that it is contrary to the experience I've had with the one engine I have built with Nickel cylinders. However, based on my experience, I will also say that you are likely to really like the Nickel Cylinders. They broke in quickly and easily and a few hundred hours down the road now hold good compressions and use very little oil.

-Cubbuilder
 
Cubbuilder,
Thanks for your input. It was way up at the top of this tread, but my problems started with only 225 hrs. on ECI nickel finish cylinders. All -4- failed. And, it is my, as well as my IA's intention to minimize it every happening again. By chance, would it be possible to find any of your logbook or invoice info that states the ring part nos. or the ECI kit no ? It would be interesting to see if your second (cast) ring is a Lycoming ring. It is also interesting that the -2- rings that were found broken in my case, were ECI top compression rings and not the "larger" cast rings. I'm also interested in history on anyone experiencing a failure on all -4- cyls. (even on std. steel cyls), at the same time. Thanks everybody. Larry C.
 
I called a friend that has some old stock Lycoming O-290 rings. He says both compression rings show a 3/4" free gap with the rings sitting out on the table.

-CubBuilder
 
Cub Builder, thanks for the "personal", I will call your friend tomorrow to see if we are talking the same part no.

As for Lycoming and customer service . . . . .I sent a "reminder" email yesterday that I am awaiting confirmation, that the Lycoming rings are indeed correct, and to confirm my conversation w/them LAST week. Got nothing today. My initial contact with them was 12/20/12. Larry C.
 
Finally got a written response from Lycoming. But, all they put in writing was that the subject rings were the same as what they have in stock. Didn't put anything else in writing. It is times like this that tort reform would be a GOOD thing.
Larry C.
 
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