How do I properly seat the #4 cylinder after I replace it?

Jmason · #1 10-15-2018, 07:53 AM

I recently had to replace my #4 cylinder because the exhaust valve stuck and now I need to begging the process of breaking it in and seating the cylinder. Does anyone have any best practices and recommendations for me? I have heard that it can take anywhere from 4-35 hours for the cylinder to stat properly and for the temps to come back down. Looking for advice and recommendations.

Freemasm · #2 10-15-2018, 08:07 AM

Assume you're talking about ring seating. Lycoming engine? Run mineral oil until oil consumption until stabilizes. Should be 5 to 50 hours IIRC, the SI. Keep ground operation to a minimum as excessive barrel heat will cause the oil to form a glaze on the cylinder wall. This will most assuredly prevent the rings from ever seating without cylinder removal, re-honing, etc. Best of luck, Sir.

Robert Anglin · #3 10-15-2018, 08:26 AM

We learned from the guys at E.C.I. that they used Phillips 20-50 XC, I think it is in all their engines all the time. It is a mineral base for break-in and is used right through the break-in and on to full T.B.O.. We tried this on a few engines and found that it works just as advertised. I don't mined adding a quart of Aeroshell 100 from time to time while not breaking in a new cylinder and out on the road someplace wear the 20W-50 XC is not around. This may start a few to get upset but we have found the hard way that mixing a few quarts of different brands of oil has never hurt as long as it is good oil made to spec.
Just an idea for your thought. Yours, R.E.A. III # 80888

tim2542 · #4 10-15-2018, 09:23 AM

I also have used Phillips XC/50 3 times now with good luck, break in and after, but I?d go with the mfr or rebuilder recommendation to preserve any warrenty. The basic rules are keep ground runs to a minimum, fly at lower altitudes and keep the power up around 75%, and whatever you do keep the cht?s down. Glazing can?t happen under 400, maybe higher but try and keep it under that. Keep in mind we instrument the top of the cylinder, so we don?t know the barrel temps. My opinion the break in is mostly over by first flight, but follow the rules for at least 10-15 hrs.
Good luck
Tim Andres

n18pf · #5 10-15-2018, 01:26 PM

I just replaced all 4 of my cylinders - first flight was today. I used Millennium cylinders so I am following their instructions at the bottom of this page:
http://www.superiorairparts.com/millennium-cylinders/

Good luck with yours. I flew for 1.5 hours and have pretty good CHT numbers, but I'm going to continue with their procedure for another 5-10 hours.

I'm using Phillips Type M mineral oil for the first 25 hours or so, then I'll switch back to XC.

lr172 · #6 10-15-2018, 01:55 PM

Quote:

Originally Posted by n18pf

I just replaced all 4 of my cylinders - first flight was today. I used Millennium cylinders so I am following their instructions at the bottom of this page:
http://www.superiorairparts.com/millennium-cylinders/

Good luck with yours. I flew for 1.5 hours and have pretty good CHT numbers, but I'm going to continue with their procedure for another 5-10 hours.

I'm using Phillips Type M mineral oil for the first 25 hours or so, then I'll switch back to XC.

Did you see a drop in CHTs/? If so, how long into your flight?

Larry

n18pf · #7 10-15-2018, 03:24 PM

I noticed some drop within the first hour, but I don't have any hard data for you. I forgot my laptop (duh!), so I haven't had a chance to download the data from the engine monitor. I'll try to get it done tomorrow and let you know. Sorry!

n18pf · #8 10-16-2018, 12:38 PM

I pulled the data from my Dynon and plotted CHTs over time. It took a while to filter out the unneeded data, but I finally got down to the flight I was interested in.

I saw a temperature drop in all 4 CHTs within 15 minutes of about 25 degrees. It didn't seem to last long because they all pretty quickly recovered to the 360 degree range (no change in MP or RPM). I saw another small drop about 50 minutes into the flight of about 5 degrees. But overall, after about 20 minutes everything seemed to be fairly stable.

The whole flight only lasted about 1.5 hours, so I don't know if that is enough time to really draw any conclusions. I intend to continue the break-in process for another 10-20 hours. But right now I am very happy with the temperatures I have!

I hope that helps.

Jmason · #9 10-16-2018, 04:51 PM

This is great information. I am 20+ hours into the replacement of the #4 Cyl and i'm still in the 410 range. I have a feeling that it glazed over. I overhauled the original cyl so i'm thinking about putting it back on and trying it again. Thanks for all the advice.

lr172 · #10 10-16-2018, 09:32 PM

Quote:

Originally Posted by n18pf

I pulled the data from my Dynon and plotted CHTs over time. It took a while to filter out the unneeded data, but I finally got down to the flight I was interested in.

I saw a temperature drop in all 4 CHTs within 15 minutes of about 25 degrees. It didn't seem to last long because they all pretty quickly recovered to the 360 degree range (no change in MP or RPM). I saw another small drop about 50 minutes into the flight of about 5 degrees. But overall, after about 20 minutes everything seemed to be fairly stable.

The whole flight only lasted about 1.5 hours, so I don't know if that is enough time to really draw any conclusions. I intend to continue the break-in process for another 10-20 hours. But right now I am very happy with the temperatures I have!

I hope that helps.

Thanks so much for digging that up. I am using Superior cyl's on my 540 build, in part due to the plateau honing and quick break in. I will be breaking in on the ground with a cooling shroud and was trying to gauge how much time I need for good ring seating.

Larry