bucko Posted July 12, 2019 Report Share Posted July 12, 2019 Just replaced the #2 cylinder in my 1965 M20-E. Will follow the manufacturer's and my mechanic's break in guidelines, but was wondering how long it took for most of you who have done it already. Ranges vary greatly, it seems. Thanks. Quote Link to comment Share on other sites More sharing options...
moodychief Posted July 12, 2019 Report Share Posted July 12, 2019 I just did the #1 on my C model. It was probably broke in at 10 hours but I continued the break-in procedures until 18 hours. The most important thing stressed to me was stay at or below 5,000 and run the hell out of it until the oil consumption levels off and don’t use any additives while running mineral oil. Quote Link to comment Share on other sites More sharing options...
moodychief Posted July 12, 2019 Report Share Posted July 12, 2019 If you still live in Texas, a good low level run to Oshkosh and back home should do it!! 1 Quote Link to comment Share on other sites More sharing options...
slowflyin Posted July 12, 2019 Report Share Posted July 12, 2019 I've had it vary significantly for the complete break in. However, most times within the first couple of hours the rings will seat. Albeit not completely but enough to reduce most of the blow by. If you have engine monitoring you'll see the temps change a substantial amount. My preference is to continue the initial break in flight uninterrupted until I see the rings seat on any new jugs. Usually a race track above the field for a couple of hours. With a new engine or a complete top end it's interesting to watch them domino one after the other. That being said, the complete break in as indicated by normal temps and stabilized oil consumption can take much longer. Not sure what the average would be but if memory serves it think around 10-15 hours. I've heard some take much longer. Steel vs chrome..... 1 Quote Link to comment Share on other sites More sharing options...
ArtVandelay Posted July 12, 2019 Report Share Posted July 12, 2019 I’ve never done 1 cylinder, full overhaul took less than 10 hours, probably 2. I added a quart of oil after 1st flight (1.5+ hours), and maybe 1/2 quart after 5 hours and that’s all I needed until I changed oil around the 12 hour mark.Tom Quote Link to comment Share on other sites More sharing options...
mike_elliott Posted July 12, 2019 Report Share Posted July 12, 2019 Bucko, what kind of cylinder? Factory new or Cerminil? If cerminil, it will be broke in quickly. Once you notice the CHTs drop, you are good to go. If Factory new, run that sucker hard for 25 hrs. Formation fly at 160 kts for a while It is important to run it high MP, vary the rpms after the first few hrs some, but maintain high MP. 1 Quote Link to comment Share on other sites More sharing options...
bucko Posted July 12, 2019 Author Report Share Posted July 12, 2019 Thanks for all the great responses. Mike, it is a used cylinder that passed all parameters, with new rings, valve guides, etc, and refurbished by a well known shop in Texas. Hope it lives up to the hype. Going to Oshkosh? Bucko Quote Link to comment Share on other sites More sharing options...
mike_elliott Posted July 12, 2019 Report Share Posted July 12, 2019 Ill be there Mon and Tues, Bucko. Quote Link to comment Share on other sites More sharing options...
201er Posted July 13, 2019 Report Share Posted July 13, 2019 Recently I had my existing cylinder rehoned, new rings, and put back. Ran it full bore for the first hour ROP down low, then max power LOP for another 2. Flew 5 hours at 75% ROP. Then flew up to northern Canada and back for about another 25 hours at 65%. Didn’t see much difference in temps or oil consumption at any point. Still have the ridiculous quart ever 3 hours I had before they did the cylinder so I’m not sure if the break isn’t finished after 35 hours or if there’s a different unresolved problem. Quote Link to comment Share on other sites More sharing options...
M016576 Posted July 13, 2019 Report Share Posted July 13, 2019 (edited) 14 minutes ago, 201er said: Recently I had my existing cylinder rehoned, new rings, and put back. Ran it full bore for the first hour ROP down low, then max power LOP for another 2. Flew 5 hours at 75% ROP. Then flew up to northern Canada and back for about another 25 hours at 65%. Didn’t see much difference in temps or oil consumption at any point. Still have the ridiculous quart ever 3 hours I had before they did the cylinder so I’m not sure if the break isn’t finished after 35 hours or if there’s a different unresolved problem. Sounds like a different unresolved problem... any other cylinders showing bad compression? The only time I saw that much oil loss on my io-360 was when my cam spalled out... and that required an OH (predictably, the issue was resolved by the OH- went back to a QT every 12-15 hours). Try moving over to a conti... I never have to put oil in the IO-550A I’m running now between oil changes. it’s got a 12qt sump though.. so I guess that’s like having to add 6qts between oil changes on any other motor . Edited July 13, 2019 by M016576 Quote Link to comment Share on other sites More sharing options...
201er Posted July 13, 2019 Report Share Posted July 13, 2019 Just now, M016576 said: Sounds like a different unresolved problem... any other cylinders showing bad compression? The only time I saw that much oil loss on my io-360 was when my cam spalled out... and that required an OH (predictably, the issue was resolved by the OH- went back to a QT every 12-15 hours). Try moving over to a conti... I never have to put oil in the IO-550A I’m running now between oil changes. Of course... it’s got a 12qt sump though... It’s about 1000SMOH on a factory reman. Never used to put much oil in. Compressions are all good but there was trouble with the oil control ring. When they took it apart, said everything else looked great apart from the control ring. But 35 hours since getting that cylinder done, still about the same oil usage. 1 Quote Link to comment Share on other sites More sharing options...
M016576 Posted July 13, 2019 Report Share Posted July 13, 2019 (edited) 3 minutes ago, 201er said: It’s about 1000SMOH on a factory reman. Never used to put much oil in. Compressions are all good but there was trouble with the oil control ring. When they took it apart, said everything else looked great apart from the control ring. But 35 hours since getting that cylinder done, still about the same oil usage. Strange. Maybe the case is pressurizing some how and sending excess oil out the breather? i should note that I’m by no means a mechanic/A&P. Just guessing. edit: when I had serious blow by, and needed the overhaul, the oil went from fresh to BLACK in less than 5 hours, and needed a qt every 2-3 hours. If you’re not seeing black oil, but that honey colored-> brown oil, then my guess would be you’re losing the oil out the breather, as opposed to blow by/oil control ring issues. But again- reference my statement above... Edited July 13, 2019 by M016576 Quote Link to comment Share on other sites More sharing options...
John Mininger Posted July 13, 2019 Report Share Posted July 13, 2019 Hi Bucko, Mike Busch has a rather comprehensive webinar on this very subject. https://eaa.org/Videos/Webinars/Engines-and-Firewall-Forward/5999617443001 Seems there's a big difference in break-in times between TCM/ECI nickel coated cylinders and chromed cylinders. Chromed take much longer to break in. See you in Oshkosh. Quote Link to comment Share on other sites More sharing options...
Ragsf15e Posted July 13, 2019 Report Share Posted July 13, 2019 9 hours ago, John Mininger said: Hi Bucko, Mike Busch has a rather comprehensive webinar on this very subject. https://eaa.org/Videos/Webinars/Engines-and-Firewall-Forward/5999617443001 Seems there's a big difference in break-in times between TCM/ECI nickel coated cylinders and chromed cylinders. Chromed take much longer to break in. See you in Oshkosh. I broke in 2 chrome cylinders a couple years ago, followed the procedures pretty much exactly, but was hard to tell when it was done because temps were never high and oil consumption was same as before. Chrome cylinders already use a little more oil. I did high power for ~10-14 hours with the varied rpm and then just ran it normal. Good luck! Quote Link to comment Share on other sites More sharing options...
Ragsf15e Posted July 13, 2019 Report Share Posted July 13, 2019 16 hours ago, 201er said: It’s about 1000SMOH on a factory reman. Never used to put much oil in. Compressions are all good but there was trouble with the oil control ring. When they took it apart, said everything else looked great apart from the control ring. But 35 hours since getting that cylinder done, still about the same oil usage. What kind of cylinders? Sounds like your consumption changed which is worth figuring out, but chrome will consistently use more oil (probably exceptions to that rule too). Mike Busch has some articles on that too. My chrome cylinders are steady at 5.5-6 hours/qt. I just live with it and keep close tracking. Oil does get dirty quick too because of the blowby. Quote Link to comment Share on other sites More sharing options...
201er Posted July 13, 2019 Report Share Posted July 13, 2019 20 minutes ago, Ragsf15e said: What kind of cylinders? Sounds like your consumption changed which is worth figuring out, but chrome will consistently use more oil (probably exceptions to that rule too). Mike Busch has some articles on that too. My chrome cylinders are steady at 5.5-6 hours/qt. I just live with it and keep close tracking. Oil does get dirty quick too because of the blowby. Not Chrome. Just whatever Lycoming IO-360A3B6 factory reman would come with. Quote Link to comment Share on other sites More sharing options...
PT20J Posted July 13, 2019 Report Share Posted July 13, 2019 2 hours ago, 201er said: Not Chrome. Just whatever Lycoming IO-360A3B6 factory reman would come with. Nitrided steel 1 Quote Link to comment Share on other sites More sharing options...
N201MKTurbo Posted July 14, 2019 Report Share Posted July 14, 2019 OK, Here is the real dope! (I've been watching to much TCM) My wife's boss had an old M38 jeep in his back lot under a rotting tarp just rusting. I told him I could make it run (It had a thrown rod). I towed it home in November. Making a long story short, I got it running in march, new bearings, valves, 1 rod and two pistons. All new rings. After about 1000 miles of running it started to get rod knock, so I pulled the pan again and found the bad bearing. There is only so much you can do for a bad crankshaft with files and emery cloth from underneath. Actually, the journals that I filed and polished looked great! The point is I popped one of the pistons out and the rings were about half shiny, so they were about 1/2 broke in. That would be about 30 hours of flying. 1 Quote Link to comment Share on other sites More sharing options...
RobertGary1 Posted July 14, 2019 Report Share Posted July 14, 2019 It’s a slope not a ledge. The bulk of the breaking happens in the first 20 minutes. Lycoming runs the first hour if you buy from them so it’s already mostly broken in. I’d say total break in is about 100 hours. That’s when I no longer see any change in temp but it’s subtle at that point. -Robert 1 Quote Link to comment Share on other sites More sharing options...
Shadrach Posted July 15, 2019 Report Share Posted July 15, 2019 3 hours ago, RobertGary1 said: The bulk of the breaking happens in the first 20 minutes. ^^^^This. Lycoming factory cylinders should be so close to fully broken in by 5 hours as to make any further changes undetectable. No cylinder should have ring to cylinder wall contact at 100hrs. Quote Link to comment Share on other sites More sharing options...
mooneyflyer Posted July 15, 2019 Report Share Posted July 15, 2019 If you have an Engine Monitor, and you should, breaking in rings is simple. Your CHT will be hotter than normal. The minute your rings break-in, your CHT will drop to normal. It's as easy as that. Phil 1 Quote Link to comment Share on other sites More sharing options...
Seth Posted July 17, 2019 Report Share Posted July 17, 2019 Mike - there was a Mooney in Florida (documented here - another M20J - 1983 I believe) who had nearly all oil escape through a burned valve in a very short time. Wondering if you have a valve toward the end of life. Keep an eye on that oil level! Is it dropping significantly under the 6 or 4 qt mark (I forget the min needed)? Have you expirmaented with where it may settle? My plane needs 10-12. Spitsbergen out anything over 10.5. The Cirrus engines take 6-8 and spit anything out over 6.5 Lycomings are different but a qt every 3 hours concerns me. What does the oil analysis show? -Seth Quote Link to comment Share on other sites More sharing options...
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