I have been running mineral oil for the first 10 hours and just did my first oil change. I haven’t really been burning any oil so far. After the change, W100 was put in and I started 10 hour cross country home. Was this a bad move and should I have stayed with Shell straight oil to complete the break in? I was under the impression that W 100 was straight mineral oil but I think I was wrong. I could always drain this tomorrow and just get a case of straight oil shipped over. Any advice would be greatly appreciated.

W100 is not mineral oil and I wouldn't use it for break-in in. I'd change it and go back to a straight 100 which is mineral oil.

Yup. Thanks for confirming my thoughts. Getting pretty shit guidance from the shop. Hopefully it’s didn’t disrupt the break in process with those few hours. I’ll swap it out but probably keep the same filter installed if that is alright.

I am breaking in my O520 UTS right now. Definitely want to stay with straight mineral oil for at least 25 hours - possibly 50. I changed the oil at 5 hours. I have about 12 hours on it now and will change it at 15. Then run another 25 hours and consider changing it to W80 at 40 hours. The majority of the break in occurs in the first 5 hours but I have read no harm in running mineral through 50 hours. I am fairly certain the rings seated in my engine. I am consuming zero oil - since the first oil change at 5 hours. Maybe that's why your IA suggested going to W100. I think it is best to err on the conservative side. Run the engine hard and burn lots of fuel and wait on the detergent oils.


Josh

IF the shop did a good job with honing the cylinders, your rings were 90% seated in the first hour. I used to run in engines at night on the test cell, with short stacks, and you could watch the flame change color usually in the first few minutes, and the oil burn would go down significantly right away, if it was going to go down. Don't baby it and and that'll do more for seating rings than anything else you can do...as long as it was honed right.
Mineral oil for the first run or two wont hurt anything, but if your oil use and such as stabilized, you're not going to gain appreciably.
John

Titan recommended breaking in on Philips 20W50 which is an AD oil. I've broken in two engines on it with zero issues, an O-320-A2B and an IO-360-A1A. I think the guidance to use mineral oil is way less important than keeping the ground run time minimal and the high power time HIGH power.

hardtailjohn wrote:IF the shop did a good job with honing the cylinders, your rings were 90% seated in the first hour. Don't baby it and and that'll do more for seating rings than anything else you can do...as long as it was honed right.
John

I agree with this. Big bore continentals break in very quickly if you run 85%-90% power.

Newer Lycomings, on the other hand can take many hours to stabilize. We have a Husky and its O-360 wasn't broken in until it had nearly 100 hours.

Waiting on my Remanufactured io550 from continental (supposed be this month, now they are saying December!). … being at 7000 feet AGL I May not be able to make 80% power, … I was thinking with a new motor it might make sense to circle above the airport for a bit, but now thinking best course of action might be to tuck tail and run to lower altitudes about half an hour away so I can make more power, … any alternate advice would be appreciated

Try to get them to run it on the bench before delivery. They say most of the seating is done in the shop if you pay them a little extra to dial it in there. I’m really really glad I did that. It was super hard to avoid taxing at a controlled airport, make sure OAT was reasonable, stay low enough to make 24”, fly low enough to make the hp but not over speed the airplane in turbulence. etc etc. The list goes on. My engine runs great now but I’m pretty sure I would have fucked it up if the whole break in was on my shoulders.

I just bought a Lycon XP470 and they ran it on the Dyno and and I never have seen and oil burn. I changed oil after 10 hrs and then put 20 more and about to put 20 more on mineral oil and never flew above 5400 for any length of time. Mostly 75% hp and really happy with the motor so far. CHT temps are at a delta of 23 at 2600 rpm and at 2500 rpm I get a little less delta. I don't think I need another 20 hrs but why not?