View Full Version : Engine break in procedure C85 Stroker

05-09-2021, 11:59 AM
Hi all, my J3 is almost ready to get back in the skies. I have overhauled my C85 and done the stroker upgrade and was wondering what every one recommends as a engine break in procedure? I have previously broken in 0320's with a high power setting two hour run at close to sea level, I am a bit concerned that my standard J3 only has just over 2hrs endurance by my calculations and was wondering what everyone else had done?

bob turner
05-09-2021, 01:17 PM
I just flew mine normally, which is to say, the pattern. I am now at 250 hours with no mishaps save a piece of dirt under the relief valve at ten hours, and I burn a quart every twelve hours. I did use mineral oil for the first 25 hours.

05-09-2021, 01:33 PM


05-17-2021, 03:57 AM
Finally got her up and running! I flew around the area for a while at full throttle but the temps crept past the 200 degree mark on my oil temp gauge and I got worried so throttled back and cooled her down a bit. How hot would you be happy to let the oil get and for how long?


05-17-2021, 05:13 AM
See NOTE 1: https://rgl.faa.gov/Regulatory_and_Guidance_Library/rgMakeModel.nsf/0/73e923a0d5faef7e8525670e004526a4/$FILE/E-233.pdf

Oil temperature maximum limit is 225F. The temperature is likely to come down a bit after the engine is broken in.

This is a good article on the subject: https://generalaviationnews.com/2018/03/18/best-oil-temperature-engine/

05-17-2021, 05:49 AM
The trick is to run it hard enough to break the rings in, but not too hard that you overheat the engine and glaze the cylinders if they are chrome.

05-17-2021, 08:49 AM
Thanks very much!

05-18-2021, 09:13 PM
Look for a Lycoming SB on breaking in engines. They give you a complete program on breaking in.

05-18-2021, 09:18 PM
Service instruction 1427C engine break in from Lycoming

bob turner
05-19-2021, 12:59 AM
Continental says the green arc goes to 225, and you can operate there without damage. Why it gets that hot might be a different story.
Why would a Lycoming break-in procedure be better than Continental? Smarter engineers? More experience?

05-19-2021, 09:14 AM
Thanks Guys, I appreciate the help

Crash, Jr.
05-19-2021, 10:12 AM
Oil temperature maximum limit is 225F. The temperature is likely to come down a bit after the engine is broken in.

My engine must be really broken in since it won't ever get above 140 degrees oil temp. I'm always amazed to see a J3 that actually makes good oil temp.

bob turner
05-19-2021, 10:25 AM
I am running three, and fly others. On a 70 degree day I expect around 180 degrees on what appear to be good gauges. When it hits 100 I expect 210 on the gauge.