Break-in Procedure

-The back story-

   ~After 35hrs had been logged on my engine, I was beginning to notice a little blow-by coming from the crankcase breather tube. This blow-by seemed to be slowly increasing with time. By the time 100hrs rolled around, I needed to investigate why this was, even though I knew that some blow-by in piston engines is quite normal. I performed a borescope on all 6 cylinders and found cylinder #6 had some serious scuffing. After contacting UL Power about the findings, I was told this was normal and not to be worried, but everything else I was hearing from the canard community was the opposite. I finally worked up the courage and pulled the cylinder to inspect it. Upon seeing the wear patterns on the cylinder wall, along with a very obvious layer of glaze, I decided to pull all the cylinders and have them honed. Honing also meant new rings, so this was major surgery in my mind. After pulling the heads and cylinders off the engine, I also noticed a good layer of hardened carbon on the pistons around the heads. Removing the carbon wouldn't be fun, but I had Berryman B12 Chemtool to thank for the softening soak. So now, my cylinders were left in the hands of a trusted local machine shop to hone, while I was scrubbing away at all that black death. Thankfully, the honing came out great and the cylinders looked factory new, ready for break-in. A few weeks later I had clean pistons, all new rings, and honed cylinders all put back together again and an engine that was ready for fuel. Now here is where common sense and traditional wisdom kicked in. Every piston engine needs a proper break-in if peak performance and long life are going to be expected, and UL power engines are no exception to the rule. Back when I first fired up my engine, I was committed to following UL Power's advise religiously, however, I was shocked to see an almost non-existent break-in procedure in the UL Power engine manuals. For example, as of this write-up, the most current operating manual for the UL Power 520is states on page 11:

"To run in a new engine, it is recommended to limit the speed at 3000 rpm for the first 5 hours.

That's it? Yep. No other break-in procedure is given. Furthermore, the manual also states on page 15:

"Do not use special brake-in oils as these don't guarantee the same quality of lubrication to crankshaft, camshaft and tappets."

   So now, knowing UL Power only recommends a minimum of semi-synthetic oil if not a full synthetic oil (page 15), it now became increasingly clear why I had glazed over cylinder walls which led to blow-by. In fact, before pulling my cylinders, only 3 of the 6 passed a leak down test. With all that said, I was now faced with the decision to repeat my first actions and follow the manual, or listen to conventional wisdom and break-in this engine the way I knew it needed to be done. Of course I chose the later. 
-Doing it right this time-

My new plan for break-in was to follow the procedure given by ECI, to the letter and allI will say is WOW. Using the ECI procedure was exactly what this engine needed. After only 3 hours of break-in, every cylinder passed compression with less than a 5% leak-down and my prop was going to need a for sale sign in exchange for a bigger prop. I was 3 hrs into a 50 hr break-in period and already my engine was performing better than it ever had. Over the next 25hrs, oil consumption and engine temps were both steadily going down. My most recent flight was 5.5hrs long and at the end I had only used 4oz of oil. 
   With all that said, I must recommend the use of the ECI break-in procedure for all new UL Power engines. Contrary to what UL Power states, These engines are no different than any other engine in that they need and deserve a proper break-in.

For more information on the ECI break-in procedure, visit:

Cylinder #6 borescope

Post Honing

Chem Dip clean

Coming together


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