Breaking In R-1340

[Chipfire]

Running in a zero time R-1340

SB1183 suggests using straight oil for 50 hours.

Do you use Grade 120 or 100?

[shrike]

Use which ever grade is appropriate for climactic and operating conditions. ie Use whatever grade you would if you weren't breaking it in.
The important part is to use a non-detergent oil. During break-in you'll be getting a lot of carbon and metal (normal). You want it to fall out of the oil in the sump rather than have it be suspended an recirculated. Your first oil change will look terrible.

The 50 hours is more a guideline than gospel. Check you compressions often and track your oil usage. When you compressions come up, and your oil usage goes down and stabilizes, it's broken in. That could be 15 hours, that could be 75 depending on operating regime.

[AG pilot]

I would ask your engine overhauler what he recommends.

Many years ago when I ran a R1340's on my spray plane, the overhauler was using Phillips 25W-60 on the test cell, and on his recommendation, I continued to use it. The engine was seated for the most part from the test cell run, and settled in very quickly. Usually an overhauled engine would use a pint/hr or a little more, which I was happy with. I did run a filter and changed the oil/filter every 50 to 75 hours.

The engines were never abused, but did not lead a low power life either. When I started a load and was heavy I would begin at 30"@ 2050 rpm. Coming back empty I would be down to 24" and 1850 rpm. I would usually overhaul about 1200 hours. I always had better luck with the last half of an overhaul than the first half!

Just my experiences. Good luck!