Steve Barnes
Well Known Member
I just completed a complete engine overhaul. I sent the cylinders out to a large well known cylinder rebuilder. I now have 32 hours since overhaul and all the bottom plugs have excessive oil on them. Some more than others.
This is the fourth engine engine that I have broke in. The first 3 ended up as they should. I used the recommended breakin procedure. The CHT's came down as they should after a few hours but was having fouled spark plugs and hard hot starts. As soon as I added full power on take off the plugs would clear up. First oil change is when I first found oily plugs. Cleaned the plugs changed oil again with the recommended mineral oil. I ran the engine hard for another 22 hours. The plugs weren't fouling as bad as before but was still having difficult hot starts. Drained oil and checked the plugs and all the bottom plugs were oily.
Should I continue to run hard with mineral oil?
Pull the cylinders off and send back to the cylinder rebuilder?
The cylinders are the original steel barrels as purchased from Lycoming 1200 hours ago.
The only thing I could think of is the rebuilder installed the wrong rings in the cylinders.
Any advice from you Lycoming experts would be much appreciated. Steve
This is the fourth engine engine that I have broke in. The first 3 ended up as they should. I used the recommended breakin procedure. The CHT's came down as they should after a few hours but was having fouled spark plugs and hard hot starts. As soon as I added full power on take off the plugs would clear up. First oil change is when I first found oily plugs. Cleaned the plugs changed oil again with the recommended mineral oil. I ran the engine hard for another 22 hours. The plugs weren't fouling as bad as before but was still having difficult hot starts. Drained oil and checked the plugs and all the bottom plugs were oily.
Should I continue to run hard with mineral oil?
Pull the cylinders off and send back to the cylinder rebuilder?
The cylinders are the original steel barrels as purchased from Lycoming 1200 hours ago.
The only thing I could think of is the rebuilder installed the wrong rings in the cylinders.
Any advice from you Lycoming experts would be much appreciated. Steve