Seat engine rings

[Warren Janzen]

Hello, I have a 0-360 engine that is consuming some oil. ~1/3 to 1/2 qt per hour. Been working on ifr approaches. With it running full rich so much I wonder if I need to seat in my rings some. Is it possible to tie down the tail and chalk the wheels and run it hard on the ground for a few minutes? If so how long and what power settings and prop setting? I don't want to over heat the engine. Don't have time for a 25 hour long cross country trip to seat them in. Any tips appreciated.
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[Ed Asmus]

Hmmmm.....In my opinion, running the engine hard on the ground for any period of time should be avoided unless absolutely necessary to trouble shoot a problem and then kept to an absolute minimum. Reasons being, cooling issues, sucking debris through the prop, etc... A few questions are: is this a recently overhauled engine or recent top end work? If this is the case, the engine should have been flown at high power settings to break in the cylinders. There are specific procedures to break in cylinders and none of them that I am aware involve low power sustained flight such as during approaches. Is this a new development/change in engine behavior? If this is the case, then a problem likely exists. Any particular reason you do not lean while shooting approaches?

Comments: Though the oil consumption would be considered high, I believe it does not exceed Lycoming's maximum consumption which I think is a quart in two hours (verification needed of this comment). Leaning is always a good idea and though I realize it can increase your workload during approaches, the mixture only needs to be rich during the missed approach (assuming within a couple thousand feet of sea level, if you're in the high country, full rich would likely not be appropriate even then.) My opinion is your mixture being full rich is not the likely cause of the oil consumption however I'm no expert. More information is needed to determine if a problem exists.

[Warren Janzen]

Thanks for the reply. The engine has about 1300 hours on it. Couple of cylinders have been pulled and honed back in 2009. In 20 hours of flying I've added about 7 quarts. That is .35 quarts per hour. Thought I might put some Mineral Oil in it next oil change just to see if I can get the rings to seat back in. As a IFR student, doing as much of the landing checklist before the procedure turn etc causes me to run full rich for a longer period of time each approach. Been chasing oil leaks, have them mostly fixed, just looking to find the consumption issues. Have a little blow by it seems. I have had others recommend against not running it on the ground for debris. I'll lean it out and do a little longer trip in it. Thanks.

[Pat Elliott]

I'll bet you've broken an oil control ring. rings don't become un-seated.

[Alan Cheak]

Running the engine hard on the ground is the dumbest idea I've heard. You cannot break an engine that way. As I recall 1/3 of a qt per hour is the max oil consumption for a O540 engine. Not sure what the max oil consumption of the O360 engine is. When my engine, an O540 was doing this, I did an oil change and cut open the filter. To my horror there was enough aluminum flakes to cover the palm of my hand. The culprit was a piston plug that was disintegrating in the cylinder and also had begun to ream a hole in the side of the piston where the wrist pin connected to the piston plug. My mechanic said we needed to pull the cylinders to see what else was happening. Doing that on the last cylinder that we pulled parts of the ring came out in chunks. So that's two cylinders that were bad. I did not have the money to overhaul the engine so I elected to to a top to all of the cylinders. I could have just replaced the two cylinders and put in new rings on all of the cylinders but being new to aircraft ownership I at least wanted to start with somewhat of a clean slate.

Warren you need to have a mechanic look at your engine. You cannot add a little MMO to fix what is clearly something wrong internally. Hey don't feel bad I have an engine that is now beyond TBO so I too have been looking to put a reman in my plane. Good luck.

Alan