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Old October 29th 18, 06:55 PM posted to rec.aviation.soaring
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Default Break-in for our newly overhauled towplane engine

On Monday, October 29, 2018 at 1:05:38 PM UTC-4, Retting wrote:
Seems a bit much......what needs to be accomplish is the ‘seating’ of the piston rings without glazing the cylinder walls, not being chromed.
To do this, ideally, is from the beginning, one run high idle for 1 min, shutdown and check for oil leak. Then, and here it gets fun, fill up with gas, start, quick mag check and takoff max power , then set 27/27 on the engine and fly around until you’re just about out of gas. Pay close attention to CHT stay within reason as dictated by your overhauler. The seating will be affirmed when oil consumption drops to nil and the CHT starts to stabilize somewhat lower (5hrs).
Because all this was done at high speed, better cooling, we now fly at normal tow power and speeds and observe CHT , oil consumption for a 1-2 hours and if all is well....begin trial towing monitoring the engine (10 tows).
The engine only cares about temp, and oil consumption is a clue to health.. Your after tow letdown procedure is the most important part of the tow.
I use the 20/15/10/ idle at 500’ increments of altitude method.
Oil change and filter inspection at the 5/10/25 hour mark initially. Oil with a camguard additive is high on my list.
You were advised ‘10-18’, meaning we’re waiting. For what? This should have been provided to you.
Seating of the pistons, oil consumption stabilized, CHTs happy.
Good news, weather is getting cooler for the break in. And you’re about to get tons of opinions and advice. Common sense will serve your club well.
Take it all to your overhaul guy and come up with a plan He’s looking out for no. 1.
After that.....tow away...just don’t let the engine know. 😜
R


I agree with R. After 5 hr if everything is right, we're towing. No need to run close to $1000 worth of gas through it and incur a lot of no revenue wear. Plus that is a lot of pilot time.
UH