Just wanted to fish for the procedures and experiences out there on this subject.

Our overhauler and our mechanic both say no towing for 10-18 hours.... We can do this, of course, but we are eager to get back to towing as soon as we can.

Any experience or procedures out there that might get us towing sooner? But we will not compromise long term engine health.... Thanks in advance.

Cheers,
Jim

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

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

On Monday, October 29, 2018 at 10:04:34 AM UTC-4, wrote:
> Just wanted to fish for the procedures and experiences out there on this subject.
>
> Our overhauler and our mechanic both say no towing for 10-18 hours.... We can do this, of course, but we are eager to get back to towing as soon as we can.
>
> Any experience or procedures out there that might get us towing sooner? But we will not compromise long term engine health.... Thanks in advance.
>
> Cheers,
> Jim

Depends on who did the overhaul and the test procedures. One of the best in the business was Joe Sylvia in Miami, now long gone. Test procedure after rebuild was to run on a test platform built on the back of an old flatbed truck. Joe would run the engine until the rings were seated, that would indicated a temp drop to normal temp range. At that point the engine was removed from the test stand and installed on the airplane. His advice was to go fly, and yes the CHT and oil temp are the two important factors. This whole process should take about two hours or less of run time. Go TOW !