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Break-in prop - hoping to borrow

My Lycoming manual says to run 65-75% power for 50 hours or until oil consumption stabilizes. If I use a quart in 4 hours now how do I know it won't get better if I continue to run it hard?

Re: cylinder pressure and the notion that a cruise prop is beneficial. Does it matter if it's a 150hp or 160hp engine? 7.5-1 vs 8.5-1. What does that do to cylinder pressure? What about guys running 10-1? Lycoming doesn't differentiate in any publications I've found.

Why do they imply ashless dispersent oil is bad for a normally aspirated engine at break-in when they require it for turbocharged engine break-in?
 
Break an engine in at high power. Same reason an automotive engine needs to be loaded with the transmission. High pressure expands the rings allowing them to seat, otherwise you get a film of oil between the ring and the cylinder wall and it glazes over the cross hatch and will never break in. Turbo charged engines create more pressure and need AD oil to break in with the extra pressure.

I have installed 11.5 to 1 pistons/cylinders in an engine going to the world aerobatic contest along with several sets of 10.5 to 1s. The engine builder that provided the cylinders had us break them all in like everything else but was adamant that we monitor temps.

I like to know why but sometimes the science is over my head and just doing what an expert tells me works and I can spend my time worrying about something else.
 
Jeff,

I have a prop you could borrow. In Cleveland but could be coaxed to meet you in Michgan. Pretty sure you have my email.


Tim
 
Jeff,

I have a prop you could borrow. In Cleveland but could be coaxed to meet you in Michgan. Pretty sure you have my email.


Tim


Thanks, Tim. I appreciate the offer. I actually just got a PM from another dot orger that is very near to me and he has offered either a Borer 8244 or a 7458 cruise prop for me to use.

Thanks everyone for the offers and all the advice.

Jeff
 
...... a 7458 cruise prop for me to use.
Use this one. Throttle to the stop and go. I had a new 172 picked up in Wichita by a friend. I told him to push the throttle to the stop and fly it home. Only pull the throttle back when the rpm wanted to exceed the red line. The flight started with the throttle hard against the stop, by the time it arrived home it was well back from the stop. That engine always ran beautifully, until a jerk wrecked the airplane. I believe in the "run it hard" break in.
 
Glad to hear your engine will get spruced up during the winter, outside of the big flying season. You’ll be raring to go!

You could save some Avgas money by skipping the port & polish. I had it done on my last O-360 overhaul, but not on the current one. I can’t tell the difference. The aircraft weight makes more of a difference, IMHO.

I hope your overhaul goes smoothly. Just be sure to get a mechanic that knows their a$$ from a hole in the ground. I wish I had!


Sent from my iPhone using SuperCub.Org
 
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