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So, my questioning is not inline with the most basic of building techniques such as in what is the difference in a dry tq value as apposed to a wet one but more about the specifics of building a Lycoming air cooled engine. Like?.when measuring and adjusting the piston ring end gap, must you take into consideration of the cold set measurement of the cylinder choke? And are the rings coefficient of thermal expansion different than the rule of thumb of .004 per one inch in bore diameter used in NA water cooled engines ect?
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Ring gap
Ring gap for the choke cylinders involves a minimum gap which is measured at top dead center. The gap is also measured near the bottom of the cylinders. So for the top ring you have two sets of limits, it is a relatively narrow range between the max gap near the bottom and the minimum gap at TDC.
This is all in the overhaul manual. |
Required reading
The correct Lycoming Overhaul manual & Lycoming Table of limits.The correct parts manual for your engine.The list of AD's & SB's that reads like the Bible as to who begot who,some parts have changed part numbers many multiples of times.The Sky Ranch engineering manual. Great book with enough engineer speak to make DH happy. Manifesto: A Revolutionary Approach to General Aviation Maintenance.Until Walt retires and writes the definitive bible on RV maintenance,this is a timely as it gets. Every year Lycoming runs seminars at Airventure,its not hand's on but they do assemble and dissemble an engine and cover the basics as well as questions,Jim Doebler also teaches the course in Williamsport and NO,I asked,you can't bring your parts and build your engine at the school.How great would that be! Check out Speed with Economy. Ken spent years streamlining&testing his Mustang II with impressive results.
http://www.aopa.org/News-and-Video/A...nt-%286%29 Sky Ranch engineering manual: Operation, failure, repair, piston aircraft engines Paperback – 1991 by John Schwaner (Author) Manifesto: A Revolutionary Approach to General Aviation Maintenance Paperback – July 7, 2014 by Mike Busch A&P/IA (Author) Speed with economy: Experimental aircraft performance improvement Paperback – 1994 by Kent Paser (Author) |
So if everyone had just one trick to share, I think that would be very informative here, i cannot find a better place for this info than right here, I have read the entire ( what is your day job thread ) I know there is some serious talent here......I think the Lycoming started off as a good idea and has only gotten better over time with problems being identified and a fixed so to speak. I am sold on the EFII so I will be looking at the other aspects of the build. What is the most ingenious mod, fix, bulletin you remember?
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Engine
Some engines use stretch rod bolts others use torq rod bolts.
Bob |
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http://www.lycoming.com/Portals/0/te...od%20Bolts.pdf But you need the latest parts manual and part supercedure list to find out what is applicable to your engine model and your connecting rod part number. The full library is here for $300 - http://www.tdata.com/products-all/ly...er-engines.asp |
I've been to Tulsa and the Barrett shop twice observing how they assemble engines and came away with the feeling it would take me a life time to do it as well as they do it, plus I don't have the equipment to for some of the process, like the device used to balance a crank shaft, which is FAA approved.
But then that's a perspective from not much experience re-building any engine beyond a lawn mower power plant. When one reads about the Wright Brothers and their friend building an engine to meet their needs from scratch, assembling one today from parts should not be too overwhelming, all it takes is a serious interest in doing it. The challenge will be getting spun up on all the things that did not work over the past 75 years of Lycoming history. There is an element of wanting to be able to do everything but sometimes there isn't enough time to do it all, from assembly of aircraft to painting to interior work to building an engine from parts, unless the learning process of it is more important than flying sooner than later. :) |
My last crazy big block I built, I watched my machine shop ( who specializes in race engines ) balance the rotating assembly within 1 10th of a gram, not rocket science here.
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