Replacement Normally Aspirated Cylinder Discussion

mondtster said:
I believe the high loads on the cam/lifter interface plus the oil selection and lube system design cause more of the problems than anything else. I’ve torn down engines that have sat in unfavorable conditions for extended periods of time, fully expecting the cam and lifters to be terrible and they were fine. I suspect rust gets blamed for everything because people don’t go looking for the problem until it is too late and by that point in time it can be nearly impossible to determine the real cause of the problem.
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Yes, a lot of people blame environmental conditions for internal corrosion, and then go and ground-run the thing and ruin it. A few years ago on this forum we did some calculations as to how much volume there is in a crankcase, how much air would be moving in and out in the most extreme temperature swings between day and night, and how much moisture could be carried in there, if the air was fully saturated, over the period of a couple of years. It would be a few droplets.

All one needs to do is take that airplane first thing in the morning, run it up to warm it for an oil change and 50-hour inspection, then take off the rocker covers and see the water laying in the rocker box. Note all the rust on the inside of that steel rocker cover, too. That's on an airplane that spends every night in a heated hangar, after flying hard all day. I saw it too many times.
 
When removed, the cylinders all looked excellent. Took ‘em to a repair center that does lots of cylinder work and they said that they are nickel cylinders. Awaiting their verdict.
 
Well, this is definitely an interesting turn in the thread given the original thread title:

As it turns out, Superior cylinders aren’t available for this engine and Lycoming cylinders are near impossible to buy right now. Fortunately the cylinder overhaul shop says that these cylinders have a few mandatory parts replacements, a guide and the keepers I think, but they will be determined as overhauled when they are completed.

Lots of great discussion and feedback along the way though. I appreciate all the comments, advice and input. I am now busy sourcing parts and machine work. Trying to find the DLC tappets along with everything else.

I will follow up with a report of the results after it’s together annd again after its flown a few hours.

As it turns out I was unable to make a cylinder selection. Circumstances made it for me.
 
Got a call from the machine shop about my crankshaft today. It’s gonna be 7 weeks and $1200.
 
So what’s the deal with cylinder supply? I talked with someone this week who’s also having difficulty finding cylinders. I’m in the process of completing the purchase of another plane and might end up having to do a top because of previous owners decision to go cheap during major OH.
It’s a IO 520 that I’m dealing with.
 
Jdm said:
So what’s the deal with cylinder supply? I talked with someone this week who’s also having difficulty finding cylinders.
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That’s a common occurrence with angle valve Lycoming cylinders. Even worse if they’re narrow deck. We waited over a year for Lycoming to make a set once and ended up canceling the order before they materialized.

In my opinion, you had better hope what you have is repairable when dealing with these Lycomings at overhaul time unless you want a factory engine.
 
I’m waiting on my cylinders from my rebuilder. They have sent them out for test of the nickel. If any of them fail I’m really screwed. They seem to believe that all will be well and that I have nothing to worry about, but we will see. Thankfully they’re wide deck so I have a chance of coming up with something.
 
As a follow up, I picked up my cylinders from the cylinder shop last week. They had sent them out to have the nickel tested and certified. They called them low time cylinders, apparently based on their measurement and inspection. They are quite pleased with them and they will be zero time overhaul. I am fortunate that these cylinders rebuilt so well. Finding new replacements would have added lots of time to the project.

I expect them to be running the engine this morning. We might have low ceilings that will prevent flying for test and break in. I think the last time I flew it was January. I did the vast majority of parts sourcing and leg work for this overhaul myself and it has been a long, rocky road.
 
Nice job. Take the bad weather day to review the break-in procedure. Come up with a solid plan of action. Think about the details of where and how you intend to accomplish the break-in flights.
 
Good suggestion. I did the same thing on my freshly rebuilt Cessna engine a few months ago. It now has almost 50 hours. I will review between now and when I put on the headset.

Along the same lines, how many hours of test flying are recommended before venturing off on a trip with passengers?
 
MBDiagMan said:
Good suggestion. I did the same thing on my freshly rebuilt Cessna engine a few months ago. It now has almost 50 hours. I will review between now and when I put on the headset.

Along the same lines, how many hours of test flying are recommended before venturing off on a trip with passengers?
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2 rebuilt/overhaul engines at the same time?!
 
Well, not exactly the same time. One was complete about the time the other began. At least I haven’t been without something to fly.

My flying budget has taken a hit this year.
 
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