Mister701 wrote:....If you decide to replace just one cylinder make it a nickel plated one. They break in faster. I've had a cylinder overhauled by a truly competent shop and the rings never did seat, even after 100 hours. Had it been nickel plated or chromed before re-assembly would it have worked better? I don't know. You might send out your cylinder cores to be chromed then do the re-assembly yourself but make sure you get the proper rings and piston for that particular kind of chrome. ....

I dunno about nickel, cerminil or whatever, but I've always heard that chrome cylnders were the toughest to break in. When I bought new cylinders for my old C170's C-145 at overhaul time, I got plain old steel. Broke in easy & worked out well. I think the advantage to chrome is that if the airplane sits a lot, they won't rust up as quick. And since my airplanes don't sit....

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Whee wrote:
Me overhauling my own cylinders isn't about saving money or doing things on the cheap, it is about gaining education on something I really enjoy.

Great comment.Taking things apart, and learning how a piece of equipment works gives me a better understanding of the design and engineering, as well as a healthy respect for maintenance. I've tinkered with outboards motors, tractors, boats, ham radios, chain saws, whatever. In so doing I have learned to appreciate what I can do and what I should not do. The knowledge gained allows me to better diagnose complex problems, and in fact to be able to often catch things early on before TSHTF.

It's interesting when you sort of half ass a repair because you don't have the right tools, diagnostic equipment, skill levels, or experience. I learn a lot from my shortcomings. I've half-assed a lot of lawn mowers repairs, antenna work (ham radio), but none of that is mission critical. I respect the fact that planes are way way different. I wouldn't mind taking things apart, I'd just never actually install it back for real time use. I'm speaking Experimental of course. I suppose if I had a LOT of experience, A&P, and a LOT of knowledge, I might feel differently, but I don't see that day coming anytime soon for me. YMMV.

Jon - great to hear you are onto a new engine and even looking at doing some core work on it yourself.

My only suggestion would be, there are many things to know when doing a cylinder job like this, which aren't written in any manual or SB. A lot of things which are passed on through A&P apprenticeship and building competency under those who learnt the hard way. I would suggest getting close supervision from an IA certified guy, someone who you trust.

For example, an IA who I trust told me of individual cylinder replacements that you need to do work to account for the different tolerances for parts of different ages / degrees or wear. This applied to the pushrods or rotator caps or something, I can't recall. But my point is, it's all beyond a lowly mechanical engineer like me! I would need to learn from one who knows.

whee wrote:I really appreciate you guys that responded. I totally get where you are coming from and agree for the most part. I'm not someone that likes being forced to rely on someone else for services especially when I think I have the ability to do it myself with just a little direction. These days it seems difficult to get the experienced guys to share their knowledge so often us younger guys have to reinvent the wheel. Because this will be a family plane reliability is top priority which is the main reason I'm not going to use the engine I currently have. However, I have no interest breaking in new cylinders and a new airplane at the same time. I've done that I I'll be surprised if that engine makes it half way to TBO before it needs a top overhaul. I'm planing to put together this engine, run it for a couple hundred hours then top it with all new cylinders. That will allow me to learn about cylinder work, break in the airplane and the cylinders separately, and ultimately end up with a reliable airplane.

But hey, all this is off topic...all I wanted to know was the basics or cylinder work and/or a document that gave me some direction.

Whee,

I still don't see how this plan makes any sense. You say you're looking for reliability, for your family's sake. What about for your own sake, while you're "breaking in" your airplane?

There is absolutely no rocket science to breaking in an aircraft engine properly. I've done so with ten or fifteen, and nary a problem. Just read up on it a bit, then do it. Breaking in an engine while working toward your phase 1 completion has been done thousands of times without issue, and in fact is likely the norm.

Consider all the time and effort you're putting into that airframe. Why wouldn't you want the absolute best engine up front on the very first flight of that airframe.

Maybe I just didn't understand your point. But, your logic doesn't make any sense to me at least.

Then again, that's why they call em experimental......

MTV

I understand what Jon's trying to do. I've thought about when I get to building a plane that I might try to find a solid but higher time engine similar to what I would ultimately put in for the initial test flying in order to minimize the variables.

I've also thought about just getting a new one built and paying the shop to break it in on a dyno.

Either way, MTV has a great point. A lot of guys have gotten to tbo and beyond after breaking in during phase 1 on new builds.

Jon, I haven't done any aircraft engine work ever so I don't know how valid my opinion is, but I'd have that new motor gone through by a reputable shop. And send them the heads from your old engine as well to see if they think any are good enough. I can't recall if you knew the history on the old engine, though.

It's a shame that today's aviation gasoline engine is so behind compared to our current automobile gasoline technology in regards to advancements when the opposite was true in the 20's and 30's. Thank you FAA.

CamTom12 wrote:I've thought about when I get to building a plane that I might try to find a solid but higher time engine similar to what I would ultimately put in for the initial test flying in order to minimize the variables.

I've also thought about just getting a new one built and paying the shop to break it in on a dyno.

We just flew the break-in hours off and logged the time. It was not an issue with good test flight planning.

We had a brand new set of 6 cylinders, which we needed to run in and break in. The cylinders and engine had never turned over before we started it. We just followed the instructions from the manufacturer. We pre-oiled the engine with hot oil, did one ground run of about 5 minutes to run in and prove everything worked (then did a bunch of trouble shooting...) - and immediately took it flying for break in the next week, with no more ground work, taxi testing, nothing to glaze the cylinders. T/O and straight to 75% power and hold it there for the first 20 hours or until the oil consumption stabilised. We planned all the regular lower power flight testing (circuits, deep stalls, slow flight etc) for after the break in period was complete.

This December we are approaching 400hrs TT and the second anniversary of that run in - so far the engine works perfectly, runs cool, makes almost no metal and consumes very little oil - no oil is added between changes.

It will take many years to see if we make TBO and beyond, but at this stage the borescope suggests everything is looking great.

CamTom12 wrote:.........I've also thought about just getting a new one built and paying the shop to break it in on a dyno.....

Engines shops which have test stands, test clubs, etc generally "run in" new engines for up to a couple hours. This doesn't negate the need for a proper "break-in", which is not the same thing. But a good run-in is the best start for a successful break-in.

I'd did the cylinders on my 520. The history before ECi...Ni ceramic coated the bores unknown. 394 hours when I bought the engine. The only tools I didn't have for a shade tree overhaul was the long neck valve seat grinder motor/drive. And the correct hone for the bore. Bought a black and decker unit off eBay. Bought adapters to make my Souix seat grinder set up work... Had the valve guide mandrels. Bought the hone set up from ECi. Ground valves were well within specifications. Bores measured at new narrow limit. Valve guides measured nearly new narrow limit. Haven't flown the engine yet.

Buy overhauled cylinders. They will save you money.



I prefer new. That way you know what you have. I think there is 700 on these. This is the third one I pulled off of this airplane in two years.

I came across Chuck Ney Enterprises's website and was reading about their cylinder overhaul process. I found it interesting that they purposefully remove the choke from the cylinder bore and claim 7-10% more hp and cooler head temperatures. I'm curious what you all think about that. I remember someone shared a story about a cylinder shop in CA, I think, that was using a automotive machine to bore aircraft cylinders. The FAA caught them and they went out of business.

whee wrote:Curious about the cylinder overhaul process. Anyone know of a SB or something that talks in detail about cylinder work?

Whee,

A good start after pulling a suspect jug would be Continental's SID97-4F "Cylinder Bore and Piston Fit Specifications." It details the tolerances/limits for various cylinder/piston measurements. With the correct tools, you can measure your cylinder and be able to better judge a suitable course of action (ie: re-honing, oversizing, plating, ...)


Chris