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

I really enjoy engine work and would like to do as much of the work on my engine as I can. I've found another TCM IO-360 to buy, thanks Hotrod180, but it needs a new cylinder. I have the six that were on the engine I currently have and I think some of them are useable. I'd really like to prepare the cylinders for installation myself but don't know the airplane specifics. Check clearance, hone, new rings and reinstall? I've looked for a TCM service bulletin but haven't found anything.

Also, I have one cylinder that isn't any good and I thought it would be cool to tear it all apart including unscrewing the bore. Anyone know how the overhaul shops accomplish this?

After doing cylinders in various shops all over country I now use Aircraft Cylinder repair in Las Vegas ( they have a web site) as the best I have found . They have the equipment - knowledge and parts to do it right (as well as a Repair station certificate ) to do it right. Pulling cylinders is a no brainer - putting them back on takes a A&P .

A lot more work goes into the valves/guides/seats than the actual "cylinder" part of a jug. You can check the id, round and check for cracks, especially check the wear at the top (ridge?). Do you know the times on the cylinders you have?

I had to pull a cylinder recently due to a stuck exhaust valve. I did the removal work myself and the install under A&P supervision. The cylinder was inspected, repaired (valve grind, new exhaust valve guide, honing, etc.) in less than a week by Premier Aircraft Engines in Troutdale, OR, for $400. The point being, quality cylinder work can be done for a reasonable price and it might not be worth the time, tool cost and traing to do it yourself.

The overhaul manual for the Cont. IO-360 should cover all that. Google it, I think there is a source to download for free. I'll try to remember to look in the O-470 OH manual I have to verify coverage tomorrow when at the hangar.

Remove cylinder, make a table lamp from it, and buy a new cylinder needless to say, i've had poor experience with overhauled cylinders.

I'm having a spare rebuilt right now at Ken Vike in Kamloops BC. I really hesitate about doing this as new cylinders really are the cheapest deal in aviation. A stupid little switch from Cessna is $200, but a new cylinder with piston, rings, valves and springs and gasket set is about $850??? Go figure.

I've got the IO360 overhaul manual in pdf forum somewhere and completely forgot about it. Thanks for reminding me flyfish.

Sometimes I think we forget that the EAB category exists so people can build airplanes for their education and recreation. 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. I don't plan to overhaul all the cylinders because 5 of them were in perfect working order when the 6th sucked a valve after recent work. At Least 1 of the 6 others I have should be useable and I want to participate in making it so. I'm not sure how much time the cylinders have on them. The engine has 1200 SMOH but I don't have the longs prior to the overhaul. Last I looked a new cylinder was $1600ish.

Pulling and checking valves I know how to do; replacing seats and guides is what I don't know about. I also am not sure about honing a blind bore prof I should even bother homing and re-ringing the good cylinders. I doubt the overhaul manual will discuss that kind of stuff. And wouldn't it be cool if I could unscrew the barrels and get them Nikasil coated then screw them back together.

Something interesting; someone on here said TCM cylinders have a choke in the bore but the six I have do not. Wonder what the deal is.

Anyways, thanks for the thoughts. I'll dig out my manual and see what it says.

My view has nothing to do with the cost. It has everything to do with reliability. All six overhauled cylinders had been off my O300 before 200 hrs. Two of them, more than once. Overhauled cylinders are a waste of time and un reliable. Your comment about not knowing how much time is on the cylinders, should be a big flag as to why you should replace them. Metal fatigure is real.

Sometimes it makes sense (and cents) to overhaul cylinders, but many times it does not. One of the things I've seen more than once is that when folks brag about the great deal they got on a cylinder overhaul they end up with trouble not far down the road. The reason is that the cylinder was repaired not overhauled. The cost of truly overhauling a cylinder is cheaper than a new one, but it's close enough to make you think.

As far as doing them yourself for educational purposes: It requires a non-trivial amount of specialized equipment and tools. You'd have a hard time doing them yourself. However, that does not mean that you can't find someone with a cylinder shop to let you watch, help, or whatever.

I had a cylinder off my C180 last May. Failed the compression test (45/80) due to a leaky exhaust valve. As usual with a Continental, the guide had worn which eventually allowed the valve to wobble around, which then erodes the valve & valve seat. Sent it off to Premier Aircraft Engines in Troutdale OR. They fitted a new exh valve, exh guide, intake seal, & valve keepers, re-honed the bore, and provided a gasket set & a ring set. Including the flat labor rate of $275 per cylinder, the total was $702 & it was back to me inside 10 days. Excellent service.

I don't know exactly what constitutes overhauling of a cylinder. Per the regs, there is no such thing as a "top overhaul"--there is an engine overhaul (aka "major overhaul"), anything less is just a repair. An engine overhaul must be done per the mfr's overhaul manual. As an example of that, Cliff of Aircraft Magneto Service told me this last spring that when he does a "500 hour inspection" of a Bendix mag, he replaces everything that needs replacing. If he does an "overhaul", he must do it per the Bendix overhaul manual- they call out a whole list of things that MUST be replaced, whether they need it or not. So he explained to me that the 500 hr inspection was as good as an overhaul, only cheaper because you're not replacing a bunch of good parts.

If I was having a major overhaul done on an engine, I would buy brand new cylinder assemblies. if I had one bad cylinder on a mid-time to high-time engine, I would (and have) have that cylinder repaired as required. Per my above post.

A guy I know asked why I didn't pull all 6 cylinders (off my 1250 hours SMOH engine) and have them overhauled. I told him for the same reason that when I get a flat tire on my car, I just have the flat fixed instead of buying 4 new tires.

I started in the overhaul shop in the cylinder dept. We did round engines (985-4360), and 2 of us pumped out a complete set of 9 from start to finish in about 4 days. Like was said, the mfg's don't say much about top overhauls, and many places that "overhaul" cylinders, do nothing more than run a ball hone down the bore to scratch it, and maybe grind valve seats and faces. We went as far as screwing heads off. It is a pretty involved process to get things right. You can get by doing it at home with a homemade setup sometimes, but I wouldn't venture there if I was you.
Guide angles, guide bores, guide profiles, seat bore angles, seat bore depths, seat inside and outside diameters, head angles, thread integrity, clocking, bore measuring, choke, base profiles, stud integrity, spring seats, profiles, recoil rates, height, and a bunch of other things I'm sure I'm leaving out are all things that were checked by us, not to mention non-destructive testing of everything. It's pretty involved to do it right.
All that being said, you are more than likely capable of pulling valves, measuring guides and valves, facing seats, measuring spring heights, honing and getting ready to put back on and enjoying! I'd say go for it! Use that manual and your brain, and you'll be fine. About the most important thing on a TCM IO-360 is baffeling.... make sure it's good and tight fitting!
John

Re overhauling a cylinder yourself-- you're gonna have to buy the new parts required anyway, so the only extra costs would be the labor involved. $275 per cylinder isn't much to pay for the cylinder shop's expertise and specialized tools and equipment.

Whee,

One of the problems I see with what you propose is the fact that you don't know the history of those cylinders. I've seen so many instances of metal fatigue in cylinder failures that I simply won't accept an overhauled cylinder on my engine.

As to you wanting the experience, why not learn to forge and heat treat the metal in the airframe too? Working cylinders requires lots of specialized equipment. Note that there are very few mechanics who do their own cylinders, and lots that won't assemble engines, and not because they're working on certificates engines.

Remember, at the end of the day, you're putting your family in that airplane, and flying over some inhospitable country.

MTV

None of the process is difficult, but the investment in tooling is significant. However, I can appreciate the interest in education.

The grinding wheels and mandrels will add up to a hundred if you look around, and the base wrenches can be had for 25 or less each. The special compression tool is almost required, although standard automotive varieties can be used with a bit of creativity. Penetrant, developer, and a good light are also another 50-60 at the low end. The ring cutters, compressors, hone, arbors, polishers, and the rest are all items from your auto parts store, but if you don't already have these, they will add up fast. All this assumes your cylinders only need minor work and replacement of guides, springs, etc, or even seat reassembl y(another cutter, more $).

I lent my gear to a gentleman who used it to go through the cylinders on his experimental TCM. He probably did a perfectly good job on it (again, the tasks are not difficult, and well documented), but it didn't matter. He suffered a head separation from fatigue on the maiden voyage of his 4-years of pure craftsmanship and love. This is a very rare, unlucky outcome, but still one that is possible.

You might consider buying a new cylinder or one with a known history and getting an education from disassembly and reassembly. It might work out better than hundreds in tooling anyway.

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.

Ive found the cost to overhaul 4 cylinders with new exhaust valves costs the same as buying 3 new ones.

There are a lot of good resources for the IO360 series. There are even some DVD's which one of the local EAA chapters has and looked interesting. But the factory overhaul manual leaves little to the imagination, and several pubs on the interwebs add even more to them. I only have the mans for my own engines, but looking quick at a few of the places I like to look at yields something closer to what you seek:

https://www.redskyventures.org/free_stuff.php
http://rvplane.com/pdf/XP360_OverhaulManual.pdf

Your problem doing your own cylinders at home will be achieving the proper Abbott-Firestone curve. In some cases you will also need to be aware of the choke built into the cylinder by Continental or Lycoming as well. Have you ever wondered why the feds certify engine shops? It's not just bureaucratic nonsense. One might well find a used cylinder honing machine for $10K perhaps so that you can dial in the proper profile but then you might as well go into the business full time to justify the outlay in equipment. One simply cannot hone cylinders with a handheld drill and hone from J. C. Whitney. I know of a famous shop in California where the owner got busted using a computer controlled automotive hone on aircraft cylinders. He blew the choke out of every cylinder he overhauled. That's not good on an air-cooled engine. He's out of business now and widely regarded with disdain in the industry. Oh well.

Here is a good article that describes the intricacies of a proper hone profile.

http://www.enginebuildermag.com/2000/09 ... -finishes/

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. If you do that bear in mind as MTV cautions; you can zero time the cylinder but you can't zero time the metal.

All in all, the lower end of these old tractor engine designs are pretty simple and amenable to DIY work but it's in the cylinder where the power is created. You undoubtedly have the right smarts to do cylinder work but you probably don't possess the equipment or ready access to the right parts. You very well might build yourself a 100 to 200 hour engine at great expense and then have to do it over again. It's very unlikely that you'll home build cylinders that will go to TBO.