I Could but I Can't

[W.J.Langholz]

Cylinder repair

Alot you you guys are A-P IA's and are allowed to do your own work. My delema is that I can do the work but....I'm not allowed to.... So I order 2 new Titan cylinders and was thinking of sending out the 2 that I take off for repair.

1) If they are repairable, will they come back as good as a new one
2) has anyone done this recently and what could I expect to pay?


A little back ground for you, o-300 Majored in 1968,(Ibought this plane in the middle of 2008) now has 1750 hrs since major. Increased oil burn(useage) over the last 6-8 weeks. Compression check last week yeilded,72,72,40,62,74,78 after warm up. Rechecked #4 and was 61, with the hours stated I decided to replace it also.

[GAHorn]

1: Rebuilt cylinders, while "serviceable", are rarely "good as new" due to the simple fact that new cylinders have no "cycles" on them while rebuilt cyls ... do. You can only bend a paper-clip so many times and the head will blow off when it cracks at the juncture with the steel cyl sleeve. (Ya dident know that a paper-clip had a head and a sleeve didja?)

2: The best way to get a quote for this work is to ....get a quote for this work from people who do this work. I recommend J & J Air Parts, 430 N Bryant St Pleasanton, TX. Phone: 830-569-3891 and Sentry Aircraft Cyliners 2731 Ludelle St, Fort Worth, TX 76105 Phone (817) 531-2729

You might find someone in your own neighborhood, but unless you intend to personally deliver, supervise, and pick them up.... shipping is shipping no matter where they are done.

Question: Do you really need a couple of rebuilt cylinders sitting around, rusting, at your place? Or would you rather get the value out of them by trading them in for new cylinders? Both facilitites mentioned above will give you a trade-in if you purchase your new cyls from them.

[Bruce Fenstermacher]

W,

Like most other work, if you have the equipment and skill and can find someone properly licensed to supervise and sign off your work, you can do it yourself.

You will need a way to clean and inspect the cylinders for cracks. Equipment capable of measuring precisely the cylinder bore as well as the valve guides. You will need the equipment to remove and insert valve guides as well as ream the guides. Equipment to remove and reinstall valve seats then cut the seat and valves. Most people don't have at least some of this equipment specifically for these cylinders, it is not all the same cutters and reamers as used on other machinery like cars and tractors.

I have access to the correct equipment and skill and have done exactly this. And while I'm satisfied with my work I recognize my experience level at overhauling aircraft engine cylinders stands at exactly the 10 or so I've done. On my side of the fence I'm feeling good about my overhauls but someone sitting on the other side of the fence may not be so excited about my experience level and the job done. In short doing the overhaul myself saved me money (so far) but probably has no value to anyone else.

If I had to spend any money buying any of the equipment to do this I wouldn't. I'd send them out to people who have the equipment and experience and then what ever I got back would at least have some value to others if I needed or choose to sell.

George does have good advice about trading them in if you can. As for cylinders sitting around just in case you need them only time will tell if that will pay off.

[HA]

if you already ordered the new Titan cylinders, then you have a couple of cores. you can get them fixed up to be servicable spares or sell them to someone (usually better to do this as exchange cylinders when you buy). Unless you're going to run that old engine forever I wouldn't put new cylinders on it, you're at TBO both time and calendar anyway. So I would have exchanged my bad jugs for servicable repaired units, or gotten them fixed (where was the compression going? maybe you just need hone and rings, although if I have a jug off I'm going to check/fix the valves/guides/seats and there's an AD on the rocker shaft ears for a dye pen check), depending on your hurry.

an excellent engine shop in MN is Bolduc Aviation, stellar reputation, they could fix up your jugs for you if that's what you want. http://www.bolducaviation.com

good day to be on the phone since if it isn't snowing on you yet it will soon

[W.J.Langholz]

HA
roger on the SNOW,SLEET,ICE, AND RAIN......

leakage thru the crank......even though the rest seem to be strong at this point, also ie hours, I was going to put on the redone cylinders also. Never thought about a core exchange...dah..brain fart.....

I had change 1 out last fall (#6) which now has 100 hours on it.

I do have access to the equipment...in this neck of the woods the sign off is as rare as a good CFI.

W.

[c170b53]

Pulling the cylinders will give you a good idea as to whether you are going to get more time out of it.

[W.J.Langholz]

Number 3 is off and new one back on. Cracked top ring. Number 4 is off alot of play in the top ring but didn't look as bad as what I thought it was going to be.

I feel good .....I only busted my knuckles once today

W.

[blueldr]

I kind of figure my break point for new cylinders is about fifteen hundred hours. On condition before that time. Likely new cyliders after that time.The
C-145/O-300 bottom end is almost always good for three thousand hours or more if it is not grossly abused. It's a really bullet proof engine. I've seen a flying club C-172 bottom end make it to thirty six hundred hours twice using the original crank without regrinding. This airplane flys almost daily, weather permitting, and has been the greatest workhorse airplane I've ever seen. It gets regular maintenance but it isn't coddled. The oil is changed regulary and there is no filter. The airframe received an extensive inspection, repair , and upgrading, including painting and new upholstery, a few years ago. The airplane is used for primary and instrument training, proficiency flying and "just for fun" flying.