New cylinders or overhaul - all six

[DoubleOught]

Going to preform a top overhaul, do new cylinders last longer than overhauled cylinder? any advise ? 4 out of 6 bad . ?????

[cessna170bdriver]

I have been VERY pleased with my ECI Titan nickel carbide coated cylinders. I bought that particular type knowing that my flying is sporadic at best. Compressions were in the 70's right out of the box, all 80's and 79's at annuals, and all above 75 even after sitting idle once for 13 months. I haven't priced cylinders lately, but the last time I did, the price difference between new and overhaul made it a no-brainer to go with new.

[Bruce Fenstermacher]

I think the advice your will find most often is new will last longer than overhauled, in most cases. It's simple. What kills a cylinder in most cases is a crack. Overhauling cylinders can't remove cycles of heating and expansion and cooling. New cylinders have 0 cycles.

If you are replacing these cylinders yourself and you don't charge yourself for time and you like to tinker with your aircraft, overhauled might be the way to go. If your paying someone to change out the cylinders, new will probably work out better for you in the long run.

Many times it comes down to what you can afford right now.

[bagarre]

Keep in mind that there is no way to know how many hours or heating/cooling cycles are on an overhauled cylinder.
It will be dimensionally correct and within limits but that doesn't address the fatigue in the metal.

Personal opinion (cuz everyone has them). I'd keep cleaning up my current cylinders until they can't make compression, have a crack or are otherwise unusable and then buy a new one when needed. But that's cuz I know they were new 800 hours ago and I prefer the devil I know.

[flyboy122]

Just did cylinders on my 360 Lycoming and went through the same decision. In my case the jugs had only 400 hours since new (!), but had sat for years and were pitted. I added up having it bored it out, oversize pistons, rings, valve job, etc... and got pretty close to the price of a new cylinder assembly. Still, it killed me to scrap these low time factory cylinders. The kicker was a coworker who reminded me to think about resale. Would you rather buy a plane with punched out, massaged, 30 year old jugs, or brand new, latest greatest, everything 0 timed jugs? I bought the new ones, and am very happy with my decision. The bonus was I didn't have to do any work cleaning them up, painting, messing with valves, etc....

Note: The above math assumes I would have to send the cylinder out for the machine work. If you have the boring machine, valve seat grinder, etc... available, that changes the math substantially. It seems like in the old days every FBO did overhauls and had those tools, but not anymore. I guess that's the price we pay for $900 (which less face it, is pretty darn reasonable) cylinder assemblies.

DEM

[DoubleOught]

Thanks for all the advise, I had given thought to resale value, heating and cooling cycles, down time waiting for the work to be done then be shipped back to me, plus my anal repentive ideals about having six new matching cylinders instead of six mixed matched cylinders. My O300 has less than 800 hrs on a MOH, but continually have trouble with cylinders. I think I'll go new and add a new baffle also, everything else is serviceable . Thanks again / OOW

[bagarre]

What are the troubles you're having? Compression?

These engines are known for not making good compression all the time. Specially when they are flown at lower power settings to conserve fuel.
If you're not making compression, try flying 10 hours at a higher power setting and lean for best power. Then check it while the engine is still hot.

Just a thought. I'd hate to see you spring for new cylinders if you don't have to.

[DoubleOught]

Hot, cold, leaned out at wide open could not make but 2300 Static. Two worst were 30, 40, two at 55, two "good" ones were 65. I think new is the answer. That way I'll know what I have , a base line so to speak.

[bagarre]

Hot, cold, leaned out at wide open could not make but 2300 Static. Two worst were 30, 40, two at 55, two "good" ones were 65. I think new is the answer. That way I'll know what I have , a base line so to speak.

?? 2300 RPM static is all you're supposed to make.
But those are some pretty low numbers. Maybe carbon build up on the seats? I had one once that wouldn't go above 30 (still made good runup). A few whacks of the exhaust valve with a plastic mallet and we made 70.

[hilltop170]

If you get new cylinders, the ECI Titans are the only cylinders I know of with valve rotators. Valve rotators will help keep the valves from sticking. They also have bayonet sockets for CHT probes and you should also consider the new style push rod tubes like the big bore Continentals have.

[DoubleOught]

Three months later and its done, but with Christmas, New Years & a few health issues that's not to long. Replaced all six cylinders with Superior Mellinnium total package. My A&P, AI, test pilot best friend flew it yesterday for 2 full hours according to break in recommendations , with no problems , at 1 hr. 10 min. Temps peaked and started to drop ( good sign ) for the remaining time he ran between 75 & 65 % as recommended . After landing and put it back in hanger to look it over real good. No oil leaks anywhere, exhaust pipes dry , everything looks great could not be happier, now it's my turn, being second is a small price to pay for an annual . OOW

[GAHorn]

Perform an early oil and filter change.

[DoubleOught]

10/4 I have mineral oil in it now, I'll change oil and clean screens at 5 hrs or Saturday which ever comes first. I forgot to mention in the first two hours of flight, I only lost half a quart. OOW

[170C]

With your new cylinders you should be good for a lot of good flying. Don't baby that engine however. Its made to run anywhere up to 2700 rpm's.

I have wondered what, if anything, was/is different in C-145/O-300 engines vs GO-300 engines. I realize the GO has the propeller reduction gearing, but otherwise is there anything different to permit 3200 rpm's? I understand the recommended tbo is lower on the GO.

[GAHorn]

The GO engine's cylinders required better cooling and a heavier head-casting. It's cylinders could be used on the C145/O300 but not the reverse...and so it didn't take long before the mfr's wised up and only made the heavy cylinders (which is what you buy these days when buying new.)

The GO300 had a shorter TBO because the engine ran around at 3400 RPM or thereabouts and it simply wore them out. It'd be like running your car downt he highway in second gear all the time... Lots of get-up-and-go... but not much durability.... and that gearbox was not built for high gyroscopic manuevers or rapid power changes...so the engine didn't enjoy nearly the durability-reputation of the C145/O300...which is loafing at 2700 RPM or less.