IO360 Cylinder Cost

[Chewka]

Hi folks,

I just got the bad news that my #1 cylinder is cracked from the spark plug hole to the intake port on my 81 J model. Engine is 900 SMOH.  Could this be due to overheating or manufacturing flaw?

 

What are you folks in states paying for new cylinders these days?  $1800?

 

Thanks,

Brenden

Calgary, AB

 

 

[N601RX]

If only replacing a single cylinder most people would probably just get an exchanged overhauled cylinder.  Most  cylinder shops will have a used one overhauled and ready to ship out.

 

New ones are close to 2K now.

[rbridges]

I have an O-360, but I've heard the IO-360 cylinders are more expensive.  I don't know about 1800, but I was thinking they were well over $1K each.

[M016576]

I have an O-360, but I've heard the IO-360 cylinders are more expensive. I don't know about 1800, but I was thinking they were well over $1K each.

The io-360 uses angled valves on the cylinders. Lycoming is the only manufacturer, and they are about twice the cost of every other cylinder out there (new). $2000 or so per jug.

[pinerunner]

I wonder if it might be due to over-tightening the spark plug. I think learning to change and inspect our own spark plugs is a good thing; but getting the torque right is important. IO-360 cylinders are about double the cost and around $2000 new. I thought long and hard about it and decided to get an E model anyway.

[KSMooniac]

http://www.airpowerinc.com/productcart/pc/cylinders.asp?catid=70&subcat=75&mfgid=TL&prodid=11604&x=IO360

 

$2053 at Air Power right now.  Sorry to hear about the crack...could be a casting flaw or perhaps too much plug torque.  Heat and improper engine operation could have helped it crack too.  Was it a factory overhaul, and/or were new cylinders used?

[rbridges]

The io-360 uses angled valves on the cylinders. Lycoming is the only manufacturer, and they are about twice the cost of every other cylinder out there (new). $2000 or so per jug.

Gotta feel sorry for IO-390 guys. I heard their jugs were double that.

[chrisk]

http://www.airpowerinc.com/productcart/pc/cylinders.asp?catid=70&subcat=75&mfgid=TL&prodid=11604&x=IO360

 

$2053 at Air Power right now.  Sorry to hear about the crack...could be a casting flaw or perhaps too much plug torque.  Heat and improper engine operation could have helped it crack too.  Was it a factory overhaul, and/or were new cylinders used?

 

Wow!  Kind of makes me feel like the TSIO 360 cylinders are a bargain at $1438.   OF course I will need 50% more!

[Danb]

Chrisk it cost more to fly faster....

[chrisk]

Chrisk it cost more to fly faster....

But not that much more!     For the TSIO 360,  6x1438 = $8628.  And for the IO360  4x2053 = $8212.  But on the other hand, I don't know what the cylinders cost on a Bravo

[MB65E]

Bravo is not an Angle Valve correct?... Been a while. That said, it's probably similar cost as the IO360 cylinders due to the oil galley mods to the head. To the OP The only problem with overhauled cylinders from a shop is there is no way to verify TT on the cylinder unless it is tracked by the owner. Might ask around to see who has first run Angle valve cylinders. I got lucky, My engine shop, had a fresh set of cylinders from a 800hr TT engine from Japan. We overhauled those cylinders, they were hardly worn... In Japan, the country has a mandatory engine retirement at 800hrs. Engine shops here in the states buy these excellent cores! I would contact Pacific Continental Engines in Southern CA.

Nobody welds cylinders anymore. Thank goodness!

Good luck,

Matt

[Chewka]

Thanks for the input guys.  The cylinder was put on as part of the factory overhauled engine that was installed about 900 hrs ago in 2002.   This factory overhauled engine had 1845 hrs since new when it was installed.  We ended up getting a cylinder kit from Progressive in Kamloops, BC for 2700 CAD.  I saw that Air Power had it for 2050 USD but with exchange, shipping, duty?, and tax and the fact that we could have it here the next day, we went with Progressive.  I suppose the old one will make a nice, expensive paper weight for my desk.  It would be nice to know what causes these types of things without just accepting them.  I have only seen photos so far of the hairline crack and I can't tell yet if there is evidence of spark plug over tightening or a casting flaw.  

[cujet]

I don't put too much faith in "overtorqued spark plugs" causing cracking. Here is why: 

 

Aluminum has a distinct fatigue limit. Quite simply, aluminum accumulates cycle fatigue. Either through many, many small cycles or far fewer large cycles. It matters not whether it's a wing spar through turbulence, or a cylinder head subject to combustion events. Aluminum has predictable behavior.  Add in the heat of combustion and the violent nature of combustion, and the fatigue limit is reached earlier than in the wing spar example. 

 

Lets look at what we can control. We can operate the engine at somewhat different RPM's, thereby changing the number of cycles. We can control the BMEP (cylinder pressure) of the engine via throttle and mixture (and engine design) and we can control operating temperature through power settings, operating conditions and cowl flaps. Other variables such as baffling airflow and climb angle, climb speed and so on come into play. All of these (and more) variables will affect the "cycle count". 

 

I hate to say "just accept it", but there is no question that such cracking is normal in aircraft engines. This issue has never been fully resolved. As you might have guessed, new cylinders (not overhauled) will result in much lower risk of cracking. As will proper operation and cooling. It would be interesting to see a graph of the lifespan of specific cylinders. I'd guess Lycoming angle valve cylinders fail prior to the 2nd overhaul with high frequency. 

 

My cylinders had 1700 hours total time on them when I overhauled them. We very carefully checked for cracks and there were none. However, I don't hold the belief that I will get another 2000 hours out of them. Time will tell. 

 

 

 

 

 

Interestingly, we now test aerospace aluminum alloys with piezo drivers that cycle the aluminum at extremely high frequencies. This accelerates fatigue testing and has proven to be a worthwhile tool. Most aluminum fails in predictable ways. 

 

However, I wanted to add that Lycoming cylinder heads are also subject to other stresses. The valve guides and seats are pressed in. They expand and contract at slightly different rates than the aluminum does. But the big one is the stress created by screwing the barrel into the head. It's an interference fit and produces a perfect seal. Imagine the stresses located around this area. 

 

Shock cooling: I'm not a big believer. 4 billion flight school airplanes doing stall practice and other ham fisted operational practices have fewer cracked cylinder heads. This does not mean one should shock cool an engine, and expect longer life. But it is a data point against the theory of shock cooling resulting in instant, massive damage. I do know this: data download study shows that throttling up for takeoff results in far greater temperature change rate than does pulling an engine back slowly to idle at cruise alt. 

[Piloto]

"4 billion flight school airplanes"

 

Woow!!! that is more airplanes than people in China. What country is this?

 

I agree with you on the fatigue accumulation. That is why I have always done the overhauls with the local shop with new cylinders kits. When you send your engine to the factory for overhaul you may end up with overhauled cylinders that have 2000hrs of use. Cylinders are the most stressed part of an engine, in particular tensile stress during the power stroke. At each power stroke there could be molecular bonding failures that accumulates with use and eventually causing a crack.

 

José.    

[Guest]

Jose,

The factory only installs new cylinders during overhaul. Check on their web site.

Clarence