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Excitement today


larryb

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Two seconds after full power on my takeoff roll today, this happens. A nice bang, vibration, smoke. I aborted the takeoff. I did taxi back to my hanger. Oil was pouring down the nose nose wheel but there was still 5 qt left in the sump when it was all over.

The cylinder was an overhaul exchange put on before my ownership. Engine running great prior. Cool CHT, etc.

Larry

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In 2004 the engine log says "Reinstalled 3 cylinders after repair, and installed 1 used overhauled cylinder." That was 800 hours ago. I have 4 yellow tags for that work as well. I'm not sure which of the cylinders were repaired and which was the used overhauled one. I've owned the plane for the last 3 years and 350 hours.

 

Larry

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You are lucky. My two power losses on takeoff in my Grumman Cheetah each occurred when I was at about 300 ft altitude with no runway left. I'll take yours any day of the week!

Unfortunately you will now be facing a big bill but the good news is, you get to make the choices and you will KNOW what you are flying behind. That is worth something.

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I haven't seen too many Lycomings fail like that. Continentals are another story. I bet the compression was fine right before it came off. Looks like it was cracked a long time. Thanks for the detailed pixs. That helps us look for external blow by. I'll take a new Lycoming cylinder please!

Well done!

-Matt

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Classic cylinder head separation. Reason enough to not trust reworked heads. After 5-8k hours, the fatigued Aluminun lets go. What was the density alrirude at time of failure?

It was cracked and leaking for some time. That third photo, the lower right you can see the dark crack and the fin staining for about 1/4 of the circumference.

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Yes, if it had to happen, it was a best case scenario. Home field, early in the takeoff run. I made the first turnoff from the runway! 

 

My main MSC is not at my field. I've been in touch with them as well as a local shop that will help me get back in the air. I did the teardown myself today, I was anxious to see if there was any other damage in the motor. Everything else looks fine. The cam looks fine. Pistons clean, rings free, no sludge or deposits, etc. A quick look at the other cylinders shows no evidence of similar distress, although I'll be checking a lot closer. Here is a list of the damaged parts:

 

cylinder, of course

hydraulic lifters. They were ejected, and I didn't find all the parts. Probably on the runway or taxiway.

valve cover, got dented when it hit the cowl.

spark plug leads, lead pulled out of #1 lower spark plug end.

fuel injector line bent at injector, needs replacement

intake runner got bent

various baffling got bent, will need repair.

 

Needless to say, the next cylinder will be brand new. Parts already on order.

 

Larry

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Byron:

 

     I was thinking the staining on the lower 1/4 of the cylinder was just oil from the event. But I imagine you are correct and that it is blowby. I will inspect that area more carefully. Density altitude was -200'.

 

Larry

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  • 2 weeks later...

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Follow up. I've looked carefully at the broken cyl. The staining is certainly blowby from the crack before separation. Here is the baffling outside of that area. Note how it is discolored. Much more discoloration than any of the rest of the baffling. It would have been hard to see the fins of the cyl due to the baffling. But if you notice this discoloration I would pull it back and check the cylinder too.

The new cylinder is on the plane. We have all the parts to finish except one pushrod needed to get proper tappet clearance. Should be ready to fly next week.

Larry.

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Byron is right on. I have seen these a couple of times. One was a 252 with overhauled cylinders en route from San Juan PR to FLL. After I told him how safe the trip was he had a cylinder separation failure in the vicinity of GTK. He landed safely with no damage to the plane but a bill for $50K to replace the engine at GTK. I told him he was better off ditching the plane near the beach and collecting the total loss from the insurance. Insurances do not cover engine malfunction.

I always ask for factory new cylinders at engine overhaul. Metal fatigue combined with cylinder honing weakens the cylinder. Is a receipt for cylinder separation.

José

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Byron is right on. I have seen these a couple of times. One was a 252 with overhauled cylinders en route from San Juan PR to FLL. After I told him how safe the trip was he had a cylinder separation failure in the vicinity of GTK. He landed safely with no damage to the plane but a bill for $50K to replace the engine at GTK. I told him he was better off ditching the plane near the beach and collecting the total loss from the insurance. Insurances do not cover engine malfunction.I always ask for factory new cylinders at engine overhaul. Metal fatigue combined with cylinder honing weakens the cylinder. Is a receipt for cylinder separation.José

Not sure I would council someone to save $50,000 by ditching their plane when it needs work. My life would be worth more than an engine overhaul.

Clarence

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Byron is right on. I have seen these a couple of times. One was a 252 with overhauled cylinders en route from San Juan PR to FLL. After I told him how safe the trip was he had a cylinder separation failure in the vicinity of GTK. He landed safely with no damage to the plane but a bill for $50K to replace the engine at GTK. I told him he was better off ditching the plane near the beach and collecting the total loss from the insurance. Insurances do not cover engine malfunction.

I always ask for factory new cylinders at engine overhaul. Metal fatigue combined with cylinder honing weakens the cylinder. Is a receipt for cylinder separation.

José

I'd add a recipe for cylinder separation is getting the things hot in excess of 400 again and again. If temps are kept under 380 I think people would find that cylinders might last 5k or more hours easy....

I'm not a fan of new parts. They are unproven and fail.

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I'd add a recipe for cylinder separation is getting the things hot in excess of 400 again and again. If temps are kept under 380 I think people would find that cylinders might last 5k or more hours easy....

I'm not a fan of new parts. They are unproven and fail.

Problem is you don't know the history of reworked cylinders. Running them hot has led to many a top oh.

And what's the savings really, say 4k max in an IO360?

Considering these plus the fact that aluminum has no endurance limit, I'll take new cylinders.

I'll run them my way from day one without any question marks.

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Problem is you don't know the history of reworked cylinders. Running them hot has led to many a top oh.

And what's the savings really, say 4k max in an IO360?

Considering these plus the fact that aluminum has no endurance limit, I'll take new cylinders.

I'll run them my way from day one without any question marks.

I too would never buy overhauled cylinders and I agree whole heartly with you. I should have clarified better but the only cylinder I would re-work is one of my own, not one out of the scrap pile.

Also a set of new cylinders and Pistons on a J is just short of 10k because of the wide deck angular valve proprietary lycoming design. There not like continental or other cylinders as lycoming thinks there gold!

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