fredy wrote:Thanks for all the inputs. I talked with my engine shop today and like the unanimous voice on this thread, will be pulling the engine and splitting the case to make sure the core is good. The shop said it is not uncommon for broken valve springs on new cylinders that sit prior to being put into service because the springs get pitted, and then fail at those spots. This engine was overhauled 3 years before the plane got off the ground, so that's conceivable. As far as the broken cylinder, he said it is extremely uncommon to crack there and thinks either part or assembly issue. Either way, we'll get it straightened out and rebuild what's needed.

Would rather spend the money on flying, but better to pay for the maintenance on the ground verse paying for the lack of it in the air...

Peace of mind.......................

Priceless!

I'm curious if there is a SB on valve springs from ECI or Continental. I just know of the SIL98-9C recommended 12 year TBO and/or TBO time. The tear down is smart thing even though it sucks for it to be down, but the comfort of a clean running motor with your loved ones on board is priceless. Should make a thread for the tear down process if you don't mind, would be an interesting thread for everyone to learn from.

I call BS on the valve spring sitting for 3 year issue. If this is the shop that built the motor I would run away. There is a reason the valve spring failed and it is not that it did not move for 3 years think about it!!!!! I have heard of springs braking or weak but not from sitting unused for 3 years. You would have to be sitting in salt water to have that much pitting. ANYONE ELSE?? Find the reason the top came apart before you put it back together. I would say bad/wrong parts or improper assembly.
DENNY

It's not the same shop that built the motor, and at this point is only a theory having just seen pictures of the carnage. The tear down will hopefully provide the truth regarding the issues, but I will save that for them since I do not have the experience with engines to determine what was wrong. I'm using a highly regarded shop that I trust, so I'm confident once they have the motor in their hands they will figure out what was wrong and get it fixed properly.

As long as you're looking into theories, look into the possibility that the engine was started without a propeller and ran at very high RPM. It looks to me like the valve train has taken a pretty bad beating, like maybe the valves were floating. The chunks of metal maybe be the hard surface material from the cam or the rocker arms.

Ohh that's ugly,
Without something to give scale of size in the first pic I can't say for sure where those parts came from but my best guess is that it is from one of the inside springs. the curve and size seems right. Lost seems to have a very good thought about overspeed.

My first thought was push tube that were too long but as someone else stated those can be way out of spec, and still function OK, there is a lot of slack in hydraulic lifters.

I think the notion that the damage is caused by corrosion or even micro pitting from long storage is pretty weak. The parts look to be very clean and corrosion free. The only damage from long term storage I might look for would be a weak spring from being under compression all that time.

The broken pin boss is likely from the valve spring binding up and not allowing the valve to move thereby locking the rocker arm, this means something has to break, rocker arm, push rod, cam lobe, pin or pin boss. Whatever was the weakest link in that chain had to fail.

I would certainly agree that this engine needs to come apart, have a very thorough cleaning and have ALL components tested and measured, you seem to have the right plan.

Please let us know how it all comes out.

Shane

Lost wrote:As long as you're looking into theories, look into the possibility that the engine was started without a propeller and ran at very high RPM. It looks to me like the valve train has taken a pretty bad beating, like maybe the valves were floating. The chunks of metal maybe be the hard surface material from the cam or the rocker arms.

An overspeed is possible in flight too. Continentals classifies them by rpm and calls out remedial action required. Don't remember if I saw this on the TCDS, a SB, or just where. Seems to me that 3 out of 6 cylinders having this failure is indicative of something (but not sure what). I wouldn't guess defective products, more likely faulty assembly or something like the overspeed thing.

Curious if the cause of this was resolved?

Tim

DENNY wrote:I call BS on the valve spring sitting for 3 year issue. If this is the shop that built the motor I would run away. There is a reason the valve spring failed and it is not that it did not move for 3 years think about it!!!!! I have heard of springs braking or weak but not from sitting unused for 3 years. You would have to be sitting in salt water to have that much pitting. ANYONE ELSE?? Find the reason the top came apart before you put it back together. I would say bad/wrong parts or improper assembly.
DENNY

I'm curious about this comment Denny. I have a PPONK with 400ish hrs on it and found a broken valve spring. Engine never sat and it was built by Steve. No other issues. So was it just a bad part or was it a wrong part? FWIW, it was dinensionallydifferent then the one my engine shop sent me to replace it...

Parts do fail even at low time, sometimes stuff happens. What I would do is check to make sure the rest are OK. Now if you said you had several go at the same time then I would think defective run or improper part/installation. As far as new part being different then the old. I would call Steve and ask him what parts/vender he used. Over the years parts come form different suppliers so they may look different.
DENNY

I guess I never did follow up. I pulled the engine and sent it off. Shop said the parts were all correct and for whatever reason, it must of had a bad batch of springs. In the end the cost was tear down/inspection/assembly manhours plus a new jug, main bearings, all new valve springs, and hardware (~$6500). There were a few light scratches on the main bearings, but no damage to the crankshaft journals. The engine has been running great the past 3 years and 400 hours.