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I have visited some prior discussions related to this but I am now faced with the possibility of having a good plane but have some concerns about the engine which has less than 20 hours in the last 6 years (plane has been hangared in a climate controlled hanger). One earlier thread suggested budgeting for a top end. I plan do do a PPI if I go forward but not sure that this would completely catch any potential issues. Is the main concern the cylinders or is this a deeper concern (i.e., crank and bearings, etc)  that might involve an OH? Also if just a top end, what would be a good budget number? Any thoughts?

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Dental cameras are a nice way to look at cylinder surfaces...

oil analysis may shine a light on cam follower issues...

Worst case the cam and followers are accessible without splitting the case...

Not like a Lycoming cam...

Share the pics...

PP thoughts only, not a mechanic...

Best regards,

-a-

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Corrosion is always the concern.  Like all engine cylinders are easily replaced if corroded, unlike a Lycoming, in a Continental engine the valve lifters are removable with a little work allowing for inspection of the lifters and the camshaft lobes.

With such low use, I would pre-oil the engine with a pressure pot before starting it.

Clarence  

Edited by M20Doc
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Insist on having a couple of the lifters pulled at the prepurchase.  It really doesn't take that long.  Had this been done on mine, I could have been spared the overhaul I'm doing now - or at least priced it into the deal.

For example, if the lifters are corroded but it hasn't been run and the cam is otherwise ok - it is not that hard to change out the lifters.  Nickel cylinders would be a plus too.  They take away some, but not all, of the worries on the top end.

I don't know the price for the top end - I decided to just do the whole thing on mine and be done with it.  The cylinders are something like $2500 a piece so, take it from there and start adding.  

Edited by hypertech
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I’d budget 12-15k depending on cylinder choice, other parts needed, and install costs. 

However, with a new top end you might be able to get well beyond the 2-2.2k TBO if everything else is well taken care of. 

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I bought a plane that had also sat a lot. I had to do a top end overhaul within 20 flight hours of ownership. $2500 per cylinder is the going rate. If you plan to immediately fly this plane for a specific mission, find another bird. If you have time on your hands, use the low time as a negotiation tool.

Sent from my SM-N950U using Tapatalk

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2 hours ago, irishpilot said:

I bought a plane that had also sat a lot. I had to do a top end overhaul within 20 flight hours of ownership. $2500 per cylinder is the going rate. If you plan to immediately fly this plane for a specific mission, find another bird. If you have time on your hands, use the low time as a negotiation tool.

Sent from my SM-N950U using Tapatalk
 

I had a different story. I bought a plane with an IO-550 that had about 80 hours over the last couple years about 4ish months ago. Just put 135 hours on the engine in the last 4 months of ownership. Engine is currently at 1530 hours and has never had a cylinder changed. Engine is a TCM IO-550 G

Edited by Niko182
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2 hours ago, Niko182 said:

I had a different story. I bought a plane with an IO-550 that had about 80 hours over the last couple years about 4ish months ago. Just put 135 hours on the engine in the last 4 months of ownership. Engine is currently at 1530 hours and has never had a cylinder changed. Engine is a TCM IO-550 G

I can echo your experience.  Mine was an IO-360 that sat for almost a year and had only a couple of hours over the previous couple of years.  We treated the engine as if it was a new engine, and flew it like we were breaking it in.  We also changed the oil very often, 5-10 hrs, for the first few and sent all samples out for analysis.  All analysis came back fine and the numbers actually improved with each oil change.  Part of the oil's job in the engine is to clean, so we ran the engine and let it do its work and changed it often so we always had fresh "clearner" running in the engine.  After all of that, no major work needed to be done.  We are keeping an eye on one cylinder becuase it has slightly lower compression than the other 3, but still well within limits.   We are at about 75hrs since purchase and have only had to clean an injector and replace the spark plugs.

I'm knocking really hard on my wood desk as I type this though.  :D

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If there is no visible outside corrosion on the cylinders there is none inside. Just pour a  little bit of oil through the spark plugs cylinder holes and rotate by hand the prop to lubricate the cylinder walls before starting.

José

 

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If there is no visible outside corrosion on the cylinders there is none inside. Just pour a  little bit of oil through the spark plugs cylinder holes and rotate by hand the prop to lubricate the cylinder walls before starting.

Id stick a borescope in first before doing anything.
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12 minutes ago, teejayevans said:


Id stick a borescope in first before doing anything.

And although it sounds silly, make sure you look at the top of the cylinders with the borescope (as in the portion of the cylinders on the top of the engine and not the half closest to the valves and plugs). My mechanic just finished a top overhaul on a Continental engine where the purchaser had a PPI with a borescope review of each cylinder. Even had pictures. When the owner showed them to the mechanic, he kept insisting there could not be rust in the cylinders since the pics showed nothing. His face fell when the mechanic pointed out they each picture showed the bottom half of each cylinder. The owner finally realized the effect gravity has on oil, and the top of every cylinder showed rust and pitting. Painful, but now the engine is humming like a well tuned machine.

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Best way to find about engine condition is to actually run it. Bearings conditions is best assessed by oil pressure on idle (warm) there is no borescope inspection that will check them.

José

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3 hours ago, Piloto said:

If there is no visible outside corrosion on the cylinders there is none inside. Just pour a  little bit of oil through the spark plugs cylinder holes and rotate by hand the prop to lubricate the cylinder walls before starting.

José

 

I dunno about that one.  Mine sat for about 4-5 years with about 50 hours or so (with only 10 hours in the last 2 years) right after a rebuilt engine went in.  The outside was, of course, pristine because all the cylinders still had intact paint.  When they borescoped the cylinders for the PPI, there was some light corrosion inside, but not enough to be a deal breaker.  After a couple years of running, on my last annual the cylinders looked fine, and oil analyses have stabilized.

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On 8/10/2018 at 6:54 AM, Piloto said:

If there is no visible outside corrosion on the cylinders there is none inside. Just pour a  little bit of oil through the spark plugs cylinder holes and rotate by hand the prop to lubricate the cylinder walls before starting.

José

 

Patently untrue. There’s plenty of engines that look perfect on the outside and corroded on the inside. They’re vastly different for one. Inside is steel polished parts and the outside is painted aluminum.  Also, condensation forms inside the engine and that precipitated corrosion. 

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On 8/10/2018 at 8:54 AM, Piloto said:

If there is no visible outside corrosion on the cylinders there is none inside. Just pour a  little bit of oil through the spark plugs cylinder holes and rotate by hand the prop to lubricate the cylinder walls before starting.

José

 

I don’t think that Conintenal paints the inside of the cylinder bore anymore.

Clarence

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