Sit too long?

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zbrown5

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Pouring over the logbooks of a 1975 200hp non-turbo arrow I’m looking at. 1650 TSOH (1991) and 700 since top end in 2000. It flew about 75 hours a year until 2009, then only about 10-25 depending on the year. It sat most of 2018 with only a couple hours. 75/75/77/77 compression.

Question is should I be relatively comfortable with the compressions and a bore scope test? Would also like to see oil analysis.
 
answer, who knows. my personal encounters with sitting engines. airplane 1. engine bought sight unseen, no logs, pulled pan and acc case to check oil pump ad. all looked good inside. engine sat on stand in hangar for 3 years until airframe ready for it. that was 16 years ago and engine still running strong, no metal and good comps. airplane two, 600 since overhaul but sat in hangar for about 5 years without running. got it running and in annual, flew it about 20 hr and a cyl went low, pulled cyl and found tappet starting to spall. it at rebuilders now. so, you can never tell with a engine that sat a while. both those engine sat in hangars less than 60 miles apart in texas. one went bad the other did not. its a crapshoot, price is the determining factor.
 
unsafervguy said:
answer, who knows.
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^^^^ That!

I purchased my aircraft with an O-360 that flew about 4 hours in 5 years at about 285 to TBO. Multiple sources said my engine would be toast in less than 50 hrs. Still going 130 hrs later and hasn't made any metal. BUT, I knew I was taking a chance and was ready (and still ready) to pay for an overhaul should it become necessary. Approx 150 hrs to TBO...
 
Had a Warrior with a similar story. Bought half ownership and flew the plan for 9 years with no problems. Had one cylinder replaced because a spark plug insert came loose. Last comp were in the mid 70's
 
zbrown5 said:
Pouring over the logbooks of a 1975 200hp non-turbo arrow I’m looking at. 1650 TSOH (1991) and 700 since top end in 2000. It flew about 75 hours a year until 2009, then only about 10-25 depending on the year. It sat most of 2018 with only a couple hours. 75/75/77/77 compression.

Question is should I be relatively comfortable with the compressions and a bore scope test? Would also like to see oil analysis.
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I don’t think I would be terribly worried, but what part of the country. If the North central plains probably ok, Florida Would concern me more.
 
I bought a Cherokee that flew 10-20 hours a year for five years, summer flying only. 400 hours later (knock on me/wood) still running strong. But that’s only an example of one.
 
tawood said:
I bought a Cherokee that flew 10-20 hours a year for five years, summer flying only. 400 hours later (knock on me/wood) still running strong. But that’s only an example of one.
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How many hours and years SMOH? That’s what makes me wonder too is that the crank and everything in the bottom of the engine is 27 years old.
 
ktup-flyer said:
Thats why you do a prebuy
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What is a prebuy going to do? They gonna tear the engine down? They are all a gamble. A new engine has a better chance of having a engine failure than a old one. You never know..... I bought a 172 with 1100 SMOH and it started making metal after 15 hours. I had a 540 with 400 SMOH and the crank broke in half. I have had engines that sat a long time run better than any of them.
I just bought a IO-550 powered Bonanza yesterday. It has not been cranked since 2014.
 
pigpenracing said:
What is a prebuy going to do? They gonna tear the engine down? They are all a gamble. A new engine has a better chance of having a engine failure than a old one. You never know..... I bought a 172 with 1100 SMOH and it started making metal after 15 hours. I had a 540 with 400 SMOH and the crank broke in half. I have had engines that sat a long time run better than any of them.
I just bought a IO-550 powered Bonanza yesterday. It has not been cranked since 2014.
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It'll tell you a lot more than asking people on the internet if a plane that has sat for X amount of time is still good.
 
ktup-flyer said:
It'll tell you a lot more than asking people on the internet if a plane that has sat for X amount of time is still good.
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Yea... Get 10 mechanics and get 10 different opinions. That's why I look at the planes I buy myself. It isn't rocket science. If it looks like it was drug out of the river walk away. Not hard to tell how it was maintained.
 
zbrown5 said:
That’s what makes me wonder too is that the crank and everything in the bottom of the engine is 27 years old.
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When they're that old some are ok and some are not. There are a lot of things that can contribute to an engine's health or lack of it.

You'll get all sorts of answers on what is likely to cause problems and what won't. I haven't seen it be that simple. I just overhauled an engine that had 600 hours on it and spent its life in the desert yet the cam and lifters rusted out. There was rust in this engine in places I've never seen rust before. So the dry country location did nothing to help it. I've also pulled cylinders off an engine on a float plane that sat inoperative for 5 or so years in a moist environment and the inside of the engine looked great. You just never know.

I'm in the middle of overhauling another engine right now. This engine has had two cam and lifter replacements since it was last overhauled in 1986 and it needs another one due to rust. But that is the only rust I've found in the engine so far. It probably would have continued running for a while before becoming a problem but there were other problems with the engine that triggered the overhaul.

If I were going to buy this airplane I'd expect to be doing an engine overhaul in short order but hope it lasts for a while.
 
idahoflier said:
^^^^ That!

I purchased my aircraft with an O-360 that flew about 4 hours in 5 years at about 285 to TBO. Multiple sources said my engine would be toast in less than 50 hrs. Still going 130 hrs later and hasn't made any metal. BUT, I knew I was taking a chance and was ready (and still ready) to pay for an overhaul should it become necessary. Approx 150 hrs to TBO...
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You OH right at tbo or going to OH her when you see fit? Just curious
 
zbrown5 said:
How many hours and years SMOH? That’s what makes me wonder too is that the crank and everything in the bottom of the engine is 27 years old.
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Had 400 SMOH, but also over 15 years SMOH, when I got it. O-320 is tough(er) to check for corrosion too, but my mechanic did his thang...seller was reluctant when my mechanic asked to pull a jug, but it was the only way I'd buy it so they relented.
 
mondtster said:
....If I were going to buy this airplane I'd expect to be doing an engine overhaul in short order but hope it lasts for a while.
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This.
When I bought mine, even though it only had 400 smoh, because it sat I fully expected to do an overhaul soon. The fact that I'm now 3 years/400 hours later without making metal, is a nice surprise.
 
pigpenracing said:
Yea... Get 10 mechanics and get 10 different opinions. That's why I look at the planes I buy myself. It isn't rocket science. If it looks like it was drug out of the river walk away. Not hard to tell how it was maintained.
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thanks guys. Will see what she looks like.
 
Huckster79 said:
You OH right at tbo or going to OH her when you see fit? Just curious
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That is a great question! I'm leaning towards OH around TBO because I have one cylinder that is in the 60's while the remaining 3 are in 70's. That cylinder hasn't gotten any worse, but it hasn't gotten any better either and I would rather put the cost of replacing it towards an OH. Also I intend to keep the aircraft for a while so I would rather get the benefit of a fresh overhauled engine where I know exactly how it has been operated...
 
Update- I did some more digging in the engine logs and the cam, pistons, and wrist pins were replaced, as well as all cylinders in 2001. I didn't know if cam replacement was part of an top overhaul or not. That was 700 hours ago.
 
Briar Rabbit said:
I don’t think I would be terribly worried, but what part of the country. If the North central plains probably ok, Florida Would concern me more.
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Nope. Very short flights and ground running matter MUCH more.
 
idahoflier said:
That is a great question! I'm leaning towards OH around TBO because I have one cylinder that is in the 60's while the remaining 3 are in 70's. That cylinder hasn't gotten any worse, but it hasn't gotten any better either and I would rather put the cost of replacing it towards an OH. Also I intend to keep the aircraft for a while so I would rather get the benefit of a fresh overhauled engine where I know exactly how it has been operated...
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What's wrong with a cylinder in the 60s? Is the oil analysis look bad?
 
Same here looking at getting an Arrow. My question is, how different are maintenance costs per month/year on an Arrow with Retract and Constant Speed over say a Cherokee?
 
Eric Horton said:
Same here looking at getting an Arrow. My question is, how different are maintenance costs per month/year on an Arrow with Retract and Constant Speed over say a Cherokee?
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Sure. I owned a Warrior II before owning an Arrow II, so I can offer you an anecdote to that very question.

Overhaul/exchange of the powerpack. 2.2AMUs installed plus system flush in 2016...looking back on the books it lasted a hair below 8 years, which is a bit low imo, but it happened across two successions of owners. So there's some variance in operating style we unfortunately will not be able to normalize for. Then the gear sidebrace stud NDI inspection (4 hours labor, intervals 500 hours) back in 2015. One discretionary MLG actuator re-seal plus R/R (3 hours + gaskets) back in 2014. That's it, no kidding. 383 hours as of today's flight I just got back from. So less than 3AMUs in actual mx? Since gear swings at annual are a requirement for all retracts and thus a sunk cost for any retract you choose to upgrade into.


Oh yeah the prop. Mine has the original non-suffix/non-B suffix prop hub, which means I get some folks to run the eddy current probe every 100 hours (per AD) for a couple hundred bucks. I could fill it with hydro fluid for marker duty as an AMOC, which costs the same as an overhaul so I don't do it. Ditto for putting a B-hub. Prop shop would magically condemn the blades and I'd end up scrapping a perfectly good prop. So I just keep on keeping on the eddy current inspections. I'd have to put 1600 hours on it before I break even on just installing a new prop. I know I'll never own the thing that long, so I don't. To each their own.

The rest will be of course, your specific insurance premium for retract time. For me and my background it's a fart in the wind (700 bucks vs 580 on the warrior? anyways ballwash). Basically insurance rates singularly a function of hull value. You'll have to see what premium you get as a function of your specific experience.

Hope this helps.
 
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hindsight2020 said:
Sure. I owned a Warrior II before owning an Arrow II, so I can offer you an anecdote to that very question.

Overhaul/exchange of the powerpack. 2.2AMUs installed plus system flush in 2016...looking back on the books it lasted a hair below 8 years, which is a bit low imo, but it happened across two successions of owners. So there's some variance in operating style we unfortunately will not be able to normalize for. Then the gear sidebrace stud NDI inspection (4 hours labor, intervals 500 hours) back in 2015. One discretionary MLG actuator re-seal plus R/R (3 hours + gaskets) back in 2014. That's it, no kidding. 383 hours as of today's flight I just got back from. So less than 3AMUs in actual mx? Since gear swings at annual are a requirement for all retracts and thus a sunk cost for any retract you choose to upgrade into.


Oh yeah the prop. Mine has the original non-suffix/non-B suffix prop hub, which means I get some folks to run the eddy current probe every 100 hours (per AD) for a couple hundred bucks. I could fill it with hydro fluid for marker duty as an AMOC, which costs the same as an overhaul so I don't do it. Ditto for putting a B-hub. Prop shop would magically condemn the blades and I'd end up scrapping a perfectly good prop. So I just keep on keeping on the eddy current inspections. I'd have to put 1600 hours on it before I break even on just installing a new prop. I know I'll never own the thing that long, so I don't. To each their own.

The rest will be of course, your specific insurance premium for retract time. For me and my background it's a fart in the wind (700 bucks vs 580 on the warrior? anyways ballwash). Basically insurance rates singularly a function of hull value. You'll have to see what premium you get as a function of your specific experience.

Hope this helps.
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I appreciate the info! The one I am looking at had a recent power pack replacement and a bunch of other landing gear maintenance done so hopefully it wouldn't need too much for the next 500 hours or so on maintenance. Heard some horror stories about "guys going broke on retracts" so a little spooked but wanted to see what the experience was like from others. Thanks!
 
Eric Horton said:
I appreciate the info! The one I am looking at had a recent power pack replacement and a bunch of other landing gear maintenance done so hopefully it wouldn't need too much for the next 500 hours or so on maintenance. Heard some horror stories about "guys going broke on retracts" so a little spooked but wanted to see what the experience was like from others. Thanks!
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Once again, depends on the retract. Not all retracts are created equal. Some have some parts costs that will quickly exceed your yearly operating budget in one mx expenditure. Those are the ones I decided to stay away from, but I'm not gonna start another holy war on here. PM me if interested in those details. BL, I don't consider the Arrow to be in that category. Lord knows I didn't buy this thing because it was the fastest.
 
Eric Stoltz said:
What's wrong with a cylinder in the 60s? Is the oil analysis look bad?
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I figure it's going to degrade further necessitating a replacement. Lycoming says it must be replaced when it gets below 60. The oil analysis is elevated on Fe and if I remember correctly Cu, but the problem is that I haven't run it enough for any meaningful trend data. Plus there are stories on this very site where oil analysis was great right up to a catastrophic failure, so while I still have oil analysis done I don't necessarily rely on it heavily.

There is definitely something going on with it because both plugs in that cylinder had oil on them, so it probably has worn guides or a bad ring. The annual is due next month so will know more then...
 
zbrown5 said:
Pouring over the logbooks of a 1975 200hp non-turbo arrow I’m looking at. 1650 TSOH (1991) and 700 since top end in 2000. It flew about 75 hours a year until 2009, then only about 10-25 depending on the year. It sat most of 2018 with only a couple hours. 75/75/77/77 compression.

Question is should I be relatively comfortable with the compressions and a bore scope test? Would also like to see oil analysis.
Click to expand...

The main problem with Lycomings that sit is camshaft corrosion. The cam is up high and doesn't sit in the oil. Cams pretty much rely on an oil film which doesn't last that long after running. (that's why they get 25 bucks or more for camguard). A long sitting engine can check fine and initially run great and it can take many hours for the cam to wear down. That said, sitting Lycomings are a crap shoot, sometimes the above happens and engine starts showing issues a couple of oil changes down the road. Others run well past tbo with no problems. An oil analysis now won't show the cam metals YET. Only way to be sure is to loosen a jug and slide it partially out to check camshaft.
 
Flybuddy said:
The main problem with Lycomings that sit is camshaft corrosion. The cam is up high and doesn't sit in the oil.
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Continental's cams don't "sit in the oil," either. They're just under the crankshaft where they get dripped on for awhile after shutdown. The high-up cam suffers from moisture condensing on it when sump heaters are used to warm the oil; any water in the case evaporates and condenses on the colder upper surfaces, including the cam and lifters.
 
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