Another “Hangar Queen” Question

VF84Sluggo

VF84Sluggo

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VF84Sluggo
Bear with me on this, as it’s probably been covered, but here’s my question/concern:

I’m looking at a plane that was involved in a landing mishap with a prop strike. The engine was opened, inspected and appropriate repairs made. An, ahem, “top” overhaul was done.

Thing is, the airplane has just been sitting for almost two years, not flown since the mishap. Owner (an A&P) says engine has had a “ground break in run.” He did another ground run (yeah, I know, grounds runs hurt) said cal temp was up to 300 deg (which we all know means no moisture burn off) to do a compression check. Didn’t say why a check wasn’t done on the June 2018 annual.

Anyway, compression was 68, 70, 74, 69 over 80. Perhaps this is normal as the rings haven’t seated yet I’d think. But a bigger concern is the long un-broken-in sit time on the cylinders. Could be a candidate for another “top”.

Thoughts?
 
Those compression are excellent. Flying her for a while will increase compressions a bit.

My bigger concern is the prop strike being serviced by the A&P owner. Many would treat this situation as an INOP engine. Someone within out an economic interest must do the engine IRAN in a prop strike. Un-flown since the prop strike is a red flag with a rotating red beacon on top.

If you absolutely LOVE the plane, negotiate as if you need a new engine, because you probably do to maintain it's value. Brokers would devalue this plane by 30%+ since the engine is a wild card. If he had flown 200 hours since the Engine & Prop IRAN, then the devaluation would not be so steep.
 
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Also according to Mike Bush, you cannot idle a plane enough to get it hot enough to remove condensation in the engine. It simply must be flown long enough to get it hot enough.

We had a guy on the field nicknamed "Colonel Run-up". After loosing his medial he ran-up his plane on the ramp to get his 400hr engine warm every 2 weeks. 3 Years later he finally sold it and the plane would not make static power and needed a new engine since the cam lobes went flat.
 
You could see if he would be willing to pull a couple of cylinders, but my guess is he won't. Without that, you have to assume the engine needs to be overhauled, from a buyers perspective.
 
Pull the spark plugs and scope the cylinders. If you can, scope the crankcase and look at a few cam lobes. That should tell you the corrosion situation.

If corrosion is bad, then you have negotiation on your side. If corrosion is good, then the prop strike question is next and not sure how you negotiate that with a seller who may just wait for the next sucker in line.
 
Also when you negotiate the price down, rather than quoting SGOTI or Mike Busch, I'd carry a copy of Lycoming Service Letter L180B with you and ask him: did you follow this? Of course based on what you wrote, the answer is no so that might give you some leverage to lower the price.
 
Huh? Top overhaul done after a prop strike and that is what was repaired? Cylinders would not be my items of concern, unless they were already toast. You need the crank & cam checked, bearings inspected, etc. If there is no doc showing that was performed, I'd run not walk away from this. Likely explains why it's been sitting as someone doesn't trust it. Think about what happens internally with a prop strike. Cylinders are used to abrupt up/down actions. Happens every time a plug fires, right? The crank, cam, and gears are used to rotations and no movement or other forces.

Correct you can't idle the motor to get the oil hot enough. You need it HOT, and I mean 170+.

My .02.
 
Skydog has a diplomatic tactic as a good approach. You'll rarely win an argument with an A&P owner in this situation. There are too many good plane that come up for sale. This one needs to be the all time beauty queen to move forward if it were me.
 
VF84Sluggo said:
Bear with me on this, as it’s probably been covered, but here’s my question/concern:

I’m looking at a plane that was involved in a landing mishap with a prop strike. The engine was opened, inspected and appropriate repairs made. An, ahem, “top” overhaul was done.

Thing is, the airplane has just been sitting for almost two years, not flown since the mishap. Owner (an A&P) says engine has had a “ground break in run.” He did another ground run (yeah, I know, grounds runs hurt) said cal temp was up to 300 deg (which we all know means no moisture burn off) to do a compression check. Didn’t say why a check wasn’t done on the June 2018 annual.

Anyway, compression was 68, 70, 74, 69 over 80. Perhaps this is normal as the rings haven’t seated yet I’d think. But a bigger concern is the long un-broken-in sit time on the cylinders. Could be a candidate for another “top”.

Thoughts?
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If the engine was opened and the repairs made after prop strike, then the need for a top end overhaul was found and done.
What's the problem?

Engine sat for 2 years, now we have a problem, what was done prior to storage?

Nothing?

well now it is time for another teardown and IRAN.

Ground running this engine is normal, but setting after isn't.
 
Good stuff, thanks.

But to be fair, I did express the concerns about internal corrosion, and the owner/seller has offered to pull a cylinder. Seems like removing a plug and borescoping the cylinders, seeing how they look, as was suggested, would be at a minimum the thing to do.

Also, there were other internal parts replaced, not just a “top” done. The crank was inspected and found to be ok. So again, to be fair, the innards did get a going-through.

The owner did include a doc listing what all was repaired internally, or found to be in satisfactory condition. Also, after re-reading the emails, more correctly the engine was “assembled and installed in October 2017”, which would be a year after the prop strike. Then a ground run in April 2018 (why the 6 month gap?). Owner said when he tore down the engine there was no rust or corrosion on the cam, crank, lifters, etc. And like y’all, I’m wondering why the “top”?

Anyway, this is all a shame. The plane is sweet. The airframe repairs are excellent. Then again, maybe I’m making more out of this than need be.

Thanks for the inputs, gents!
 
NordicDave said:
Un-flown since the prop strike is a red flag with a rotating red beacon on top.
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LOL...but, again, an explanation: as a result of the mishap, the owner lost his medical. His buddy (an EAA Tech Advisor) who did the initial flights on the plane has stopped flying due to advancing age. So the owner said there was essentially no one in his area who could fly the plane (a biplane)
 
A "Top" overhaul has naught to do with the damage that would have been caused by a prop strike. Often the thing that's really damaged are all those little gears back in the accessory case. The crank itself is pretty hefty.
 
Look over the engine, trying negotiate a decrease in price due to the engine issue. Odds are its just fine. Of course, be careful on your first flights and try and stay near runways in case anything happens. I'd say go find another airplane, bit biplanes are just a bit more scarce on the ground.
 
flyingron said:
A "Top" overhaul has naught to do with the damage that would have been caused by a prop strike. Often the thing that's really damaged are all those little gears back in the accessory case. The crank itself is pretty hefty.
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The owner said the throttle was at idle when the prop strike happened. He hit a REIL light on landing, bent the left main back, which caused the prop strike.
 
flyingron said:
A "Top" overhaul has naught to do with the damage that would have been caused by a prop strike. Often the thing that's really damaged are all those little gears back in the accessory case. The crank itself is pretty hefty.
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Most common damage to a crank is a bent prop flange. .005" wobble and they are not repairable.
 
Ok, some more info from the owner, and mega-apologies for incomplete info when I started the thread...still great food for thought, though, in y’alls replies.

The reason for the top was this: the engine, Lyc O-320, had 63 hrs SMOH at the time of the mishap. When the cylinders were pulled, they appeared to be “glazed.” Chrome cylinders. Owner was not happy with his break-in, nor was his engine shop (owner told me the engine shop said even 75% power is not enough ‘hard’running in the first few hours with chrome). So the cylinder were re-honed, new rings, and the need for a new break-in.
 
Make sure all the parts were sent off for NDI as required by Lycoming. If that paperwork is there, you should be fine. It takes time to tear down the engine, send all the parts off (almost all of them) and re-assemble. He likely wasn't in a hurry, either. Change the oil, fly it and start sending samples to Blackstone for trending.
 
For the amount of time that plane was idled, if I was sure that the crank and other parts that may be affected were properly non-destructively tested, I'd just borescope it and go flying if the cylinders were OK. Otherwise, maybe hone them and ring it. I'm assuming it was hangared.
Back to the strike itself, I decided to Q-tip our Skyhawk's propeller by using the runway one windy day (another "chain of events" thing that started with too much chatter on the airwaves); the [150 hr. since major] engine didn't even slow down. It made a very bell-like sound. Of course, one wingtip dragged the ground. The mechanic on the field checked the crank runout, which was perfect, I got a new prop, and flew it to home base. My partner in the plane was advised by the insurance company that they would pay for a complete tear-down inspection; I wondered why, then found that the counterbalances and other bits can get a bit wonky if accelerated too quickly. Not knowing that was my ignorance; good insurance guy! My partner said he wouldn't feel good about the plane unless that was done, so I OK'd it. We also had new rings installed, because it was open. All parts tested OK, but at least everyone was cool with it; all that it cost was a couple weeks on the ground—the insurance company didn't even charge the deductible. And they paid for the rental plane that I used to deliver the prop to the incident runway! Now the old one sits behind my drum kit in the corner of my office; maybe I'll sell it to someone who wants a to cut it down.
 
VF84Sluggo said:
Ok, some more info from the owner, and mega-apologies for incomplete info when I started the thread...still great food for thought, though, in y’alls replies.

The reason for the top was this: the engine, Lyc O-320, had 63 hrs SMOH at the time of the mishap. When the cylinders were pulled, they appeared to be “glazed.” Chrome cylinders. Owner was not happy with his break-in, nor was his engine shop (owner told me the engine shop said even 75% power is not enough ‘hard’running in the first few hours with chrome). So the cylinder were re-honed, new rings, and the need for a new break-in.
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OK now I'd walk,,,, Chrome Cylinders... yucky. They may need several more sets of rings to brake in and stop using oil.
 
Interesting. I figured since I'd be keeping the plane in coastal south Alabama, with all that lovely humid air, chrome cylinders might be a good thing. But doing a little reading a bit ago, it does seem that breaking in chrome cylinders can be hit or miss.

Which is the NEXT thing: before I'd set out on a 1000 mi cross-country behind this engine, I'd want to fly it local, very local at first, for at least 5 hours of high-power flying for that initial break-in. Not to mention the close inspection after each flight to make sure things aren't coming from together to apart.

And of COURSE the plane is kept at a small airport, short-ish runway, kind of narrow, with tricky crosswinds not uncommon. Hmmmm...how many more links in the chain can I find? LOLOL
 
VF84Sluggo said:
Interesting. I figured since I'd be keeping the plane in coastal south Alabama, with all that lovely humid air, chrome cylinders might be a good thing. But doing a little reading a bit ago, it does seem that breaking in chrome cylinders can be hit or miss.

Which is the NEXT thing: before I'd set out on a 1000 mi cross-country behind this engine, I'd want to fly it local, very local at first, for at least 5 hours of high-power flying for that initial break-in. Not to mention the close inspection after each flight to make sure things aren't coming from together to apart.

And of COURSE the plane is kept at a small airport, short-ish runway, kind of narrow, with tricky crosswinds not uncommon. Hmmmm...how many more links in the chain can I find? LOLOL
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As Tom alluded to, the main reason I wouldn't want chrome cylinders is they're used/reworked and tend to burn oil. But I wouldn't let a set of chrome cylinders get in the way of an airplane purchase if everything else is ok. Especially if the airplane is something a bit unique.

I'm reading between the lines a little but it sounds like you're looking at an experimental biplane? One of the more important questions I'd be seeking answers to prior to setting out on a trip with the plane is if the phase 1 hours have gotten flown off. It sounds like this plane may not have gotten much use since completion.
 
NordicDave said:
Skydog has a diplomatic tactic as a good approach. You'll rarely win an argument with an A&P owner in this situation. There are too many good plane that come up for sale. This one needs to be the all time beauty queen to move forward if it were me.
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Did you really use the word diplomatic in reference to me?! :idea:

:lol:
 
mondtster said:
I'm reading between the lines a little but it sounds like you're looking at an experimental biplane? One of the more important questions I'd be seeking answers to prior to setting out on a trip with the plane is if the phase 1 hours have gotten flown off. It sounds like this plane may not have gotten much use since completion.
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Yes, you are correct. I owned one of these 25 years ago, wish I’d never sold it. Hard to find. Don’t come up for sale often.

The plane has had all the requisite hours flown. Less than 70 hrs AF and SMOH when the crunch happened :(
 
Just a data point. I have an 0-320 with 4 Chrome cylinders from Boulduc. 1-3-4 cylinders at ~230 hours and #2 at 55 hours. I burned 2 quarts in 33 hours

EDIT- Ooops, just looked at my paperwork and I have Nitride-hardened cylinders
 
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