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How long can a 170 sit and still be flyable?

Posted: Sat Aug 11, 2012 12:15 am
by Romulus
Hello All,

New to the forums. I've been shopping for a 170 for some time. Found one for sale up here in Alaska for super cheap. The plane has not been in annual for 5 years however the owner says he has flown it a little bit in that time and goes out to run the motor 'every so often'. It appears to be in decent shape, no obvious signs of damage or corrosion and no known damage history. Im not terribly familiar with the o-300 so not sure how it puts up with not being run much. It did upper 70's last time it was annualed. So, would you bite on a 170B with a 3300TT and 1300SMOH for $21,000 despite the sitting?

Re: How long can a 170 sit and still be flyable?

Posted: Sat Aug 11, 2012 1:22 am
by pdb
It's a bit of a roll of the dice.

Has it been sitting in cold dry storage in the interior or on the moist coast? if it was properly stored that would be one thing. If it's been started but not flown long enough for the oil to get hot enough to boil out the water vapor in the oil, which is a product of combustion, the owner may have done more harm than good. How happy will you be to discover that it has rust in the engine?

Spend the money to have a good mechanic look at it first but it's still may be a crap shoot. You may luck out or you may need to buy a new engine shortly.

Do you feel lucky?

Re: How long can a 170 sit and still be flyable?

Posted: Sat Aug 11, 2012 2:06 am
by Bruce Fenstermacher
Pete's just about said it all. Do you feel lucky? Get someone to look it over who knows the plane. Money well spent to better your odds.

Re: How long can a 170 sit and still be flyable?

Posted: Sat Aug 11, 2012 2:46 am
by wingnut
I would add that I currently have 3 aircraft in the hangar that the customers have owned for years. Brought to us because they had an annual inspection performed by a "different mechanic" than the previous mechanics. All 3 aircraft have damage history, which would normally not be a problem. The problem is all 3 aircraft were not repaired, they just had a band-aid put on them. I can't stress enough to have a good structural inspection completed before you buy. Most mechanics know how to check out mechnical things, but most do not know how to look at structural issues.

Re: How long can a 170 sit and still be flyable?

Posted: Sat Aug 11, 2012 4:28 am
by cmsusllc
After selling my 170 I brought a 170A into my hanger that is owned bt a friend and did a thorough annual and was pronounced good to go. The last time I flew this plane was almost 6 years ago. It was run, including the occasional ramp runs, a total of 6 hours since then. I took off after a good run up and circled over the airport for a while running at a high power setting to help clean up the rust. I then ventured out keeping airports and flat land under me at all times. After about an hour everything was feeling good and I was over a grass strip about 10 miles from my home airport so I pulled the power and did a few stalls to feel out the rigging. All was normal so I applied power again to return home. WOW! Nasty vibration. I circled back over the grass strip to trouble shoot. Mags and everything were normal with no change, more power meant more vibration, less power was better. Definately lost a cylinder. Temps and all else were normal so I decided that I had a stuck valve. I circled a few more laps to gain some altitude to make a run for home which was uneventful.
Back at the hanger I opened the cowl to check temps with a gun, Found #2 much cooler so pulled a plug to feel compression, none that I could tell. Put a compressonn guage on it and had 0 / 80. Pulled the valve cover for a look and both were looking good. Looked in the cylinder and both valves looked fine as far as I could see but I could see some scratches in the cylinder wall. Called my mechanic and decided we need to pull the jug. We found the cylinder lightly damaged and the piston with broken rings, missing glands between the ring groves and the top edge of the piston looking like a cutting torch had been taken to it right in front of the intake valve. The piston was heavily scored on down the skirt.
The cylinder has been replaced and has 4 break in hours on it and everything looks good, so far. Also this engine only has 100 hours since major, including all new cylinders, but about 10 years ago.
Shake the dice, you just don't know.
Scott

Re: How long can a 170 sit and still be flyable?

Posted: Sat Aug 11, 2012 2:59 pm
by blueldr
$21,000 is petty cheap. You can afford to do a lot at that price.

Re: How long can a 170 sit and still be flyable?

Posted: Sun Aug 26, 2012 7:09 pm
by GAHorn
[quote="Romulus"]...been shopping for a 170 for some time. Found one for sale up here in Alaska for super cheap. The plane has not been in annual for 5 years however the owner says he has flown it a little bit in that time and goes out to run the motor 'every so often'. ...quote]

That's one of the WORST things you can do to an inactive engine.... "run the motor 'every so often'.." :(

It's better to PROPERLY PRESERVE it ....and NOT run it until ready to return it to service.

Running it "every so often" exposes it to the water by-products of combustion without getting it hot enough/long enough to rid the moisture..... It's a set-up for internal corrosion/rust/sludge....and corroded oil-sump that can later fail in-flight.

Having said that, there are lots of cases where owners have operated these engines after long periods of inactivity and had few problems. It's a good engine for reliability, over-all.

Re: How long can a 170 sit and still be flyable?

Posted: Sun Aug 26, 2012 8:48 pm
by blueldr
Frankly, it sounds to me like a damn good deal. If it is in reasonably good shape and the engine can be run and thoroughly checked out, I wouldn't hesitate at the quoted price. There are a lot of sorry C-170s for sale for a lot more money than that.
As I said in my above comment, you can do a lot for that kind of a price if you really want a C-170.
I would be skeptical about the no damage history, but look carefully for repairs. Damage is only a problem if it is not properly corrected.
You only mention that this airplane is a 170. If it is a straight C-170, get a good punch test on the fabric. My alaskan experience has been that fabric will have a very long service life up there, but not forever.

Re: How long can a 170 sit and still be flyable?

Posted: Mon Aug 27, 2012 1:34 am
by Brad Brady
I agree with Del. 21,000 is cheep... although problems WILL show up, so.....expect at least another 12.000 in repairs......just my thoughts...

Re: How long can a 170 sit and still be flyable?

Posted: Mon Aug 27, 2012 12:26 pm
by Paul-WI
When I bought 58D it had flown 9 hours in the previous 10 years with the past 3 years before I bought not being flown at all. 300 hours later and still flying great. I agree that it really depends on too many variables to determine if this is a good or bad thing in your situation. I think personally that I have been very lucky that I have not had any major problems other than a stuck valve once - and that I don't think was from sitting around not being flown.

Good luck!

Paul

Re: How long can a 170 sit and still be flyable?

Posted: Mon Aug 27, 2012 5:04 pm
by GAHorn
Romulus wrote:Hello All,...So, would you bite on a 170B with a 3300TT and 1300SMOH for $21,000 despite the sitting?
Of course, most comments are subconsciously made with a belief there are operating radios and instruments and no killer-corrosion such as spar or rear bulkhead cracks, etc.. You've got a lot to do before giving him $21K, despite the over-all good-feel about it. (Not to mention to find out about it's Title, Liens, etc., and if the seller actually has the authority to sell it. :wink:

Re: How long can a 170 sit and still be flyable?

Posted: Mon Aug 27, 2012 5:13 pm
by bagarre
Which one do you enjoy more? Flying airplanes or Fixing airplanes?

If you like to tinker, re-wire, overhaul, clean up, replace, clean more up, paint and buck some rivets (and have access to an A&P)..this may be a good deal.

If you don't really want to work on a plane but really want to FLY the thing; buy the most expensive one you can afford and go fly.

This plane sounds like it will be work. That's not bad if you don't mind the work. Its a real joy kill if you want to fly as much as possible tho.