I am considering purchasing a half share in a local 1953 170B. I am meeting with the owner on Tuesday to discuss some particulars and see if we are both on the same page. At this point I haven't reached the point of doing a pre-buy, just some preliminary research.

I know there is a lot of C170 knowledge on BCP. So what problem areas should I be cautious of with this aircraft? Anything I really need to ask the owner about?
Also, the engine is at 1250 TSMO. I realize it could need an overhaul tommorrow, but I am curious if I should be nervous about the hours on the engine or should I expect it to go for a couple hundred more hours? At this point I don't know how long ago the engine was overhauled.

Thanks, ( and don't tell me to just buy a Maule )

Matt

I have the 170 C model (a '56 172 ) with the O-300. What a smooth and reliable engine.

Assuming it has decent compression and oil pressure and no big leaks, you can likely expect it to go several hundred hours. Like all small Continentals, they will leak a little oil out through the pushrod housing seals. No biggie, just live with it until you have to take the cylinders off then there are new style seals. Actually the old seals work better if you throw away those old "hog rings" and use Breeze type hose clamps. Use about 4 ounces of Marvel Mystery Oil in each 20 gallons of gas. You will have to clean the plugs a LITTLE bit more often but the Marvel oil helps keep the valves sealing better and the valve stems lubricated. Go thrugh the engine compartment and make sure everything is tied down correctly with chafe protection... all the lines, ignition wires, small copper primer and oil lines, etc. Know where everything has to be locked down and know where something has to have a little room to move with the engine. This stuff will prevent a lot of failures and wear items... the basic block and cylinders of the O-300 is pretty bullet proof. It'/s the accessories, lines, wires and attachments that will cause problems not likely the big parts.

Thanks for the info EZ. I believe all the compressions are in the high 70s.

Wing attach blocks on wing spar carry through (under headliner) - corrosion

Inner wing corrosion.

Broken internal ribs in the rudder from improperly using a clamp type rudder lock.

Vertical stabilizer fairing bracket broken at leading edge from people grabbing it as a handle during ground movement. Even if the bird has tail pull handles (a mandatory mod IMO) people still use it and put pressure on it while swinging the tail.

Door latch springs broken? Door latch strike plate damaged or worn?

Door hinges cracked or extremely worn? (hard to repair or replace)

Flap tracks worn with play in them? $$$

Gear straight and aligned properly?

Mag AD complied with?

Cowling hatch latches in good working order?

Carb overhauled any time recently? If so there are synthetic parts in there now that are sensitive to ethanol - are they braking down?

Air box - bushings for carb heat flapper worn?

Gear box damage.

Tailwheel leaf spring not replaced in a long time. Should be replaced every few years particularly if doing rough landings.

O300 exhaust not replaced or overhauled in a while. The exhaust baffles corrode and break down after a few years.

Seat tracks, seat roller housings and seat rollers worn. Need replacing?

Then there is the engine

Have you lurked on the 170 Association forum? I know... there are some strong personalities over there... but look past that and there is a wealth of information and persons willing to help. Here is a good place to start:
http://www.cessna170.org/forums/viewtopic.php?f=2&t=1969



Good luck...
K

Thanks for the info guys. I have a A+P friend who will get involved if I pursue this further, but I at least I have some good topics to discuss with the owner this week.

Any engine questions or issues I should bring up? I believe the owner has flown it about 50-75 hours a year.

kg wrote:Have you lurked on the 170 Association forum?
Good luck...
K

Thanks, wasn't aware they had a forum. I will take a look.

Be sure to check the main "channel" piece on the rudder.
They are often cracked around the "Hinge Blocks" and there are no new parts.
May have to look for a whole rudder if that channel is not salvageable.

Also check where the flap tracks enter the back of the wing.
There is a small 90* bracket on each side of each track. They are often cracked and difficult to repair. The repair involves adding a second bracket so you end up with two brackets on each side of each track.
That is probably the most difficult repair I ever had to do.
All of the relatively newer Cessnas I have looked at now come with double brackets.

Check for side play in the yokes. It is a bitch to pull the whole control unit out of the floor to replace the bushings and long bolt on the bottom between the rudder peddles.

Those were my hardest repairs and they were done to a plane "fresh out of annual."

Chris C

fern_hopper wrote:

kg wrote:Have you lurked on the 170 Association forum?
Good luck...
K

Thanks, wasn't aware they had a forum. I will take a look.

You'll find a lot of information on the 170 forums.

Parts which are difficult to find or expensive are:
Oil pans for the C145 / O300. They have a low spot that holds water if they sit a long time and it corrodes a hole in the bottom of the pan.
Crankshafts. TCM no longer supports the engine so if you need one, the used market is your only option.
Upper door hinges.
Door latches, but they can be repaired on your shop bench.
Prop spinners-- you can find them but they are $$$$. They get cracked when an overzealous mechanic uses his power tool to tighten the screws.
The front of the cowling gets cracks .... Used cowlings are rarely available as they get busted in the crash and new cowlings are big bucks. Cowling repairs can be made by a good sheet metal man though.
Tailwheels take a beating and they are getting expensive. Over 1K for a new one from Alaskan Bushwheels.

K

In my experience the 0-300 bottom end will make tbo the cillenders need to be redone every 6-800 hours usually just valve guides and rings

Re the engine. As cc says, the bottom ends go forever, the cam is in the bottom so gets more oil than the Lycoming ones do. If the cylinders have the 1250 hrs on them that the engine has you are likely looking at doing them in the next 200. As 1950's aircraft go, they are about as dependable as it gets, and as easy to maintain. It's a boon if it has an alternator as the little generators were anemic. Fun and easy to fly. You'll learn what toe brakes are for.

oldtech wrote:It's a boon if it has an alternator as the little generators were anemic.

No argument about the generators being anemic. If it's a long taxi after landing I turn off any electrical draws that don't need to be on (which is nearly all of them, flying around here). On the other hand, I asked my IA about converting to an alternator and he discouraged it. He pointed out that he frequently replaces bad alternators, but that generators seem to go and go and go.

-DP

Fresno Air Parts for overhaul kits for the original starter and original generator. At the price of these kits I rebuilt both of them every three years..simple if you do not run them until they quit. They have an add in Trade-A Plane.

oldtech wrote:Re the engine. As cc says, the bottom ends go forever, the cam is in the bottom so gets more oil than the Lycoming ones do. If the cylinders have the 1250 hrs on them that the engine has you are likely looking at doing them in the next 200. As 1950's aircraft go, they are about as dependable as it gets, and as easy to maintain. It's a boon if it has an alternator as the little generators were anemic. Fun and easy to fly. You'll learn what toe brakes are for.

Thats good news about the bottom end. The plane has a 60 amp Jasco alternator I believe.

Easier to fly then a pacer? Thats what I am used to right now.

Easier to fly then a pacer? Thats what I am used to right now.

Than a tailwheel Pacer? Oh hell yes. The 170 is a pussycat on landing so long as the gear is aligned properly.