The International Cessna 170 Association

Airplanes...they have cost me more money than two ex-wives!

My 1952 B model has had two major overhauls in it's 50 year existence - first in 1960 at about 700 hours and in 1974 at 1,450.

Here it is 2002 and 2,250 hours airframe and engine (still with the powerplant it was delivered with.) I've been fighting cylinders one at a time since I bought the thing in January 2000...leaking exhaust valves, worn guides, worn-out rocker arm towers and such. The only two cylinders that haven't been off the engine since 1974 have egg-shaped wear in the rocker arm towers (number one, with no bushings, obviously first run) and a missing bushing on the number six. That's it - I bought six brand new Superior jugs, with the idea of topping it.

For this job in these parts, there is no choice as far as I'm concerned. Ray Stillwell has been an A & P since 1956. He specializes in re-builds, and has done many O-300s in his day. He did the 150 Franklin on my Stinson, and does top-notch work.

So after the cylinders are off, I mention this might be a good time to pull the rear case and the sump, because the oil leaks are getting pretty bad.
He gives me one of his looks, and I know what is coming next! I beat him to it..."well, the only thing left on the mounts are the two cases halves and the crank and camshaft; how much do you think it would be to just go ahead and major it? He comes up with a very reasonable number. I think about it overnight and then tell him to go ahead.

It's probably overkill on my part - oil pressure in cruise is 45 psi and 30 at idle. If the sump and rear case weren't leaking so bad, I probably would have stuck to the original plan. But the only real downside was the money; VERY real- but I do fly my airplane IFR and night VFR. Plus 28 years IS a long time...this is from a guy who was flying a 1946 Stinson around on an engine that had NEVER been re-built since new (48 years and 450 hours, probably some kind of record!)

If you guys are interested, I'll keep you posted as events warrant...Russ Farris

NO WUNDER YER PLANE IS SO POLISHED! HEK I GOT FOUR HUNNERT HOURS TAXYEN ROUND THE PATCH TRYIN TU FIND THE GAS PUMP!

AS FER THEM EGG SHAPE HOLES IN THEM ROCKY BOX BOSSES YER JUS LUCKY THEY DINT BECOME U SHAPE AND LET YER SHAF RATTLE ROUN BY ITSESF! I JES HOPE THU SEEPIN IN YER SUMP AINT SUMPIN MORE SERIOUS THAN SQUISHY GASKETS.

Russ...Keep us posted I'm almost in the same place. I have put 3 new cylinders on in the last 100 hrs or so. I think I had better finish up and replace the other 3. I will be making the same decison on breaking open the case or not.
Bob

Yes Russ, please keep us posted. You are not that far away from me and I might consider your overhaul man when my turn comes up. So far, so good on all jugs. 400 STOH and 900 SMOH in 1974. Compression good and oil pressure right up under the redline. Rocker areas look good on the two cylinders that I have installed the pushrod conversion kits. The only thing I noticed that bothered me is the fact that the rocker shaft rides back on the aft portion of the rocker cover with a clear wear pattern I would think that the rocker cover should be built up in the load bearing area if it is normal for the rocker shaft to ride against it Now where is that tree I need to knock on right about NOW

Russ, I went thru this four years ago on my engine. My $11,000 rebuild job turned into a $15,000 job. Most of the increase was my doing - it's hard not to get carried away. I had a B&C starter installed, had the new cylinders port polished and flow balanced, had the new style push rod tubes installed. Then there was the stuff they found, cracked cluster gear $900, leaky oil sump $600 (repaired by Drake welding mentioned in previous posting, which just started leaking again). While it was painful, it does give ya that warm fuzzy feeling about your engine when your flying over that rough terrain. Good luck.

Karl

An adventure in the making, that's for sure!

Aircraft Specialties called with the bad news...my C-145 crankshaft has a length-wise crack in the front main bearing area. I have mixed emotions about this, like the old joke about watching your mother-in-law drive off a cliff in your brand new Mercedes! While obviously upsetting, it's not as bad as having the thing break at 6,000 feet at night with my family on board. I'm glad I decided to major the engine. I wonder if that 1956 mid-air where my airplane's prop cut off half the stabilizer of a DC-3 started it...of course, it's only 50 years old!

My mechanic has already found four eight bolt crankshafts, all yellow tagged by Aircraft Specialties. Three are .010 under and one is standard size, which of course I would prefer. All four are priced at around 3,800 bucks, which seems high to me. I know the eight bolt flange for the C-145/O-300A is getting tough to find, and the price probably is a reflection of this, but I'd appreciate some input from the collective minds out there.

And if anyone has a good one for sale, at a reasonable price, I'd love to hear from you...thanks, Russ Farris

How about a 6-bolt crank? Guess that'd be out of an O-300D. I don't know,but I think the O-300C used the same 6-bolt crank,and possibly also the GO-300.
An awful lot of O-300D's out there,parts availability might mean a lower price. Of course,then you'd need a 6-bolt prop....
Seems like I remember somebody telling me a year or two ago that they'd bought an airworthy .010" under crank for around $2500.
Good luck.
OR, maybe you should buy Dave Clark's good used engine. Check his posts.....

Eric

Russ Farris wrote
"All four are priced at around 3,800 bucks, which seems high to me. I know the eight bolt flange for the C-145/O-300A is getting tough to find, and the price probably is a reflection of this, but I'd appreciate some input from the collective minds out there. "

Russ
This is about what I paid for a runout O-300D a couple of years ago with a guarantee on the the crankshaft and crankcase. I swapped props with the guy and had (have) numerous parts to sell. My good crankshaft paid for most of the 0-300D. Also have an oil pan and a yellow tagged crankcase if you or someone else needs them. The future parts availability influenced my decision to go to the newer engine. Headquarters has the STC for the engine swap. Paul

Russ

I would rather have a fresh ground -.010 yellow tagged crank than a worn to service limits standard crank. The standard crank must be at new limits to build a good engine. The fresh ground -.010 will probably outlast your lifetime.

zero.one.victor wrote:How about a 6-bolt crank? Guess that'd be out of an O-300D. I don't know,but I think the O-300C used the same 6-bolt crank,and possibly also the GO-300.
An awful lot of O-300D's out there,parts availability might mean a lower price. Of course,then you'd need a 6-bolt prop....
Seems like I remember somebody telling me a year or two ago that they'd bought an airworthy .010" under crank for around $2500.
Good luck.
OR, maybe you should buy Dave Clark's good used engine. Check his posts.....

Eric

The O-300-C and D cranks both have 6 bolt prop flanges. But the GO-300 cranks do not have ANY prop flange at all. (They have a pilot gear to drive the gearcase.)

Duh! I DO know why they call it a G (geared) engine. What was I thinking?

Eric

Russ, the latest GA News has this ad:
"O-300-D crankshaft magnafluxed,$2950 outright.Specialty Aircraft 800-500-6786,www.specialtyaircraft.com"
That crank takes a 6 bolt prop.

Eric

Magnafluxed... do they mean just that or is it overhauled and yellow tagged? Would one still need to send it out for plating the flange and such?

I didn't really know what they meant by that either,that's why I put their whole ad in my post in quotes. If it was yellow-tagged,seems like they would have said so. "magnafluxed" doesn't necesarily mean airworthy.......

Eric

Right Eric, it needs to be dimensionally checked, runout of flange etc also to be yellow tagged which is what I meant. My buddy here has built about eight 0-300/C145s in the last couple of years says only one of them had a good crank on teardown! I didn't know it was that bad. Then there's the oil pan problem. Meanwhile I've been exercising my C-145 a bit but the time will come when it needs to come off for the conversion. I'm busy on items in the cabin to get done first anyway. It's going to be REAL nice next time you see it!