the little C-90

[weirdjim]

So you've got a little small-bore Conticoming that has been sitting for six months. Prior to starting it up and getting iron oxide imbedded into the rings, what can you do to wash the stuff down so that it won't get the rust into the mechanisms?

Thanks,

Jim

 

[Henning]

So you've got a little small-bore Conticoming that has been sitting for six months. Prior to starting it up and getting iron oxide imbedded into the rings, what can you do to wash the stuff down so that it won't get the rust into the mechanisms?

Thanks,

Jim

Phosphoric acid, best to disassemble the top end and clean everything up and give it an assembly lube. You can also fill it in through the top plug holes and do a slow pull through to wet everything, then flush with CRC Electromotive and spray in some lubricant and fire it up, get it hot, then change the oil.

 

[Tom-D]

So you've got a little small-bore Conticoming that has been sitting for six months. Prior to starting it up and getting iron oxide imbedded into the rings, what can you do to wash the stuff down so that it won't get the rust into the mechanisms?

Thanks,

Jim

Some engines will set for years, and have very little rust in the cylinders, others won't go that long, so to start bore scope it see what you are dealing with.
It's best to remove the cylinders and use a brush hone and clean it up. re-ring it, if required, and touch up the valve grind, and ream the guides while you are there.

 

[Silvaire]

Yes and it can seem random as to why. When I bought the Champ it had been sitting outside tied down and forgotten at the edge of the airport for years. I cleaned it up, changed the oil and that was about 5 years and 700 trouble free hours ago. Pictured below however are the magnetos out of a Citabria that had sat in a hangar for several years.

 

[Tom-D]

Yes and it can seem random as to why. When I bought the Champ it had been sitting outside tied down and forgotten at the edge of the airport for years. I cleaned it up, changed the oil and that was about 5 years and 700 trouble free hours ago. Pictured below however are the magnetos out of a Citabria that had sat in a hangar for several years.

That just exposes the cylinder corrosion is the least of your problems.
There is no oil on any market that will stop electrolysis on gears, cams / lifters and ring to cylinder wall.

 

[Tom-D]

This engine is a rainy day project, it's raining, so I guess I'll go pull it and open the cases to see what is in there.

 

[bnt83]

Corroded magneto parts is common.

My biggest interest is camshaft and lifter condition. How long ago was the engine apart and how many hours? If total age of the cam, crank, lifters and case can be determined, that would be interesting too.

I'd be pretty interested in seeing what the inside of a 50 year old engine looks like that has never been apart before.

Side Note, I pulled the mags off an engine that has averaged 36 hours a year since it was brand new (46 years ago) and the corrosion on the gears looked nothing like above. The gears are original. Engine has never been overhauled.

 

[bnt83]

I too agree that spalling and corrosion problems seem random.

 

[Tom-D]

this engine. 2251.7 TT. 417 from major 6/30/2002, logs start at 2/12/92 time was calculated at that time to be 1456.8. It has had 2 prop strikes since then one at 27.7 TSMO. and 134. SMOH. and time now is 417.4 SMOH

added pictures:

Bearings look great, lifters show spalling, cam is showing some wear tracking due to the lifters, I haven't run the crank numbers yet. but the log shows that it is already cut 10 under.

 

[bnt83]

Looking good! Show us any show stoppers.

 

[Peter Bell]

Yes, it is starting to look better, certainly since that horror first day when Tom pulled the cylinders off. But it was no real surprise, the motor has been bad to fly behind for a while now. I started to perceive a difference in it, not particularly in performance, more roughness and exhaust note, 18 months ago and it had gotten exponentially worse over the last 6 months. I'd pretty much lost confidence in it and that was one of the reasons I dragged Tom in.

As Tom said, I'll be going for nickel cylinders and cylinder preventative measures. It just goes to show that being a really fussy owner, and I am, can't prevent the effects of poor usage cycles.

I've always said, I'm a perfect example of how not to treat a small aircraft engine - for those who wonder I work overseas in the oil industry, six weeks on/off. And a perfect example of that middle aged quandary of working hard enough to be able to afford toys, but then hardly having the time to use them. So my chance to fly the 120 is more like one month flying, two months sitting.

Oh, Tom- you might have posted a photo of when the plane had actually had a polish :wink2:

Peter

 

[Tom-D]

Yes, it is starting to look better, certainly since that horror first day when Tom pulled the cylinders off. But it was no real surprise, the motor has been bad to fly behind for a while now. I started to perceive a difference in it, not particularly in performance, more roughness and exhaust note, 18 months ago and it had gotten exponentially worse over the last 6 months. I'd pretty much lost confidence in it and that was one of the reasons I dragged Tom in.

As Tom said, I'll be going for nickel cylinders and cylinder preventative measures. It just goes to show that being a really fussy owner, and I am, can't prevent the effects of poor usage cycles.

I've always said, I'm a perfect example of how not to treat a small aircraft engine - for those who wonder I work overseas in the oil industry, six weeks on/off. And a perfect example of that middle aged quandary of working hard enough to be able to afford toys, but then hardly having the time to use them. So my chance to fly the 120 is more like one month flying, two months sitting.

Oh, Tom- you might have posted a photo of when the plane had actually had a polish :wink2:

Peter

The cases and rods went to Chuck Ney's shop today.

The crank is in perfect condition, we will fit it with new M.010" bearings, 8 new lifter bodies, 8 hydraulic units, 8 new lifter cups, Plus 8 new rod bolts, nuts, and keys. A gasket kit.

The cam is fair to better condition, I do not know if the profile is correct, so that will go for IRAN at Aircraft specialties.

 

[Tom-D]

Oh, Tom- you might have posted a photo of when the plane had actually had a polish :wink2:

Peter

It's still a sweet aircraft even with my greasy prints all over it .

 

[Peter Bell]

Thanks Tom,

Good lessons to be learned from the whole affair, by any owner. It seems the bottom end stayed well protected by my oil changes, but the top ended suffered from my schedule.

Looking forward to you being able to show the results of a Tom Downey rebuild on here.

 

[Mason]

So my chance to fly the 120 is more like one month flying, two months sitting.

:wink2:

Peter

Might I suggest finding a trusted friend/partner who could put a few hours on the airplane in your absence, strictly as a maintenance prevention procedure? A few hamburger runs, like once a week, might do it.

 

[Peter Bell]

Might I suggest finding a trusted friend/partner who could put a few hours on the airplane in your absence, strictly as a maintenance prevention procedure? A few hamburger runs, like once a week, might do it.

Mason,

Tried that already with two friends, both of whom went their own way with work soon after we talked about the idea. Needing tailwheel experience drastically reduces the potential of finding someone.

I hate not looking after stuff, but, unfortunately I might just have to put this down as a casualty of my relatively well paid lifestyle.......or, find more friends.

 

[Tom-D]

Mason,

Tried that already with two friends, both of whom went their own way with work soon after we talked about the idea. Needing tailwheel experience drastically reduces the potential of finding someone.

I hate not looking after stuff, but, unfortunately I might just have to put this down as a casualty of my relatively well paid lifestyle.......or, find more friends.

The nickel cylinders should take care of the idle period problems.
Plus I have a set of dehydrator plugs I'll donate.

 

[Tom-D]

Might I suggest finding a trusted friend/partner who could put a few hours on the airplane in your absence, strictly as a maintenance prevention procedure? A few hamburger runs, like once a week, might do it.

That would be a hell of a lot of trust for a C-120 that has three tip-ups in 400 hours.

 

[Henning]

this engine. 2251.7 TT. 417 from major 6/30/2002, logs start at 2/12/92 time was calculated at that time to be 1456.8. It has had 2 prop strikes since then one at 27.7 TSMO. and 134. SMOH. and time now is 417.4 SMOH

added pictures:

Bearings look great, lifters show spalling, cam is showing some wear tracking due to the lifters, I haven't run the crank numbers yet. but the log shows that it is already cut 10 under.

How does the line bore look?

 

[Henning]

That would be a hell of a lot of trust for a C-120 that has three tip-ups in 400 hours.

 

[Peter Bell]

That would be a hell of a lot of trust for a C-120 that has three tip-ups in 400 hours.

....none of which were the present owner's, my pride needs to mention.

( reaching out for the biggest piece of wood to touch that I can find)

 

[Tom-D]

How does the line bore look?

It will look perfects when it comes back from being lapped and line bored, by Chuck Ney's shop. he has done well over 100 cases for me never a problem.

We lost Chuck back in Dec 2014, I hope his shop continues the quality he was so famous for.

It was a long time prior to his passing that he stopped running the machine shop, so I'm hopeful.

 

[Tom-D]

....none of which were the present owner's, my pride needs to mention.

( reaching out for the biggest piece of wood to touch that I can find)

Sorry, I should have mentioned that.

 

[Henning]

....none of which were the present owner's, my pride needs to mention.

( reaching out for the biggest piece of wood to touch that I can find)

Just stay away from the brakes until you clear the runway and you will have it 99% licked, keep your heels on the floor and typically you're fine. The other 1% is because of having to slam the brakes last moment due to taxi technique. Make sure you swing enough to keep a good mental picture of what's where and don't let any area be blanketed for more than a few seconds. When I taxi a tail dragger I look like a meandering drunk staggering back and forth down the taxiway.

 

[Tom-D]

Just stay away from the brakes until you clear the runway and you will have it 99% licked, keep your heels on the floor and typically you're fine. The other 1% is because of having to slam the brakes last moment due to taxi technique. Make sure you swing enough to keep a good mental picture of what's where and don't let any area be blanketed for more than a few seconds. When I taxi a tail dragger I look like a meandering drunk staggering back and forth down the taxiway.

Have you ever sat in a 120? you have no problem seeing every thing.

 

[Peter Bell]

Have you ever sat in a 120? you have no problem seeing every thing.

...well, I didn't see a full engine rebuild coming up 5 years after I bought it

 

[Tom-D]

...well, I didn't see a full engine rebuild coming up 5 years after I bought it

I wish I could see 5 years ahead too.

 

[Mason]

Mason,

Tried that already with two friends, both of whom went their own way with work soon after we talked about the idea. Needing tailwheel experience drastically reduces the potential of finding someone.

I hate not looking after stuff, but, unfortunately I might just have to put this down as a casualty of my relatively well paid lifestyle.......or, find more friends.

Well maybe you can't see the forest for the trees.

You have an A&P handy who is not only an engine guru but is no doubt quite proficient with a tailwheel machine.

 

[Mason]

What is it about these forums that makes complete strangers know exactly the answer to every problem?

I've been in the hangar opposite Tom for several years, so I'm quite aware of whether he wants to fly my 120 or not. With that can we maybe just get back to what the insides to my C90 look like.

Gee! It was only a suggestion. Sorry if that doesn't work for (both of) you.

I have some tailwheel time in Champs and C-140s, not to mention a couple hours in my Uncle Art's Cub and Stinson, and would be glad to fly your bird an hour or two a month but I don't believe we live in any proximity for that to happen nor do we seem to be on a common wavelength.

Good luck.

 

[Peter Bell]

Gee! It was only a suggestion. Sorry if that doesn't work for (both of) you.

I have some tailwheel time in Champs and C-140s, not to mention a couple hours in my Uncle Art's Cub and Stinson, and would be glad to fly your bird an hour or two a month but I don't believe we live in any proximity for that to happen nor do we seem to be on a common wavelength.

Good luck.

Hey Mason

Yeah, I removed my answer because I realised I'd taken your suggestion the wrong way. Maybe, I'm just getting a bit touchy that my life's decisions seem to be on display, when all Tom started talking about was the insides of my engine.

Thanks for the thought
Peter

 

[Mason]

Hey Mason

Yeah, I removed my answer because I realised I'd taken your suggestion the wrong way. Thanks for the thought
Peter

No problem and as I said, good luck. Your airplane looks really great in those pictures, polished aluminum is just fantastic.

 

[Capt. Geoffrey Thorpe]

That would be a hell of a lot of trust for a C-120 that has three tip-ups in 400 hours.

Time to replace the Grabyear brakes with Clevelands.

 

[Tom-D]

Well maybe you can't see the forest for the trees.

You have an A&P handy who is not only an engine guru but is no doubt quite proficient with a tailwheel machine.

I have a major rule when it comes to flying others aircraft.

I won't fly it if I can't buy it or wouldn't want to own it.

In Pete's case If I flew the 120, and any thing happened, I simply would never feel right about it.
beside it's a moot point, I have no medical.

 

[Tom-D]

Time to replace the Grabyear brakes with Clevelands.

done long long ago.

 

[Henning]

I have a major rule when it comes to flying others aircraft.

I won't fly it if I can't buy it or wouldn't want to own it.

In Pete's case If I flew the 120, and any thing happened, I simply would never feel right about it.
beside it's a moot point, I have no medical.

Too bad the 120/140 didn't fall into the SP exemption.

 

[Tom-D]

Hey Mason

Yeah, I removed my answer because I realised I'd taken your suggestion the wrong way. Maybe, I'm just getting a bit touchy that my life's decisions seem to be on display, when all Tom started talking about was the insides of my engine.

Thanks for the thought
Peter

I started this thread due to all the chitter chatter about what happens to engines that set for long periods of time.
and what normal wear we see due to that.
I was expecting to see much more wear caused by the iron oxide from the cylinders. But surprise surprise that filter and frequent oil changes save that crank.
As we both noted the rod bearing had way too much clearance than we could except. The reason for that in my opinion is, they were not reworked at last overhaul.

 

[Tom-D]

Too bad the 120/140 didn't fall into the SP exemption.

That would not change any thing.