Engine age vs hours

When I bought my Arrow last year, the engine had 1300 hours and 29 years on it. It ran great, good compressions, no signs of corrosion during the prebuy. Five months later a fatigue crack appeared in the case underneath the #2 cylinder. Having to OH an engine less than 6 months after buying the airplane kinda hurt.
 
NordicDave said:
Yup, but conventional wisdom in this thread is calendar time is no factor in engine longevity.
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I wouldn't say that. It's a factor. Just not the only factor.
 
I have same exact engine and similar hours SMOH and years since overhaul. I've put ~200 hours on the plane, runs flawlessly so far. Good oil analysis results as well. Data point of one.
 
Roy Lee Kinser Jr said:
I feel like I'm beating a dead horse with another engine question thread, but I can't seem to find something that speaks to this specifically.

I'm looking at buying an older Cherokee with a Lycoming O-360-A3A engine. The aircraft itself is nearly perfect for my mission. 3100 AFTT and 750 SMOH. The issue is the date of that overhaul, which was 19 years ago, far exceeding the 12 year suggestion from Lycoming.

From reading similar threads, I know folks take engines beyond that recommendation, but I'm uncertain how common that is and certainly unsure as to how fraught with complications that is. So I'm curious, are guys out there really taking running engines out of service for OH due to years or is that just a suggestion that most brush off? Has age been the source of issue for others out there?

Again, sorry for beating a dead horse, I just can't seem to decipher the right mix of low airframe hours, low OH age, has all the avionics needed, NDH, etc etc.... it seems like that is impossible and I'm going to have to compromise somewhere.
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What I did: Bought a Cherokee ~550 SMOH, (15 years on OH) bought it as run out, and been flying it since. Here in the humid southeast, that's a gamble. Which, in my case has paid off. (so far) I fly it as often as I can. ~ 50hours/year, or more.
 
Jmcmanna said:
When I bought my Arrow last year, the engine had 1300 hours and 29 years on it. It ran great, good compressions, no signs of corrosion during the prebuy. Five months later a fatigue crack appeared in the case underneath the #2 cylinder
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The only factor in all of the above that is relevant to fatigue cracking of crankcases in engine total time. Neither hours or years since overhaul have any relevance to crankcase fatigue cracks, since crankcases are not often replaced at overhaul and cracks do not grow unless the engine is running.

My engine at 1100 hrs total time, 48 years old, is less likely to crack its cases than a freshly overhauled 10 year old engine with 2000 hrs total time on the cases. The only benefit of an overhaul in that regard is that it might catch a cracked case before the crack grows enough to leak or cause other worse symptoms.
 
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A review of my best friend's old PA-28 180C showed that the original engine went 3600hrs with very little maintenance except for standard oil changes, etc. They replaced it with a factory new engine, and he bought it with around 1900 hours on that second engine. After running it to close to 2500 hrs TT on that engine, a hailstorm decided that he needed an airplane upgrade...

More to the story: the next owner (perfectly flyable airplane) ran that engine for another 100hrs or so before it started making some metal. Then they pulled the trigger and put another factory new engine on the bird. Unfortunately, about 20hrs later a loose fuel line caused the thing to catch fire on the ground and total the airplane (for reals this time!).

What's the moral to the story? You choose the punchline...
 
NordicDave said:
I understand. I was more sarcastically commenting on the few edge cases of guys with “my engine is over 30 yers old and no problem here...”.
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More than a few, (my 1977 o-320, 900 hours, doesn't leak either). I think calling me and the others "edge cases" only shows the problem with your blanket statement.
 
Weekend Warrior said:
More than a few, (my 1977 o-320, 900 hours, doesn't leak either). I think calling me and the others "edge cases" only shows the problem with your blanket statement.
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My own engine was last O/H'd 31 years ago and running strong. It's my belief if we look at the totally of the GA fleet most engines are more recently overhauled. Just looking at the fleet for sales over the years on Trade a Plane or Controller, it's very rare to see a plane's with last O/H'd engines from 3 decades ago.

Not saying pilots here don't have a old engine based on calendar time, but just more engines in the fleet are newer than this. Time is a factor, but not a determiner. Seems like most long date engines suffer from cylinder or cam/lifter corrosion necessitating and overhaul.
 
NordicDave said:
My own engine was last O/H'd 31 years ago and running strong. It's my belief if we look at the totally of the GA fleet most engines are more recently overhauled. Just looking at the fleet for sales over the years on Trade a Plane or Controller, it's very rare to see a plane's with last O/H'd engines from 3 decades ago.

Not saying pilots here don't have a old engine based on calendar time, but just more engines in the fleet are newer than this. Time is a factor, but not a determiner. Seems like most long date engines suffer from cylinder or cam/lifter corrosion necessitating and overhaul.
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Based on the ads I usually see and knowing the planes I work on, there are fewer that remain within the calendar TBO requirements than those that aren’t. Most are 20-30 years old it seems, or in other words were overhauled when GA was still quite popular. With the exception of some newer aircraft and those flying quite regularly, the average owner will not invest in a new engine unless they absolutely have to. They’ll milk it and sell the airplane when it gets too bad.

Regarding your corrosion comments on old engines, they’re real. I can count on one hand how many of the engines I’ve overhauled have made the hours TBO, the majority of them have aged and rusted out. The one I just did had 600 hours in 30 years and rust got the cam and lifters and there are many more just like it. I’m staring at another plane as I write this that will be lucky to have 500 on it before the plug is pulled.
 
mondtster said:
Based on the ads I usually see and knowing the planes I work on, there are fewer that remain within the calendar TBO requirements than those that aren’t. Most are 20-30 years old it seems, or in other words were overhauled when GA was still quite popular. With the exception of some newer aircraft and those flying quite regularly, the average owner will not invest in a new engine unless they absolutely have to. They’ll milk it and sell the airplane when it gets too bad.

Regarding your corrosion comments on old engines, they’re real. I can count on one hand how many of the engines I’ve overhauled have made the hours TBO, the majority of them have aged and rusted out. The one I just did had 600 hours in 30 years and rust got the cam and lifters and there are many more just like it. I’m staring at another plane as I write this that will be lucky to have 500 on it before the plug is pulled.
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Good post, it was insightful.
 
mondtster said:
Based on the ads I usually see and knowing the planes I work on, there are fewer that remain within the calendar TBO requirements than those that aren’t. Most are 20-30 years old it seems, or in other words were overhauled when GA was still quite popular. With the exception of some newer aircraft and those flying quite regularly, the average owner will not invest in a new engine unless they absolutely have to. They’ll milk it and sell the airplane when it gets too bad.

Regarding your corrosion comments on old engines, they’re real. I can count on one hand how many of the engines I’ve overhauled have made the hours TBO, the majority of them have aged and rusted out. The one I just did had 600 hours in 30 years and rust got the cam and lifters and there are many more just like it. I’m staring at another plane as I write this that will be lucky to have 500 on it before the plug is pulled.
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That makes me sad. Someone who is fortunate enough to own a plane, should fly it frequently.
I always surpass TBO and end up on condition.
 
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