pmh wrote:
Why overhaul it into something that could give more problems
That’s a philosophy I am cautiously following myself. My O-320 is at around 1000 hrs total time and 45 years, never overhauled. I just did the annual inspection with my A&P IA friend and found compression 78/77/78/76, very clean plugs, minimal oil seepage and not a spot of anything in the oil filter media. I’d love to know if it once had a top overhaul off the books, the long term prior owner was a professional engine man, but there’s no way to know. My biggest concern is the cam because the engine has clearly sat idle for long periods in its past, but there does not seem to a cause for concern.
Not the same as running an engine past TBO (in hours) but perhaps worth a post.
pmh wrote:
We have almost 2700 hours and 16 years on a IO360-l2a.
As far as I know we have no problems running it on condition.
Reading articles from Mike Busch it seems there is no benefit to mess with it before it develops problems. We have low oil consumption, high compression, no problems. Why overhaul it into something that could give more problems.
Why not change registry?
In a few years there is no one left in national CAA to deal with this and these things will be equal in all EASA countries.
I don’t want to overhaul the engine, but I’m not alone in deciding this. The engine now has 2920 hours and extending it beyond 3000 would probably necessitate an owner declared maintenance programme. Several people in the club are a bit scared about that. (The 3000 hour limit — or rather TBO+50% — is an old requirement of the Swedish CAA which they can’t enforce anymore but the current maintenance programme includes that provision AFAIU.)
Has the engine ever gone for a few weeks or more without flying, and has it always flown for 1hr or more?
What has been the usage? Club outings, PPL training…?
Any prop strikes / prop damage of any kind?
Oil analysis and oil filter definitely opened and checked?
I would not make this decision on compression alone. Note that, for example, you can lose 40% of valve travel (due to a shagged camshaft) and lose only 10% of the power, which most casual flyers won’t notice.
There a fair element of luck. Our factory overhauled o320 gave up the ghost at 1400 hours and it had been flown regularly. It was scrap.
O-200 from jade made tbo+20% although had some clinders replaced (cant remember how many)
Our o-200 from norvic made tbo+20% to (had 2 cylinders replaced)
A o-235 overhaul by NM cam went at 1400 followed by a cylinders 200 hours later.
We have an o-200 overhauled locally by a one man band shop and I have to say that’s by far the smoothest o-200 I’ve sat behind. Has about 400 hours on it now.
Peter wrote:
Has the engine ever gone for a few weeks or more without flying, and has it always flown for 1hr or more?A few weeks, yes, more than a month, no. It has frequently been flown less than 1hr.
What has been the usage? Club outings, PPL training…?
More of the first that the latter.
Any prop strikes / prop damage of any kind?
No.
Oil analysis and oil filter definitely opened and checked?
No and yes.
I would not make this decision on compression alone. Note that, for example, you can lose 40% of valve travel (due to a shagged camshaft) and lose only 10% of the power, which most casual flyers won’t notice.
This engine certainly produces full power. The aircraft meets book figures for cruise performance.
The oil consumption is about 0.1 l/hr
Peter wrote:
shagged camshaft
What a sad cautionary tale. If only the pilot had:
1. used low ground effect to reduce drag while accelerating to Vy, or
2. listened politely to a/g’s advice and then made his own mind up about which runway to use, or even
3. rejected his uphill take off and turned around to take off downhill…
And 4., I’m asking myself why not spend a few minutes with a dial gauge to check valve travel while we do the annual compression test? It would be as easy as pie.
Peter wrote:
I would not make this decision on compression alone. Note that, for example, you can lose 40% of valve travel (due to a shagged camshaft) and lose only 10% of the power, which most casual flyers won’t notice.
Depending on the type of propeller fitted, you can often check engine power output directly by verifying static rpm. This is particularly useful for comparison over time with the same engine and prop. It’s easiest with a fixed pitch prop, but can be done with others. With my electrically actuated pitch control I just run it to full fine pitch and turn off the prop electrical power prior to checking rpm at full throttle. I do this on occasion with a strobe tach through the windshield, about once a year.
I think this link has been on here before.
Bulletproof engines
Although the basis of this engine has been around for years, it seems to have hit the sweet spot in the new 172s.
“It’s a 180-HP engine, it’s de-rated and I’ve had them come in here with 4000 hours on them,” says Dave Allen of Poplar Grove Airmotive, near Rockford, Illinois.
“American Flyers runs them for 4000 hours, they put cylinders on at 2000 and a fuel servo and run them another 2000 hours. I haven’t seen anything else do that,” he adds.
Airborne_Again wrote:
We’re needing an overhaul of an IO-360-L2A engine soon. The engine runs really well and we can accept some downtime, so we’ll do an actual overhaul rather than swapping it for a different overhauled engine.
Do you have any recommendations for good overhaul shops in Europe? Also, of course not unreasonably expensive as far as that is compatible with “good”.
Thanks for all suggestions! I’ll be back with our experience of the ship once the overhaul is done. (Or with our experience of going for a owner declared maintenance programme if that route turns out to be feasible.)
