I really thought someone would post it, but I got to do it :
A club 172 in the midwest reached 5000h SMOH and the engine still had no corrosion. They mainly faced high oil consumption in the last years.
A very interesting story for all club members and managers.
Jujupilote wrote:
A very interesting story for all club members and managers.
I’m not that surprised. My club ran an IO360 to 3400 hrs before overhaul. There was no technical reason for the overhaul when we eventually did it, but some people in the club were getting nervous…
It’s an impressive number on the financial side but it’s hard to to abuse an IO360 as they fly just fine if they fly often, I would be more impressed to see someone doing 5000h on TSIO360? actually, I can wage an overhaul price if TSIO360 can go past 1500h without one cylinder giving up, even with Mike Bush himself flying it 
I think in club environment people tend overhaul an IO360 at 2000h TBO because they don’t know the rules on “running on condition” or don’t want to “take the responsibility”…while private owners will overhaul IO360 due to that unlikely prop strike at 1999h
When I let overhaul my former O-300 it had 3500 SMOH (got 3 cyls done over times and was still within calendar limit) and still going strong, only had to get a quart oil per 4 flight hours at the end. I guess much depends on frequent flying – just from feeling they stand to repair, not fly.
Ibra wrote:
actually, I can wage an overhaul price if TSIO360 can go past 1500h without one cylinder giving up
Be careful!
I have one installed on the left wing on 2007 and now it has about 1380hrs and running already “on condition” due to 12yrs.
Every cylinder original. Since last 250hrs every annual/100hrs inspection shows completely NO loss of cylinder pressure (72-76/80) and NO oil consumption increase. Engine uses about 1qt/10-12hrs.
Oil changed every 25hrs.
Only Aeroshell W100 or W100plus. Never 15W50.
Carefully warmed-up on 1000rpm.
Never exceeds 1000rpm during start-up – (very rare in GA world).
Leaned brutally during warm-up.
Always full power takeoff – kept for 2-3 minutes to “exercise” engine.
Climb 75% power – at least 200F rich of peak on leanest cylinder – never less.
Cruise 55% power – never more – always lean of peak. At that power you cannot harm the engine. TAS at FL100 – 144kts. Enough for me. About 20F LOP is the best if you can keep it on all cylinders. No deposit on spark plugs.
Carefully monitored “Cooling rate” during descends. Requires engine monitor. Avoid more than 50F/min especially when higher than 360-380F CHT.
Relatively low RPM vs MP during cruise. Of course acc to the power table.
Of course no flight training and no touch&go’s.
I have one installed on the left wing on 2007 and now it has about 1380hrs and running already “on condition” due to 12yrs.
You are getting close I gather left wing mean twin? not sure if it changes much on thermomechanical loads but flying engines on twins past their TBO makes lot of sense (until they disintegrate is not an issue neither 
)
Ibra wrote:
I gather left wing mean twin?
Yes. A Seneca.
In the right conditions, most engines would reach 3-4k hrs, but they would be shagged by then and the overhaul will cost a fair bit more. Which doesn’t matter if it is a flying school.
Corrosion is a wholly separate thing. In Arizona you see iron and steel lying on the ground with hardly any rust, after 100+ years A regularly run engine will not have any internal corrosion.
I disagree.
The type of engine dictates how many hours it will run. The O-235 is much more likely to make TBO than an O-200.
Same with the lycoming O-360 which is much more likely to make TBO than the 6 cylinder continental equivalent.
Of all the different lycoming and continental engines out there the O-360 has the best longevity. However it’s a moot point as the UK forces engine overhaul at TBO for aircraft operated by flying schools.
Now if you want an engine that will do 5000 hours everytime. With no cylinder work. In fact nothing but routine maintenance then look at the 80HP Rotax 912. A wonderful engine.
This article is very relevant
