Lycoming O-360 engine replacement

DKirkpatrick

DKirkpatrick

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DKirkpatrick
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Hello,
Looking at a Cessna 172-RG… airframe looks good, engine running with 2450 smoh… wondering how big a deal it would be to replace the Lyc O360 with a Lyc IO360?
Would like to generally if it’s viable or just not worth the expense.
Thanks
 
Is there an existing STC? I know nothing about Cessnas except it has a high wing. Would this bring the rating from 180 to 200HP? If changed, would it lose the ability to use autogas? Unless it was low cost, and proven increase in perf, I think - no.
 
With the absolute pain it is going to be if there isn't an STC, don't do it. Just replace the engine with the same model. Your mechanic will like you a lot more.
 
Agree that it's not worth the expense to put in a different engine. If you buy it, you will be overhauling the engine soon so price it accordingly (engine beyond TBO run-out). But there's no reason to replace the engine now if it's still running fine. Absent any symptoms, keep running the engine while closely monitoring the oil screen and filter debris and UOA. It should let you know when it's time to overhaul.
 
Those have a D2000/3000 series magneto? Nobody wants them. Worth knowing what mag(s) are on it.
 
DKirkpatrick said:
Would like to generally if it’s viable or just not worth the expense.
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As mentioned, if there is not an active STC or OEM supported alteration for that swap, it would definitely be on the expensive side. However, having been involved in a number of engine swaps on both airplanes and helicopters, whether that swap would be considered viable or economically feasible falls to you and the reasons behind it. Regardless, a quick check on the FAA DRS under STC Listings and an email to Cessna about any swap potential will answer those 1st two questions.
 
DKirkpatrick said:
how big a deal it would be to replace the Lyc O360 with a Lyc IO360?
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Other people have already told you the juice might not be worth the squeeze.

But you might want to consider a port and polish with a powerflow exhaust. Depending on who you're willing to believe, that might get you the same power increase.
 
AV8R_87 said:
... But you might want to consider a port and polish with a powerflow exhaust. Depending on who you're willing to believe, that might get you the same power increase.
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The Powerflow exhaust sounds like an easy decision if you need to replace the exhaust anyway. It does improve power and efficiency. However, in reality it's not that simple because it requires more maintenance (additional inspections & periodic parts replacement). So it's a trade-off.
 
MRC01 said:
However, in reality it's not that simple because it requires more maintenance (additional inspections & periodic parts replacement). So it's a trade-off.
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True. Might be compensated somewhat by not having to deal with the maintenance requirements of a fuel injection system.
 
MRC01 said:
The Powerflow exhaust sounds like an easy decision if you need to replace the exhaust anyway. It does improve power and efficiency. However, in reality it's not that simple because it requires more maintenance (additional inspections & periodic parts replacement). So it's a trade-off.
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I have over a 1000 hrs easy without looking, on a powerflow exhaust on a 1980 172N with a H2AD 0-320. Exhaust has been on 2 different H2ADs.
It takes 10 minutes to remove it after cowl removal, 20 minutes to clean the slip joints and re anti sieve them and another 15 minutes to reinstall the exhaust on a 172 by myself.
Minimum maintenance if you ask me.
Do it about every 12 months since 2019. The exhaust sounds great, loud and proud.
Climbs 1000+ fpm with just me in the plane even during the summer months.
Combine it with a balanced propellor, is a great combination. You can hear it in ground effects.
The only part I replaced was the sound baffle which is a cone shaped piece that fits into the exhaust pipe outlet since 2018.
6bf3613c-2a32-4c79-86ff-130c621ab4ac.jpg

48e187a0-ba54-4135-9956-e89286224be1.jpg
 
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I'm a fuel injection guy, but there are advantages to carbs. It's not as simple as FI > non-FI.

IMO buy it and get that O-360 overhauled at a good shop. There are very few things as satisfying as a fresh engine and prop on a new-to-me plane.

Take the money you saved from the good idea fairy and pump it into top shelf maintenance for the retracts. There are very few things less satisfying than belly landing with a fresh engine and prop.
 
Gary Ward said:
I have over a 1000 hrs easy without looking, on a powerflow exhaust on a 1980 172N with a H2AD 0-320. Exhaust has been on 2 different H2ADs.
It takes 10 minutes to remove it after cowl removal, 20 minutes to clean the slip joints and re anti sieve them and another 15 minutes to reinstall the exhaust on a 172 by myself. No help needed. Minimum maintenance if you ask me. ...
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Isn't it a glasspack that also requires replacing the packing material? I used to do that on my motorbike every year. By the end of the year it sounded raspy and the new packing made a big difference - much quieter and deeper less raspy tone.

Gary Ward said:
... The only part I replaced was the sound baffle which is a cone shaped piece that fits into the exhaust pipe outlet since 2018.
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Ah I see you already answered that!
 
MRC01 said:
Isn't it a glasspack that also requires replacing the packing material? I used to do that on my motorbike every year. By the end of the year it sounded raspy and the new packing made a big difference - much quieter and deeper less raspy tone.


Ah I see you already answered that!
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No glass pack material,
There is no muffler, the pipes lead into a collector that dumps into the exhaust pipe.
 
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Gary Ward said:
No glass pack material, lol.
There is no muffler, the pipes lead into a collector that dumps into the exhaust pipe.
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Interesting. Powerflow did a presentation at the NW Aviation conference last year and said it was a glasspack design that requires periodic changing of the packing material. Perhaps all the models aren't like that. Or maybe they changed the design.
 
MRC01 said:
Interesting. Powerflow did a presentation at the NW Aviation conference last year and said it was a glasspack design that requires periodic changing of the packing material. Perhaps all the models aren't like that. Or maybe they changed the design.
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Not on my system, there's no muffler.
 
DKirkpatrick said:
Hello,
Looking at a Cessna 172-RG… airframe looks good, engine running with 2450 smoh… wondering how big a deal it would be to replace the Lyc O360 with a Lyc IO360?
Would like to generally if it’s viable or just not worth the expense.
Thanks
Click to expand...
If you are part 91, if it has good compression, and not making metal, keep flying it.

These engines routinely do 2x that number.

Do you follow Mike Bush?

www.savvyaviation.com

Savvy Aviation - Take Control of Your Aircraft Maintenance

Savvy Aviation is not a maintenance shop – we’re the industry's largest team of general aviation maintenance experts. Our experienced analysts and veteran A&P/IAs empower you with expert troubleshooting, insight, and advice.
www.savvyaviation.com www.savvyaviation.com
 
Gary Ward said:
Not on my system, there's no muffler. ... The new sound baffle actually made it run and sound better.
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I believe the source of the confusion is that I used "muffler" in the general sense as "a part of the exhaust system that absorbs noise". This would include a "sound baffle".
 
MRC01 said:
Interesting. Powerflow did a presentation at the NW Aviation conference last year and said it was a glasspack design that requires periodic changing of the packing material. Perhaps all the models aren't like that. Or maybe they changed the design.ai
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It has been a while since I've maintained an aircraft with a Powerflow on it, but I don't believe there is anything in the airworthiness limitations requiring the periodic changing of the packing. It is a recommendation in the ICA to do so however, which is likely where the confusion arises from. Some people will insist on doing all the services, others won't.
 
TCDS only lists one approved engine so you will 100% need an STC if one even exists.

I did find a possible turbo STC that may or may not be available:

"there was a STC issued to install a turbo charger on a C-172RG. It was issued to Flite Craft out of Pagosa Springs, CO. That company folded. The company that took over the after market turbo charger world is www.rajay.aero. It is producing turbocharger kits for airplanes these days but the 172RG is not on its current approved models list. You can call at (888) RAJAYPARTS or email at: [email protected] if you're interested in adding a turbo."
 
20-ish years ago I looked at getting an STC for engine swap from a small Franklin to a small Conti of same HP, similar weight, same config, same prop flange, and similar engine mount. I talked with an A&P that got an engine change on a 175(get rid of geared) and he said the STC would run around $50-60k and take at least 18 months. But then, we would own the STC and could sell it to others. It was an orphan airframe, and the potential sales to other planes was like single digits. I passed.
 
bnt83 said:
Those have a D2000/3000 series magneto? Nobody wants them. Worth knowing what mag(s) are on it.
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The engine in the 172RG is a non-siamese magneto variant of the O-360 (-F1A or -F1A6). Solid engine. You're probably thinking of the 540 in the 182RG, O-504-J(o L)L3C5D. D suffix at the end signifying siamese mag.

He could probably run that engine to 3000smoh if it was used as a trainer (it prob was) and ran frequently. But one should be prepared for the overhaul, and the sticker shock of it in the present market. It's unlikely the seller will agree to discount to account for current overhaul costs, which is where these runouts go to sit and rot due to that impasse.
 
DKirkpatrick said:
Hello,
Looking at a Cessna 172-RG… airframe looks good, engine running with 2450 smoh… wondering how big a deal it would be to replace the Lyc O360 with a Lyc IO360?
Would like to generally if it’s viable or just not worth the expense.
Thanks
Click to expand...
Any O to IO change requires substantial fuel plumbing changes ahead and behind the firewall. The are a few STCs that exist for such conversions - think big bore IOs in 182s, but the 172RG was just made as a complex/commercial trainer before the regs changed. So many have very high time, were used as trainers, and generally aren't worth the cost of gear parts replacement over a fixed gear 172. It's just a niche airplane that might get you 8 knots over a 172. But each to their own.
 
Steamflyer said:
Any O to IO change requires substantial fuel plumbing changes ahead and behind the firewall. The are a few STCs that exist for such conversions - think big bore IOs in 182s, but the 172RG was just made as a complex/commercial trainer before the regs changed. So many have very high time, were used as trainers, and generally aren't worth the cost of gear parts replacement over a fixed gear 172. It's just a niche airplane that might get you 8 knots over a 172. But each to their own.
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Buy one and break the gear handle off in the down position.

They are cheaper than same year fixed gear models.
 
And bringing it back to memory lane! Many are still here, many are gone, some have passed, some I don't miss at all. All poo flinging in good fun. The OP was never heard of again (standard), even left the profile pic as-is lol. I present: The 172RG thread of 2013.

Notable mention for my own post #73, where I on-the-nose foreshadow what would become my own hobby-death almost 10 years to the date. It's kinda wild to read your own "obituary" lol. Henning's commentary was of course, also the source of future skepticism of his 310's demise back then too.

I'd also highlight I would go on to purchase a retract to replace my warrior in the summer of that year, with the arrival of my son. Power loading was the reason, not speed. The added 40HP through the 10 years I owned it served us ok, but it was mediocre performance, and got scary one hot go-around in 2022. 250hp would have been my preference if I had to do it over again and had the finances for it. The gear annoyed me through the years and canceled a few trips, but didn't eat me out of house and home. If inflation rates had held steady through the 2020s as they did for us in the 2010s, the Arrow would still be flying, as I would have been ok with that engine overhaul cost projected out from 2013 cost-basis.

Closing the loop with this thread topic, I'd be curious to see how those 2013 Cessna retract part prices quoted then have held up in 2026. Can a 172RG actuator even be found anymore at any price? I'll make the same pitch I did back then, for poo pooing retracts and still ending up in one: Show me the money. When the capex is sufficiently discounted, you give me enough incentive to deal with the mx premium. I could make the argument for the Arrow back then (this is before bolt hole repetitive inspection AD death knell of course), not sure I could make it for the 172RG. But who knows, maybe the OP got a really good deal on it compared to the inflated prices of fixed gear 172, given they are workplanes and their pricing reflects that nature.

As a bottom-feeder given my price point, I'll always fly "the trash". As such, I'll never outright write off undesirable options if the numbers can pencil out. And that's fine, being the captain of my own ship has always been the inducement for me, so I'd still give the ol' gutless a chance if the numbers work. Guess I've become more charitable in my "advanced age" lol.
 
This thread took a hard turn. I have a plane that has had an engine swap, and is a very robust retract. My engine swap was very useful, added 36hp. The Bonanza gear is a thing of beauty. Used on the 55 Baron. Hard to destroy and a manual extension is almost unheard of in flight. Back to the regularly scheduled Cessna engine programming.
 
...And as has been explained ad nauseam, since not EAB, options are captured by mothballed-STC, or outright lack of STC, nor business case for it. It's not a new question, the answer hasn't changed.

It just so happens to be a question that has ailed this specific category of airplane (the retract trainer class) more than others. Reason is OEMs didn't want to poach sales from their legacy 6 banger cruisers, and kept it "cheap" by keeping the hamstrung power loading. This isn't unique to gutless, arrows had the same issue, as did twinkies and seminoles/duchess. There was no business case for most to make horsepower upgrades, which is self-evident definitionally, given said lack of market for STC in 2026. To say nothing of the moribund resale market for the complex trainer fleet post TAA implementation.

BL, want more HP out of a gutless while keeping the airframe/wing placement/door combos? Buy a R182 or 177RG, which of course is gonna run ya a premium and come with its own set of opportunity costs that a 172 airframe does not. Catch-22. The market is captured, but it's predictable. Yes, a sunk cost for the OP if he overpaid for the gutless, as the only option is to overhaul exisiting. Me, I'd fly to fail that engine, like I did the Arrow, and the Warrior before it. Always sold at loss, always much less of a penalty than the engine overahul price-risk. Less of an issue if "forever airplane", but I never considered them forever airplanes.

/thread. The "de-rails" are more fun tbh.
 
Barrett50 said:
This thread took a hard turn. I have a plane that has had an engine swap, and is a very robust retract. My engine swap was very useful, added 36hp. The Bonanza gear is a thing of beauty. Used on the 55 Baron. Hard to destroy and a manual extension is almost unheard of in flight. Back to the regularly scheduled Cessna engine programming.
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So what airplane? Which engine swap?
 
bonefishpete said:
Bonanza IO-550 swap I presume.
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Those are injected to begin with. And it’s about the same engine as the 520 most are born with. Just stroked.

As for prices for things like forged landing gear parts in a 172RG, figure 2-4x price increase from 2013 as one poster was wondering. Often used is only option.
 
MRC01 said:
I believe the source of the confusion is that I used "muffler" in the general sense as "a part of the exhaust system that absorbs noise". This would include a "sound baffle".
Click to expand...
Honestly, the pic looks more like a flame cone than a sound baffle.
 
DKirkpatrick said:
Hello,
Looking at a Cessna 172-RG… airframe looks good, engine running with 2450 smoh… wondering how big a deal it would be to replace the Lyc O360 with a Lyc IO360?
Would like to generally if it’s viable or just not worth the expense.
Thanks
Click to expand...
Can anybody tell me the names of the group that flies in Pagosa springs every day particularly the one in the red plane that goes up towards Pagosa peak I'm a local here in Pagosa a hiker and a fisherman so I've had my eyes on the planes for a while now not to mention I got like 3,000 simulated hours on flight simulators and 2 hours real flight and about 10 hours diagnosing my brother's avionics mechanic for United he got to take the graveyard apart and make full cockpits for our fight simulators that was before 9/11 though LOL
 
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