IO-346 with IO-550 cylinders

labbadabba

labbadabba

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labbadabba
Looking at a listing for a Mousketeer:

http://www.ebay.com/itm/262126580188?forcerRptr=true&item=262126580188&viewitem=

In the description the seller indicates that the Con IO-346 has been fitted with IO-550 cylinders. Is this pretty common? I know they are similar in bore. But would this improve performance of the 346? Would it increase the reliability of the 346? I know it doesn't have the best rep out there...
 
My Google-fu and search of the FAA STC database was weak on this. I don't know if it's legal, but I don't see why it wouldn't be possible one thing you would have to look at on the application is cowling clearances because they are differently shaped heads, but I don't think a BE-23 would have a problem. Someone on the mouse forum probably has a good answer. I think it would make a nice improvement.
 
Henning said:
My Google-fu and search of the FAA STC database was weak on this. I don't know if it's legal, but I don't see why it wouldn't be possible one thing you would have to look at on the application is cowling clearances because they are differently shaped heads, but I don't think a BE-23 would have a problem. Someone on the mouse forum probably has a good answer. I think it would make a nice improvement.
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Yeah, I had some trouble finding anything on the Google. I know the 346 has a bad rep but apart from opinions and lack of parts surplus, I've not seen any hard data that points to the 346 powerplant being a lemon. My only complaint is that it's rated at 165hp which is a little weak considering it's attached to a heavy/draggy airframe.

But at this point, I'm not really into speed. I'm really looking for comfort and a stable IFR platform. My personal XC trips are <>300nm so I don't need a fireball airplane at this point.
 
Help me remember.... Which version of the Musketeer earned it the moniker "Mighty Mouse"?
 
AggieMike88 said:
Help me remember.... Which version of the Musketeer earned it the moniker "Mighty Mouse"?
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Model 23-24 Musketeer Super III had a Lyc IO-360 at 200hp.

I assume it was probably this since the production models that followed were Sundowners.
 
labbadabba said:
Yeah, I had some trouble finding anything on the Google. I know the 346 has a bad rep but apart from opinions and lack of parts surplus, I've not seen any hard data that points to the 346 powerplant being a lemon. My only complaint is that it's rated at 165hp which is a little weak considering it's attached to a heavy/draggy airframe.

But at this point, I'm not really into speed. I'm really looking for comfort and a stable IFR platform. My personal XC trips are <>300nm so I don't need a fireball airplane at this point.
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I only have known a couple people with them, but they weren't really unhappy about the quality of the engine. I'd suspect with 550 cylinders, a tuned exhaust pipe, and some injection system modification, it shouldn't be that hard to make 180 or even 200hp.
 
Henning said:
I only have known a couple people with them, but they weren't really unhappy about the quality of the engine. I'd suspect with 550 cylinders, a tuned exhaust pipe, and some injection system modification, it shouldn't be that hard to make 180 or even 200hp.
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I love the fantasy world you live in.
 
labbadabba said:
I know the 346 has a bad rep but apart from opinions and lack of parts surplus, I've not seen any hard data that points to the 346 powerplant being a lemon. My only complaint is that it's rated at 165hp which is a little weak considering it's attached to a heavy/draggy airframe.
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Actually, in its day the IO-346 had a good reputation, being basically 2/3 of an IO-520. But fuel injection in the low end of the market hadn't caught on yet, and the A23 ("Musketeer II") was the only application for that engine, and that only for a short time. Thus, the only problem with it now is that it's an orphan and some parts are made of unobtainium.
 
Checkout_my_Six said:
no worries.....the crank and the cam will be just fine. :lol::goofy:
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:confused: The cam doesn't care how much horsepower you're making. I'm sorry, that's a massive forged crank, if it can't handle 200hp, then WTF is wrong with their forging process?:dunno: We're talking .57 HP/CI here, give me a break, that's on par with a 13hp BS Vanguard at 25cuin, and a single cylinder design is the toughest there s on a crankshaft because it delivers all the hp in one pulse per 2 revolutions. Are you seriously going to tell me that our airplane engines are weaker than lawn mower engines?:rofl:
 
What 4-cyl case are these 550 cylinders fitted to???? A Lyc 540 and 360 share the same cylinders. Not so with TCMs.
 
Tom-D said:
You volunteering to do Henning's paper work for the major modifications he suggested?
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I didn't suggest anything, the OP is listing a plane with the discussed modification, I was just speculating on what the plane that is using this combination is getting for horsepower out of a modification that has already been done. I was just trying to find under what authority they did it.

It's not my mod, I just speculate it will be fine, while you guys are assuming it's a handgrenade.
 
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Checkout_my_Six said:
I'd volunteer to laugh.....:rofl:
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Dude.. Did you bother to click the link in the OP?, it is listing a $14,000 plane with these modifications. Why in the **** do you want to make this about me?:dunno: What the **** is wrong with you guys? Are you that ****ed up over me?:dunno::confused: I will lay down $1000 right now says that engine puts out 180hp with standard exhaust and 200hp with tuned exhaust, heck, it may make 200 on standard exhaus since it's now an IO-366. It's not an imaginary Frankenstein engine, it exists in a $14,000 Musketeer; FMD.
 
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Henning said:
Dude.. Did you bother to click the link in the OP?, it is listing a $14,000 plane with these modifications. Why in the **** do you want to make this about me?:dunno: What the **** is wrong with you guys? Are you that ****ed up over me?:dunno::confused: I will lay down $1000 right now says that engine puts out 180hp with standard exhaust and 200hp with tuned exhaust, heck, it may make 200 on standard exhaus since it's now an IO-366. It's not an imaginary Frankenstein engine, it exists in a $14,000 Musketeer; FMD.
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I'd pay that much to see the look on the PMI's face when he read the 337.
 
Henning said:
Dude.. Did you bother to click the link in the OP?
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I did, and it does not mention any of the modifications that came from you. thus the fantasy world comment.
 
Tom-D said:
I'd pay that much to see the look on the PMI's face when he read the 337.
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That's why I was Googling for an STC or advertised mod, I hadn't heard of it done to a 348 before, but since they go on a 520, there's no physical reason they won't go on a 348. I would bet someone in the Mouse club did a Ex R&D run for an STC or field approval. That's the only plane I can think of that used it.
 
I'm with Tom on this. There probably wasn't any testing or even analysis done supporting the slightly changed first mode torsional natural frequency of the propeller/crankshaft/piston etc.
 
nrpetersen said:
I'm with Tom on this. There probably wasn't any testing or even analysis done supporting the slightly changed first mode torsional natural frequency of the propeller/crankshaft/piston etc.
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Why do you suspect that? You have no idea who owns that plane or who did the mod, or do you? :dunno: There was a senior engineer at Douglas who had one of the ones I know, and had he done it, he most certainly would have. Don't prejudge what you don't have evidence of
 
labbadabba said:
Looking at a listing for a Mousketeer:

http://www.ebay.com/itm/262126580188?forcerRptr=true&item=262126580188&viewitem=

In the description the seller indicates that the Con IO-346 has been fitted with IO-550 cylinders. Is this pretty common? I know they are similar in bore. But would this improve performance of the 346? Would it increase the reliability of the 346? I know it doesn't have the best rep out there...
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IO550 cylinders have the exact same bore as those on a IO346 or IO520. The 550 displacement comes from a longer stroke (different crank throw) compared with the IO520. And an IO346 has the exact same displacement per cylinder as an IO520.
 
So, do they use the 520 cylinders because the 346 cylinders are no longer produced? Does it make any difference at all in the performance or quality of the engine?

(provided no tuned exhaust and other mods of course...)
 
nrpetersen said:
I'm with Tom on this. There probably wasn't any testing or even analysis done supporting the slightly changed first mode torsional natural frequency of the propeller/crankshaft/piston etc.
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You think not? The kit came from Continental. You still think it's just a slap together?
 
If it is truly a kit from and blessed by Continental I agree that the changed vibration characteristics have been accounted for but it just might be propeller specific.

Large four cylinder engines beat torsional hell out of a propeller/crank combination, especially if there is no damper at the rear of the crankshaft. Hence the operating rpm restrictions on some combinations. It isn't the sort of thing simply done by an IA on a 337 unless there is an engineering trail.
 
nrpetersen said:
If it is truly a kit from and blessed by Continental I agree that the changed vibration characteristics have been accounted for but it just might be propeller specific.

Large four cylinder engines beat torsional hell out of a propeller/crank combination, especially if there is no damper at the rear of the crankshaft. Hence the operating rpm restrictions on some combinations. It isn't the sort of thing simply done by an IA on a 337 unless there is an engineering trail.
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This engine is a weird one made for one application, a beechcraft no less.
https://en.wikipedia.org/wiki/Continental_IO-346
 
JHW said:
just speculating, after lycoming made inroads at beech with the duke and the 56TC, continental might have been willing to do anything to not lose another airframe
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That is about the only logical explanation...
 
nrpetersen said:
If it is truly a kit from and blessed by Continental I agree that the changed vibration characteristics have been accounted for but it just might be propeller specific.
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If the cylinders have the same length / diameter and differ by part number, how would that change "vibrations" that get to the propeller?
 
N801BH said:
That is about the only logical explanation...
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They could also have been looking for a better market competitor for Lycoming's O-320/O-360 series engines than their IO-360. With a lot of common parts and accessories shared with the IO-520 it makes a lot of sense from a manufacturing economics standpoint.
 
Henning said:
They could also have been looking for a better market competitor for Lycoming's O-320/O-360 series engines than their IO-360. With a lot of common parts and accessories shared with the IO-520 it makes a lot of sense from a manufacturing economics standpoint.
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Agreed...
 
Capt. Geoffrey Thorpe said:
If the cylinders have the same length / diameter and differ by part number, how would that change "vibrations" that get to the propeller?
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The slightly longer stroke (assuming new pistons that might be heavier?) will slightly reduce the first mode natural frequency of the whole driveline.

They all (i. e. the natural frequencies) tend to be around 220 Hz which is the fourth harmonic for 2200 rpm. At cruise I could hear it in our 172M as a ringing just below middle C on a piano (which is 256 Hz I recall). The O-320s are not as hard on props and cranks as the O-360s per dinner talks with a McCauley engineer, but the 4 cylinder Continentals would probably be in the same range of concern.

6 cyl engines are more complex and involves multiple modes as I understand.
 
The IO-346 seemed like a logical move at the time, dipping into the parts bin to make an economical four-cylinder engine with some IO-520 components. Continental's other engine in that horsepower range was the geared six-cylinder GO-300, and we know how that worked out in the C-175/C-P172D. Even the prototype C-336 Skymaster first flew with GIO-300s, before the first IO-360s were delivered.

Continental had gotten good press with fuel injection in the IO-470-C in the J35 Bonanza (1958), so this was an opportunity to try it in the lower end of the line. Cessna, though, had found those early fuel injection systems incompatible with fixed-pitch propellers (especially in a training environment) in an experimental C-175 with a GIO-300 and later in the USAF T-41C with an IO-360 and fixed-pitch propeller.
 
Pilawt said:
The IO-346 seemed like a logical move at the time, dipping into the parts bin to make an economical four-cylinder engine with some IO-520 components. Continental's other engine in that horsepower range was the geared six-cylinder GO-300, and we know how that worked out in the C-175/C-P172D. Even the prototype C-336 Skymaster first flew with GIO-300s, before the first IO-360s were delivered.

Continental had gotten good press with fuel injection in the IO-470-C in the J35 Bonanza (1958), so this was an opportunity to try it in the lower end of the line. Cessna, though, had found those early fuel injection systems incompatible with fixed-pitch propellers (especially in a training environment) in an experimental C-175 with a GIO-300 and later in the USAF T-41C with an IO-360 and fixed-pitch propeller.
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I want to know your official job title was at Cessna.
 
Henning said:
They could also have been looking for a better market competitor for Lycoming's O-320/O-360 series engines than their IO-360. With a lot of common parts and accessories shared with the IO-520 it makes a lot of sense from a manufacturing economics standpoint.
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It would be my opinion the Continental did not want the bad press of having those engines unsupported, because they were no longer manufacturing the original cylinders. so they sold a change over kit.
 
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