engine reliability in the 235-260HP range

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DLrocket89

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Hi everyone,

I'm (hopefully) going to be starting a Bearhawk sometime in the next year or so. I'm planning on putting it on amphibious floats eventually, so I'd like to put a bigger engine on it (in all honesty, the IO-390 seems like the "ideal" but the cost is so crazy compared to a used, near TBO 470 or 540.)

So, my question revolves around the Lycoming I/O-540 and the Continental I/O-470. Max engine weight on the Bearhawk is 400lbs, so that rules out the angle valve I/O-540s which make 300HP, and also anything turbocharged, etc.

What are the comparative reliability rates between the Lycos and the Contis? If I look on a used site like trade-a-plane or barnstormers, you can get a near TBO O-470 for like $3K, with accessories. You can get nowhere near that for a Lyco. Why? Do the Conti's get to heck sooner, do they throw rods, do they...????

Just wondering...I know that the Conti's are a little worse the HP:weight ratio area, are there any things that can be done to lighten them some?


EDIT: any other engines out there that might work too?
 

orion

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Although not a hard set rule, Continentals do tend to be a bit lighter so may have better application for you. However, that light weight at times is an issue - the engines need to be matched with prop but the lighter weight of the Continentals often results in a much narrower rpm operating range since potentially damaging harmonics could occur. As such, when choosing an engine, make sure you can get a prop for it that will have the widest green arc.
 

DLrocket89

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Great Avweb article, thanks.

I always thought they were a bit heavier than Lycos...works for me either way.

Thanks for the replies!
 

orion

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Well, as I said, it's not a set guideline and does depend on the engine model you're looking at, the power level and of course, your accessories. If we look at some comparisons of similar power we see the following:

Lycoming
Model Power Weight
O-360 180 269
O-540-B 235 366
O-540-E 260 368
IO-540-K 300 443

Continental
IO-360-KB 195 327
TSIO-360 225 300
IO-520 300 459
IO-520 285 415
IO-520 310 436

So, as I said, the comparison is not all that clear unless you're looking at specific engines (sorry, don't have 470 data). True, the Continentals are heavier below 200 hp since the Lycs are four cylinder and the Conts are six. I just remember that when I was looking for engines for several of my past projects (including the 470's), the Lycs ended up with higher installation weights that the Continentals however, the Lycs had more flexibility as to which prop due to their greater resistance to torsional vibration buildup. But this again has exceptions so in the end it's probably good to see what engine you can find for your project (as opposed to which one you'd ideally like) and then live with the specifics of that choice.
 

Tom Nalevanko

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Alpine, WY
Thanks for the comprehensive list. You could add the Continental IO-550-N 310 HP and 465 lbs. if one is interested in something that heavy.
 

Vector

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Does the article posted by Wally explain why IO-470S are not used a whole lot on aerobatic mounts. Am I wrong on this?
 

Pops

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We are building 4 Bearhawks in my hanger. My Bearhawk is about 3/4 finished, and will have a Lyc-360, non-electic, small 5 amp gell cell battery for handheld radio and GPS. No upholstery except seat cushions. Trying to beat the weight of the prototype. If its not there, it weighs nothing, cost nothing, and is 100% reliable. Dan
 

Southron

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Back in the 1970's I owned a Beechcraft Sierra with the IO-360 engine, It had fuel injection and I LOVED the idea of not having to fiddle with a Carburetor Heat lever every time I pulled the power back.

What I DIDN'T LIKE ABOUT THE 360 was that it was impossible to crank when "Hot."

Back in those days I was flying long X-countrie's on business and usually picked a smaller field to land and refuel.

I would shut the engine down to refuel. Then I could count being stuck on the ground for a couple of hours waiting for the engine to cool down before I could restart it. Needless to say, that "Played Hades" with my schedule for that day.

Mechanic after mechanic worked on it-but no one could ever "cure" the problem.

I finally sold that airplane because I got tired of the "Hassle of the 360."
 

Toobuilder

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What I DIDN'T LIKE ABOUT THE 360 was that it was impossible to crank when "Hot."

I finally sold that airplane because I got tired of the "Hassle of the 360."
I hear this from time to time and even see it on the ramp - owners grinding away on the starter...

However, I have flown injected Lycomings ranging from 180 to 310 HP around the desert southwest almost exclusively for the last 5 years and I can count on one hand the times I could not get an engine to fire on the first try, hot or cold. I've certainly NEVER been stranded! While there may very well have been something wrong with your particular engine/airframe, yours is not typical of the fuel injected Lycomings in general.
 
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Southron

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Well, I purchased that Sierra for a really cheap price-that might have been why!

Other than that, it was a GREAT AIRPLANE.
 

Toobuilder

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Perhaps technique? My favorite for a hot start is:

Mixture - ICO

boost - off

Crank engine

Advance throttle to full until engine fires

Engine will fire on the residual fuel and then start to die - Rapidly advance mixture to rich as the engine dies

Engine will catch on the rich mixture and accelerate - rapidly return throttle to idle

Run boost pump as required if pressure fluctuates.


Essentially, you are simply clearing the engine of the flooded condition caused by the injectors boiling off and spitting into the cylinders. 99 times out of a 100, the engine will fire during the clearing process and if you are fast, you can "catch" the engine before it dies. If not, you now have a cleared engine and you can use the "normal" start process.
 

Southron

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It has been so long since I owned that Sierra (30 plus years,_ I forget what "Hot Start" procedure I used [not very successfully.]

Thanks for your reply!!!
 
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