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IO-360 in an RV-9A?

Doug Rohrer

Well Known Member
I have to make a decision soon on the engine I plan to use in my RV-9A build. I know the O-320 is the recommended engine, especially the 160 HP version. While looking for a used O-320, I ran across an IO-360 B1B rebuildable engine. It appears that the cost to rebuild this engine (sitting for years/probably rusted inside) would be similar to an O-320. Using the search function shows several -9 builders have successfully used the 360/180HP engine in their planes. Tracking through the Lycoming literature seems to indicate the B1B variant would work on a -9 with a -7 cowl and engine mount. Van's cannot confirm for sure this engine would fit with available factory components, so I am asking the experts. Has anyone used an IO-360 B1B in a -9 and what issues could I expect other than those listed above? Am I correct in my assumption about rebuild cost? Thanks.
 
Stupid question... if inside is rusted, then what components will you be keeping - maybe just the cases and chrome cylinders back to size?
 
Van's cannot confirm for sure this engine would fit with available factory components, so I am asking the experts.

I believe you have asked the experts. The only real difference between the 2 is climb speed from my experience. The 9 is a fast and economical machine with the designed engine designation by Van's although I'm pretty sure I will be dumped on by some with this view.
 
One fit under my Sam James cowl.

Van's is very concerned that with the (I)O-360 up front, the -9 will go right past its Vne.

I would probably have to agree as in level flight at 75% power and 8,000' DA, mine will cruise right at 200 mph, 10 under Vne.

You will have to control the throttle, especially when going downhill.

This is not an endorsement of installing the large engine as the airplane does very well with an O-235 up front.
 
Vne can be exceeded at idle power too, that's a pilot problem, not an equipment problem.

I've got an IO360 under my James Cowl as well, and the performance is excellent, I've never thought for a moment that I made the wrong decision. You can always pull the throttle back and use less power if you want, but when you need it (that's spelled W A N T...) there is no replacement for displacement. You'll need to carefully look at your CG and move equipment around where possible to offset the noseweight, like the battery aft of the baggage compartment and some remote avionics as well.

Yes, it will cruise fast. Yes, you have to use the throttle just like any other control item to stay in the flight envelope. And yes, it will climb like a banshee and REALLY cruises well up in the mid-teens where the wing is happy.

And no, Vans is not happy about it and won't support it - but they'll still sell you parts.
 
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It has nothing to do with VNE!

Since it has been a while, I guess another clarification is appropriate...

I have posted numerous times in the past but the most recent I found is HERE

No sense writing out the same thing again...... look at the link if interested.

Vno (Maximum structural cruise speed) is the engineering design factor for max HP decision.

Not Vne

An RV-9 with more than 160 HP can easily fly above Vno in level flight at max continous power (or less).

You may not think that operating within the yellow arc range is a big deal...... well it is.

If you use a bigger engine, and fully understand and avoid operating above Vno then you will probably never have a problem.
If you own an RV-9 with an engine bigger than 160 HP and still think that Vne is your limiting factor, you may some day have one........

One thing to keep in mind is that Vno is a indicated derived airspeed. So regardless what HP you have, as long as your INDICATED speed is in the green arc you should be fine. So at higher altitudes it is not likely to be an issue (as long as you TAS remains below Vne). At lower altitudes, 180 HP engines at normal cruise power settings will easily push you above Vno.
The reason people get the idea that Van's doesn't like bigger engines is shown in this (and many other) threads.
If you incorrectly understand the issues related to using a bigger engine.... and spread that incorrect info to others, it clearly demonstrates the dangers involved with this sort of thing.

Please don't anyone follow up to this with "my wings haven't fallen off yet" (and get this thread derailed so that it gets closed).
Everyone can say that until it happens (God forbid) so it is not a valid response.

The important thing here in the forums is that correct information be provided, so that people don't make serious decisions based on incorrect info and then have someone get hurt (or worse).
 
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I am just about finished with my 9A. I had planned all along to put a O-360 in because my airport was at 8000' elevation. I flew with a friend out of Rifle CO (5540') on my first RV flight - at about full gross in his 9A and we had plenty of power. Vlad came to visit and we flew up near Aspen and had plenty of power. I still planed on the O-360, but a screaming deal came up on a O-320 I couldn't pass up so I decided because of experience, it would be fine.

I moved to Idaho and the elevation is only 2500' so Im sure it will be great. If I still lived in Aspen, I may want the additional hp, but I am happy how things worked out.

As mentioned, you can go too fast at idle. If you can't control the throttle, you probably should stick to a 172.

Scott -good reminder that it is VNo to be watched. Edit: my point is you can get yourself in trouble no matter what engine you have in your plane.
 
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As mentioned, you can go too fast at idle. If you can't control the throttle, you probably should stick to a 172.

You are right, but isn't that the case with nearly every airplane that can fly.
So why is that regularly used as a reason for justifying using a larger engine?
Operating primarily out of a high altitude airport like you mentioned, would be a good reason..... saying that any airplane can go too fast at idle is not.
 
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If it fits, you must acquit

Wow a guy asks a simple question about the fit and cost of a certain engine and.... :mad:

There are times I wish my -10 had 50 more HP!

regards
-Marc
 
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The OP had a 9A with a 160 hp O-320 previously so he already knows the performance with that combo.
 
Climb

What?s your mission? Mine is time to climb baby. Io360 with CS Prop on the RV-9 equals a climb that make me smile every time. I?m not a speed demon and I am very respectful of the VNO VNE limitations of the design thanks in large part of Scott?s posts. The last thing we all want is for the -9?s to start having the same failure rates that the -7 have.

Nevertheless, I have not regretted my decision one bit. That?s being said, the IO320 with CS Prop would be my second choice had I not already had an non-weighted crankshaft angle-valve 200hp engine laying around. However, I really love the IO320 engine/CS Prop combination and highly recommend it for the -9.
 
Van doesn?t recommend a 360 for the 9. He?s the man what did the engineering and I for one follow the advice from the design engineer. If you have a background in aircraft design and can reverse engineer the 9, go ahead and put whatever engine you want in your 9.

As for the clowning question as the 9 & 7 have the same cowling and the 7 is approved for a 360 I would think it would fit in a 9
 
Original

Doug,
Per your original question I assume that you are comparing the cost of a 320 ready to rock and roll verse a 360 that can be re-built for approximately the same price. I have been on both ends of this equation in the past and can only share that I have never had a rebuild come in for the original estimate, and by that I mean it's never costed less. So on that basis I, personally would chose the 320...all previous points can be taken into account as well.
 
Doug,
Per your original question I assume that you are comparing the cost of a 320 ready to rock and roll verse a 360 that can be re-built for approximately the same price. I have been on both ends of this equation in the past and can only share that I have never had a rebuild come in for the original estimate, and by that I mean it's never costed less. So on that basis I, personally would chose the 320...all previous points can be taken into account as well.

Yes and no.

When I bought my ECi kit engine the difference between the 320 and 360 was $500 and 20 pounds. Since i knew I was going to run Catto, I'm still lighter than a 320 with a metal fixed pitch prop.

With an overhaul, all bets are off, until you open it up and know what you have.
 
Thanks to All

Glad to see the thread got back on track after a little drift. As my friend Fearless stated, I have about 500 hours in a -9A with a 160HP O-320 that was lost in a landing accident near Oshkosh 3 1/2 years ago. The plane performs great at the 160HP level, but since I am starting from scratch, I thought I would consider a 360 if a deal came along. Others have done so successfully. Vans did say the -7 cowl and engine mount will fit the -9 if that's what I want. I just have to confirm the 360 has the right sump, carb/throttle body configuration, etc. So the search goes on...
 

Seems to me that everyone should build taildraggers!

Doug, it all depends on what prop you want to put on your -360. As I mentioned above, my O-360 and Catto FP prop is lighter than an O-320 with a metal FP prop. If I put composite CS prop on it, I would still be lighter than a 320 with a metal CS prop, which is approved.

As you build, you once again have to go through the Q&A process to figure out which configuration, options, etc. you want in your plane.

As you pointed out, your -9A with a 160 hp (I)O-320 was a good performer. There is absolutely nothing wrong with that engine.
 
Seems to me that everyone should build taildraggers!

Oh you can say that again!:D careful though you will upset a few training wheel owners:D

An 0360 low comp (for auto gas) & composite prop would be a nice compromise as everything to do with aviation is a compromise:)
 
I thought the O360 B1B only produces 168hp.

If this is correct, would the folks concerned about too much horsepower for the 9A still be concerned?
 
I thought the O360 B1B only produces 168hp.

If this is correct, would the folks concerned about too much horsepower for the 9A still be concerned?

Probably. Some folks put way too much emphasis on an arbitrary limit that was set in stone and proclaimed to be "The Limit."

Yes, there are reasons to limit horsepower on any aircraft design. No, those limits are not likely to be sharp-edged leading to a "you will die" scenario if you approach 100.1% of that limit. Yes, there will always be people creeping across that line a little, just like we drive too fast on the highways. And yes, there will always be people wagging fingers at those who do it.
 
Yes and no.

When I bought my ECi kit engine the difference between the 320 and 360 was $500 and 20 pounds. Since i knew I was going to run Catto, I'm still lighter than a 320 with a metal fixed pitch prop.

With an overhaul, all bets are off, until you open it up and know what you have.


Seems to me that everyone should build taildraggers!

Doug, it all depends on what prop you want to put on your -360. As I mentioned above, my O-360 and Catto FP prop is lighter than an O-320 with a metal FP prop. If I put composite CS prop on it, I would still be lighter than a 320 with a metal CS prop, which is approved.

As you build, you once again have to go through the Q&A process to figure out which configuration, options, etc. you want in your plane.

As you pointed out, your -9A with a 160 hp (I)O-320 was a good performer. There is absolutely nothing wrong with that engine.
If weight is a concern but you still want the HP a 360 provides you should not discount this engine:
http://www.continentalmotors.aero/titan/engines/x340.aspx

I have 592 hours on the ECI IO-340. I would not want any other engine on my 9A. Weight on the nose gear was an important factor. So, running the IO-340 with a 3-blade Cato is ideal. The engine turns out to be 8 lbs lighter than a 360 and still has 180 HP. I know the traditional 320 or 360 engines are pretty much the norm for RVs but the 9 does very very well with the IO-340. At least my 9A does! Anyone contemplating what engine to use in the 9 should give it consideration.

Live Long and Prosper!
 
It is kind of funny that no one even raises an eyebrow when larger than recommended engines are installed in RV-4, -6, -7, and -8's.

I guess only the -9 will fall out of the sky when over engined.

One thing to keep in mind, and we in the RV world often forget this. The O-320 150 hp Lycoming was designed to lift a four place engine. In our little planes, they are a great choice, if you keep everything light.

When I had the O-290 of all of 135 hp in my RV, it was a GREAT combination. When I would travel with the local RV gang for a couple of hundred mile trip, I would take off first and when I would enter the pattern, the last airplane ahead of me would be just touching down.

The bigger engines really only gain you in ROC and not so much in cruise speed. Even then, 1400 FPM is nothing to shack a stick at.
 
Lots of good info on this and related threads. After shopping for both O-320 and O-360 used engines, I found a deal on an O-320 that was a fresh rebuild on the lower end with no cylinders, which was what I was looking for. I just received my new Lycoming cylinders and will start the assembly process as time permits. The money saved compared to a new engine will go a long way towards the panel I want. Thanks for all the responses. I am sure we all learned something about engine choices in this thread.
 
The bigger engines really only gain you in ROC and not so much in cruise speed. Even then, 1400 FPM is nothing to shack a stick at.

That's pretty much it in a nutshell, yes. But I sure do enjoy holding 2000+ off the runway!

Somebody asked me the other day how long I hold that climb rate coming off the runway. My answer was "Long enough that nobody thinks I did it by accident."
 
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