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O-320 Engine change??

I have a RV7 I purchased that has a O-320 (160 HP) engine with a fixed pitch propeller. Not sure of pitch or type of propeller. I am unable to put a constant speed propeller on it that I know of. It runs great and I am enjoying the 150 Knots of GS but it can very slow on take off in the summer with fuel and a second person on board. Based in DFW area. I've talked with most others who at least have a O-360 (180 HP constant speed prop) engine on their 7's. So I am considering a change in the future to:

1. O-360 (180 hp with constant speed prop)
2. IO-360 (200 hp with constant speed prop)
3. other options???

Looking for opinions and why. I believe both of the above will work with the same engine mount and I know I will have to redo the cowling for sure. This I will have to research more. I am a fan of fuel injected and I have tons of experience with the IO-360 and being a wonderful engine but is 200 HP to much? Looking for options and good combinations of prop and engine, even if it is keeping the 160 hp with a different prop.
 
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All engines can have one of three mount styles - conical, dynafocal, dynafocal II (relatively uncommon)

IO-360's come in both parallel valve - 180hp and angle valve - 200hp.

Larry
 
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My Rocket weighs 1200 pounds and has 330+ HP.

I'd like 50 more HP.

There is no such thing as "too much" HP.
 
More info needed
What engine / prop do you have now?
What performance factors with the current engine do you not like?
What performance return do you want?
What budget are you willing to pay for this performance boost?
 
If you are only concerned with cruise speed.........

HP makes very little difference on cruise speed. If you have a problem with current take-off and climb, you might consider a change. Otherwise, keep on ginning!
Do you have 150 or 160 hp? If you have 150 and it come time for overhaul, you might consider changing pistons to 8.5 - 9 compression ratio.

Another consideration is a C/S prop. Some O-320s can use C/S, others cannot.

First we need to know what you have and what you desire.
 
My RV-6A has an O-360 (180 hp) with a CS Hartzell. I cruise at 60% power (108 hp) and see 155 KTAS.
An O-320 (160 hp) in my airplane run at 67.5% power would yield the same cruise speed.
I find that I have more than adequate power for economical cruising, but the extra power comes in handy when I visit airports where the density altitude is over 10,000 ft.
 
I have updated the information with more detail:

I have a RV7 I purchased that has a O-320 (160 HP) engine with a fixed pitch propeller. Not sure of pitch or type of propeller. I am unable to put a constant speed propeller on it that I know of. It runs great and I am enjoying the 150 Knots of GS but it can very slow on take off in the summer with fuel and a second person on board. Based in DFW area. I've talked with most others who at least have a O-360 (180 HP constant speed prop) engine on their 7's. So I am considering a change in the future to:

1. O-360 (180 hp with constant speed prop)
2. IO-360 (200 hp with constant speed prop)
3. other options???

Looking for opinions and why. I believe both of the above will work with the same engine mount and I know I will have to redo the cowling for sure. This I will have to research more. I am a fan of fuel injected and I have tons of experience with the IO-360 and being a wonderful engine but is 200 HP to much? Looking for options and good combinations of prop and engine, even if it is keeping the 160 hp with a different prop.[/QUOTE]
 
Yes!

My RV-6A has an O-360 (180 hp) with a CS Hartzell. I cruise at 60% power (108 hp) and see 155 KTAS.
An O-320 (160 hp) in my airplane run at 67.5% power would yield the same cruise speed.
I find that I have more than adequate power for economical cruising, but the extra power comes in handy when I visit airports where the density altitude is over 10,000 ft.

I have an 0-360 9:1 185HP with CS Hartzell and see the same results as David. Where the extra power comes in handy, is at density altitude airports which I frequent in the West.
 
I am still building, so I don't have direct experience, but I just went through the engine/prop decision, so I will tell you my opinions.
1) As stated above, there is no such thing as too much power. There may be control system issues, but never too much power. That said, there is such thing as too much weight and too little money.
2) more power with a fixed pitch is almost, but not quite as good as a C/S prop with less.
3) Angle valve engines are heavy and expensive, and they only have more power at the top end of the rpm range. Can help with T/O with a C/S prop, but of no real value with a fixed in climb. You have to be able to get to max rpm and a fixed won't get you there.

In my opinion, the sweet spot of performance, weight and cost is a 180HP (I)O-360 with a C/S prop. If that is too pricey, do a fixed pitch. If it is too heavy (which it isn't) go with a C/S and an (I)O-320. The perfect choice for a 6 or 7 (or 9 for that matter) to me is a 180HP IO-360 with a C/S prop and P-mags. If I already had an O-320, though, I would put a C/S prop on it (if I could) and call it good unless the engine needed to be replaced. New engines are ridiculously expensive.

Tim
 
If what you want is performance, then go O360 and CS prop. If you are going from a spam can, then you will be pleased. Just don't ever fly an RV with a O320 and fixed pitch prop because handling will suffer with a nose heavy RV. If you are happy with it, go for it.

Many people just want to get from point A to point B. Others (like me) fly an RV for the amazing feel of the aircraft...... your choice
 
I have updated the information with more detail:

I have a RV7 I purchased that has a O-320 (160 HP) engine with a fixed pitch propeller. Not sure of pitch or type of propeller. I am unable to put a constant speed propeller on it that I know of. It runs great and I am enjoying the 150 Knots of GS but it can very slow on take off in the summer with fuel and a second person on board. Based in DFW area. I've talked with most others who at least have a O-360 (180 HP constant speed prop) engine on their 7's. So I am considering a change in the future to:
.
[/QUOTE]

I have a 6A with an IO-320 and Catto FP prop. I cruise at 160 KTAS LOP @ 8.1 GPH @ 8K. My T/O rolls are pretty short and would never be afraid of a 2000' runway. It is quite possible you just have a poor performing prop or it is not the correct pitch. I wouldn't condemn the engine before exploring other potential reasons for the under performance.

If I had to deal with 10K DA's all the time, I would probably upgrade my engine or prop, but down here near SL, I am very happy with the lower cost alternatives that I selected.

Larry
 
Flying a 6A with an IO-320 and constant speed. Love this combo, great performance in takeoff, climb and cruise. We live on the wet coast so mountain flying…high elevations are normal. We get an honest 165 knots cruise between 9500-12,500.
It costs so much to be fooling around with engines id be super reluctant to even consider it because I’m so happy with what we’ve got. As others have suggested, consider repitching the prop or see if you can get an electric constant speed prop.

I run with RV’s that have 180 hp and there is little to no difference in performance. If they are fixed pitch I usually outperform them right across the board, if they are constant speed some cruise a few knots faster, others not so much.:)
 
Engine swap.....or not......

Just don't ever fly an RV with a O320 and fixed pitch prop because handling will suffer with a nose heavy RV. If you are happy with it, go for it.
Many people just want to get from point A to point B. Others (like me) fly an RV for the amazing feel of the aircraft...... your choice

+1

SuzieQ has an O-320 with a (BEAUTiful) Warnke "Almost Constant Speed" wooden prop, sadly no longer available. Somehow, it seems to bite into the air better as speed increases. I do have the Landoll Harmonic Balancer (would not trade it for it's weight in gold) and love the performance and handling. Field elevation here is 5,200 feet.

What Gasman was saying that if you ever fly an RV that is as light as possible, making it more nimble, you will not want anything else. Van himself has said as much.....

SuzieQ does very well cross-country (152kts at economy cruise with the old-style wheel pants....those are probably going to be upgraded....) which is WAY faster than many other airplanes I've flown. I can keep up with everyone I have flown with....and love sneaking up on Bonanzas or Mooneys...... :D She can top 174kts (200 mph!) but is sucking 10 gph to get there. Naaaaa; I'm good! I like 6.5-7gph..... Her handling, like Gasman says, is beyond amazing! I'm with him there!

I LOVE my RV-4 just the way she is......(do I hear a Billy Joel song in the background.....:p)
 
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More Info

Our RV-6 has an O-320-D1A, 160 hp, a Slick mag and a Lightspeed Plasma III. We have a Catto FP and cruise around 155 knots or so, burning just under 8 gph. The lightweight Catto along with a lightweight starter condemns me to always looking for ways to get weight off the tail, but the airplane handles beautifully. A friend had the same engine in his -6 with a Hartzell constant speed prop and the acceleration on takeoff was of course dramatically better than our airplane. The -6 across from our hangar has an IO-360 with a Hartzell blended airfoil constant speed. It does not really have a takeoff roll, just leaps into the air like a sparrow. Cruises right at 180 kts. I don’t know what his fuel burn is and the handling is more towards the stable, big airplane feel. You take your choice and then pay your $. Side note, we had a Warnke 72-60 on our airplane originally but I believe it was for a 150 hp airplane. Says so, right on it. I damaged it taxiing into a plastic stanchion. The Catto was a huge improvement. If you’re going to stay with the simplicity and economy of a FP, I believe Catto is the gold standard. If there’s a square pad on front or back of your engine, you can probably hand a CS prop on your engine. You’ll also need to pull the plug out on the front end of the crankshaft.
 
+1

SuzieQ has an O-320 with a (BEAUTiful) Warnke "Almost Constant Speed" wooden prop, sadly no longer available. Somehow, it seems to bite into the air better as speed increases. I do have the Landoll Harmonic Balancer (would not trade it for it's weight in gold) and love the performance and handling. Field elevation here is 5,200 feet.

What Gasman was saying that if you ever fly an RV that is as light as possible, making it more nimble, you will not want anything else. Van himself has said as much.....

SuzieQ does very well cross-country (152kts at economy cruise with the old-style wheel pants....those are probably going to be upgraded....) which is WAY faster than many other airplanes I've flown. I can keep up with everyone I have flown with....and love sneaking up on Bonanzas or Mooneys...... :D She can top 200kts but is sucking 10 gph to get there. Naaaaa; I'm good! I like 6.5-7gph..... Her handling, like Gasman says, is beyond amazing! I'm with him there!

I LOVE my RV-4 just the way she is......(do I hear a Billy Joel song in the background.....:p)

You have a -4 with an O-320 that can do 200 knots? VNE is 182 knots true..
I agree that a 320 engine/wood prop combo is a sweet flying plane!! My neighbor has that combo, and I love to fly it.. just so sweet. I’m not downgrading my O-360 & metal prop to get there though, but I very much enjoy flying hood when I can!
 
You have a -4 with an O-320 that can do 200 knots? VNE is 182 knots true..
I agree that a 320 engine/wood prop combo is a sweet flying plane!! My neighbor has that combo, and I love to fly it.. just so sweet. I’m not downgrading my O-360 & metal prop to get there though, but I very much enjoy flying hood when I can!

I lied! Well, I misspoke. I jumped from mph to kts. She'll do over 200 mph or 174 kts. Van's web site brags a 160hp RV-4 with a wood prop will do 205mph. I've seen that but things up front are working REALLY hard....!:eek: (I had to go in and edit that post......:rolleyes:)
 
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Thank you all for the replies as it gives me a lot to think about. After really thinking about it it does not make financial sense to change the whole engine. What we would like to do is get a constant speed prop because when we fly formation, we are starting to do a lot of it, this airplane will not slow down with the fixed pitch prop. My O-320-D2J does have a mount on the case for a governor but will need to find out if it can support a CS prop or not. Are there other options as I have seen electric CS props but have never talked with anyone whom has one.
 
Thank you all for the replies as it gives me a lot to think about. After really thinking about it it does not make financial sense to change the whole engine. What we would like to do is get a constant speed prop because when we fly formation, we are starting to do a lot of it, this airplane will not slow down with the fixed pitch prop. My O-320-D2J does have a mount on the case for a governor but will need to find out if it can support a CS prop or not. Are there other options as I have seen electric CS props but have never talked with anyone whom has one.

Bottom line you need to determine if you have a hollow crank or not. Hollow ... and have a governor pad... you should be able to install a conventional CS prop. Not hard to determine. Pull the prop and have your neighborly A&P look.
 
Thank you all for the replies as it gives me a lot to think about. After really thinking about it it does not make financial sense to change the whole engine. What we would like to do is get a constant speed prop because when we fly formation, we are starting to do a lot of it, this airplane will not slow down with the fixed pitch prop. My O-320-D2J does have a mount on the case for a governor but will need to find out if it can support a CS prop or not. Are there other options as I have seen electric CS props but have never talked with anyone whom has one.
One day you may have to change, then think about changing. I flew around behind a -320 CS (Whirlwind) in my -8 for quite a while. My *good* friends always waited on me. ;) But the reality was, as already mentioned, I had less climb, a few less knots on the top end, and far better cooling as compared to the guys with the -360 parallel valve. After 8-10 years, my case eventually developed a crack, and I changed to a -360 parallel valve engine. And the climb outs are noticeably improved.
 
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Have your friends slow down a little. My 150HP O-320, wooden FP prop, RV-6 is well capable of flying all the FFI prescribed procedures. Granted, the pilot is working hard (probably harder than the CS O-360 drivers in the formation) but that’s just another challenge to overcome with hard work and perseverance. Spend the money on gas instead of firewall forward changes-it will provide a dividend of making you a better pilot.

Thank you all for the replies as it gives me a lot to think about. After really thinking about it it does not make financial sense to change the whole engine. What we would like to do is get a constant speed prop because when we fly formation, we are starting to do a lot of it, this airplane will not slow down with the fixed pitch prop. My O-320-D2J does have a mount on the case for a governor but will need to find out if it can support a CS prop or not. Are there other options as I have seen electric CS props but have never talked with anyone whom has one.
 
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