S

Sid Lambert

Well Known Member
Has anyone done the O-320 to O-340 conversion in their RV?

Do you have any performance data on it? I was set on doing it but the prop guys say it's not worth too much on the top end but it will pull better on the bottom end.

Any insight is appreciated.
 
Then the question is, will you get the same speed at a lower fuel burn?
What is the cost of a new prop? Can you offset that with the fuel savings?

He is correct, there is not much top end difference between an O-320 and O-360 but you really gain in the climb.
 
Bill,

I'm getting a new prop either way. I would say that the ~$6000 price of going to the 340 over redoing my 320 would have to be a lot of fuel savings.

I think we are a lot alike in the sense of wanting to hop it up a bit given the opportunity. (my piston and your prop strike)

I'm just trying get the best bang for the buck.
 
A well-built O-320 can take you to Vne in level cruise in an RV-4 with the correct prop. The question is how quickly do you want to reach Vne?

The O-340 upgrade is likely not going to save you any fuel at all, in fact you'll probably end up using more fuel while enjoying that added climb power too often. ;)

Instead, spend $4K on the Sensenich ground adjustable composite prop for the O-320.
 
I've also eye'd the -340 option. Part of my justification is the re-cowling/baffling, etc. that might come from a -320 to -360 swap. Has anyone moved from -320 to -360? What was the impact to baffling, cowling, etc.? Exclude the carb/fuel delivery equipment - I have a good grasp of that and it's multiple variables.
 
Low Pass said:
I've also eye'd the -340 option. Part of my justification is the re-cowling/baffling, etc. that might come from a -320 to -360 swap. Has anyone moved from -320 to -360? What was the impact to baffling, cowling, etc.? Exclude the carb/fuel delivery equipment - I have a good grasp of that and it's multiple variables.
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Ok, It is time for a post on this subject. I installed the ECi IO-340 with a Catto 3-blade prop on my 9A from the onset. So, I do not actually have experience converting from a 320 to a 340 but I have been flying about 300 hours now with the 340 engine on my 9A. What I can address is Low Pass' questions concerning cowling/baffling, etc. The cowling is going to have more to do with the fuel injection vs. carb issue not the 320-340 issue. I used the stock 320 motor mount and the stock 320 baffling that came with the 320 firewall forward kit. I am using the fuel injection cowling and snorkel for an IO-360 Vans sells for an RV7 not because of the 340 engine but because of the forward facing cold air induction for the fuel injection. This also affected the exhaust since the crossover exhaust spanned directly in front of the forward facing sump. I have the 4 straight pipes because of this issue. I did have to use a different throttle cable than was supplied in the firewall forward kit but again, this was due to the fuel injection location and not the difference in the 340. There are some internal items inside the engine different due to the longer stroke but the external components of this engine are like a 320. There is one exception, though it did not pose a problem. The tapered cooling fins on the 340 cylinders are different than the stock 320 cylinders but even this did not cause any issues with the baffling. The baffling fit like a glove.

Performance is on par with what I have seen with my buddies' 360 equipped 7's. I can climb with them, cruise with them, and just ever so slightly, in certain situations, burn less fuel doing it. For the most part though the differences between the 360 and the 340 are inconsequential. The advantage is that my engine weighs ~10-12 lbs less than the 360 for the same level of performance. And it was this weight savings that was a major motivator for going with this engine.

If anyone is interested in more specific info I am happy to discuss any questions you may have. I am happy with my decision of installing this engine. It has worked out very well for me.
 
Neal@F14 said:
... Instead, spend $4K on the Sensenich ground adjustable composite prop for the O-320.
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Do NOT use this prop until Sensenich figures out what is going on with this prop spun by O-200 engines. See Sensenich NOTIFICATION NO. CN-1-13 for details.

You are better off with a Catto cut for your engine / airframe combination.

Low Pass said:
I've also eye'd the -340 option. Part of my justification is the re-cowling/baffling, etc. that might come from a -320 to -360 swap. Has anyone moved from -320 to -360? What was the impact to baffling, cowling, etc.? Exclude the carb/fuel delivery equipment - I have a good grasp of that and it's multiple variables.
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When I changed my O-290-D2 to an O-360 I was able to reuse the P-mags, fuel pump, alternator (if it hadn't been damaged), starter (assuming it has the correct number of teeth.), and a few other parts. The engine mount, baffles, prop, exhaust, carb, prop extension, and a few other bits had to go. Your cowl will be the biggest question. If you stay with a composite prop, you might get away with using your longer engine mount but if Van's recommends a shorter mount, then you will have to trim your cowl, maybe. You could always talk to Sam at Saber and get a prop extension to put between your new engine and CS prop.

When I had to buy a new engine I took a very close at the IO-340 and decided for $500 less I could put an O-360 up front with little weight penalty.

It comes down to personal choice.
 
N941WR said:
Do NOT use this prop until Sensenich figures out what is going on with this prop spun by O-200 engines. See Sensenich NOTIFICATION NO. CN-1-13 for details.
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The Sensenich notification is only for the composite prop they make for Continental engines.

The 2GO prop for the Lycomings is a completely different prop and is not affected by the 6th order harmonics problem. The blades are a different design, and the hub is a different design. The Lycoming engine also has a flywheel, whereas the Continental engine does not. Additionally, Sensenich has performed extensive vibration analysis on the 2GO prop / Lyc 320 engine combination. Sensenich NOTIFICATION NO. CN-1-13 does not apply to the composite ground adjustable prop for Lycoming O-320 engines, the "2GO" prop, which I have and it runs "turbine" smooth on my aircraft.
 
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Neal@F14 said:
The Sensenich notification is only for the composite prop they make for Continental engines.
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Yes, the notification only applies to the O-200, as I mentioned. However, until they resolve this issue, I would not recommend it to anyone.

The solid carbon props are much stiffer than either aluminum or wood core composites, which is why there is a harmonic issue.

What is not mentioned in that notification is that at least one O-200 was destroyed as a result of the prop. Most just puke the right, non-impulse coupled mag at less than 50 hours. I know one cub-a-like that has less than 200 hours on it and hasn't had a mag even make 50 hours.
 
Again, the 2GO prop is a different construction than the 72AE prop and is NOT a solid carbon fiber prop. Its blades are hollow core and have an internal I-beam construction different from the 72AE blades.

To extrapolate the 72AE prop's problems related to the Continental O-200 to the 2GO prop on the Lycoming O-320 at this point in time is completely unfounded and frankly, wrong. The installed base and experience with this prop in the field thus far has demonstrated it to be a very good prop with excellent performance and no known problems.

It's unfortunate that the 72AE prop is having problems on many LSA's with the O-200 and Bendix mags. I have a personal friend who's facing the issue right now on his O-200-equipped Legend Cub, but it's unfair to condemn the entire Sensenich carbon fiber prop lineup just because one particular prop model /engine combination has exhibited problems.
 
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Neal@F14 said:
Again, the 2GO prop is a different construction than the 72AE prop and is NOT a solid carbon fiber prop. Its blades are hollow core and have an internal I-beam construction different from the 72AE blades?
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I agree and wish them luck as this is a nice looking prop.

Neal@F14 said:
?To extrapolate the 72AE prop's problems related to the Continental O-200 to the 2GO prop on the Lycoming O-320 at this point in time is completely unfounded and frankly, wrong?
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The issue is two fold and is the reason I suggest caution until they figure it out.

1. If the stiff prop is causing O-200 engines to fail (one of the most tried and true designs, BTW) and that becomes very expensive for the aircraft owner as I doubt you will get the prop manufacture to pay for your new engine. Not to mention that the props are destroying magnetos.

2. Props are not something you want to play with. Should one fail and throw a blade, there is a very good chance the imbalance will quickly tear the engine off the airplane.

I have not ?condemned? these props, all I have done is suggested we have utilize some constraint until this works it course and Sensnich

Neal@F14 said:
The installed base and experience with this prop in the field thus far has demonstrated it to be a very good prop with excellent performance and no known problems.
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Performance on your friend?s Legend Cub is most likely very good, right up until the prop causes problems.

All I?m saying is that we should recommend caution until this is sorted out. This is a new prop design, with new style blades, construction, and hub. Unfortunately our airplanes are not all the same and what works for you may not work for the next guy. As has been discussed before; different pistons, ignition, airframes, accessories, etc. can all cause different harmonics (as pointed out in the notice from Sensenich).
 
I am getting ready to put an O340 in my RV4. I upgraded an O320 and bought the kit from ECI at a substantial savings over other outlets. It came with a new crankshaft, rods and pistons. I sold all of my internal parts that I didn't get new. I originally decided I didn't want to put a new engine in my 4 because I bought an 8. I tried to sell it on this website for what I had in it and as usual unless you are giving it away, most aren't interested in it. I have decided to just put it in my 4 and see what happens. I put all new parts in it as well as 4 new cylinders and have about 12K in it about half of what a new engine would cost. Do what you want to do......:cool:
 
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