Engines 360 vs 320

[AlanNZ]

Good afternoon all, before I start I know this question is as bad as the primer wars / but I'm a little unsure which one to go for. What I want is the most econimcal to run and maintain without being a pain to fly.

There is a guy I talk to a lot who is a LAME that has built 3 RV's. He tells me the difference between the two engines is very small in performance (from a flying perspective) but large from a cost of ownership / running. He tells from his experiance the 360 is far more maintance intensive than the 320.

Talking with the guys at Van on the build line they seem to concer with my LAME as far as these two engines are concerned. Please note I'm talking Fixed pitch only!

What are the comments from the group on this as it seems to me to make good sense to use a 320 if this is the case?

Thanks in advance.

 

[Vlad]

When I am flying with somebody I wish I had 360. When alone on a loooong trip I wish I had 235 Your choice it IS a primer war

 

[Sam Buchanan]

Good afternoon all, before I start I know this question is as bad as the primer wars / but I'm a little unsure which one to go for. What I want is the most econimcal to run and maintain without being a pain to fly.

Neither engine is a pain to fly, both are well suited to a RV-7.

There is a guy I talk to a lot who is a LAME that has built 3 RV's. He tells me the difference between the two engines is very small in performance (from a flying perspective) but large from a cost of ownership / running. He tells from his experiance the 360 is far more maintance intensive than the 320.

This has not been proved in the field. I assume you are talking about the 180 hp O-360. It is basically just a slightly stroked O-320, they will have very similar maintenance requirements.

Talking with the guys at Van on the build line they seem to concer with my LAME as far as these two engines are concerned. Please note I'm talking Fixed pitch only!

I suspect the Vans person you were talking to was referring to the 200hp IO-360 which is indeed more complex to install and cool.

What are the comments from the group on this as it seems to me to make good sense to use a 320 if this is the case?

Go with whichever engine is the easiest for you to obtain. Either one will fly your plane beautifully with similar operating cost.

 

[DanBaier]

Go with whichever engine is the easiest for you to obtain. Either one will fly your plane beautifully with similar operating cost.

Good advice. I've operated Cherokees for over 40 years - my experience has been that O-360 parallel valve vs O-320 relative to maintenance issues is insignificant.

I'd be inclined to vote the O-360, but truthfully, if there was a good O-320 candidate around as I was building, I'd grab it. In context, the flight time difference from western NY to northern FL would only be about .3 or .4 hours more with the O-320.

 

[RV Jerry]

THE 360 IS NO MORE EXPENSIVE TO MAINTAIN THAN THE 320 ,FUEL BURN WILL PROBALY BE LESS ON A XCOUNTRY. FUEL PER HR. WILL BE ABOUT THE SAME AT THE SAME GIVEN SPEED AS THE 320. RESALE WILL BE CONSIDERLY MORE. FUN FACTOR A LOT MORE FINALLY THE RV-7 CAN USE MORE NOSE WIEGHT HAVE BUILT 30 PLUS RV'S THE 360 IS USUALLY ENGINE OF CHOICE REGARDS JERRY

 

[roee]

There is a guy I talk to a lot who is a LAME that has built 3 RV's. He tells me the difference between the two engines is very small in performance (from a flying perspective) but large from a cost of ownership / running. He tells from his experiance the 360 is far more maintance intensive than the 320.

Seems unlikely. If the comparison is between the parallel valve O-360 and 320, then the two engines are nearly identical in all aspects except that the 360 has a longer stroke. The two engines are practically identical in external dimensions, weight, purchase cost, operating procedures, and maintenance. Fuel burn should also be practically identical at a given power output. But with the 360 you have an additional power reserve compared to the 320. Use it when you need/want it. In simple terms, the extra horse power will translate to a modest increase in cruise speed, and a substantial increase in rate of climb.

I'm wondering if in your conversation there was confusion with the angle valve IO-360, which is a very different engine, and may very well have higher costs associated with it.

 

[PCHunt]

PM sent

Alan, check your Pvt Messages.

 

[paul mosher]

io-360

The 200hp io-360 will really bite you if you need to buy a cylinder. I paid $1900 each a few years ago. I don't think Superior builds a cylinder for it so you have to go Lycoming.

 

[roee]

The 200hp io-360 will really bite you if you need to buy a cylinder. I paid $1900 each a few years ago. I don't think Superior builds a cylinder for it so you have to go Lycoming.

Again to clarify, you're talking about the angle valve 360, which is a very different animal than the parallel valve 360 and 320.

 

[humptybump]

Vlad already said most of what I hold as my opinion.

You can fly a 180 hp as if it were a 160hp but you can't do the opposite. If you have the need for speed, then you have the answer.

I fly an RV-8 with a 150hp and a fixed (wood) prop. I can easily keep up with the 150/160hp RV's out there but the guys with 180/200 and constant speed props will out climb me and out run me. That's OK. I want a 150-160kts plane (Once I get high) that burns 7.5 +/- gph. Thosecare my mission parameters.

You can take a bigger engine and throttle back and get pretty close. I can't "throttle up".

As Sam noted, an O320 does very well across the fleet of RV's. I enjoy 400nm legs and flying at 10,500/11,500 when the weather is favorable. These planes can handle the range of engines and there RV grin is just as big

 

[CODon]

O-360

I have a parallel O-360 and am not looking back. Bought a run out engine that turned out to be quite sound. Flew it off and pulled it last week for a rebuild during the winter months. Probably not the best way to go but it fit the timeline and budget. There are a lot of options, but think it is just best to get the decision behind you and keep on building.

 

[wirejock]

rebuild

I have a parallel O-360 and am not looking back. Bought a run out engine that turned out to be quite sound. Flew it off and pulled it last week for a rebuild during the winter months. Probably not the best way to go but it fit the timeline and budget. There are a lot of options, but think it is just best to get the decision behind you and keep on building.

CODon
Not to hijack the thread, but I was interested in the runout/rebuild experience. I am on a tight budget and am considering a mid time.
Would you do it again? Was there any saving vs installing a new engine? Did the runout make the first hours easier not having to break in a new engine while flying the bugs out of a new airplane? Thoughts?

 

[dealfair]

Thoughts on engine times

CODon
Not to hijack the thread, but I was interested in the runout/rebuild experience. I am on a tight budget and am considering a mid time.
Would you do it again? Was there any saving vs installing a new engine? Did the runout make the first hours easier not having to break in a new engine while flying the bugs out of a new airplane? Thoughts?

Larry,
My old mentor used to fly the 7th Fleet Commander & SEATO VIPs all over the Pacific in a 4 engined C-118 (DC-6) back in the 1960s. He told me they NEVER allowed an engine with less than 500 hours to be installed on it. They had to have tested proven engines on that aircraft. Only grunt carriers & cargo planes flew with new low time engines. That should tell us something. MORAL: don't reject a good mid term engine out of hand. 1,000 hrs in a RV covers a gob of miles.

Good luck & Cheers,

 

[Ron Lee]

Go with the O-360. How many people remove an engine to install one of lesser horsepower versus the other way around?

My opinion is such that I tell people who want to buy an RV is to get one with an O-360 (not all RV models).

If you are buying a new engine, getting an (I)O-320 instead of an (I)O-360 would be a mistake in my not so humble opinion. I am not suggesting an angle valve 360 engine.

 

[dealfair]

Ditto what Ron Lee says. I have an O-320 in my -4 because it was available, good price, quick, etc., etc., like Sam described. It performs well; but I want an O-360. I've never met an RV owner, yet, with an O-360 who wished for an O-320.

 

[AlanNZ]

Thanks for advice

Firstly to clarify I'm talking about a 180hp 360 vs a 160hp 320. The thing I find strange is that I used to own a pa28 161 and fly with 2 friends (one in a 172 and the other in a pa28 also) they Both had a fuel burn of about 40 to 45 litres but I guess that depends on how hard you push them, after all more fule = more HP as a rule of thumb.

In New Zealand the 320, 160hp is far more common than the 360. From my perspective I'm most likely going to be using a mid time engine and the 320's are more available (and the difference is price is substantial).

I think you have all raised very good points for the parallel valve 360 and therefor will be on the lookout for one. I'm thinking of importing from Wentworth from the USA.

With thanks.

 

[LifeofReiley]

Build with an O-320 as Van himself would... bullet proof, economy, light... it is all you need. I guess the O-360 guys wished they had the IO-408ac now.

 

[humptybump]

One of the most common compliments I get about having a simple 150hp RV-8 is "Van would love this plane". I hope so i love it.

I don't recommend others hang the lower compression O320 on their project. It's all a personal choice. That said, every time I talk to the builder of my plane (we talk regularly and have become good friends thru the plane, RV's have that affect on people) I end up telling him, "you built the plane I've always wanted!"

Build what you want. Be happy with what you build.

 

[Captain Avgas]

The thing I find strange is that I used to own a pa28 161 and fly with 2 friends (one in a 172 and the other in a pa28 also) they Both had a fuel burn of about 40 to 45 litres but I guess that depends on how hard you push them, after all more fule = more HP as a rule of thumb.

Alan, the reality is that the Brake Specific Fuel Consumption (BSFC) of both the Lycoming 320 and 360 (parallel valve) is identical at .43 lb/Hp-hr. In other words they will both consume .43 lbs of fuel to generate 1 horsepower for one hour.

This means that both engines will burn the same amount of fuel at the same horsepower. The only difference being that you can call on more horsepower from the 360 if you need it (at a higher fuel burn of course)
.
Or put another way, if you travel cross country with a 320 producing 120 HP (75% power) you will have the same speed and fuel burn as with a 360 producing 120 HP (67% power). However you will be running the 360 engine at a lower percentage of power which should provide for superior engine longevity (all other factors being equal).

Some of those mountains in Kiwiland are pretty big so a few extra horses from a 360 may come in handy when you need them. At other times just throttle back and get the same fuel efficiency and speed as with a 320.

 

[Mel]

About building with a mid-time or run-out engine...

I installed an O-320 with 2500 hrs. when I built my -6. The engine had a good run sheet and history, and was bought from a very reputable Air Salvage co. I flew the engine for 3 years before rebuilding it. And even at that time, everything met all tolerances.
I would do it again in a heartbeat!

Everything else being equal (seldom is) I would chose the O-360. But I certainly wouldn't let that be a big deciding factor. Horse power has little to do with speed. It has more to do with take-off and climb, which the RV does great even with the lower compression O-320.

 

[Sam Buchanan]

Firstly to clarify I'm talking about a 180hp 360 vs a 160hp 320. The thing I find strange is that I used to own a pa28 161 and fly with 2 friends (one in a 172 and the other in a pa28 also) they Both had a fuel burn of about 40 to 45 litres but I guess that depends on how hard you push them, after all more fule = more HP as a rule of thumb.

In New Zealand the 320, 160hp is far more common than the 360. From my perspective I'm most likely going to be using a mid time engine and the 320's are more available (and the difference is price is substantial).

I think you have all raised very good points for the parallel valve 360 and therefor will be on the lookout for one. I'm thinking of importing from Wentworth from the USA.

With thanks.

I too purchased a mid-time engine from Wentworth. Here is something for you to think about:

http://thervjournal.com/overhaul.htm

The only way you can be assured of what you are buying is to buy a new engine. In the long run, engine cost will be about the same.

 

[SeanB]

Mission

I think the choice boils down to your mission. I live in Colorado and the field elevation is 6874 ft msl, where it is commonly above 10K DA. After takeoff and heading west, there are these rather large piles of rock and dirt to consider. No way I would hang a 320 instead of a 360 in this case.

Also, I hope to get in and out of remote airstrips from time to time.

What if I fly to OSH or Cabella's and buy a bunch of things? If I'm getting closer to full gross, sure won't hurt to have the extra umph.

The RV-7 is aerobatic. A little extra horsepower could be good.

As already pointed out, on a cross-country the 360 can be tuned in for economy.

The 360 wins in all cases in my application, but the 320 would be fine for certain missions. How will you fly??? That makes the decision for you.

 

[Subwaybob]

I installed an O-320 with 2500 hrs. when I built my -6. The engine had a good run sheet and history, and was bought from a very reputable Air Salvage co.

Mel, did you get that here in Dallas (Lancaster)?

 

[GEM930]

When I am flying with somebody I wish I had 360. When alone on a loooong trip I wish I had 235 Your choice it IS a primer war

What he said!

I'm one of those guys that pulled his 320 and is in the process of installing a 360. My problem was there are 3 other (almost 4) RVs at my field. When I was flying by myself I was satisfied with the performance. When I flew with other RVs... I wanted MORE POWER!!! The kicker for me was a trip from California to OSH in my buddy's 360 RV-7. I was in charger of fuel calculations and burn was always within about .2 gph of what my 320 would have been for the same speed. My 320 was a great engine and ran like a top, but I'm just a sucker for "keeping up with the Jones" I guess.
I can't comment yet on the actual difference as I'm still in the process of the install and I opted for a constant speed propeller as well, so it would not be an apples to apples comparison anyway. I do believe that if resale value is of any importance to you the 360 RVs seem to sell for more.
Good luck! I'm sure you will be happy with what ever choice you make.

 

[roee]

Build with an O-320 as Van himself would... bullet proof, economy, light... it is all you need.

The parallel valve 360 is just as bullet proof, economical, and light as the 320.

All things being equal, choosing the 320 over the 360 is like leaving money (horsepower) on the table. The only good reason mentioned so far for choosing a 320 is if you happen to get a really great deal on one. Otherwise, the 360 is clearly the better choice.

And Van is a very practical thinker. I think he'd agree.

BTW, I think it's funny how people invoke Van's name that way. "What Would Van Do?"

I guess the O-360 guys wished they had the IO-408ac now.

Nope. For a serious racer with an unlimited budget, the 408 may be a good choice. For the rest of us, balancing all considerations (performance, weight, reliability, economy, flexibility in fuel types, etc.), the parallel valve 360 is still the best choice out there.

 

[rockwoodrv9]

O360 on the -9

Im convinced - I will be going with a O360 for the -9 I am building. The Aspen airport is 7815 and Rifle about 6000. On a nice, warm day, with a full load, I think I will appreciate the 20 extra hp.

 

[Mel]

YEP!

Mel, did you get that here in Dallas (Lancaster)?

Air Salvage of Dallas.
Lucky is the best guy in the world you would want to do business with.

 

[LifeofReiley]

The parallel valve 360 is just as bullet proof, economical, and light as the 320.

Yes... my good friends Aerosport O-360 went totally south (trashed) at 480 hrs just a couple of months ago... bearings, crankshaft, all trashed. When you run 'em hard, I'll stick with the 320 @ 178 hp.

 

[roee]

Yes... my good friends Aerosport O-360 went totally south (trashed) at 480 hrs just a couple of months ago... bearings, crankshaft, all trashed. When you run 'em hard, I'll stick with the 320 @ 178 hp.

Interesting. I'd like to know more about your engine (its exact configuration), what caused it to fail, and under what operating conditions, etc. And I'm especially curious if there's a good reason to your belief that a 320 would not have suffered the same fate. Please share more info about your incident (start a different thread for that).

In any case, I have to point out that both the 320 and 360 have well established service records in the field over many decades and millions of flight hours, and both have proven highly reliable. That doesn't mean they never fail. But very rarely fail if built, installed, maintained, and operated properly. I don't know what happened to your particular engine and why, whether it was the result of defect, error, or if you were just one of the few unlucky ones. But in any case, remember that one incident does not negate the broader service record.

 

[Sam Buchanan]

Im convinced - I will be going with a O360 for the -9 I am building. The Aspen airport is 7815 and Rifle about 6000. On a nice, warm day, with a full load, I think I will appreciate the 20 extra hp.

That long -9 wing will climb like a charm on 160hp....at any USA field elevation. Choose the 180 if you wish but don't consider it essential for excellent performance from a RV-9A.

 

[rockwoodrv9]

9 performance at higher elevations

That long -9 wing will climb like a charm on 160hp....at any USA field elevation. Choose the 180 if you wish but don't consider it essential for excellent performance from a RV-9A.

I agree for sure. David L. from the forum came over from Craig CO and gave me a ride from the Rifle airport. We were off the ground and climbing at about 120 knots and over 1000fpm. We were not at gross, but we were not light either. A Lear was coming in from Denver, so Dave lowered the climb to about 800fpm and we were sailing off at about 145 knots. It was cold, but that RV 9 put a shame to the 182 I used top fly. Im not going to even mention the Piper 140!

If I found a good deal on a 320, I would jump on it and be perfectly happy. With so little cost difference or weight for the 360, I just think it makes sense to consider and look that way first. I know it isn't exactly to spec from Vans, but I don't live in a typical area. Those mountains are big around here!

 

[Jerry Cochran]

Dare I mention...

Resale? At some point, all of our beloved RV's will be sold. It is my firm belief that the 360 is way more of a sale enhancement than the 320 and the price one gets will reflect that. I had a lovely -6a with IO-360 that would go LOP at less than 8gph all day long.


.

 

[Sam Buchanan]

Resale? At some point, all of our beloved RV's will be sold. It is my firm belief that the 360 is way more of a sale enhancement than the 320 and the price one gets will reflect that. I had a lovely -6a with IO-360 that would go LOP at less than 8gph all day long.

Just thinking about the RV-6's of the same generation as mine (1999) I believe condition and panel have a considerably larger impact on resale value than engine size. The 360 may appeal to a larger pool of buyers, but I don't think the 320 will suffer much of a price disadvantage provided we aren't comparing fixed-pitch to CS prop.

I have a friend who has been surfing RV ads for quite a while and he tosses them to me for my opinion. This buyer is far more interested in condition of the aircraft than whether it has a 320 or 360. I suspect he is typical of a buyer who places high priority on a plane that has received good care.

A recent build probably would have higher resale with the larger engine....just because some newbies have been convinced the plane won't perform with a 320. But once our planes reach "maturity", condition seems to sell planes more than engine size.

 

[Mile High Relic]

Just thinking about the RV-6's of the same generation as mine (1999) I believe condition and panel have a considerably larger impact on resale value than engine size. The 360 may appeal to a larger pool of buyers, but I don't think the 320 will suffer much of a price disadvantage provided we aren't comparing fixed-pitch to CS prop.

As with most things, the answer is often "it depends." I spent a lot of time searching for and eventually buying an RV-6 and the panel was one on the things that I viewed as the easiest to change. However, you can have a huge variation in the amount of eye candy in a panel, so as you say panel variations affect the price a great deal. However, having looked at ads pretty much daily for all of 2010, I'd say that the 0-320 vs O-360 definitely reflects resale a lot as well, and unlike panels, it affects the price even more than it should.

I think that is the point. If you choose an O-360 over an O-320, you will likely get all of that back (and maybe more) in resale. Sort of like AC in a car in AZ. With panel options you will only get a percentage back.

I've owned 6's with both, but for the people looking for an already built RV, I'd say the 0-360 is what they want, and the prices show it. It took me awhile to settle on exactly what I was looking for, but when I did, for the Denver area, it was a well built 180 HP IFR plane, and that was that.

 

[JonJay]

Yes... my good friends Aerosport O-360 went totally south (trashed) at 480 hrs just a couple of months ago... bearings, crankshaft, all trashed. When you run 'em hard, I'll stick with the 320 @ 178 hp.

I suspect there is a lot more to the story here. I would hate to see a good company get trashed because "my buddy" had an issue. I fly behind both, 0320 and IO360, so I either don't have a dog in the fight or I have two, depending on how you look at it. But I consider Aerosport Power to be one of the best out there.

I will rest on the other argument I think you are trying to make, seriously....

 

[sglynn]

IO-320 for sale

Hey, a friend of mine has an IO-320 used for sale. Anyone interested? email me and I'll help you get in touch with him. He is not building an RV.

 

[LifeofReiley]

I suspect there is a lot more to the story here. I would hate to see a good company get trashed because "my buddy" had an issue. I fly behind both, 0320 and IO360, so I either don't have a dog in the fight or I have two, depending on how you look at it. But I consider Aerosport Power to be one of the best out there.

I will rest on the other argument I think you are trying to make, seriously....

Never trashed anyone... Nice RV6, regular oil changes with filter, never ran lean period!!! , 480 hrs engine is trashed. Over the top maintenance for sure! We will soon figure out the cause for sure, looks like a build up error.

 

[roee]

Never trashed anyone... Nice RV6, regular oil changes with filter, never ran lean period!!! , 480 hrs engine is trashed. Over the top maintenance for sure! We will soon figure out the cause for sure, looks like a build up error.

I'll be curious to hear more about your engine when the facts are in.

And I'm still completely puzzled as to why you're suggesting that a 320 in place of the 360 would not have failed. That suggestion is even more puzzling given that you suspect it was a build error. ??? ???

 

[LifeofReiley]

I'll be curious to hear more about your engine when the facts are in.

And I'm still completely puzzled as to why you're suggesting that a 320 in place of the 360 would not have failed. That suggestion is even more puzzling given that you suspect it was a build error. ??? ???

Build error as in the engine builder did not torque the rod caps to spec. When we get the facts, I'll state them... not until then. I don't know any 360's running 3150 RPM's racing period! They can't handle it! 320's will do it all day long. Mainly CHT issues, but Lycoming sends out crankshafts up to 25 grams out of balance... that is OK tolerance for them. We balance ours. They send out rods 7-10 grams out of balance, we heal toe balance ours. We port, polish and match flow the cylinders with matched pistons. We even Cryo wear parts. I've done it with 360's and 320's, the 320's always win in life span.

 

[NickAir]

320 vs. 360

320 vs. 360

Reiley has a point.
The 320 has a shorter stroke and likely handles higher revs better.
The 360 has a longer stroke and is slightly heavier, (negligible.)
The angle valve engines: Most say to stay away from them for a standard RV application.

In a RV7 the 360 does demand better resale as has been seen over the recent years. Also, in a RV7 the 360 and a C/S prop improves the CG, although as Van says, build it light.

Many different missions, wants and needs from many different RV pilots.

The popular general RV7s, recent years, seem to be the following specs:
IO-360 with Constant Speed Prop. and glass panel w/ 2 axis AP.

I have had both:
RV6 O-320 carb w/ fixed Alum. Sens prop. (Loved that plane, all of it!)
RV7 IO-360 F/I w/ Constant Speed Prop. (Love this plane, all of it!)

 

[roee]

...when operated properly

I don't know any 360's running 3150 RPM's racing period! They can't handle it! 320's will do it all day long.

3150 RPM -- yikes! Both engines are specified for max 2700 RPM.

Both engines have proven highly reliable when operated within their specified operating limits. Operate outside those limits at your own peril...