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IO-360 variants

S

SabreFlyr

Well Known Member
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I'm considering a -14A project and want to look into engine options. I've read the earlier thread that dealt largely with options that might allow the use of mogas. I'm not particularly interested in that. What I am interested in is a reasonable construction budget. With that in mind, I've been trying to determine which versions of the IO-360 I can consider. As I understand it, it has to be an angle-valve model with horizontal induction. Are there any other requirements? Which version is in the -14 prototype? -A1B6? Is the -C1D6 also an appropriate variant? Are there others? I would like to be able to use a CS prop.
 
From Van's Facebook page:

SELECTING AN ENGINE FOR THE RV-14/14A

The RV-14/14A was designed around (follow closely now) the Lycoming IO-390-A3B6. This is a:

? four-cylinder
? horizontally-opposed (the ?O? in ?IO?)
? horizontally-inducted
? fuel-injected (the ?I? in ?IO?)
? angle-valve
? normally-aspirated

engine rated at 210 hp

This engine is comparatively new and is found almost exclusively in the Experimental market. It hasn?t had the need or time to mutate into the bewildering variety of versions that older Lycoming designs have achieved. The version we sell ? the IO-390A3B6 ? is configured with a standard Lycoming sump, Bendix-style injection, Slick magnetos and a forward mounted prop governor. Because very few IO-390s appear on the used market, we can assume that any IO-390 in an RV-14/14A will have been purchased from Van?s and will fit the RV-14 without trouble.

ENTER THE IO-360

It?s been apparent from the beginning that the IO-360 Lycoming engine is so similar in configuration, weight and power to the IO-390 that it might also be suitable. We decided to try this when we built our RV-14 prototype and have found that this engine is indeed a good match to the RV-14 airframe.

Since the IO-360 is available on the used market for prices far less than a new IO-390, it is an attractive option for builders who are on a more limited budget. It also opens up a new can of worms.
First, we have to define some terms. There are THREE completely different kinds of IO-360:

? the common Lycoming parallel valve four cylinder engine, usually rated at 180 hp. They can be horizontally or vertically inducted.
? the completely different Lycoming angle-valve four-cylinder engine rated at 200 hp. These are always (dare we say that?) horizontally inducted.
? the Continental IO-360 six-cylinder engine rated at 210 hp with the induction system mounted on top of the engine.

For the RV-14 the only suitable IO-360 is the Lycoming angle-valve 200 hp version.

This engine has been production for decades and when we wanted to test a 200 hp version of the RV-14, we installed an IO-360-A1D6 in our RV-14 taildragger prototype ? simply because we already had one. It is working well ? physically it fits fine, produces plenty of power and works well with the weight/balance envelope.

The IO-360 exists in a bewildering variety of versions. Only some of them will work.

One of the most important red flags is the location of the propeller governor. The IO-360-A1D6, like the IO-390, has the governor mounted on the front left side of the crankcase. Many, probably the majority, of IO-360s have governors mounted on the rear accessory case, where it physically interferes with the steel engine mount/nose gear of the RV-14A and causes many ducting/wiring/routing problems for the RV-14. From what we can tell, it is not feasible to convert a rear governor engine to the forward governor configuration. We recommend that RV-14 builders avoid IO-360s with rear-mounted governors.

Some IO-360s have been removed from aerobatic airplanes and are equipped with different sumps and induction systems. We have not investigated, let alone prototyped, any such engine and recommend anybody contemplating putting one in an RV-14/14A do some serious homework before they buy.

There are two or three companies building Lycoming ?clones? ? engines similar to, but probably not identical to, the Lycoming. These engines can come in almost any configuration the buyer wishes, but again, Van?s has never seen most of these engines, and has certainly never investigated which, if any, of the many available versions might work in the RV-14/14A.

To summarize, we recommend that RV-14/14A builders choose Lycoming-type engines that are

? four-cylinder
? horizontally-opposed
? horizontally-inducted
? angle-valve
? normally-aspirated
? forward-governor
? standard Lycoming sump

and rated between 200-210 horsepower.

The only engine that Van?s sells that meets all those criteria is the IO-390-A3B6. The 200 hp IO-360-A1B6 engine we sell for the RV-7/8 is a rear governor engine, and unsuitable for the RV-14/14A.

Builders contemplating buying an engine from some source other than Van?s will be responsible for making sure their engine is suitable. Calling Van?s for information (?I?ve found an IO-360-X4B12?# out of an Egyptian Air Force Malmo-Boero. Will it work??) will not help. Contact Lycoming or an expert engine shop for details of a given model, and insist on seeing photos or examining the engine to determine whether it will work.
 
Well, I've read the engine information on Van's website (and forgot about the requirement for a forward-mounted prop governor). But, what I'm really asking is which suffixes meet those requirements (e.g., -A1D6). I've found some information helping me to interpret the letters in the suffix but don't think I've come across a suffix that indicates horizontal induction (and have forgotten the others).

I've found this:

http://www.meyette.us/LycomingEngineNumbers.htm

But it would be a lot easier if I could find a good guide to the interpretation of the suffix letters (and, perhaps they aren't in a consistent fashion to allow such a guide). "Same as -A1A except for..." Makes it awful hard to find the right combination of suffix letters that meet all of the requirements.

To summarize in my case then, I need an injected, hollow-crank, angle-valve, horizontal induction, forward governor engine. Am I missing anything else? :rolleyes:
 
J Hartline said:
Scott,

Do you know if Vans plans to offer the IO360-A1D6 at some point in the future?
Click to expand...

Right now with the OEM pricing offered by Lycoming, Vans can sell a new IO-390 A3B6 for a lower price than the 200 HP IO-360 A1B6 sold for the RV-7 & 8 (but not compatible with the RV-14).

So, there is a good chance that the IO-360 A1D6 would also be more expensive than the IO-390, but if you are interested, contact Gus at Van's and he could probably get a price quote for you.
 
rvbuilder2002 said:
Right now with the OEM pricing offered by Lycoming, Vans can sell a new IO-390 A3B6 for a lower price than the 200 HP IO-360 A1B6....So, there is a good chance that the IO-360 A1D6 would also be more expensive than the IO-390.
Click to expand...

And, for that reason, plus the advantages of a more standard installation, my search may be futile. I was just hoping to come up with a list of IO-360 variants that I could search for on the used market to come up with a reasonable budget for a lower-cost project.
 
SabreFlyr said:
To summarize in my case then, I need an injected, hollow-crank, angle-valve, horizontal induction, forward governor engine. Am I missing anything else? :rolleyes:
Click to expand...

That pretty much covers it (I don't think a solid crank angle valve engine was ever produced by Lyc. but anything is possible).

Unfortunately, the model codes of Lyc engines don't cover every detail (at least not in a way that anyone outside of specific people at Lyc. likely understand).

My recommendation would be that before someone considers any engine purchase, if it is not new or from a rebuilder that can go over these details and confirm it is what you need, that you get photos from a number of different angles so that you can confirm these details yourself.

What to look for -

Angle valve engine - the rocker (valve) covers are trapezoid shaped (vs mostly square on a parallel valve engine)

The front upper left side gov mount pad is easy to see....

The fwd induction is easy to see..... (the servo is mounted on the front of the oil sump, pointed fwd), or the mounting hole in the sump if a servo is not installed.

A hollow crank will have a hole in the front center of the crankshaft (it might have a plug in place from test running with a test club and for storage)

Having said that, there are a few odd angle valve engines around. I believe they were only used in single engine Aerocommanders. They have odd cyl, that look similar but require a different rocker cover gasket, and I think the exh. and intake ports are swapped around in the head to accommodate an unusual induction system. I am pretty sure they all had aft gov. so if you use the standard criteria for evaluating suitability, they should be excluded by that.
 
Why angle valves?

So...I'm a little new here. I understand front mounted prop governor, horizontal induction, opposed 4 cylinder, and natural aspirated, but why angle valves specifically? Is it just to match what's used in the FFW kit and assure fit? Or is there another reason?
 
One of the design parameters was 200-210 HP.

That is the HP of the angle valve engines.

The angle valve engines are heavier than the parallel valve engines.
If issues with C.G. are to be avoided, that excludes the use of a parallel valve engine.
 
Would using a fixed pitch propeller open up more engine options, since there would be no governor at all?
 
kamikaze said:
Would using a fixed pitch propeller open up more engine options, since there would be no governor at all?
Click to expand...

Yes, and no.

It would remove the no aft gov. requirement, but it would likely induce a C.G. problem.
I am not aware of any heavy fixed pitch props that would be appropriate for an RV-14.
 
rvbuilder2002 said:
Yes, and no.

It would remove the no aft gov. requirement, but it would likely induce a C.G. problem.
I am not aware of any heavy fixed pitch props that would be appropriate for an RV-14.
Click to expand...

Would that mean you can't install a fixed pitch prop on the -14? So what is the point to follow the "build light" philosophy if any weight lost is to produce an adverse effect to the aircraft C.G.?
 
Debovsky said:
Would that mean you can't install a fixed pitch prop on the -14? So what is the point to follow the "build light" philosophy if any weight lost is to produce an adverse effect to the aircraft C.G.?
Click to expand...

You can still build light in other areas (avionics, upholstery, paint, etc) without significant adverse impact to the CG, but it would be nice to know what weight range of propellers is acceptable on the -14. The real question isn't "Can you use a FP prop?" but rather "What is the minimum propeller weight that can be used while still allowing two adults and 100 lbs of baggage to be loaded within the aft CG limit?" I asked Vans for the W&B data on the -14A at Oshkosh and was told they could make it available at some point but not yet.

I don't plan to use a FP prop but would like to use a Whirlwind CS instead of a Hartzell. The Whirlwind weighs 41-42 lbs (depending on the model) including the spinner, and this is significantly lighter than the aluminum Hartzell that Vans' demo aircraft are running (55 lbs without the spinner), so without any W&B numbers it's TBD whether the Whirlwind prop will be acceptable without losing the ability to use the full baggage capacity of the -14. I hope Vans hasn't designed the -14 such that the 55 lb Hartzell is the only acceptable prop!
 
Debovsky said:
Would that mean you can't install a fixed pitch prop on the -14? So what is the point to follow the "build light" philosophy if any weight lost is to produce an adverse effect to the aircraft C.G.?
Click to expand...

I didn't say can't. I just said C.G. change from base line design would have to be kept in mind.

This is nothing new.....

Older models of RV's (3, 4 & 6) were designed favoring the use of a lighter fixed pitch prop. The later models more favor heavier props (either fixed pitch metal or constant speed).

There are builders of other RV models that use light weight (wood/composite) fixed pitch props and end up adding heavy crush plates, or add on weights to get the empty C.G. to where they want it.

There are no metal fixed pitch props (that I am aware of anyway) of appropriate pitch for 200 - 210 HP and the speed that an RV-14 is capable of.

So in the spirit of building light, on an RV-14 that is best done by avoiding the all leather 100 lb interior, every airplane gadget known to man, and an excessively heavy paint job.
 
czechsix said:
I don't plan to use a FP prop but would like to use a Whirlwind CS instead of a Hartzell. The Whirlwind weighs 41-42 lbs (depending on the model) including the spinner, and this is significantly lighter than the aluminum Hartzell that Vans' demo aircraft are running (55 lbs without the spinner), so without any W&B numbers it's TBD whether the Whirlwind prop will be acceptable without losing the ability to use the full baggage capacity of the -14. I hope Vans hasn't designed the -14 such that the 55 lb Hartzell is the only acceptable prop!
Click to expand...

If WW props have been used on the RV 7, 8 & 9, I see no reason it couldn't be used on a 14(A) but I can not confirm that (but you can do it your self).

W & B computations are pretty simple to do as long as you have the weights and arm position for the item you are changing.
W & B charts for all the RV models are available HERE

I will try and remember to post the finished C.G. position of the 14 & 14A next week. With that info, it is easy to compute what effect a different propeller would have.
 
I replaced a relatively heavy CS McCauley on an RV6 with a CS WW RV200 and had to move the ELT out of the tail and the battery as far forward as possible to manage the CG.

The CG change between the WW and the Hartzell is probably manageable but will require having a full understanding of what is currently installed on the airplane.
 
Follow up to providing C.G. data

A new document has been posted to the Downloads section of the Van's web site. The document can be accessed HERE

It contains samples of the W & B data for the RV-14 and RV-14A prototypes.
 
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