N

N459RC

Member
My engine is in need of rebuilding and I was thinking of changing my O-320E2D to an O-360. I have a Sensenich and would probably change to a Catto prop to offset the weight. Does anyone know what all would have to be changed in the process?
 
i'm fairly certain just about everything firewall forward would have to change, exhaust, engine mount, airbox, cowl, spinner, etc

If i were in your shoes, i'd put higher compression pistons in that engine and perhaps a hollow crank for a CS prop
 
Just a thought

I would consider keeping the 320 and modifying it for increased power during an overhaul. Might save some $$. A 180hp and OEM level reliablty are very achievable......unless your priorty is the ability to run 87 octane auto-goop..er..fuel in which case the 360 is probably the way to go. My .02, Russ
 
bkthomps said:
If i were in your shoes, i'd put higher compression pistons in that engine and perhaps a hollow crank for a CS prop
Click to expand...

-E2D already has a hollow crank. It will not accept C/S prop because of front bearing set-up, crankcase, and accessory case configuration.
 
Mel said:
-E2D already has a hollow crank. It will not accept C/S prop because of front bearing set-up, crankcase, and accessory case configuration.
Click to expand...

If I remember correctly, Divco can machine the case, the gov pad and also machine for the larger front crank bearing after the oil path is drilled.

I would have the case checked anyway before reassembly IMHO.
 
conversion

Different crankshaft, connecting rods, cylinders, pushrods, pushrod tubes,carb. Some of the crankcases are eligible for 320 or 360. Cam and most of the small parts-gears-etc are the same.
 
O-340 stoker

I would check into the ECI O-340 stroker kit for the O-320. I have not done it or know of anyone that has, but what I read sounds promising...
 
Stroker, Cold air intake/injection, CS prop.

180HP+, marginal weight increase, lots of performance increase.
 
Thanks for the replies so far. If I did this I would go with a new kit engine so the main thing I was concerned about was engine mount, cowl and exhaust and other things like that.By the time I sold my engine core & prop I don't think the cost would be that much higher.
 
But...

an O320 can also be set up as 1/2"... if you elect to. This really has nothing to do with the question asked, it is change over from 320 to 360.
 
Having done this, but not by choice, here is what it took me to do this.

I started with an O-290, which is exactly the same length as an O-320. What I’m getting at is, you need to find out what the dimensions of the O-360 are because if it is longer, you will need a new cowling. That alone could be a deal breaker.

The O-360 is about 20 lbs heavier than an O-320, so moving to a Catto prop or a Whirlwind CS prop would probably keep your W&B in check. More so if you put a Flyweight starter up front and installed P-mags. (A pair will save you three pounds up front and while that doesn’t sound like much, that far forward makes a big difference.)

My O-360 engine mount is 10” forward of the firewall. The old mount for my O-290 was a full 12” from the firewall. Never having installed an O-320, I don’t know what the distance is for that mount. The 12" mount is used for the O-235 and O-290, not the O-320.

You probably won’t have to change the engine mount but I’ll just about guarantee you will be making a new FAB, the O-360 carb has a larger throat than the O-320.

Your fuel lines and pumps will transfer right over, so that isn’t an issue.

As mentioned earlier, your exhaust will have to change as the O-360 is wider than the 320. Depending on your cowling, this might also be an issue. My 360 heads rock right between the SkyBolt fasteners I used, so depending on how your top cowling fits, that might give you fits. (Pun intended.)

You will also need new baffles.

Now, if I can talk you into changing over to a TW -9 while you are at it, things get a little more complex.

In my case, because my cowl was damaged, I replaced it with a James Holy Cowl and cooling plenum. I did this more for looks than anything else.

(See the August, September, and October 2011 issues of KitPlanes for details on the installation.)
 
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Due to the longer engine mount, you will need both mount and cowl to fit the width of the O360. The exhaust should not be an issue, send the crossover tubes to Vetterman for an extension for the 1" cut out off for the O320. Of course the spinner set-up will depend on the prop you choose. :)
 
Here's a good reason NOT to swap to a 360 (or hot up the 320 to 180 HP) in an RV9A....Vans, the aircraft designer, adamantly recommends against it.

The RV9(A) was designed for a maximum 160 HP.

Here's what Ken Krueger has to say:

We resolutely recommend against any more
than 160 hp in the RV-9A. It puts the pilot and his passengers
closer to the edge of the envelope, even in what
feels like ?normal? flying.
This answer seems unsatisfactory for many because "hot
rodding" homebuilts is a time-honored tradition. Timehonored
or not, it is potentially hazardous. Yes, it can be
done "legally" because of the broad freedoms afforded
homebuilders. But, in homebuilt airplanes, "legal" (i.e.,
have an airworthiness certificate), and "safe" (building an
airplane that operates within the design envelope) can be
vastly different.
 
Have to wonder if a smart insurance company would try to make use of the fact that Van reccommends against such a large engine to deny coverage in the event of an accident. Even if they try to use that as a factor, defending against it in a courtroom may not be all that easy.
 
Ask yourself, why?

Personally I have built 2 RV's and rebuilt another "sort of RV". The two I built have 0-320's and were within 10lbs of Van's prototype of both models(RV4,6). The rebuild was my Harmon Rocket which has 150 more HP than Van recommends for the RV4 and was 25 lbs heavier than John's prototype.

The flight characteristics of the two very light, stock airplanes is in a word, delightful. I do have some comparison as I get to fly numerous (213 as of this week) RV's in my consulting business. The ones that really make me smile the most are the light, straight, stock airplanes. The bigger engine/metal C/S airplanes climb better and cruise close to VNE however comma, they tend to be nose heavy and not as much fun to do aerobatics, a passion of mine.

When you consider a 360 for the Nine, consider some pretty smart guys penning the airplane for a specific mission. The Nine's mission originally was a light, efficient, non aerobatic sport trainer for the 0-235. Van felt there was a market for a lower cost RV that could exploit the market for the lower cost smaller Lycoming and expand the RV market. The first prototype actually had an 0-235 installed. Tragically Bill and Jeremy Benedict lost their lives in the prototype enroute to Sun N Fun many years ago. The crash however had nothing to to do with the powerplant.

The basic design and mission is unchanged. If you want to bolt a big engine on an RV9, my recommendation is to go for a ride in the second prototype Nine which has an 0-320 in it. Talk with Ken Krueger and others up there, then make your decision. As Bob B. stated, Engineers know what they are doing. If you still want a 0-360 powered RV, I recommend building something else.

My Dos Centavos...
Smokey
 
I think besides Bill, I'm the other guy in this thread so far that has actually done this. Interestingly enough, the cowl can be salvaged due to the differences in the 320 & 360 engine mount but its a pain and you better be good with glass! That being said, the easiest thing is to just sell the entire FFW for "x" price and buy new parts (and use it as an excuse to throw on a SJ cowl). It's easier and faster to just pull the 6 bolts and sell the entire package to another builder, and start from scratch - otherwise you spend a LOT of hours just to get to the zero point. Go buy a new engine (kit or otherwise) and have fun!

Some of the opinions here aren't based on facts, but some of the suggestions are good. Prop bolt sizes are a non-issue with either because the bushings are a quick & easy change. Lyc dash numbers can be irrelevant in many regards because you can so easily make most of them into what you need, though some are orphans (think H2AD). Cases can be modified, etc...

I will say from first hand experience that the -9 with a catto, 360 & SJ cowl is a SWEET machine (oh...TD is a big plus in that regard). :) As for weight, a 360 with a catto will be equal to or lighter than a 320 and a Hartzell....so that argument goes away. With the prop properly pitched, you won't "cruise above redline", but it'll sure takeoff nicely in the hot/humid summer days and that Catto is a smooth prop! It flies evey bit as nice as a 320/CS powered plane.

Back to the 320....the reason I did this was because we built a -6 the way Van intended with a 320/FP prop. Compared to my 360/FP plane I wasn't impressed-so off went the 320 and on went a 360/cs. It's true the light planes fly best, but done right you can keep you 360 plane close to a 320 powered one in weight (or you can build a fat Pig with either engine too).

Just my own personal biased 2 cents as usual!

Cheers,
Stein

PS, as long as insurance compaies continue to cover and pay for RV's with completely alternative engines (with a much, much, much higher incident rate), a 320/360 argument is almost moot from that standpoint. How about crazy modified 320's vs. stock 360's? Where do you drw the line?
 
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