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RV-6 Engine change

N710B

Member
Hi all,

I'm new to the group and just purchased an RV-6 with an O-320E2D. I plan to change it to an O-360 fixed pitch and am curious as to some of the details of what I will need to change. Is it the same engine mount/baffling? Differences in accessories? What model O-360 works best? Thanks in advance.

Dave
 
Engine is 1.5" wider. Carb & filter assembly hang down about 1" lower. So cowling may have to be changed out or modified. A new 360 baffle kit is easier than trying to rework the 320 to fit. Exhaust may have to be modified or changed out. Spinner will have to be reworked or changed out. Air filter could be modified to work, but Vans has a filter box kit for the 360 engine. Starter & alternator should be interchangeable if both engines are same vintage. I would assume you would get proper mags with the new engine.
Above is assuming you are talking 180hp O-360 parallel valve and not a 200hp IO-360 angle valve which basically means replace everything.
 
Hi all,

I'm new to the group and just purchased an RV-6 with an O-320E2D. I plan to change it to an O-360 fixed pitch and am curious as to some of the details of what I will need to change. Is it the same engine mount/baffling? Differences in accessories? What model O-360 works best? Thanks in advance.

Dave

Dave,
Welcome to VAF!

Unless the 320 has a hole in the case (or something else physically wrong with it), fly it the way it is for a while. The 320 is a fine engine, and might surprise you with the amount of performance it gives the 6. It also will go well past TBO time with normal care and regular oil changes. If you're just looking for more get-up-and-go, try a constant speed prop first. You'll get more performance for less money (and hassle) than a complete engine swap.

(Is it just me, or is the popcorn extra tasty this morning? :D )
 
o-320 E2D

Unless I have been misled, the E2D is a solid crank so it can't be converted to a constant speed.
 
Thanks for the responses. That is what I was afraid of. Someone mentioned that it shouldn't be a difficult change, but kinda thought that might not be the case. I bought it with a timed out engine, planning on overhauling it when it started going downhill. From the sounds of it I'll just go with the high compression pistons. I'm really happy with the performance in every aspect, other than takeoff from a higher elevation grass strip. Guess I could switch from the cruise prop as well.
 
The Titan stroker crank is a ~$4k option to add 20 hp to an O-320. Might be worth considering if you're looking for more power.
 
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Thanks for the responses. That is what I was afraid of. Someone mentioned that it shouldn't be a difficult change, but kinda thought that might not be the case. I bought it with a timed out engine, planning on overhauling it when it started going downhill. From the sounds of it I'll just go with the high compression pistons. I'm really happy with the performance in every aspect, other than takeoff from a higher elevation grass strip. Guess I could switch from the cruise prop as well.

My E2D has a hollow crank but the case isn't machined for a governor.

If your engine is still 150hp, a change to the 160 cylinders will provide a nice boost. Leaving the prop as-is will give you a climb prop. A 160 with a 150 prop is an excellent climber and still has pretty good cruise performance.
 
O-340

A 'stroker' O-340 with the Titan crankshaft should be a direct replacement for your O-320, same size and weight, but with O-360 power (180hp). That's what I intend to replace my O-320 with one day (hopefully in the very, very distant future).

-jon
 
O320

I have an O320 E2D 150 hp in my RV-4. I have owned my RV-4 since 2009 an my engine works like a top; knock on wood.

Unless you really have to, I'd run the O320.

Just my opinion of course. Whatever you decide hope it works out for you.
 
Like Sam says, the -E2D has a hollow crank but won't allow for C/S because of the front bearing configuration. High compression pistons are the simplest way to increase hp.
 
Agree

All things considered, I agree with Mel and Sam. I had a 150hp and changed the Pistons to 9:1 along with heavy wall pins. It really brought the engine to life and turned a good cruise prop into an great all around climber.
No changes to structure and didn't have to change carb either.
Cj
 
Concur

The potential 20-30 hp performance gain may be marginalized by the high cost of swapping out a perfectly good O-320, the minimal performance gain, the added 25 lbs fwd of the firewall, increased fuel usage, time spent re-engineering the swap and time spent in Phase 1.

Keep it light and simple.

Possibly put a Catto prop on your current configuration, it may provide additional performance for minimal effort and cost.
 
Sam, if you have a hollow crank, wouldn't that change the engine designation? I thought that by definition, an -E2D has a solid crank...:confused:

Where did you see this? I've never seen an -E2D with a solid crank.
 
Hi Mel, I bought an RV-6A with an O-320-E2D installed, and was told it had a solid crank. I have been trying to find something online that would state which crank it has, unsuccessful so far.

I do see that it has an O-235 front bearing on that crank, and I assumed that meant solid crank?

Waiting to be properly educated!! :)
 
The other issue with 360 conversion

Along with what others have mentioned here,
The motor mount is different for the 360....it is a bit shorter, to keep the c.g. in the right place.
Whether that moves the crank flange back, I don't know for sure. But I suspect the cowl would have to be changed (either because of this, or because of the width increase and carb location, as mentioned by others).

So, engine mount, baffles, cowl....its pretty much a complete re-do of the FWF.

On the flip side, if that O-320 is not making metal, and has good compression and not burning too much oil, just keep running it. I'm not convinced they ever truly "time out". I've owned a Citabria with a 320 that we decided we should overhaul after 3200 hrs. It was pretty much like new inside.

On the other side though, I've known of an O-320 that went downhill very fast at 1400 hrs with dramatic loss of power, high oil consumption and metal in the oil screen.
The difference was it was left to sit unused for a prolonged period and then returned to hard service. I think it was a camshaft rust problem.

And when it does come time to overhaul, some of the options suggested here will get you a nice boost in power.
 
Along with what others have mentioned here,
The motor mount is different for the 360....it is a bit shorter, to keep the c.g. in the right place.
Whether that moves the crank flange back, I don't know for sure. But I suspect the cowl would have to be changed (either because of this, or because of the width increase and carb location, as mentioned by others).

So, engine mount, baffles, cowl....its pretty much a complete re-do of the FWF.

.....

I think your motor mount comment is for the RV-7 series only.

The RV-6 motor mounts are the same for O-320 and O-360 engines. I changed in mid-build with no mount problems.

There are two cowl lengths though depending on the length of the prop spacer, and the depth of the "carb scoop" between the two models changes, but a replacement scoop is available that can be spliced onto the existing cowl.
 
I think your motor mount comment is for the RV-7 series only.

The RV-6 motor mounts are the same for O-320 and O-360 engines. I changed in mid-build with no mount problems.

There are two cowl lengths though depending on the length of the prop spacer, and the depth of the "carb scoop" between the two models changes, but a replacement scoop is available that can be spliced onto the existing cowl.

And more specifically...... All the side by side engine mounts are the same except when installing an O-320 on an RV-7(A). In that one case only, a longer mount is used to move the lighter engine fwd. The difference is within the usable size of the cowl so the cowl is trimmed slightly less during installation.
 
Back when I finished up the 2009 7A with a 320 the cowling Van's shipped me was labeled 235 cowling as was the shipping/packing slip. It looked narrower... not as "fat" as the 360 cowl. sure looked good on the plane. :) And that extra 2.5" firewall clearance made it easy to work on the back side of the engine.
 
There may be an answer right around the corner ...

A 'stroker' O-340 with the Titan crankshaft should be a direct replacement for your O-320, same size and weight, but with O-360 power (180hp). That's what I intend to replace my O-320 with one day (hopefully in the very, very distant future).

-jon

I have converted my RV6 from an O-320 (160 HP) to and O-340 Stroker (~180 HP). My RV6 is "old school" and has the tight O-320 cowl so an O360 carb would NOT fit.

I have had issues with the originally supplied 340 carburetor (M-S Experimental for the 340). I didn't like the EGT spread. Lots of work with ECI to get it dialed in but we decided that I would change over to fuel injection.

Working with Don at Airflow Performance on a new fuel injection product for the 340 that will fit within the tight O-320 cowl of the earlier RV6's if that is what you have. (This should fit in some of the tight RV4 cowls as well, I believe.)

We hope to have some data in a week or so that can be shared. If not then right after the holidays. Test flight with the prototype (and resultant data) showed significant improvements. The engine pulls STRONG!

Now, if your cowl is the later/larger cowl that accommodates the 360 then you are probably good to go.


James
 
RV7 0320 mount

And more specifically...... All the side by side engine mounts are the same except when installing an O-320 on an RV-7(A). In that one case only, a longer mount is used to move the lighter engine fwd. The difference is within the usable size of the cowl so the cowl is trimmed slightly less during installation.

Are there any examples out there of the long RV7 mount being used on an RV6? Seems it would be a logical thing to consider with a wood prop to keep c of g forward.
 
Are there any examples out there of the long RV7 mount being used on an RV6? Seems it would be a logical thing to consider with a wood prop to keep c of g forward.

None that I am aware of.
It might be a bit extreme for the RV-6. It works for the RV-7 because the fuselage is a little bit longer, and the emp. is a little bit heavier.
 
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