Engine swap from 320 to 360

[Jesse]

I am thinking of pulling the 320 out of our -6A and putting in the 360 that is listed in the classifieds section. Should it be a drop-in replacement? I understand CG issues, but the engines should be the same size from engine mount to prop flange, right? Has anybody done this that would be interested in sharing their experiences?

 

[Sig600]

PM me, we'll make that 6a of yours a screamer!

http://www.eaa902.org/Lycoming_Engines.pdf

I would say it should be close. Your bigger challenge will probably be the baffling (which I have with the engine I'm selling).

 

[rvbuilder2002]

An O-360 is one inch wider. The baffling will have to be redone.
The exhaust system will be 1 " too narrow.
The induction scoop on the bottom cowl is not deep enough for the taller MA5 carb, and the FAB air box from the O-320 wont work on the O-360 That's assuming both engines are carbureted).
You would also need a different prop (don't know if the engine you are looking at comes with one).

 

[Jesse]

Ok, the exhaust will have to be changed. Can the baffles be modified? The 360 will be injected. The 320 is carbureted. Will the cowl fit? I don't mind doing a new fab.

 

[rvbuilder2002]

Ok, the exhaust will have to be changed. Can the baffles be modified? The 360 will be injected. The 320 is carbureted. Will the cowl fit? I don't mind doing a new fab.

The baffles could be modified... would require adding 1/2 inch to each inlet ramp and 1/2 inch to each aft portion behind the cyls.

As for cowl.. that one is a little tougher to answer.... I think all of the injection servos are the same height as an MA5 carb so the inlet scoop would be wrong, but I am not absolutely sure on that one. You could have the seller measure the servo from bottom flange to top flange and compare that to your MA4SPA carb. If they are close to teh same, you might be able to make it work.

 

[flyer174]

If you are going to fuel injection you will have to add a high pressure boost pump in the cabin floor also...

 

[Jesse]

If you are going to fuel injection you will have to add a high pressure boost pump in the cabin floor also...

I already have a high pressure pump on the shelf, so that isn't a problem.

 

[Speedy1]

Jesse,

I recently upgraded the engine in my RV-6 from an Aero Sport Power IO-320-D1A to an ECI Titan IOX-370 (essentially a stroked 360 that makes 205 HP!) and it was not a difficult job.

The distance from engine mount to prop flange does not change, so there is no issue with spinner clearance. As mentioned in previous posts, the baffles will have to be widened or replaced. My -6 had almost 2000 hours on it and the baffles were getting a bit raggedy, so I replaced them. I finished the airplane in 2002 and at the time the baffles were a frustrating puzzle, but the current baffle kit from Van's is much better.

You will need the high pressure fuel pumps (electric boost and mechanical engine driven) and don't forget the fuel pressure gauge, too. 5 psi for carb, but 30 psi for fuel injection.

I was able to reuse the throttle and mixture control cables without modification, but I did have to rotate the control arms on the fuel servo to get the correct motion (push for full throttle and full rich). I'm not sure how they are arranged on the carburetor but that's something to look at and plan for.

The exhaust system crossover tubes will need to be longer for the wider 360, but I had a local auto exhaust shop make a couple of short extension pieces which just slipped on and I reused my existing Vetterman exhaust. Easy, quick, and most important, cheap!

Intake scoop clearance is the one place where you may have an issue. When I built mine, you had to choose a scoop size and glass it onto the lower cowl. I originally had a Bendix fuel injection servo on the 320 which was taller than a carb so I used the 360 scoop which also fit for the engine swap . If you have glassed-in 320 scoop the fuel injection will not fit, otherwise you should be OK.

Your old prop will not fit the new engine. Flange bolts on the 320 are 7/16" and the 360 uses 1/2".

Weight and balance will not be an issue, and the slightly forward CG change is actually a good thing. (less pitch sensitivity with full load)

I absolutely love the performance of my -6 with the new engine, and I would be happy to answer any other questions you have. If you want to talk, my cell # is 864-245-0557.

Danny Kight
RV-6 N722DK
RV-8 N297NW

 

[captainrichhill]

Thicker skin tail?

Did you guys have the thicker skins for the tail already? That was an issue that prevents me from researching the HP upgrade in the 6/6A.

 

[Kyle Boatright]

I am thinking of pulling the 320 out of our -6A and putting in the 360 that is listed in the classifieds section. Should it be a drop-in replacement? I understand CG issues, but the engines should be the same size from engine mount to prop flange, right? Has anybody done this that would be interested in sharing their experiences?

Jesse,

Would it make any sense to buy higher compression pistons and flowed cylinders for your -320 and get a HP gain without as much effort?

 

[smokyray]

Fifteen Percenter...

I am thinking of pulling the 320 out of our -6A and putting in the 360 that is listed in the classifieds section. Should it be a drop-in replacement? I understand CG issues, but the engines should be the same size from engine mount to prop flange, right? Has anybody done this that would be interested in sharing their experiences?

Hi Jess,
You and I have had this discussion per the recent conversion of my RVX from and 0-320A to an 0-360J2A.
My goal all along was a 15% gain in HP with ZERO weight gain. As you know, I actually reduced the RVX overall weight by 5lbs. The end result was a 15% gain across the board in performance and a cost overrun of around, you guessed it, 15%!

Difficulty?
1. Baffles: as you know since you built mine, the 0-320 baffles won't work without some cutting as the 360 is wider. New 0-360 baffle kit from Van's is needed.
2. Mount, a Dyna to a Dyna or Connie to Connie should match up perfectly depending on model.
3. Prop will need to be replaced as well as extension and crush plate, difference is lugs, hole size and pitch.
4. New Airworthiness Certificate. You know the drill, all too well.
5. New W&B (if it changed). Logbook entry.
6. Cowl scoop: Van's FAB won't work with MA4-5 as it is much bigger than the MA4-SPA. Fuel Injection/FAB/Ellison TBI will. Or custom build your own air-box (as I did). Or cut the cowl and glass on a bigger scoop.

Otherwise it's a win win. However comma, my conversion of my RV4's 0-320 to 10.4:1 compression+balance/blueprint to 178HP was much easier and required none of the above except a new prop, drilling my Carb jet and a bigger cockpit to hold my bigger grin! The Hot Rod 0-320 runs equally well and as fast as the 0-360J in the X. The cost factor will be the consideration. Hot Rodding your 0-320 might be a more cost effective option. I sold my old engine FWF and overall my cost was....fifteen percent above estimate!
Call me anytime...

V/R
Smokey

PS:Until you bolt a GE F110 (F16C) in an RV, the performance gain will be slight, but noticeable.

 

[ChiefPilot]

PS:Until you bolt a GE F110 (F16C) in an RV, the performance gain will be slight, but noticeable.

I checked with Van's on this and was told this conversion was not recommended. I also asked about the Pratt motor and they similarly rejected the idea.