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  #1  
Old 12-19-2015, 04:25 PM
IowaRV9Dreamer's Avatar
IowaRV9Dreamer IowaRV9Dreamer is offline
 
Join Date: Jan 2005
Location: Marion IA
Posts: 1,118
Default Do I need a new bottom cowl?

"All" that is left on my plane is the cowl and engine. When I ordered the kit, I was planning an o-320 with a carb. The engine core is an O-320-E2A (150 HP, vertical induction)

I'm now planning to convert it to an IO-320, 160 HP.

I've seen several references on this site that say I will need a "360 cowl" for the vertical fuel injection servo. The bottom cowl I have is part number COWL,6/6A BOT. 0-320

I'm not sure what the difference would be between a carb and a vertical servo - but maybe there is one as far as how the FAB interacts with the cowl.

My plan was to mount the engine bottom end (to position the spinner backplate) and then mount the top and bottom cowl to the fuselage... all prior to building the engine.

I don't want to waste work on this if I need a different bottom cowl.

Any info would be great. What is the difference between a "320 cowl" and a "360 cowl" anyway?
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Dave Gribble VAF #232
Building RV-9A N149DG (slider, IO-320, IFR)
Restored and Flying Beech Super III N3698Q
Marion IA

Struggling with fiberglass

There is no sport equal to that which aviators enjoy while being carried through the air on great white wings." Wilbur Wright, 1905
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  #2  
Old 12-19-2015, 06:33 PM
pilot2512 pilot2512 is offline
 
Join Date: Aug 2007
Location: Spring, TX
Posts: 494
Default

Hello fellow 9a builder. I also have a 0-320 that I am converting to FI. When I ordered my finish kit, I ordered for FI and I just check in my bedroom and the lower cowl is labeled 0-360. Page 12-4 of the construction manual says there are 3 cowls. O-320, (I)O-360 180hp and IO-360 200hp. Sorry I can't tell you the difference, but it looks like you will need theO-360 cowl. I'm hope to start fitting the cowl this week.

Jay
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  #3  
Old 12-19-2015, 09:24 PM
sheepdog sheepdog is offline
 
Join Date: Jul 2009
Location: Clear Lake, IA
Posts: 57
Default Bottom cowl

I had the same problem with my 6, how I solved the problem was to Cut the forward portion of the air scoop back and fiberglass around a round shampoo bottle for the intake form, some 3inch scat tube back to the vans air cleaner.

See big wheeled Rv in forums for a photo
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  #4  
Old 12-19-2015, 11:02 PM
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bruceh bruceh is online now
 
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Default

Peter McCoy had this issue and solved it by grafting on a wider lower scoop.

http://www.myrv9.com/Main/FK/Pages/FinishKit_06.html#64
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  #5  
Old 12-20-2015, 08:15 AM
krw5927 krw5927 is offline
 
Join Date: Aug 2010
Location: Wichita, KS
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Default

Quote:
Originally Posted by IowaRV9Dreamer View Post
Any info would be great. What is the difference between a "320 cowl" and a "360 cowl" anyway?
I found this one out the hard way. I built my 9A with the O320 cowl because I was installing an O320 with MA-4SPA carb. The O360 uses a MA-5 carb which is taller, so the entire cowl scoop needs to be about an inch lower to accommodate this taller carb and the filtered air box.

I later bought a new O-340 Stroker from Titan, and while it came with another MA-4 carb, the mixture distribution was initially horrible and I realized immediately I should've gone injected. Switching over, however, is impossible because the bendix-type fuel servo is about the same height as the MA-5 carb, requiring the O360 lower cowl.

There is an as yet un-publicized effort by Airflow Performance to make an injection setup that will fit in the O320 cowl. Hoping they come up with a solution soon because I will be buying.
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  #6  
Old 12-20-2015, 09:11 AM
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RVbySDI RVbySDI is offline
 
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Location: Tuttle, Oklahoma
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Default

I have the IO-340 in my 9A. I ordered the RV7 IO-360 cowl and the snorkel from Vans. My engine has the forward facing cold air induction. I also could not use the cross over exhaust because it ran right in front of the forward facing induction. I orderd the 4-pipe exhaust from Vetterman. It sounds complicated but once I had all of the correct components it all fit together like a glove. I made zero modifications to anything. I just bolted the components on and moved on with the next part of the build.
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  #7  
Old 12-20-2015, 09:12 AM
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IowaRV9Dreamer IowaRV9Dreamer is offline
 
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Location: Marion IA
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Default

Quote:
Originally Posted by bruceh View Post
Peter McCoy had this issue and solved it by grafting on a wider lower scoop.

http://www.myrv9.com/Main/FK/Pages/FinishKit_06.html#64
Thanks Bruce (and others) - the pictures help. I guess I need a new bottom cowl, or I get a fiberglass adventure like Peter McCoy had
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Dave Gribble VAF #232
Building RV-9A N149DG (slider, IO-320, IFR)
Restored and Flying Beech Super III N3698Q
Marion IA

Struggling with fiberglass

There is no sport equal to that which aviators enjoy while being carried through the air on great white wings." Wilbur Wright, 1905
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  #8  
Old 12-20-2015, 02:09 PM
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IowaRV9Dreamer IowaRV9Dreamer is offline
 
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Default

OK - I've confused myself. I found a post that that the following heights, measured from flange to flange:

MA4-5 carb: 6 3/8"
RSA-5 fuel servo: 5 1/2" inch

So this means that I could add a 7/8" spacer between the servo and the FAB, so the inlet would end up in the same place. In other words I can use my cowl as is?
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Dave Gribble VAF #232
Building RV-9A N149DG (slider, IO-320, IFR)
Restored and Flying Beech Super III N3698Q
Marion IA

Struggling with fiberglass

There is no sport equal to that which aviators enjoy while being carried through the air on great white wings." Wilbur Wright, 1905

Last edited by IowaRV9Dreamer : 12-20-2015 at 02:41 PM. Reason: added link
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  #9  
Old 12-20-2015, 02:49 PM
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JoeBlank JoeBlank is offline
 
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Location: Molalla, Oregon (KOL05)
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Default 2 Choices

Dave,

From a factory perspective, you have 2 choices. I went through this a few years back during my IO-320-D1A installation on an RV-6. The 320 cowl is set up to match the height of the carb but when you got to Fuel Injection, the servo is about an inch taller so the existing cowl won't work.

Option 1 -
Sell the COWL,6/6A BOT. 0-320 on VAF and then buy the COWL,6/6A BOT. 0-360

Option 2 -
Keep the COWL,6/6A BOT. 0-320 and also order the FAB-6-SCOOP-360-1. Cut the existing scoop off the cowl and graft on the new one. It can be installed with screws/nutplates or simply bonded with epoxy and a few layers of glass matt. The removable version may make it easier to perform oil changes without cowling removal. Your choice...

Call or E-mail Tech Support at the factory if you need further clarification...
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  #10  
Old 12-20-2015, 10:52 PM
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rvbuilder2002 rvbuilder2002 is offline
 
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Location: Hubbard Oregon
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Default

Quote:
Originally Posted by IowaRV9Dreamer View Post
OK - I've confused myself. I found a post that that the following heights, measured from flange to flange:

MA4-5 carb: 6 3/8"
RSA-5 fuel servo: 5 1/2" inch

So this means that I could add a 7/8" spacer between the servo and the FAB, so the inlet would end up in the same place. In other words I can use my cowl as is?
No, because an O-320 does not use an MA4-5 carb. It uses an MA4-SPA (which is shorter than the MA4-5 or the fuel servo, and is what your O-320 cowl is sized for)

Your only (simple) options are what Joe posted.
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