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Do I need a new bottom cowl?

IowaRV9Dreamer

Well Known Member
"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?
 
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
 
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
 
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.
 
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.
 
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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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...
 
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.
 
I had a 320 in my '8 for several years. I swapped it out for an injected 360. I didn't want to change the cowl or graft on a new intake. I made a new airbox using epoxy and glass. It allows the servo to recess down into the box by 1/2 inch. I then used a Bracket air filter. It's been that way for 12 years. So I have the sleek 320 inlet cowl instead of that huge 360 inlet hanging down.
 
Dave,
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...

I did this when I changed the O-320 to a 360. Was not as hard as you might think. Cut off the old scoop with a cutoff wheel, fit the new scoop in flush using some sheet metal squares and clecos to hold the cowl and scoop flush. Put some fiberglass squares between the clecos on the inside to hold everything in place and after they cured, took out the clecos and layed in some tape on the seam. Filled the gap with micro and it is impossible to tell it was ever changed (from the outside).

A lot cheaper than just the shipping cost on a new cowl!
 
Looking for advice on installing FAB-6-SCOOP-360

Reviving my old thread because today is the day I found out that my O-320 cowl will not work with my O-320-E2A sump, the Vans FAB, and my fuel injection servo.

  • There are two problems. The first is that the body of the servo hits the sidewall of the snout. You can see in the first picture that the left side (mixture arm) of the servo is up against the inside of the cowl scoop. Also, the FAB instructions say that the mixture arm should point down, which will make it worse.
  • The second problem is that the hole in the scoop it way too high. You can see in the second picture that the upper edge of the FAB is almost below the scoop.

I don't want to change out my cowl, and I understand that I can buy a new scoop from Vans. I think I need FAB-6-SCOOP-360 or possibly FAB-6-SCOOP-360-1, if I have a "Type S cowl" whatever that is. I'll call and ask. In any case I'm hoping that the new scoop has both a lower intake and is wider up high.

I'm looking for a build log where anyone has changed the cowl scoop. The one in the thread above is gone, and I can't get anything helpful out of the search function.

Also, I have a couple questions:

1 - When I cut out the old scoop, I will have to cut through the honeycomb section. What is the proper way to treat the exposed edges?

2 - I'd like to hear if people have done screws/nutplates or quarter-turn fasteners, and what spacing has worked? I have milspecs on the rest of the cowl.

3 - Can I attach the nutplates directly to the existing lower cowl, or would it be a good idea to attach some aluminum first (maybe with pro-seal?)

Thanks for any info?
 

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Reviving my old thread because today is the day I found out that my O-320 cowl will not work with my O-320-E2A sump, the Vans FAB, and my fuel injection servo.

  • There are two problems. The first is that the body of the servo hits the sidewall of the snout. You can see in the first picture that the left side (mixture arm) of the servo is up against the inside of the cowl scoop. Also, the FAB instructions say that the mixture arm should point down, which will make it worse.
  • The second problem is that the hole in the scoop it way too high. You can see in the second picture that the upper edge of the FAB is almost below the scoop.

I don't want to change out my cowl, and I understand that I can buy a new scoop from Vans. I think I need FAB-6-SCOOP-360 or possibly FAB-6-SCOOP-360-1, if I have a "Type S cowl" whatever that is. I'll call and ask. In any case I'm hoping that the new scoop has both a lower intake and is wider up high.

I'm looking for a build log where anyone has changed the cowl scoop. The one in the thread above is gone, and I can't get anything helpful out of the search function.

Also, I have a couple questions:

1 - When I cut out the old scoop, I will have to cut through the honeycomb section. What is the proper way to treat the exposed edges?

2 - I'd like to hear if people have done screws/nutplates or quarter-turn fasteners, and what spacing has worked? I have milspecs on the rest of the cowl.

3 - Can I attach the nutplates directly to the existing lower cowl, or would it be a good idea to attach some aluminum first (maybe with pro-seal?)

Thanks for any info?

Dave, how did you move forward on this. I am building a 9A, have the scoop to modify my o-320 lower cowl. Pics? PM me if you want, would love to chat!
 
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