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Power and Propeller

Need STC/337/Field Approval
Author Last Post
The standard PPonk C.R. is 7.5:1
 I would have Ly-Con do the carb.  There are multiple examples of shops messing up the carb conversion.
Do you have an accurate, verified fuel flow gauge on your aircraft?  It will be helpful ensuring all is well upon install, as will (and more importantly) a multi-point CHT/EGT probe engine monitor.

 
Hi Folks, I cracked the code on how to do this.  "This" being taking an IO520D or F from a Cessna 185, stripping off the  fuel injection system, adding a carburetor, and dropping the whole thing into a Cessna 180.  Here's how:
You start with the Pponk STC ($1550 as of this posting date).  That gets you the 520 case and cylinders, however the Pponk engine is really an O470 with 520 cylinders using 7 to 1 pistons, so this only gets you partway to the goal.  There is a DER in Georgia that will approve a 337 written up by your mechanic for $750 to allow the use of 8.5 to 1 pistons in the 520.  In other words, what comes stock in the IO520, so that gets you almost to the finish line.  Pponk will send you the DER's contact information if you give them a call.  The next to last step is that you must modify the carburetor that comes off an O470 (I think it is as simple as drilling out the jet for increased fuel flow) or you can buy a modified carburetor from one of Pponk's licensed shops.  Lastly, the prop you had on your O470 won't work on the 520.  I'm going to be using the same prop that was used on the 520 when it was on the 185, which is an 86 inch McCauley seaplane prop.  It is a C58 and Pponk has copies of field approvals that I can use to get my own field approval with the help of my mechanic and his relationship with the local FSDO.  So, the paperwork isn't cheap, but at least this is how you can thread your way through the process legally to install an O520 on your 180.
Texas Skyways and I think Air Plains will also put an O520 in your 180, but they won't sell you an STC.  They insist on doing the work themselves, wichi isn't necessarily a bad thing, but in my particular case it would no longer be cost effective if I had them do the work.  My regular mechanic will be able to do the work for me and the whole deal will be significantly cheaper.
And to think it only took a week of phone calls and internet research to figure this out!
 
 First thing is to get in contact with your FSDO and find a friendly FAA employee. Have all he documents that show that this has been done before and how and how you are going to do installtion and that your installation will be no different, you will need to get your mechanic involved or one that has a PMI at the local FSDO. The FAA does not like to give Field Approvals anymore although some FAA inspectors will, they are all different so they may require you get a DER to approve and or create the data to be approved. Since the engine was approved for a 185 and the installation is approved through a STC for the 180 it would seem that a reasonable FAA inspector would sign off on this, it helps if your mechanic already has a relationship with the inspector. I have worked on similar problems with my PMI (personal maintenance inspector) and have had good results. The FAA may also say since there is an STC out there already buy it or go to the shop that owns it and have them do it because that company that went to all the expense to do the STC. 

       I could ask my PMI but I would need more information and my company is in the Northwest Region so may not be much help.

            John Bentley
               BentleyAir
                  541 318 8604

On Mon, Jan 8, 2018 at 12:18 PM, Homer Phillips (hc_phillips@yahoo.com) <mailer@mail2.clubexpress.com> wrote:
View/reply online       Reply to forum at PowerPropeller@skywagons.club       Reply directly to Homer Phillips at hc_phillips@yahoo.com
Hi All,
I have an opportunity to purchase an IO-520 coming out of a 185 for installation in my Cessna 180J after converting to a carburetor (not Pponk).  So far I have been unable to find an STC, or someone who might be able to produce a 337 that I could use to obtain a field approval from our local FSDO.  This isn't unusual.  Texas Skyways puts carbureted 520's in 180's as a course of their business, but they won't sell the STC.  They will only do it if they do the work, but if that's the only avenue then this deal is no longer cost effective to me.  I'm desperately seeking someone who has the legal paperwork for converting a 520 to carburetor and installing in a 180.  Thanks to  anyone who can help.
Clay

 
Hi All,
I have an opportunity to purchase an IO-520 coming out of a 185 for installation in my Cessna 180J after converting to a carburetor (not Pponk).  So far I have been unable to find an STC, or someone who might be able to produce a 337 that I could use to obtain a field approval from our local FSDO.  This isn't unusual.  Texas Skyways puts carbureted 520's in 180's as a course of their business, but they won't sell the STC.  They will only do it if they do the work, but if that's the only avenue then this deal is no longer cost effective to me.  I'm desperately seeking someone who has the legal paperwork for converting a 520 to carburetor and installing in a 180.  Thanks to  anyone who can help.
Clay
 
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