Which STC for C172 with Franklin 180hp?

A

allPrimes

Pre-takeoff checklist
Joined
Jun 30, 2020
Messages
215
Location
Montana
Display Name
Display name:
allPrimes
Being a neophyte in the world of aviation is hindering my research on C172 engine STC. Or my Google-fu is lacking. On or the other. Perhaps both.

I met someone recently that will be selling a C172/180 with the 180hp Franklin modification in the timeframe that aligns with my acquisition timeframe. All of my thinking thus far (being a low-time student pilot) suggests that a 172/180 would fit my mission but I'm leaning away from a 6cyl 180hp with CS prop to a 4cyl fixed pitch. Regardless, I'd like to learn and read more about the STC C172 Franklin STC.

Can anyone point me in the direction of the STC associated with this conversion? I've read competing opinions regarding longevity and parts availability for Franklin engines. I also feel like ignoring this opportunity (for a straight-tail C172 with an upgraded engine) would be a bad idea. I'm not committing, but rather would like to educate myself as much as I can before letting it pass me by.

Thanks.
 
allPrimes said:
Being a neophyte in the world of aviation is hindering my research on C172 engine STC. Or my Google-fu is lacking. On or the other. Perhaps both.

I met someone recently that will be selling a C172/180 with the 180hp Franklin modification in the timeframe that aligns with my acquisition timeframe. All of my thinking thus far (being a low-time student pilot) suggests that a 172/180 would fit my mission but I'm leaning away from a 6cyl 180hp with CS prop to a 4cyl fixed pitch. Regardless, I'd like to learn and read more about the STC C172 Franklin STC.

Can anyone point me in the direction of the STC associated with this conversion? I've read competing opinions regarding longevity and parts availability for Franklin engines. I also feel like ignoring this opportunity (for a straight-tail C172 with an upgraded engine) would be a bad idea. I'm not committing, but rather would like to educate myself as much as I can before letting it pass me by.

Thanks.
Click to expand...
I don't believe the STC is available any longer.

Steve Anderson is the guy to talk to.

The PZL Franklin is no longer built.
 
bdtaz said:
When I had a Stinson 108, I bought the few parts I needed from https://www.franklinparts.com/

Susan might be a good person to chat with.
Click to expand...
She is a wealth of information, but she deals with the Franklin 165 horse.

The old Franklin 165 horse in a Stinson 108- is not the Franklin that was built by PZL

both engines are long gone.

The STC that allprimes, is talking about is a Continental IO-360-?

If want to talk Franklin conversions, it was a PZL Franklin 220 that the STC used for the C-172.

The Franklin 165 horse.
 

Attachments

  • franklin 1.JPG
    franklin 1.JPG
    86.4 KB · Views: 21
Last edited:
You may want to go to the Stinson Forum for a connection on the 180/CSP.

The Frank was a somewhat common upgrade for the 175.

Rumor was the Frank also had more actual power than a Lycoming.

One guy has a a Stinson 108-2 with the Franklin 180 and CSP.

I believe it uses the “kit” for the 172/175 but it was installed via

Field Approval .

He had it majored about 5 years and apparently there was no issues finding parts.

My personal take is the 180 Lycoming is perfect For a 172 and still in production.

I see you are in Montana so I’m assuming you need a little more power due to

elevation?

Whatever your mission extra performance could be offset by downtime

awaiting parts.

I commend your research!
 
Obviously the Seller should have the Paperwork on this.

Got into my old paper STCs. Circa 1990

SA1078WE. Franklin 6A-335-B (180 hp) with McCauley 2A31C/84S-6 Prop (Floats)

Columbia Marine Inc PO Box 179 Vancouver WA 98663


SA 1334 Frank 6A-350 -c2 and McCauley 2A31C/84S-6 Columbia Marine


SA 293NW Frank 6AO350-Ce and McCauley 2A31C21/84S06 Prop using Kit 20690

as per STC SA 360EA. Seaplane Flying Inc
1111 S E 5th St.
Vancouver WA 98661

The conversion kit was marketed with a pic in mags and Trade a Plane.

I think it was everything Firewall Forward.

Engine, Prop, Baffles , Mount etc.

This was sold in the ‘60’s.

The Stinson I mentioned received Field Approval in 1969.


The Lycoming Conversion Kits are pricey and require some work

depending on the Airframe.

Hence prices are likely much higher than the Straight Tail.

Does give a nice Gross Weight though.

hope this helps.
 
Hangar neighbor has a Franklin-powered 172 and loves it. I know of zero problems with it.
I worried about parts availability, being a less-common powerplant but he is having it o/h'd right now and it's apparently going smoothly.
 
Let'sgoflying! said:
Hangar neighbor has a Franklin-powered 172 and loves it. I know of zero problems with it.
I worried about parts availability, being a less-common powerplant but he is having it o/h'd right now and it's apparently going smoothly.
Click to expand...
It has been a few years since I worked the Franklin parts issues. I understand the main drive gear was rare.

main drive gear is the little one
 

Attachments

  • starter gear 1.JPG
    starter gear 1.JPG
    91.6 KB · Views: 19
Last edited:
Thanks for the help all. This is a research-only project right now as the aircraft isn't even on the market yet. I just wanted to learn as much as I could about the 172/Franklin 180hp conversion before I seriously considered it as a possibility. It's a good price but might not be what I'm looking for in a first plane. Regardless, learning is learning and it's generally fun, isn't it?

Let'sgoflying! said:
Hangar neighbor has a Franklin-powered 172 and loves it. I know of zero problems with it.
I worried about parts availability, being a less-common powerplant but he is having it o/h'd right now and it's apparently going smoothly.
Click to expand...

I've read on other boards that pilots without Franklin engines always fear the worst about parts availability while pilots with Franklins never seem to have a problem keeping them running. Perhaps all the negatives I've heard about Franklins are just hearsay.
 
allPrimes said:
I've read on other boards that pilots without Franklin engines always fear the worst about parts availability while pilots with Franklins never seem to have a problem keeping them running. Perhaps all the negatives I've heard about Franklins are just hearsay.
Click to expand...

just remember there hasn't a part cut for them since 1954. that was when the factory was torn down.
The Franklin Engine company does a nice job finding parts.
 
Franklin ( Aircooled Motors) is an interesting story.

check out on wiki
 
I had a Franklen on my Stinson 108. It was my 1st airplane. Bought it back 1986 while in A&P school. It only cost $4,500 but it hadn’t flown in over 10 years. The engine had trash in it. Paper towels! It was a total unknown. New A&P students had been using it as project airplane. It had been taken apart and put back together (or not) hundreds of times. The plane came with a huge box of extra parts. Luckily, I had enough there to get it airworthy.
The Franklin was the only issue. I totally disassembled the engine, cleaned and inspected every part, and reassembled. The cylinders were the problem. Parts were extremely difficult to find! Legal parts were impossible to locate unless they were used. Exhaust valves were the main issue for me. The used ones that I purchased from the trade a plane classifieds were worse than the ones I already had. Some company was making new Franklin parts but they were not certified. They were intended for air boat engines, but people were commonly using them in aircraft engines. I ended up taking my cylinders to an engine shop located at the Wetumpka AL airport. Those guys were awesome with Franklin stuff. They re-sleeved the cylinders and put new valve guides in. We ended up reusing my old valves after they machined them back to tolerance.
I actually had the airplane finished before I got my A&P license. I would run it a couple times a week on the ground. Loved to haul arse on the runway during my so called “high speed” taxi testing:)
The day my A&P ticket finally came in I signed that baby off and went flying. She flew perfectly. That old engine sounded absolutely amazing!
I currently have a 172M and can honestly tell you there’s no way I would consider swapping out my 0320E2D for a Franklin. I’m thankful for the Franklin experience, but I’ll gladly stick with my Lycoming.

Below is a pic of that old Franklin on the Stinson.
 

Attachments

  • C4C65EDE-72E1-4706-A388-B903C4B7C17A.jpeg
    C4C65EDE-72E1-4706-A388-B903C4B7C17A.jpeg
    170.1 KB · Views: 19
Last edited:
allPrimes said:
I've read on other boards that pilots without Franklin engines always fear the worst about parts availability while pilots with Franklins never seem to have a problem keeping them running. Perhaps all the negatives I've heard about Franklins are just hearsay.
Click to expand...

I have owned and maintained antique and very rare airplanes for a long time now. You need to ask yourself, what is an acceptable amount of downtime? With these old, unsupported engines and airframes you may spend months or years looking for a replacement part that is better than the one you have.

I think the Franklin parts situation is better than many people think but don’t kid yourself. It isn’t an engine with factory and aftermarket support like many of the Lycomings and Continentals have. At some point there will be a part you need that will be hard to find.
 
The internet has helped locate parts much better then the days of

long distance calls.

The 2 you mentioned are not home free either.

The Lyc 290 series were very popular and now unsupported.

Ditto for the O-435 and TCM GO-300 and others.

The C-150 uses the O-200 .

When a buds Accessory Case had the Oil Pump Cavity wear out

he to wait 6 months for TCM to produce one!
 
You must log in or register to reply here.
Back
Top