I was curious about STC SE00979AT that allows using O-200 crank and pistons in a C-85, so I called Aircraft Specialties (the holder of the STC) to find out more. I was told that “officially” it was not for HP increase but rather for parts availability. One must use the carb and mags that are specified on the TCDS for the C-85, though there may be a change in mag timing. Has anyone done this modification and seen any measurable change in aircraft performance? A/C Specialties says it cost $5775.78 plus $1000 crank core charge.
Thanks!
Larry
C-85 using O-200 internals (STC SE00979AT)
Forum rules
You must be a member of the Cessna 120-140 Association in order to post new topics, reply to existing topics, or search for information on this forum. Use the "Join" link in the red menu bar.
You must be a member of the Cessna 120-140 Association in order to post new topics, reply to existing topics, or search for information on this forum. Use the "Join" link in the red menu bar.
-
8175
- Posts: 57
- Joined: Tue May 01, 2018 7:00 am
- Name: Larry Lowenkron
- Aircraft Type: Cessna 140A
- Occupation-Interests:
- Contact:
-
6298
- Posts: 247
- Joined: Tue May 01, 2018 7:00 am
- Name: Randy Thompson
- Location: California
- Aircraft Type: Cessna 140
- Occupation-Interests: Work on airplanes and engines
- Contact:
Re: C-85 using O-200 internals (STC SE00979AT)
I have done several of them. There is definitely an increase in lower end torque.
Randy Thompson A&P IA Pilot
Hold STC SA547EA for installation of O-200 engine in Cessna 120/140 and 140A"s
Overhaul small Continentals
Hold STC SA547EA for installation of O-200 engine in Cessna 120/140 and 140A"s
Overhaul small Continentals
-
8322
- Posts: 174
- Joined: Mon Oct 01, 2018 10:48 am
- Name: Raymond H
- Location: Greenville, MI
- Aircraft Type: C-140
- Occupation-Interests: Sales Manager of Michigan Merchant Services
- Contact:
Re: C-85 using O-200 internals (STC SE00979AT)
I beleive Randy is correct. I have one myself... Theres a lot of argument with the rpm limitation if it really increases HP, and I understand the arguments on both sides... No one ever argues torque factor and I think thats where the truth may lie. I'm handy but no mechanic and still a relative nube at owning a plane... But here is why I think Randy is right.
I was thinking of getting a climb prop, I have the 7148. Now even with the STC it still is a C-85 right? The climb prop is considered the 7146 typically on the c-85 in a 120/140. So I look up the Static limits of the c-85, and borrow my mechanics prop RMP reader, so its based on reality not a 73 year old automobile tach... Well glad I didn't order a new prop on a whim...
Static limit is 2300, my C-85 with 750 hours since the rebuild with that stc was turning that 7148 at 2280 static... So essentially I do have the climb prop if I want to stay in legal limits and that the 7146 would likely put me in the 2380 range. So yes on paper its still a c-85 but theres more oomph there.
Now mind you the gain is not earthshattering... It won't turn the 140 into a super-cub
But no reason to not do it if you need an OH...
I was thinking of getting a climb prop, I have the 7148. Now even with the STC it still is a C-85 right? The climb prop is considered the 7146 typically on the c-85 in a 120/140. So I look up the Static limits of the c-85, and borrow my mechanics prop RMP reader, so its based on reality not a 73 year old automobile tach... Well glad I didn't order a new prop on a whim...
Static limit is 2300, my C-85 with 750 hours since the rebuild with that stc was turning that 7148 at 2280 static... So essentially I do have the climb prop if I want to stay in legal limits and that the 7146 would likely put me in the 2380 range. So yes on paper its still a c-85 but theres more oomph there.
Now mind you the gain is not earthshattering... It won't turn the 140 into a super-cub
But no reason to not do it if you need an OH...