The International Cessna 170 Association

My 1952 170B has a continental 145. I want to upgrade it to a 180hp constant speed. Lycoming has numerous O360 and IO360 models. Which model should I use and why. I want to do this because I do a lot of mountain flying and would like to install hydraulic retractable wheel skies for the high altitude winter flying so the added horsepower is a must have.

It is not about what models Lycoming has. It is about what models you can get an approval to install. And today, that is limited pretty much to those models allowed by STC. Stoots STCSA02282AK uses the Lycoming IO-360M1A, B. Del Air STC SA00461SE allows the 0-360 A1A, A1D or A4M.

You can get a deviation to the STC for a different model. I have the O-360A1F6. Counter weighted crankshaft so I could put on a longer propeller and it runs smoother especially on start up and shut down.

There is also an STC I got and Superior now has for a cold air induction for the IO 360 Lycoming. Stoots has put some on 172's with impressive performance figures. The 80 inch prop is approved for the A1F6 without the bolt on balancer. I think I sent all that paperwork to the club but if not can or can forward it to you

With hydraulic wheel skis lots of horsepower and props that dig you out of snow conditions you can potentially encounter are options to consider

Something to keep in mind: Unless you have an engine/prop laying around, and/or didn't pay much for your plane, the cost of an already converted 170 will likely be less than the cost of converting your own. If you really want to do it yourself, somebody told me that one of the conversions uses the firewall forward (less mount and cowling of course) right off a Mooney, which might make some scrounging for parts easier. However even it that's true, it's still going to take a monument scrounging effort, and a lot of patience, to come near the cost of an already converted plane.

I love my 180hp 170B. It's really a great all around plane and I would buy one again in a heartbeat. But looking at the costs involved there is no way I could ever justify building one myself. The math just doesn't add up.

DEM

Ya I understand the costs for the conversion will never be recoverable in resale. Problem is I think a lot of people do things for the love of it not necessarily for the financial aspect. I might be one of them.

I didn't realize to me the actual cost was BUT, what a aero plane I have . I started to write the cost figures down and stopped at $38,000 . AND I did all the work and certification myself. I started out with a brand new engine and propellor. Every thing from the fire wall forward is new. I used Harry,s STC and found it very comprehensive. Would I do the modification again ? No . Too much blood ,sweat and tears.

After doing my TCM IO-360 conversion, I had a lot of requests for cost figures. Without exception, ALL were incredibly shocked over the cost. I have to admit that I got a lot of enjoyment out of the job and out of figuring out how to accomplish certain parts of it. At the time I did the conversion on my airplane, those
conversions utilizing the Lycoming engine were fairly available on the used market, but the very few with the TCM IO-360 were NEVER available.

I have found myself in a 55' C170 project. Wanted to do the 180hp upgrade because I work at a facility that could allow me to do it "reasonably" if that is a word involved with airplanes. Anyway, it seems in my recent searches that Stoots is about the main STC on the block these days. Is the Avcon conversion out?

blueldr wrote:After doing my TCM IO-360 conversion, I had a lot of requests for cost figures. Without exception, ALL were incredibly shocked over the cost. I have to admit that I got a lot of enjoyment out of the job and out of figuring out how to accomplish certain parts of it. At the time I did the conversion on my airplane, those
conversions utilizing the Lycoming engine were fairly available on the used market, but the very few with the TCM IO-360 were NEVER available.

My Tcm io-360 conversion will be for sale when I get to be as old as blueldr. unless one of my kids wants it.

Avcon and or owners the Williams, have not been heard from for years.

I've sent a few emails to Dave Stoots to get a grasp of what he does or will do for someone wanting to install his conversion packages. The question I didn't ask and what I think is a reasonable line of thought. Does he have an STC for the O-360A1A?
Here's my thoughts, maybe I'm wrong.
The Lycoming 360A1A 1) is a simple conversion 2) engine is available and relatively reasonably affordable3) the conversion kit is reasonably priced from Del-air. Only problem here, they did not have one on the shelf.
The biggest reason I like this option is the propellor package is relatively cheap around 10K.
I have an old STC with a O-320 with a C2YL propellor, a 337 for that install but that prop is close to 15K plus spinner assy 2K. It maybe the best conversion based on power to weight ratio but (sorry if I sound like a broken record, I've mentioned this before) if the STC is no longer supported, your on your own which can be a long and lonely road when you need to replace things.
Like Bruce mentioned find an engine that has a supported STC, crunch all the numbers ie. Governor, instruments, wiring, controls, cowl mods and prop packages before your leap.
Second thoughts just leap and get prepared to being beat up by the wife for a heck of a long time.