The International Cessna^® 170 Association

Anybody?
Comments good or bad.
Please only comment if you you are familiar with the conversion. No Speculation please at IA request.

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Doug,

Get in touch with John Barrett (johneeb). I think his airplane has had the XP Mods conversion on it since 2005 or so and he's owned his airplane since 1982 or so. His knowledge of the 170 and the modification is deep, and I was surprised to learn a few things about it that you wouldn't otherwise know even if you were well-versed on the conversations here.

Sorry I'm volunteering you for more work, John. If you weren't so smart, nice, and patient, this wouldn't be an issue.

Good luck, Doug.

Thanks,Ryan

Doug,
What little I know about a engine conversion to an IO360 is pretty well covered here at the following thread http://www.cessna170.org/forums/viewtop ... ilit=io360. More in depth analysis should be available from the "Blue Leader".

On this same note,
Does anyone know if the IO360 with a Constant Speed prop is REQUIRED to have a spinner?

the O-2s don't have spinners. the C-337s do, FWIW.

I don't recall exactly what it says in the XP Mods STC, but I'm pretty sure it is allowed. I flew mine without spinner for the first few months; my IA wouldnt have signed off if it wasnt OK.

I don't know the legality of it, but co-founder John D Benham's 170 with the IO-360 never had a spinner as far as I know. It has been long enough I don't recall if John's was still fuel injected or if he had a carb. on it.

Frank,
There is no way to put a carburetor on a TCM IO-360. There is no intake manifold made that could accept a carburetor.

To answer the question of this thread, I also converted my '52 C-170B using the STC and engine mount provided by Tom Andersons XP Mods. It really makes the C-170 a GREAT airplane. I flew it with both fixed pitch props and a CS prop on AV gas, premium mogas and regular mogas. They all worked just fine. The fuel burn at C-145/O-300 air speeds was EXACTLY the same but it would climb like hell. Time to cruise climb from 1700 msl to 9500 msl at 2200 gross on a summer day went from 35 mnutes down to 11 minutes.

Do all IO-360s have vacuum pumps, or are there some models that are without them? I like the look and simplicity of venturis. Any shred of weight that can be saved, particularly ahead of the firewall I would see as a good thing.

I did mine a couple years before BL. I confirm his numbers. It is a sweet ride.

Watch the weight, esp forward. Think about lightweight engine accessories. A fixed pitch prop would help the w&b, but I prefer the constant speed prop. Moving the battery aft helps too.

Only problems are the kids grew faster than I anticipated, and the long awaited gross weight increase STC has never materialized from the various sources that promised it.

All of the TCM IO-360 engines that I have seen had pads for a vacuum pump, but the pad could be plated off if it was not used,.

A spinner (required or not) can heavily influence engine cooling (usually to the benefit as it smooths out and re-directs airflow into the cowl), so you might wish to take that into consideration when making that decision.

Ryan Smith wrote:Do all IO-360s have vacuum pumps, or are there some models that are without them? I like the look and simplicity of venturis. Any shred of weight that can be saved, particularly ahead of the firewall I would see as a good thing.

There is no requirement to install a vacuum pump. Put a blanking plate on the engine vac/pump pad, and continue with venturiis, if you like.

In light of this thread what I'm interested in seeing is a picture of a weight and balance envelope with each of your IO-360 C-170's empty weights plotted on it--before and after adding ballast. How much and where are you adding the ballast?