How many TICA 170 members have done the TCM IO360 Conversion

[GAHorn]

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.

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.

[n2582d]

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?

[blueldr]

I remember seeing one IO-360 engined C-170 that had about 12 pounds of ballast clear back by the tail just to get it within limits.
I moved my battery back behind the baggage compartment and swithhed to a size 35 battery and a stainless steel battery box. It fell within limits without ballast even when I installed a CS prop and governor.

[Ryan Smith]

It's got two less cylinders. Though the engines are a little larger displacement, it doesn't take as much metal to make four cylinders as it does six. Also, is the O-360 a little shorter? The Lycoming certainly looks like it would be a lot heavier than what that weight would indicate.

I'd like to know how similar the 170 and early 180 airframes actually were to each other. The 180 always seemed to be a larger, substantially beefier airplane, notwithstanding the physical differences of different empennage, adjustable horizontal stabilizer, and a tailcone. I've not flown a 180 to compare to a 170, but I've flown a 1959 182 some and it feels quite different from a similar vintage 172. The specs that I got from skywagons.com indicates that the 180 is also about a foot and a half longer (I read this to be that even the earlier ones were this length, even though the ones from about the mid-1960s onward have the extra rear window and appear to be a little longer because of it).

I have to say, I'm a bit surprised that there aren't more definite weights for these engines that are more widely published.

I'd also like to know why there is not a gross weight increase (to 2500lb) with the XP Mods conversion. It would seem to me that the larger limiting factor of the 170's 2200lb gross was because of the performance of the C-145, and not necessarily the strength of the airframe. I'm sure the structural analysis of the airplane is long gone by now, since I remember reading that Cessna destroyed a bunch of engineering/production data for the older airplanes many years ago.

[blueldr]

Noboby wants to come up with the money to get a new weight certification from the FAA for the up engined C-170s. Big bucks, you know.

[n2582d]

... I've seen unofficial dry weights for each of the engines (no prop) as follows, but it's hard to get an apples/apples comparison. ...

IO-360-A: 294 lbs
O-300-A: 268 lbs (no starter or generator)... .

The numbers I found from TCM vary slightly from what you listed: IO-360 C, CB, G, GB = 331.25 lbs. dry, no accessories. IO-360 A, AB, D, DB, BB, H, HB, J, JB, K, KB = 327.25 lbs. dry, no accessories. O-300 A,C,D = 248.7 lbs. dry, no accessories and 300 lbs. with accessories. Interestingly, the IO-360ES, the engine used in the Cirrus, is the lightest of the various models at 305 lbs. dry, no accessories. (TCDS says 320 lbs. dry) TCM says it weighs 370 with accessories. 65 lbs. of accessories seems heavy. The -ES is the model with the longest TBO at 2000 hrs. even though it's rated at 210 h.p.

So we're looking at something like a 78 lbs. increase in engine weight when comparing the O-300 to the IO-360 A and that's before hanging a constant speed prop on. MT props claims their 45.6 lb. prop/spinner which is STC'ed for the Lyc. conversion of the C-170 is 25 lbs. lighter than the 80" Hartzell it replaces. Tom Anderson ought to get that listed as an option on his STC.

[jamyat]

When we working up the paper for my IO360 conversion I had to look up the weight of engine so we could run a stress analysis on the engine mount. This is what I found in the Operator's Manual.

The basic engine, which includes lubrication system, accessory drives, starter adapter, intake system, mounting brackets, cylinders,and two pendulum type dampers, weighs 277.81 pounds.

Add to that the following: spark plugs 3.03
mags 11.0
ignition wires 2.41
This gives the basic dry engine weight 294.25

Add to that the following: Starter 16.25
Alternator 10.75
Volt Reg 1.75
oil cooler 4.25
This gives the total weight of basic engine and accessories 327.25

There are some other items that should be added.

tach generator 0.5
vacuum pump 1.8
prop governor 3.5
air filter 0.5

This brings the dry weight up to 333.55

The dry weight of the C145/O300 listed in Table I of the overhaul manual is 268
Table II lists the following "purchased accessories". So it appears they were not included with the engine.

magnetos 11.56
Carb 3.0
alternator 10.81
starter 15.5
We can assume it would also need the following:
spark plugs 2.54
ignition wires 4.9
Carb intake&filter 3.5

This gives a total dry weight of C145/O300 319.81. So it appears that the basic IO360 weighs 13.74 more than the C145/O300. Of course there are other things to consider. The engine mount is a little heavier, so is the exhaust, the IO360 must have a boost pump, the constant speed prop is heavier, the spinner is heavier and so is the battery. To move the battery aft behind the luggage compartment requires some additional structure and a long battery cable.

I don't know for certain that the weight of the C145/O300 is accurate because of the way it is listed in the overhaul manual with purchased accessories. However, the weight of the IO360 listed in the operator's manual appears to be accurate and that is what I used in the structural analysis.