Engine Upgrade

How to keep the Cessna 170 flying and airworthy.

Moderators: gahorn, Bruce Fenstermacher

Engine Upgrade

Postby ptporebski » Mon Jan 02, 2012 4:16 pm

Happy New Years Fellow Assoc Members,

I have a fairly low time O-300 and new prop (TSMOH 325 hrs, Prop 25 hrs) on my C-172. I have gotten to know the plane well since purchasing it and by and large am satisfied with it. But like anyone else I would like more speed. I know that there are STCs out there for converting to more powerful Lycoming and Continental engines with or without a CS prop. As I basically like my plane I have been considering this for quite some time.

If I were to do this it would be taking the plane to another level in view of the expense; so I would like to know what your thoughts on this are. My mission is that I am setting the plane up to get my instrument rating. Most of my flying is local in Florida (within 100 miles). But I can forsee having more time in the next several years. That means I would like to be able to take trips throughout the country and am wondering about increasing the cross-country capability. However, I do like the economy of the 145 hp O-300. Of course a more powerful engine will use more gal/hr. So I thought I would query the brain trust and see what the general consensus is.

If I do make this conversion, I will put the existing engine & prop in our Trademart first.
The better is the enemy of the good.
1959 C-172
User avatar
Posts: 72
Joined: Tue Jun 08, 2010 10:34 pm
Location: New Port Richey, FL - North of Tampa Bay, FL

Re: Engine Upgrade

Postby blueldr » Mon Jan 02, 2012 4:43 pm

If your desire is faster cross country travel, get a faster cross country AIRPLANE.
User avatar
Posts: 4447
Joined: Thu May 02, 2002 3:16 am
Location: Rancho Cordova, Calif.

Re: Engine Upgrade

Postby ptporebski » Mon Jan 02, 2012 4:51 pm


I could sell the 172 and go thru the hassle of finding another clean example (yeah good luck with that) of an airframe that I like as much as this one. What I am interested in is adding some speed performance to an airframe without going nuts on the fuel burn rate. I don't want a dedicated cross-country airplane. (When I complete my F8.l Falco in the next few years I will have all the speed I need.)

I would like to make my other plane a little better of an all-around machine. If I do this, I know I will be upside down in the cost vs possible sale price. On the other hand I won't be planning on selling the plane.
The better is the enemy of the good.
1959 C-172
User avatar
Posts: 72
Joined: Tue Jun 08, 2010 10:34 pm
Location: New Port Richey, FL - North of Tampa Bay, FL

Re: Engine Upgrade

Postby canav8 » Mon Jan 02, 2012 4:56 pm

Do you have wheel pants on the aircraft? The only engine option is the 180HP Lyc but it does not have a constant speed. You will gain about 35 hp modest speed but large improvement in climb performance.
52' C-170B N2713D Ser #25255
User avatar
Posts: 965
Joined: Thu Sep 25, 2008 2:34 pm
Location: Boulder City, Nevada (KBVU)

Re: Engine Upgrade

Postby bagarre » Mon Jan 02, 2012 5:14 pm

I've done quite a bit of reading in the last year, regarding engine upgrades.

A bigger engine will get you better take-off and climb performance however, your cruise will be pretty much the same.
Horse power is the worst way (in terms of money) to try to gain more speed. A few searches on this forum will easily confirm this.

If you want (slightly) more speed, consider re-pitching to a cruise prop, wheel pants, fairings nicely sealed up, new door seals and a good wax job.

But, a 180HP 172 or 170 would be a lot more fun to fly. Even if it doesn't get you there any faster.

Posts: 2620
Joined: Thu Sep 30, 2010 11:35 pm

Re: Engine Upgrade

Postby hilltop170 » Mon Jan 02, 2012 5:41 pm

Go ahead and get your instrument rating in the C-170 and devote your resourses to finishing the Falco. Since you already have the 170, you don't need to sell it to get a faster plane, just finish the one you already have.

An engine conversion will take time and about $50,000. The money will never be recouped when you sell the converted 170.

We don't know your age but the stock C-170 will qualify for flying with a driver's license as a medical when/if the proposed changes are approved.

The bottom line is probably how much spare $$$ you have to play with.
Richard Pulley
2014-2016 TIC170A Past President
1951 170A, N1715D, s/n 20158, O-300D
Owned from 1973 to 1984.
Bought again in 2006 after 22 years.
It's not for sale!
User avatar
Posts: 2960
Joined: Sat May 06, 2006 6:05 pm
Location: Retired in Alaska and the Texas hill country

Re: Engine Upgrade

Postby mike roe » Mon Jan 02, 2012 5:54 pm

A friend of mine sold his 182 and found a straight tail 172 with the Lyc 180 and constant speed. I dont know his cruise numbers bur he loves the fuel burn compared to the 182. I dont think his cruise is that much slower.
I am located in the Northern Neck of Virginia. Weather permitting I fly to a grass field at Urbanna Va. for the Oyster Festival. The person who owns the field is Alfred Scott who also owns Seqouia Aircraft which sells the Falco. He has the Falco fly in at the same time as the festival. Nice aieceaft.
mike roe
Posts: 353
Joined: Mon Nov 07, 2005 10:53 am
Location: Northern Neck of Virginia

Re: Engine Upgrade

Postby Bruce Fenstermacher » Mon Jan 02, 2012 9:24 pm

You will get a bit more speed with a bigger engine because the engine can drag the plane through the air faster of course at greater operational expense. The plane will not significantly faster to justify the expense of doing it in my mind.

Put the money towards finishing your Falco and go fast. That is what I'd do.
CAUTION - My forum posts may be worth what you paid for them!

Bruce Fenstermacher, Past President, TIC170A
N7A '49 170A -More original than most making folks GREEN with envy
N42532 '45 J-3 Clipped Wing Cub
User avatar
Bruce Fenstermacher
Posts: 9142
Joined: Tue Apr 23, 2002 11:24 am
Location: Telford, PA Based at UKT

Re: Engine Upgrade

Postby blueldr » Mon Jan 02, 2012 10:31 pm

I installed a continental IO-360 in my C-170B. I did all the work myself. I am a confirmed bootlegger when it comes to flying on the cheap. The conversion still came to about $30,000.00. If you want a high performance C-170B, and I did, conversion is the way to go. If youre looking for a faster airplane, it's not the most economical way.
User avatar
Posts: 4447
Joined: Thu May 02, 2002 3:16 am
Location: Rancho Cordova, Calif.

Re: Engine Upgrade

Postby ghostflyer » Tue Jan 03, 2012 12:19 am

I have read this post with some interest. I have been in the same situation and had a lot of blood ,sweat and tears of making this aircraft"better" I originally purchased my aircraft from a committee in a glider club which had it in pieces scattered around a number of hangar floors. Numerous "EXPERTS" had a go restoring this aircraft and only successfully kept pulling it apart and loosing parts. Some expert decided the engine required overhauling and pulled it apart and sent the different parts off to the cheapest overhaul shops around. This engine was "lost" So another engine was purchased by me when I bought the 23 cardboard boxes. of parts.
Yes I am trying to keep this story short. Just humor me for a couple of minuets. The engine was in bad shape so the pots came off and were overhauled and each cylinder was flow checked ,port and polished .the rocker gear was modified and higher compression pistons were fitted. Intake was cleaned up and polished where possible. Exhast system was fitted off a cessna 172 [bigger bore] and it was modified internally. A new carby was fitted and a remote oil filter was fitted . New mags fitted. So after playing with the fuel jets and other things [timing]etc that I do not want to talk about, the engine ready to go.. The bottom end of the engine was in good shape. The engine was fitted to a purposely built dyno for aircraft engines it was started and run for about 8 hours. We played around with all sorts of things. We had a cooling issue also. At the end of the day the engine was producing nearly 175hp at around 2800rpm. Average fuel consumption was 14.5 gals per hour[ I think].
The engine was fitted into the aircraft and we had a very modest increase in speed and climb was about the same.[ This was all done legally with E.O.s in my country]
The question is ,Would I do it again? NO, The engine was destroyed by sabtoage on the airport by a nut case . The aircraft had to land in strawberry fields. No damage to the airframe.
So a STC was purchased from Harry Delicker and a Superior o-360 fitted with a fixed pitch Sensenich prop. And the fun started again. This is a easy mod to do and Harry has it down to a fine art. This time I looked at the airframe also. The amount of junk that was behind the back seat was unbelievable and was removed. All control surfaces were checked and adjusted as per Mr Cessna requirements. We have now gained about 10 kts overal. With a better climb.l
The 170 configuration is a great all rounder and very verstile. I will not think about getting a Cessna 180.
User avatar
Posts: 662
Joined: Mon Apr 21, 2008 3:06 am
Location: queensland ,australia

Re: Engine Upgrade

Postby tweiss » Tue Jan 03, 2012 4:20 am

My two cents,
You stated your plane is a 172 that you want to put a bigger engine in. Not a 170.
If you consider the $30,000 do it yourself price as suggested above, or the $56,000 price I last checked from Del Air, I would suggest looking at a trader magazine or barnstormers type web site and compare the prices of a stock engine 172 vs. a big engine converted one.
I would be willing to bet, you could sell yours for $25,000 ish (no insult intended I have never seen it) and pick up a 180 HP 172 for $45,000 ish. and never even get your hands dirty. Better yet, I see a lot of 175's out there with 180 HP upgrades for sale which gives you about the same fuel time duration that your stocker has due to the bigger wing tanks.
Also, and I don't remember for sure, but does the Continental powered 172's have a stepped firewall? If not, when you sell it and buy one that does, it falls into the category for a gross weight increase STC.
The nice thing about looking for a big engined 172 over a 170 is that there's a lot of them, and the majority of them have not served in Alaska as a pickup truck like the 170's have.

As far as performance, it is true the 180 HP upgrade will get you off the ground shorter, and climb faster. My 170 cruises 20 MPH faster with the big engine in it. From point A to B, it burns the same amount of fuel as the stocker did (2 gpr increase, 20 mph increase). If you pull the power back and fly formation with a stocker, you will put the exact same amount of fuel in as he does when you get to where your going.

The HP increase does make a nice airplane out of the 170, 172, 175. I think they should have come that way from the factory. I just don't know that the cost to convert it today is worth it. If you wanted to look for one to buy that already has the conversion done, the 172 gives you so many more airplanes to choose from compared to the 170
Good luck, I know you'll enjoy it what ever way you choose to go.
Posts: 32
Joined: Sat Aug 27, 2005 7:28 pm
Location: Roseburg, OR

Re: Engine Upgrade

Postby ak2711c » Tue Jan 03, 2012 5:42 am

DelAir is not the only game in town anymore. Soots Aviation out of Fairbanks offers the Lycoming 0-360 180hp, I0-360 200hp, and the I0-390 210hp conversions. I don't know much about his conversions but the ones I have seen are real clean installations.
User avatar
Posts: 283
Joined: Tue Apr 23, 2002 6:29 am
Location: Soldotna, AK

Re: Engine Upgrade

Postby falco » Tue Jan 03, 2012 5:13 pm

My thoughts on the matter

Conversions cost a BUNCH of money, will reduce the useful load, and turn your airplane into one that is somewhat faster but climbs a heck of a lot better and uses a lot less runway.

More power WILL make you go faster, but it costs $$$. BL's conversion cost $30K, mine cost more like $40K. (XP mods STC, cont IO-360, that STC no longer available) The carburated lycs should be a bit cheaper to install as there are fewer mods to fuel system. With the bigger engine, CS prop, etc can push the empty weight up more than you initial calculations would lead you to believe. Mine weighs 1420 empty. With growing kids, the 200 pound weight increase from before the mod has become an issue. It comfortably runs at about 135-140 mph at 10.5-11 gph, I usually fly it about 125-130 mph on about 9 gph. Climbs GREAT. Gross weight T/O and climb at high DA are not an issue.

Consider your location and your mission profile - you say 100 mile flights in Florida. Climb performance not a big issue there. Speed? You want to go faster? or get there sooner? Not much time difference on 100 mile flights if you include the drive to the airport, preflight, tiedown, etc. You save ~10 min out of ~2 hours?

For more cost effective solutions for occasional longer and faster flights consider rental/flying club/partnership options.


don't let it get in the way of your Falco progress. As lovely as a C170 is sitting on a grass field at dusk (even a red one), there is no airplane more beautiful than a Falco, and few that come close. The world needs more Falcos.
User avatar
Posts: 152
Joined: Tue May 25, 2010 5:44 pm

Re: Engine Upgrade

Postby Flyboyak » Wed Jan 04, 2012 1:36 am

More thoughts for your engine up-grade

Here are some flight test results when I converted three Cessna 170B airplanes to the IO-360M1B 180hp Lycoming engine. Total weight after conversion between 1345 lbs and 1360 lbs. Performance at GW 2200lbs, 400ft take off roll, climb rate 1000 fpm, cruise speed 145 mph TAS at 65% power @ 6000ft with 600x6 tires, burning 8.5 gph = 17.0 mpg. Also fuel injection allows you to run lean of peak for even better fuel economy. Lower power settings showed fuel burn down to 6.2 gph @ 20 inches manifold pressure @ 110 mph = 17.7 mpg. Cessna 170B with O-300 Cont. engine 7.5 gph @ 110mph = 14.6.
My conversion to the fuel injected IO-360M1B engine requires no additional fuel system header tank or shut off valves as required on the Cont IO-360 engine, weights less and burns less. I install the Hartzell 80" constant speed props. I have found that fixed pitch props for the same performance use 2 to 3 gph more, so the constant speed props will pay back their additional cost then continue to reduce fuel cost in future flight hrs while providing the best power performance from your engine. This power to weight to thrust ratio has shown to be a great value for the investment. In these days of increaseing inflation airplanes can be great investments.
The IO-360M1B Lycoming engine was FAA certified in 2004 and has a requirement to produce 5% more horse power than rated so that the published horse power will be maintained through it's TBO of 2000 hrs. The M1B engine uses the same tuned cold air indcution sump as the 200hp and 210hp Lycoming engnes. This requirement allows the IO-360M1B to produce 190hp.
I'm working on a GW increase for the Cessna 170B, 180hp or greater to 2400 lbs. I have other projects for Cessnas in the works and you can check them out on my website www.stootsaviation.com
Posts: 2
Joined: Sun Jan 08, 2006 12:06 am

Re: Engine Upgrade

Postby gahorn » Wed Jan 04, 2012 3:16 am

As already indicated by the contributions above... any increase in horsepower will most effectively improve takeoff/climb performance, and only marginally improve cruise speeds while concurrently increasing fuel consumption..... or can maintain previous cruise speeds at near previous fuel consumption rates.
In other words, like Bruce mentioned, using horsepower to increase cruise speeds is not the most efficient method to accompish that goal. This can be made more evident by recalling the axiom that "DRAG...increases as the SQUARE of velocity!" :wink:

Also, ... on 100 mile trips, you'd have to go a WHOLE LOT FASTER to realize any benefits from increased speed. (It's alot cheaper to simply depart 15 minutes earlier.) :wink:

The most cost effective method to increase speed in these airplanes is to REDUCE DRAG by removing unnecessary antennas, proper rigging, and quit carrying around unnecessary weight like all the junk which accumulates in the baggage compartment. Plan your fuel more efficiently and quit carrying around 42 gallons of fuel to make that 100 mile flight.
(Carry 20 gallons instead and save 120 pounds of weight. You'll get off the ground shorter, climb faster, and get there faster and not burn as much fuel doing it.)
'53 B-model N146YS SN:25713
50th Anniversary of Flight Model. Winner-Best Original 170B, 100th Anniversary of Flight.
An originality nut (mostly) for the right reasons. ;)
User avatar
Posts: 17611
Joined: Fri Apr 12, 2002 8:45 pm
Location: Spicewood (Austin), Texas


Return to The Hangar

Who is online

Users browsing this forum: Baidu [Spider], Google [Bot] and 18 guests