XP MODS IO-360
Moderators: GAHorn, Karl Towle, Bruce Fenstermacher
- wa4jr
- Posts: 437
- Joined: Mon Apr 29, 2002 2:44 am
Does anyone know if there is an auto fuel STC for the Lycoming O-360, or any of the popular conversion engines? This is the make or break for me as far as conversions go. I can fly all day on $1.30/gal fuel with my O-300. If I had to pay $2.50 or more per gallon for 100LL...that may not be around much longer, I'd just have to sit in the airplane at the tiedown and have my 2 year old make engine noises for me!
John, 2734C in Summit Point, WV
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- Posts: 2271
- Joined: Tue Apr 23, 2002 12:11 am
- wa4jr
- Posts: 437
- Joined: Mon Apr 29, 2002 2:44 am
Thanks for the info Eric. I'm a long way off from needing an overhaul or exchange, but now is the time to start the research so as to be well informed. You betcha! Always mix the MMO in with my fuel when I fill my 55 gal drum at the gas station! Always love the faces of the folks when I bring my little fuel trailer up alongside my 170B for fueling...the look is priceless when they find I am flying on $1.30/gal while they have just paid $2.70/gal for their leadball producing 100LL. HOHOHO..Merry Christmas! I'll verify with AVCON about mogas in their O-360...if it will indeed take mogas then the decision whether or not to make the transistion will be more complicated for me. Simplicity, neat sound and smoothness of the O-300 vs the extra HP, weight, and slightly higher fuel burn of the O-360. Oh and yes then there is the price of the O-360 

John, 2734C in Summit Point, WV
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- Posts: 517
- Joined: Thu Aug 12, 2004 10:33 pm
Wow, who would have thought two years would make such a difference in the MoGas vs AvGas equation. I would love to get a little gas trailer, or put a gas tank in my pickup, but at $2.48 per gal. for MoGas vs $3.09 for AvGas it doesn't seem nearly as much like it's worth the trouble.
A buck 30 a gallon, man them were the days...............
A buck 30 a gallon, man them were the days...............

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- Posts: 1373
- Joined: Tue Apr 23, 2002 2:06 am
Boy, ain't that the truth. Never thought I'd be agreeing with THAT statement...A buck 30 a gallon, man them were the days...............

$3.45 for Avgas at my home base last I checked. Flew the 170 into Bradley (Windsor Locks, CT) a couple weeks ago and guess what their Avgas price was... $4.38

Doug
- GAHorn
- Posts: 21308
- Joined: Fri Apr 12, 2002 8:45 pm
- Joe Moilanen
- Posts: 605
- Joined: Sun Dec 28, 2003 5:45 am
Eric, I've got an 80" 43 pitch prop on mine and it cruises at about 105 to 108 mph at 2500 rpm. If we leave for McCall at the same time I'll bet that I'm on the ground before you get your tools out and I'll run down to the store and buy the beer and get my 3 day fishing license while you're getting your hands dirty. After I get the goodies loaded I'll help you finish torqing the climb prop down though. When we get back out of the woods I'm going to walk 3 blocks down to that good restaurant to eat breakfast while you're putting your cruise prop back on. Want me to thow a couple of pieces of toast in my pocket for you? Wish I could get up to Concrete this weekend to see ya but I've got some duties that I can't get out of. Have Fun!
Joe Moilanen
4518C
Joe Moilanen
4518C
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- Posts: 2271
- Joined: Tue Apr 23, 2002 12:11 am
Joe, it was Bela who (jokingly?) advocated a 2-prop trip to Idaho, not me. I definitely agree it isn't worth the hassle unless you're going a real cross-country (LA > NYC?). Wish I had one of those 80-43's but to me, the benefit I'd see in my normal flying isn't worth what it would cost to get one of you guys to part with one! A ground-adjustable or non-constant-speed controllable might be the ticket, but I'm sure we're SOL as far as any kind of approval or new STC goes.
How's the aerial photo business going? I'm always impressed by how much of an eye-catcher your avatar is-- hope you use that on your business advertising.
Too bad you can't make Concrete, but the weather's not shaping up to be too good anyway. I'm sure I'll see you at McMinnville later this summer. Is there gonna be a fly-in at Kelso this year? How about at Chehalis?
Eric
How's the aerial photo business going? I'm always impressed by how much of an eye-catcher your avatar is-- hope you use that on your business advertising.
Too bad you can't make Concrete, but the weather's not shaping up to be too good anyway. I'm sure I'll see you at McMinnville later this summer. Is there gonna be a fly-in at Kelso this year? How about at Chehalis?
Eric
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- Posts: 28
- Joined: Fri May 06, 2005 8:41 pm
There was an article in the Third Quarter of 2004 170 News, I think it was a reprint, about installing a 160 horse IO-320-B1A in a 170. The author goes on quite a bit about the increased speed but doesn't say much about climb. Personally I can live with 120 MPH but when I have a someone in the passenger seat and a lama and mule and a calf in the back, I need every bit of Redding's 7000' runway on a hot July afternoon to get airborne. Any of you knowledgeable fellows know anything about this installation? Especially the climb part? There are several plusses to this conversion, not the least of which is still getting pretty good GPH. Randolph
- Joe Moilanen
- Posts: 605
- Joined: Sun Dec 28, 2003 5:45 am
- cessna170bdriver
- Posts: 4116
- Joined: Mon Apr 22, 2002 5:13 pm
I've never seen an IO-320 conversion, but it seems reasonable enough other than the $$ and hassles of getting approval. As far as climb goes, physics tells us that, everything else (speed, density altitude, etc.) being the same, each additional horsepower you can get to an 80% efficient propeller will cause a 2200 lb airplane to climb an extra 12 feet per minute.Randolph wrote:There was an article in the Third Quarter of 2004 170 News, I think it was a reprint, about installing a 160 horse IO-320-B1A in a 170. The author goes on quite a bit about the increased speed but doesn't say much about climb. Personally I can live with 120 MPH but when I have a someone in the passenger seat and a lama and mule and a calf in the back, I need every bit of Redding's 7000' runway on a hot July afternoon to get airborne. Any of you knowledgeable fellows know anything about this installation? Especially the climb part? There are several plusses to this conversion, not the least of which is still getting pretty good GPH. Randolph
Miles
“I envy no man that knows more than myself, but pity them that know less.”
— Thomas Browne
“I envy no man that knows more than myself, but pity them that know less.”
— Thomas Browne
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- Posts: 517
- Joined: Thu Aug 12, 2004 10:33 pm
I remember reading that artical on the IO320 conversion, it sounded pretty cool, especially since he somehow incorporated a ram air system with it. I think though, that he never got an STC
for the change, just a field approval, and if I understand it right getting a field approval nowadays is just about impossible.

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- Posts: 451
- Joined: Sat Nov 23, 2002 4:03 pm
Bela, in the 1960's I operated an early model 336 Skymaster wth IO-360 (I recall they were A and B model) engines. There was a problem with throwing crankshaft counterweights (mine did) but that was corrected and the engines became very reliable. Smooth, and the easiest starting fuel injecton engines I've ever seen, at least on Skymasters, hot or cold. The IO-360 C and D's on 337 Skymasters were equally nice engnes.
I really lked my fixed-gear 336. Noisy and slow, but it could haul a good load out of short fields and yet fly non-stop between Jamaica and Panama or Miami. Great air taxi airplane.
On 337's I had to add Robertson STOL kits and modify the brakes by adding a second set of calipers to each wheel. FWIW-
Rudy
I really lked my fixed-gear 336. Noisy and slow, but it could haul a good load out of short fields and yet fly non-stop between Jamaica and Panama or Miami. Great air taxi airplane.
On 337's I had to add Robertson STOL kits and modify the brakes by adding a second set of calipers to each wheel. FWIW-
Rudy
C-170B N4490B
Plantation Florida
(Based at North Perry Airport,
KHWO, Miramar FL)
Plantation Florida
(Based at North Perry Airport,
KHWO, Miramar FL)
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- Posts: 552
- Joined: Mon Jul 22, 2002 7:24 pm
I've subsequently fingered out which IO-360 one
wants.
At the risk of drying up an already bleak used engine
market for these things, you want to get an IO-360KB.
The TBO for the KB is 2000 hours. The STC in question
(XP Mods) also allows for an IO-360C or IO-360K, which
both have a 1500 hour TBO.
I have no idea what applications any of these are connected
with (originally built for) but from other "3 or 4+ beer research
binges" I've been on, I want to say the KB was used on the HawkXP
and precious little else (I'd love to be corrected as being wrong
about this...???).
Makes the "right/desirable" engine a bit hard to find.... (I think
Blueldr said he searched for the right engine for some time before
finally finding one).
wants.
At the risk of drying up an already bleak used engine
market for these things, you want to get an IO-360KB.
The TBO for the KB is 2000 hours. The STC in question
(XP Mods) also allows for an IO-360C or IO-360K, which
both have a 1500 hour TBO.
I have no idea what applications any of these are connected
with (originally built for) but from other "3 or 4+ beer research
binges" I've been on, I want to say the KB was used on the HawkXP
and precious little else (I'd love to be corrected as being wrong
about this...???).
Makes the "right/desirable" engine a bit hard to find.... (I think
Blueldr said he searched for the right engine for some time before
finally finding one).
Bela P. Havasreti

'54 C-180

'54 C-180
- GAHorn
- Posts: 21308
- Joined: Fri Apr 12, 2002 8:45 pm
If I ever change my airplane from the stock configuration....it's going to get a TCM IO-360. Not anytime soon, but if I ever do......
'53 B-model N146YS SN:25713
50th Anniversary of Flight Model. Winner-Best Original 170B, 100th Anniversary of Flight Convention.
An originality nut (mostly) for the right reasons.
50th Anniversary of Flight Model. Winner-Best Original 170B, 100th Anniversary of Flight Convention.
An originality nut (mostly) for the right reasons.

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