Pros Cons of either engine upgrade for the C170? Bonus is I have access to O-360 or even IO-360 parts at times. The real blunt cost will come in when purchasing STC and prop.

For those that have been there, is it just as worth while to go with the O-360A1A from Del-Air vs the IO-360 from Stoots? Anyone know if there are any prop options with the Stoots STC IO-360? That is one spendy prop on their webpage. My best guesstimate is around at least 6k in costs savings going just the standard O-360 route.

Trying to gather parts soon for the upgrade this winter if I can swing it. As stated I have access to an O-360A1A or a IO-360B1E for the stoots conversion then purchase the cold air induction sump etc etc. It all costs money, just know where to draw the line. I operate in Idaho at high DA and the O-300 just isn't going to cut it for me for much longer I don't think. More powaaaa!

I have a few years with the Stoots Lyc IO-360M1B. Very pleased with it. There's at least one other owner on this site. Feel free to PM me with specific questions. As for the prop, I have an MT and am thoroughly pleased with it. In addition to performance, it helps offset the post-conversion forward CG.

Not sure about the plumbing of the O-360, but one benefit of the Stoots IO-360 STC is avoiding a header tank and return lines. With good baffling I find my EGTs and CHTs running really close. As for the necessary cowl modifications, it pays to find someone that really knows their sheetmetal work.

-DP

Dave Stoots claims the fuel savings of the IO-360M1B over the O-360 will pay for itself by the first overhaul. Plus the added power/performance. Certainly worth giving him a call as well as Denali Pilot. Just be prepared for a lengthy conversation with Dave with you doing most of the listening.

I have theO-360 with McCauley CS prop in my P172D. The engine was hand-built by Aircraft Cylinders & Engines of Greeley, CO, and it's been a good one. Has around 800+ hours on it now--not sure without looking at the hours on the tach, but that's not far off. Joe built it for me when the engine that was in the airplane threw a rod about 15 hours after I took delivery 14+ years ago. The back 2 cylinders have always run a bit hot, and I've had to have one cylinder worked on, last year, and a new exhaust system installed, also last year. Overall, though, it's been good.

Performance has been outstanding. Not that it makes much difference, but my airplane will outrun a new 180hp 172, even with the draggy droopy tips (I flight plan for 115 knots, which is close). It climbs well, certainly much better than a stock 172, although I've never actually calculated any climb rate. A workable maximum altitude is 14,000', although I've had her higher.

Mine's an Avcon conversion, and for a P172D, it's a bit different from the conversions for stock 172s or 170s. The stock P172D, which had a 175hp Continental and a CS prop, came with an electric boost pump and 52 gallon tanks (only 42 usable in all flight regimes, 47 usable straight and level). The flight manual says to use the boost pump on take off and landing and when switching tanks. I often forget to use it when switching tanks, but I've never had a problem with any loss of pressure. I consistently expect 9.8 gph slightly rich of peak according to my EI FP-5L fuel computer, although I flight plan for 10.

I have a couple hundred hours experience with a Continental IO-360, in a Mooney 231, so it was turbo-charged. My only complaint was that it ran pretty hot--very difficult keeping the CHTs in line, especially at any altitude. Whether a non-turbo'd version would run that hot, I don't know--never flew one.

An advantage to any fuel injected engine is that it can't get carburetor ice, but it can still get induction ice--I had that experience twice with the 231. Another advantage is that it can be run lean of peak, if that's your thing, which hardly ever can happen with a carburetor (never say never in aviation).

Whichever engine you choose, you'll find a big boost in performance in a 170. You obviously have a lot of mechanical skills that I'll never have, but if it were me, I'd go for the one that takes the least modifications to the airframe and fuel system.

Cary

First, have you verified that Del Air is actually able to provide their product? Henry passed, and some time back I recall that the company was still waiting on authorization from FAA to sell mods. In any case, that kit is well made, quality stuff. As is the Stoots kit.

I’ve flown both a bit. Dave Stoots’ mod would probably be my choice. Those IO’s make nice power, are smooth, and you can run them at lower fuel flows. And, no carb ice. They are great engines in any case, in my opinion.

As to props, as noted above, the composite props offer a lot of advantages, not the least of which is helping C.G. But they REALLY make thrust with that added HP.

A word of caution: These are not simple conversions.....they will take a massive amount of time to complete, and the instructions on either kit are, shall we say, somewhat lacking in many details. You’ll learn a lot of new skills and some new language, more than likely.

And, yes, try not to engage Dave Stoots in conversations, but if you do, bring lunch.

Good luck, youll really like the end result......they are great conversions.

One other point: stock 170 fuel tanks are a bit small for the larger engines, so understand that at some point you’ll likely be thinking about aux fuel of some flavor.....

My old 170 with O-360 was a great airplane and would take me anywhere I wanted to go.

Good luck.

MTV

mtv wrote:First, have you verified that Del Air is actually able to provide their product? Henry passed, and some time back I recall that the company was still waiting on authorization from FAA to sell mods. In any case, that kit is well made, quality stuff. As is the Stoots kit.

I’ve flown both a bit. Dave Stoots’ mod would probably be my choice. Those IO’s make nice power, are smooth, and you can run them at lower fuel flows. And, no carb ice. They are great engines in any case, in my opinion.

As to props, as noted above, the composite props offer a lot of advantages, not the least of which is helping C.G. But they REALLY make thrust with that added HP.

A word of caution: These are not simple conversions.....they will take a massive amount of time to complete, and the instructions on either kit are, shall we say, somewhat lacking in many details. You’ll learn a lot of new skills and some new language, more than likely.

And, yes, try not to engage Dave Stoots in conversations, but if you do, bring lunch.

Good luck, youll really like the end result......they are great conversions.

One other point: stock 170 fuel tanks are a bit small for the larger engines, so understand that at some point you’ll likely be thinking about aux fuel of some flavor.....

My old 170 with O-360 was a great airplane and would take me anywhere I wanted to go.

Good luck.

MTV

MTV,

I appreciate your response. Del Air is doing the conversions as we just did one in our shop for a customer end of this winter/spring. The customer bought a brand new//rebuilt engine and did all the bells as whistles while doing it. He initially was going to do the Stoots conversion but when the engine was built there was some issue with producing too much HP on the dyno and from there is a long story for which I dont know all the details to elaborate on. So in turn he ended up with a O-360 and went with the del air conversion. The whole story was odd, I really wish I understood it better. Anyhow, I havent heard anyone be disappointed with either. I am mainly looking at cost comparison. I will likely call Del Air as I have most of the standard info on email from Dave at this point.

Like every 170 owner I think hard about this every few months.

I talked to Dave Stoots, and to Chris at Del Air back in the spring.

Dave Stoots was very persuasive, and his would be my choice if I had the budget.

Chris at Delair said that he was not able to supply a kit at that time, but hoped to be able to do so by May - I have not heard back.

Personally leaning to a fixed pitch 0-360 for cost, maintenance and CG compromises. I hope to do this in the next 2 or 3 years.

I have just bought a climb prop, and installed a Sportsman, so maybe the itch has been scratched for a while.

The IO can be run LOP, an advantage

If you go to a larger engine, I can get you on the path to approval to use the 175 wings, and that can be a relatively inexpensive way to get the extra fuel capacity. When I did mine, I sold my 170 wings for enough to get a nice pair of 175 wings, so, mostly just out some time to do the swap, which was relatively easy, and certainly worth the effort.

No love for the TCM IO-360 STC?

Where's the fun in having all the parts provided for assembly, detailed instructions and a fully supported product?

daedaluscan wrote:Personally leaning to a fixed pitch 0-360 for cost, maintenance and CG compromises. I hope to do this in the next 2 or 3 years.

I have just bought a climb prop, and installed a Sportsman, so maybe the itch has been scratched for a while.

I could live with the power output of my c-145 but would like the advantages a constant speed prop provides. I have an STC'd 8042 prop that gives plenty of get up and go all the way to 95mph and then it is done. Would love to cruise faster but I am not willing to give up the takeoff performance of the climb prop. If I went with a o-360 I just can't see the overall advantage to a fixed prop? I also have a Horton STOL which I also can live with but if I started from scratch would go with the Sportsman.

I have a 54 170B with the Avcon O360 and he 80 inch Hartzell with the balancer. I am very happy with the performance, have landed behind my house a few times using about 450 feet of the 900 available without doing anything fancy, though keep in mind I am in the low lands at 1200 msl. As for cruise, it is seems to true 127-130 mph at 2200 rpm and 23 inches burning around 9 gal per hour. As for the extra weight on the nose, I am either not a good enough pilot to tell the difference or a good enough pilot that I just compensate for it without knowing. I will say that when on approach and making a steeper than normal approach with full flaps I have to carry about 2000 rpm for 65 mph and need to trim nose down a couple of swipes to trim off the forward pressure I am holding. A friend of mine did the DelAir conversion with the fixed pitch prop on his 52 a70B but replaced it with a 80 inch Hartzell with the balancer for better performance on skis. He was able to by a prop removed from a Husky that replaced it with an MT for half of the cost of new. Hartzell would not sell him the STC to put it on his 170 because they said the prop serial number was not one of the ones blessed to be on a 170, it was the same model they just didn't want to have a used prop being used rather than selling a new prop. Dave Stoots has a STC to install the prop and sold the STC to him for I believe $500, still a large savings over a new prop. All in all, any engine upgrade is great on the 170, just to bad it doesn't include a gross weight increase.

Tim

SkyLarkin wrote:

daedaluscan wrote:Personally leaning to a fixed pitch 0-360 for cost, maintenance and CG compromises. I hope to do this in the next 2 or 3 years.

I have just bought a climb prop, and installed a Sportsman, so maybe the itch has been scratched for a while.

I could live with the power output of my c-145 but would like the advantages a constant speed prop provides. I have an STC'd 8042 prop that gives plenty of get up and go all the way to 95mph and then it is done. Would love to cruise faster but I am not willing to give up the takeoff performance of the climb prop. If I went with a o-360 I just can't see the overall advantage to a fixed prop? I also have a Horton STOL which I also can live with but if I started from scratch would go with the Sportsman.

You are probably right, I would be crazy to spend that $$$ without the prop. I talk myself in an and out of doing this on a regular basis. I am looking forward to seeing what the climb prop does for me.

I sure like having a CS prop on my P172D. Not only does it give climb prop performance, but the cruise is relatively decent for a draggy airframe. I generally cruise at 21"/2400 rpm. I've tried lower rpm, but the speed drops off pretty noticeably, and the gph isn't much different. The obvious downside is greater expense, should it need to be rebuilt or overhauled. Mine's a McCauley, and it can't be overhauled any longer, although I had it resealed only a few years ago. So when it needs an overhaul, I'll be looking for a replacement.

As a fundamentally lazy pilot ( ), one of the things I like about CS props is that once set, I don't have to fiddle with power when going a little up or down in altitude, and when it's time to descend, I can just leave the rpm the same and pick up some speed to make up a little for the climb.

Cary

shortfielder wrote:If you go to a larger engine, I can get you on the path to approval to use the 175 wings, and that can be a relatively inexpensive way to get the extra fuel capacity. When I did mine, I sold my 170 wings for enough to get a nice pair of 175 wings, so, mostly just out some time to do the swap, which was relatively easy, and certainly worth the effort.

I have looked into this briefly but wasn't too concerned until the possibility of doing the larger engine. I may have to bug ya if this engine ever happens. Thank you!

Cary wrote:I have theO-360 with McCauley CS prop in my P172D. The engine was hand-built by Aircraft Cylinders & Engines of Greeley, CO, and it's been a good one. Has around 800+ hours on it now--not sure without looking at the hours on the tach, but that's not far off. Joe built it for me when the engine that was in the airplane threw a rod about 15 hours after I took delivery 14+ years ago. The back 2 cylinders have always run a bit hot, and I've had to have one cylinder worked on, last year, and a new exhaust system installed, also last year. Overall, though, it's been good.

Performance has been outstanding. Not that it makes much difference, but my airplane will outrun a new 180hp 172, even with the draggy droopy tips (I flight plan for 115 knots, which is close). It climbs well, certainly much better than a stock 172, although I've never actually calculated any climb rate. A workable maximum altitude is 14,000', although I've had her higher.

Mine's an Avcon conversion, and for a P172D, it's a bit different from the conversions for stock 172s or 170s. The stock P172D, which had a 175hp Continental and a CS prop, came with an electric boost pump and 52 gallon tanks (only 42 usable in all flight regimes, 47 usable straight and level). The flight manual says to use the boost pump on take off and landing and when switching tanks. I often forget to use it when switching tanks, but I've never had a problem with any loss of pressure. I consistently expect 9.8 gph slightly rich of peak according to my EI FP-5L fuel computer, although I flight plan for 10.

I have a couple hundred hours experience with a Continental IO-360, in a Mooney 231, so it was turbo-charged. My only complaint was that it ran pretty hot--very difficult keeping the CHTs in line, especially at any altitude. Whether a non-turbo'd version would run that hot, I don't know--never flew one.

An advantage to any fuel injected engine is that it can't get carburetor ice, but it can still get induction ice--I had that experience twice with the 231. Another advantage is that it can be run lean of peak, if that's your thing, which hardly ever can happen with a carburetor (never say never in aviation).

Whichever engine you choose, you'll find a big boost in performance in a 170. You obviously have a lot of mechanical skills that I'll never have, but if it were me, I'd go for the one that takes the least modifications to the airframe and fuel system.

Cary

Thank you for the real world info Carey!

I suggest you do some math--
figure what a bigger engine (O-360, IO-360, or the other IO-360) and suitable prop would cost.
Then add in the cost of the STC, misc parts, & the labor you might have to hire out.

Then figure out what a C180 in comparable condition would cost you--
minus however much you could sell your 170 for.
I think you will discover that its probably more cost-effective to.....
wait for it..... "just buy a 180".

I owned a ragwing C170 for many years, and thought many times about replacing it with a 180hp B model.
But with the price of a souped-up 170 being what it is, a 180 just made more sense to me.

hotrod180 wrote:I suggest you do some math--
figure what a bigger engine (O-360, IO-360, or the other IO-360) and suitable prop would cost.
Then add in the cost of the STC, misc parts, & the labor you might have to hire out.

Then figure out what a C180 in comparable condition would cost you--
minus however much you could sell your 170 for.
I think you will discover that its probably more cost-effective to.....
wait for it..... "just buy a 180".

I owned a ragwing C170 for many years, and thought many times about replacing it with a 180hp B model.
But with the price of a souped-up 170 being what it is, a 180 just made more sense to me.

Oooohhh, the big motor 170 vs 180 comparison...
I'll go make popcorn

hotrod180 wrote:I suggest you do some math--
figure what a bigger engine (O-360, IO-360, or the other IO-360) and suitable prop would cost.
Then add in the cost of the STC, misc parts, & the labor you might have to hire out.

Then figure out what a C180 in comparable condition would cost you--
minus however much you could sell your 170 for.
I think you will discover that its probably more cost-effective to.....
wait for it..... "just buy a 180".

I owned a ragwing C170 for many years, and thought many times about replacing it with a 180hp B model.
But with the price of a souped-up 170 being what it is, a 180 just made more sense to me.

The 180 and 170 are very different airplanes.

First, you may not have priced GOOD 180s lately. There are some 180s for sale, but they’re mostly either have a lot of issues, or a lot more $$$ than you’re suggesting. The days of GOOD, cheap 180s seems to have passed, if there ever was such.

Second, the 180 is a heavier airplane than the 170. Most of them are a lot heavier, truth be told, on honest scales. More weight to push around, more weight to launch, more weight to stop after landing. Not the end of the world, but it’s real.

Third, two more cylinders to maintain, and a Continental engine. Granted, some of the better engines TCM has made, but I still much prefer Lyn’s for a variety of reasons.

Fuel burn. Yes, you can pull that 470 waaaaay back in its power band, but why would you do that? So, most folks are going to burn more gas in a 180.

The 170 isn’t for everyone, and you can get upside down doing engine mods pretty quick, but for some folks, the 170 with a big engine is just a better airplane.

And, yes, I’ve owned both, and both good ones.

MTV

mtv wrote:

hotrod180 wrote:I suggest you do some math--
figure what a bigger engine (O-360, IO-360, or the other IO-360) and suitable prop would cost.
Then add in the cost of the STC, misc parts, & the labor you might have to hire out.

Then figure out what a C180 in comparable condition would cost you--
minus however much you could sell your 170 for.
I think you will discover that its probably more cost-effective to.....
wait for it..... "just buy a 180".

I owned a ragwing C170 for many years, and thought many times about replacing it with a 180hp B model.
But with the price of a souped-up 170 being what it is, a 180 just made more sense to me.

The 180 and 170 are very different airplanes.

First, you may not have priced GOOD 180s lately. There are some 180s for sale, but they’re mostly either have a lot of issues, or a lot more $$$ than you’re suggesting. The days of GOOD, cheap 180s seems to have passed, if there ever was such.

Second, the 180 is a heavier airplane than the 170. Most of them are a lot heavier, truth be told, on honest scales. More weight to push around, more weight to launch, more weight to stop after landing. Not the end of the world, but it’s real.

Third, two more cylinders to maintain, and a Continental engine. Granted, some of the better engines TCM has made, but I still much prefer Lyn’s for a variety of reasons.

Fuel burn. Yes, you can pull that 470 waaaaay back in its power band, but why would you do that? So, most folks are going to burn more gas in a 180.

The 170 isn’t for everyone, and you can get upside down doing engine mods pretty quick, but for some folks, the 170 with a big engine is just a better airplane.

And, yes, I’ve owned both, and both good ones.

MTV

There's another factor here. Ky has worked long and hard on his 170, and that's hard not to consider. When you get to know a piece of machinery intimately like he has, it's not like dealing with just a machine, but more like a vibrant being. To just swap it off for another but unknown machine can be a really emotional trip. Not everyone falls in love with his airplane, but I'd be willing to bet that Ky has.

Cary