Which ENGINE am I installing in my Zenith CH-750SD?

[@daverobinsonTnT]

At the OEMs we tend to focus upon minimizing weight as the priority; every extra pound means a pound less for payload. You’ve defined your mission for the aircraft as one of “back country” flying, presumably including camping, as well as good range. So selecting the lighter engine makes sense, if the rest of the “firewall forward” package also ends up with the total weight being less than your alternative and its “firewall forward” package. Guess it comes down to payload versus range and my choice would likely be maximizing payload - as probably the further you’d want to go, the more likely you’d want to take more stuff with you (for camping outdoors for example). I know you’ll give it way much more thought. so I’m looking forward to hearing more about your selection process. Thanks for sharing it with us 👍

[@KitplaneEnthusiast]

Dave, thanks for the comment. I agree completely with you and have already decided on the IO-360 180hp. I value the useful load more than the extra hp. Roger at Zenith also thinks 180hp will be plenty for this airplane. For any type of flying I would realistically be doing in this airplane, I think 180 is plenty suitable for me. Now, I'm accepting donations so that I can buy the engine LOL!

[@daverobinsonTnT]

@@KitplaneEnthusiast, (Mark) point me in the direction of your “GoFundMe” page 😊 if anyone on the net deserves donations, it’s you and Mike Patey for the awesome quality ‘edu-tainment’ content you guys produce and offer up for free. Thank-you so much for doing that 🙏

[@thomasmurray1807]

i just installed the 390 in my RV 14a not a thunderbolt What a rocket ship I named the plane Blue Thunder because of the preformance Everyone that has had a ride with me says how impressed they are. Airflow is the way to go . The owners are great and make you feel like you can talk with them no problem. I can not say that for Lycoming. I have a kitfox SS 7 with a Lyc. 233 thunder bolt also, have not had one problem with eithor. Have any questions give me a e-mail. Ive built 3 aircraft and I am planning to build the RV 15 when it comes available.

[@KitplaneEnthusiast]

Good info!

[@ikay2102]

I would ask Mike Patey . Out of all high density flyers he be the man to know thing or two.

[@CaptainCurt07]

*Balanced motor is definitely paramount, it’s like buying 4x4 and using it maybe 2x in couple yrs, whatever your going to do most stick with the best parameters*

[@mhilderbrand7693]

IO 360

[@scottmatthews5280]

Awesome choice, against the trend love it!

[@anthonyrstrawbridge]

👍 Lycoming IO 390 Two ten is really good one eighty not so much. Avoid the sleeves and braids whenever - wherever you can. Build your own lines AN standard everything. Why go blind if you don't have to? How to condition inspect a braided or fire sleeved line.

[@nolanbrimhall1247]

Is the weight difference in the IO-360 180 HP has parallel valve cylinders and the 200 HP has angle valve cylinders

[@Cass256]

Something to keep in mind is that you'll be happy no matter what choice you make. The airplane is beautiful, and I'm sure it will always be a "work in progress" like all aircraft are :) Personally, weight is everything in my build. The listed weight of the 390 around 9:10 is the dry weight, while the earlier listed weight for the 360 is the full FWF install (as far as I understand it). If you can do a W&B on the aircraft, you might be able to run the numbers to see if the extra 30lbs works (within CG range, good useful load, etc.). If this were my build, I'd most likely go with the IO-360-B. 180hp will give you great performance, and staying 30lbs (or more!) lighter over the 360-A (and possibly more over the 390, but I'm not sure what the FWF installed weight on that would be) will help a ton. However, if you're already too close to your aft CG, or want more flexibility with the baggage area behind the seats, the extra weight on the nose might be worth it. Hope this helps. Love the videos, it's a great inspiration to see what other builders are doing :)

[@horseman62]

no clue on the validity, but my dad always said that you'd be better with a bigger engine, running it slower, than a smaller engine, winding it up. he was also a former first lietenant pilot in the Korean War, and though was very savvy on mechanics, was NOT a mechanic.

[@nickjones6065]

You already know you’re going for the ‘big’ engine!

[@KitplaneEnthusiast]

Ya probably!

[@awash-mg8ce]

I would do the IO360 Thunderbolt Lycoming

[@Mike_S_Swift]

Didn’t hear the price difference between the 360 & 390. I’d calc the weight & balance full fuel max load and see what works best. I flew a B35 BO that needed a little weight in front. Nothing critical but the fat guy rode in front lol. Sometimes less is more if range is more important than climb rate. Would airspeed change much in cruise? Plot out the difference for typical flight with reserves. How much time saved vs fuel burn. If I went with the 390 I’d surely opt for a constant speed prop. I guess the depth of your pockets will be a determining factor for sure.

[@aggibson74]

can you get a turbo for the IO-360?

[@davejames7783]

Nobody ever says I wish I had less power! IO-390 100%

[@rolandsteadham11]

I fly in the Idaho backcountry. I have several friends that have Husky's and Scouts. They use the Lycoming 0-360-A1P, 180 HP engine and can more that carry their weight, camping gear etc. I do have one friend that opted for the 200 hp Husky. He wishes he had stayed with the 180 hp version. He burns more fuel and doesn't think he gained all that much.

[@KitplaneEnthusiast]

That’s good info-thanks!

[@williamgreen4757]

Fuel injected so no temp problems with carb heat, IO390 there are fuel work arounds. Constant 3 blade prop.

[@AJourneyOfYourSoul]

Smart man. As people who like to build, we get caught up with wanting to go with auto conversions, but something tried and true is the only real, long term choice.

[@jamesshearer5361]

Ok I see most are helping you with the one you are leaning towards. But I am am engine guy and higher horse power in the same block means less reliability. That's why I chose the 180 hp for my 7. Of course your application is different and that 390 sure is nice.🙂

[@KitplaneEnthusiast]

I’ve really been looking into this and thinking about both engines. I’m starting to think that lighter weight with more useful load is more important. I’m not one to put me or the airplane at risk and I do t ever anticipate flying into a field where I could only get out with 210hp and not 180. I really don’t envision myself flying anywhere a Cessna 180 or Super Cub couldn’t fly into. I’m really starting to think the 360 is the way to go. After the holidays I’ll contact Lycoming and see if I can plan a visit. They are only about 2 hours away from my home in Pennsylvania.

[@willarddevoe5893]

The difference between the Lycoming o235 L2C and N2C is compression. L2C goes in Cessna 152's and produces a smidge less horsepower, but you can run it harder and it's more tolerant of fuels. The N2C is more often offered for Vans planes.

[@squidten915]

I am currently in the middle of a Super Duty build as well. I also did a mental tug-of-war between the two Thunderbolt models. First conclusion , you can’t go wrong with either model. ….After lots of conversations with Roger at Zenith and Jeff at Lycoming and Nick at Arion Aircraft who is helping with the builder assist, I decided on the Thunderbolt IO360 with dual EMAGS. The only real concern that came up was (Potential) cooling issues because of the super duty’s slow speed limiting the air flow that (might) be required by the bigger engine, along with the the size of the engine compartment and baffle locations, etc… I do not think they’ve supplied an IO390 for a Super Duty yet, but somebody’s got to be first!… again, you can’t go wrong with either engine as you’ve already concluded. Cheers, Gerard

[@KitplaneEnthusiast]

Good info! I’ve talked to Roger too and he seems to think the 180hp would be perfect for this plane. Going with the 390 does present other issues. The more I think this over the more I’m leaning towards the 360.

[@telliott100]

Is turbo charging an option?

[@KitplaneEnthusiast]

No not on these engines.

[@davidrobins4025]

It sounds to me like you are happy with the choices you have made thus far. I'm looking forward to seeing the progress with your depictions in the future. Thanks.

[@telliott100]

Mark, I would go with the IO390. Density altitude is EVERYTHING to me. I live in Aspen Colorado. I have been in underpowered, hot summer day airplanes and it was NOT GOOD. More power is always desirable here. If you want to come visit my wife and I, you will want the higher power options!! Plus, landing in the back country in the mountains is AMAZING!!!!

[@klw141]

If price is not a big decision factor, no-one has ever been unhappy that they have too much power!

[@wheelerdavea]

Remember, you can always run the IO-390 at 160 or 180 or 210 HP, by adjusting the throttle and (assuming constant speed) prop controls. The IO-360 is topped at 180, no matter how hard you push the levers forward.

[@KitplaneEnthusiast]

Very true!

[@halhirsch3606]

What engine?

[@CompleteWalkaround]

I would say 360. You're going to have good take off performance no matter what. I think at the end of the day you'll enjoy the longer legs more then a shorter take off run which will already be very short. Good luck

[@KitplaneEnthusiast]

That's what Roger at Zenith says too. He said he has a lot of time in a CH-801 with 180hp and it was plenty of power.

[@flyingkub]

@@KitplaneEnthusiast Fully agree, in addtion more power can lead to other issues during take off.

[@nicka9202]

My inner Tim the Toolman Taylor say go with more power.

[@travisw9071]

Hahahahahaha love the intro!

[@dntower85]

For what your planning I would go with the 390, I don't think fuel burn is going to be that much more, I would rather have the confidence on getting out of short field in a high density altitude, than worry spending $20 more dollars in fuel. I also think with the correct prop, fuel burn difference could be nil.

[@benpoffenberger7173]

First, I would like to say, I agree totally with the Thunderbolt idea. When I replace my o-320 in my RV-4, this is what I am getting. The only drawback I can see is the time to get one. I hope that doesn't become an issue for you and gettting your Super Duty flying when you're hoping to. The real difference between your engine choices might be the compression ratios. The higher the compression, the more stress on the engine. You might consider that under your desire for reliability and also longevity of the engine. You are obviously very good at taking care of and maintaining things and making them last. So this might be important to you. Less compression means lower horsepower, but the tradeoff is a lighter engine with these options and lower fuel burn. Pair that with eMags and fuel injection and a full suite of engine monitoring, you can safely run lean of peak to reduce your fuel burn further. Lower fuel burn might mean you could carry less fuel on those high density altitude days and get back a little performance there. Emags - get 'em! Again, ticks off your desire for realiability. The classic mags in this case are worse than the new eMags - proof is the higher mx interval required with most - a sign in my book that even the manufacturers and FAA don't trust them ;-). I have a pair of eMags on my O-320 and they have never given me a problem. They also have a super nifty feature that retards the spark for starting, making it much easier on the starter, the electrical system and probably the engine itself. I have several hundred hours with no issues or mx other than condition inspections so far on mine. These also allow the use of auto spark plugs which actually work better than the much more expensive aviation types (in this case newer technology meets all your requirements - plenty of time in service to show reliability, maintenance is so easy on this one, do it yourself (even in the back country with a spare set and a wrench - but you're unlikely to ever need to, and much more cost effective. Well, you probably already found out about most of this from your own thorough research, but maybe hearing from someone else that has been actually using these things may help you with your decision. Good luck whichever way you go with it! Thank you for taking your time to put on the channel. I really enjoy and learn a lot about working on experimental planes in general from watching it! Ben

[@KitplaneEnthusiast]

Lots of good information - thanks for sharing your thoughts. The more I think about this, the more I’m leaning towards the IO-360!

[@bertayers8247]

🎱 Tough choice! I've had a I0360 in the past and it's a fantastic engine - rock solid and plenty of power. I think more horsepower will be wasted.

[@bryostdc]

The Continental Titan -370 would be kind of the sweet spot between what you’re considering. Not Lycoming, but essentially a Lycoming clone built by Continental.

[@Cavalier-lp8tr]

FYI, on 2 separate occasions I have heard from knowledgeable sources...a factory rebuild is better than the new engines. The comments seemed to say quality has taken a step back when compared. Might be worth checking out. I could be wrong, but I thought one said it's no longer a USA engine and China has a hand in them.

[@Downtownsarahbrown]

If the IO390 is really that much lighter it seems like a no-brainer! Easy to pull the power back and cruise for less fuel. Fwiw I’ve really enjoyed having an electronic ignition on my O360. Great engine starting, reliability, and nearly zero maintenance costs. Congrats on a big decision!

[@biggles5633]

I am about to commence a 750 SD build and like everyone, feel the dilemma of which engine to be a tug-of-war. I share your sentiments exactly in regard to the class of Lycoming engines but at the same time, would very much like to hear your view on your experience with the UL Power engine in your 750 Cruzer and why you did not choose UL Power again if you felt safe and confident with it. Congratulations on the channel, it is very helpful.

[@grantrotunda3100]

I think the most important question is did the guy digging for gold in the background ever find it 😂

[@KitplaneEnthusiast]

LOLOLOL!!!!

[@travisw9071]

Fuel burn = HP setting give or take? Heavier nose = more payload capacity weight and balance? Calculate for both and compare? Talk to zenith? Current thunderbolt super duties out there? Calculate power to weight based on entire airplane not just the motor? Don't underestimate density altitude, engine and airframe loose performance.... weight bad! Power good! I don't know!!!

[@johnnunez17]

390

[@justsomeguy1181]

Range is not a factor if the larger engine is used to increase cruise efficiency rather than performance. The cost of shorter, steeper takeoffs and the assumption this means more airfields available is the crux of it. Would applying the cost difference to fatter tires allow the plane to access even more fields than the more powerful engine would? The cost differential should be considered an annuity yielding the cost of money + available earnings. It could pay for some trips, which indirectly means more fields. Should longevity really have been a consideration? Will this plane accumulate more than a few hundred hours in the next 10 years? If not, amortizing the cost of the next engine with the the cost of money + the future-value of the savings on a short-lived engine is worth consideration, especially when the next engine may never happen. I say: small engine, big tires, more trips, more videos. Yay! This was not my first inclination. I tend to think bigger is better until the engine rips the snout right off the airplane. Then I think, "Oh... we need a stronger airplane."

[@markthibault8579]

What would be the anticipated useful load if you went with the 390? Will it be enough for your mission? If yes, go with the 390. If not, the extra 20-30 lbs may make all the difference if you're near the edge.

[@DavidBruner_NJ]

I like the choice either way. My feelings are similar in that I want a proven and continuously improved engine from a aircraft engine company. Anyway, if the price is still in budget and increased fuel burn and useful load reduction is not a high impact, I would go with the IO390/fuel injected/ dual electronic ignition and dual batteries.

[@phlegm314]

Sure you could go with old air-cooled designs, but maybe also check out a newer Honda conversion like what Viking supplies. You'll save almost half up front, and get a more modern engine that starts more easily, burns nearly zero oil, and has higher efficiency.

[@rayburn2007]

Io390

[@theresacaron4238]

Better to have the power and not need it than need it and not have it. Remember you can throttle back to reduce fuel flow if you're not in a hurry. I'd also get a constant speed prop to take full advantage of the engine HP. Phil

[@rustymac13]

IO390

[@pilotblue6535]

My concern with black engines is exhaust or oil leaks. Even using baby powder it is a pain.

[@ryaninman6307]

? any option to add a turbo ? Going be flying high altitude mountains.

[@KitplaneEnthusiast]

No turbo. Not even an option for this engine but I wouldn't want the complexity and weight anyway.

[@keithrogers5832]

Great choice, constant speed prop??? That might make the difference between 360 and 390. I flew a 180 hp Maule and was content until I flew the higher hp. but my missions were never beyond the 180hp. Tuff decision, I'm sure that you will come up with the best one after your talk with Lycoming, I hope that you are able to record that.

[@MrChevyman962000]

If it were me, I would take into consideration the manufacturer's power range suggestion. With more power, typically comes more weight, fuel burn, etc. More weight, requires more power, more fuel burn, etc. so, with that, I would see how far up the manufacturer's engine recommendation range where the power to weight is at the maximum for the highest effeciency. Then I would see what mods are out there to make more useful power, Fuel injection, electronic ignition, big bore kit, exhaust kit, and any other additional power that could easily be tuned out, or bolted on (keeping weight in mind).

[@KitplaneEnthusiast]

Contradictory. Anything that can be bolted on to ad power adds weight. As you say, more weight, more fuel burn, etc... Also more complexity, more wear on the engine, and would probably negate any warranty. The Super Duty can handle anything up to 230hp.

[@n206ja]

What sort of production lead time are you looking at on the Lycoming? Seems I recall it wasn't that long ago that one of the major manufacturers was so far behind that they weren't even accepting any new orders! Hopefully that's been resolved!

[@KitplaneEnthusiast]

It could be a bit of a wait. My original plan was to get the entire airplane painted, attach the wings, etc.. and then buy an engine. But now I’m thinking I’d rather mount the engine before the fuselage is painted because there’s a lot of work with fitting the cowl and I’d rather not have to worry about scratching paint. Plus, I’m thinking about making my own cowl out of carbon fiber so that’s a lot to do with a painted fuse. So I was in no hurry to order an engine, but now I am!

[@n206ja]

@@KitplaneEnthusiast I'd definitely be interested in seeing that carbon fiber cowl build!👍

[@KitplaneEnthusiast]

@@n206ja I'm not sure I will do it, but the stock cowl is very heavy. I'd sure like to save some weight up front.

[@Mrsournotes]

Since a PT6A is not a choice, I say IO-390. You’re gonna have a sweet beast of an airplane there. Also, nice to see your twin brother.😂

[@LTVoyager]

The Zenith is a light airframe and they tend to fly better with lighter engines. I’d go 360 all the way. The extra cost and weight just wouldn’t be worth it to me. You can throttle back the 390 to get a fuel burn closer to the 360, but you will always use more fuel in the 390 due to its higher weight. Just can’t escape that fact.

[@KitplaneEnthusiast]

Yes a lot of truth to what you are saying. I’ve talked to Roger and he seems to think the 180hp is plenty of power. Another big factor is price too! I hear the 390 is quite a bit more than the 360!

[@LTVoyager]

@@KitplaneEnthusiast I haven’t check prices on Lycomings lately as I am going Rotax in my S-21, but I suspect the 390 is a fair bit more money. However, for me it is balance in the airplane. RANS originally recommended the Titan 340 for the S-21 (180 HP), but when I looked at all of the advantages of the 915iS such as lighter weight, more fuel efficient, cheaper maintenance parts like spark plugs, turbocharged which gives sea level power to 15,000 feet, it was an easy choice for me. I lose some low altitude performance as the Titan has 40 more HP at sea level, but once above about 7,000’, the Rotax makes more power. I won’t be doing a lot of super short takeoffs and landings so the cruise performance trumps the landing and takeoff distance for me. Now, if I lived on a remote strip in Idaho and needed the best takeoff performance I could get, then I’d go with a Titan 340 in my case or a 390 in your case. However, realistically, I will spend 90% of my time in cruise and probably 5% or less taking off at really short strips and that favors the lighter and more efficient engine for me. It all depends on your mission and what you desire to optimize.

[@jorgmichalowski7954]

If I were you, I would take the IO 390 with 210 hp. More starting power helps you to start again from small places or forest clearings. In normal operation, the consumption will probably not be that much more than the 360 with 180 hp.

[@01boian]

Wy do You not select UL-power? You have that in your cruzer haven't you? (No offence just asking). And merry christmas to you.

[@KitplaneEnthusiast]

Yes I do and it's been an excellent engine. It's quite expensive though and UL currently has no FWF package for the SD. I do not want to have to design and weld and engine mount, and then fabricate my own cowl. Also one of my requirements I mentioned is that if I'm flying this airplane all over the country, I want to be able to stop into any FBO and have their mechanic be able to work on the engine (If I would happen to need a filter or something). Any mechanic would be familiar with a Lycoming.

[@scottk9591]

I think that for your application in the Super Duty, an IO-390 while a little heavier than the 360, is the better engine. My thinking with that is that it is better to have the extra horsepower available from the engine and not need it than need the extra horsepower and not have it. I think that regardless of whether you go with the 360 or 390, I would HIGHLY recommend you take a look at GAMI Injectors. I've personally flown behind an io-520 with gami's and I can't recommend them enough. they allow you to balance the air fuel ratios between each cylinder which helps the engine run smoother. And because the AFR's are balanced, you can run lean of peak and save fuel. Sorry for the long comment, hope this helps.

[@whathasxgottodowithit3919.]

A wise decision to go with a proper Aero Engine - IO -390 sounds about right. Not keen personally on a lot of modern engines cruising at 6000RPM, just my thoughts.

[@danielbasovitch5087]

With either engine your Top speed does not change much as the airframe itself is your limiting factor. I would opt for the higher horsepower engine, as we all say you can always throttle back!

[@Know-Way]

OK. Now that that's out of the way, What propeller are you using? Fixed pitch? Ground adjustable? Constant speed? Electric pitch? Curious, but mostly joking. Great choice on the engine IMHO. I'd go bigger with fuel range secondary. If need be I'd just stop for fuel. If I really wanted to go somewhere way out without a fuel stop, I'd add a fuel bladder with a tiny battery powered fuel pump I could pump out of the bladder into the wing. No fuel lines to run. I knew of a B-737 with a fuel bladder that flew from CA to HI and back. Lower engine weight with higher power is often the result of higher compression ratio. Higher compression ratio requires higher octane fuel to prevent engine knock. Though if the engine has knock sensors fitted, the timing (electronic ignition) will be automatically adjusted to prevent knock, at a cost of losing some power. Engine temps may be slightly higher too, with higher compression. On the fuel injection choice, for me, if it's a toss up I'd look to which is more serviceable/parts availability. I look forward to hearing more about your final choices and why. Thanks!

[@KitplaneEnthusiast]

No C/S prop. It's just too heavy. I'll definitely use a ground adjustable prop probably either the Sensenich or the Whirlwind.

[@trose0501]

@@KitplaneEnthusiast I'm not trying to sway you one way or the other but changing pitch with the Sensenich is very easy...also Sensenich is a company that isn't going anywhere anytime soon.

[@scottmiller4711]

I would go with the 390. You can always go on a diet and lose 20 lbs to even it out…😂. I would go with dual electronic ignitions, everyone I know loves them, more efficient, better fuel economy, automotive plugs vs. expensive aviation plugs and they last longer that traditional mags.

[@SpyGeorgilis]

I'm probably misremembering, but in an older video I thought you mentioned that you weren't putting fuel returns in the wings, because you were going with a carbureted engine..? Or was this about NOT closing the wings until you made a decision on that? In any case: nice engine choice(s)!

[@KitplaneEnthusiast]

With these fuel injected systems now on the Lycoming a return line to the tank is not needed.

[@acpilot320]

Great video. FP or CS prop? I'm building an RV14 and working thru the same questions. Typical engine is the IO-390, however, I'm leaning toward an IO-360 200hp angle valve with the prop governor front left (clearance issue with on rear of case). IO-360 attractive to me due price, fuel burn and parts costs.

[@KitplaneEnthusiast]

I think a C/S prop would be too heavy for the front of this airplane. I'm even worried about the extra 20-30 pounds of the 390 over the 360.

[@RafMov]

Well explained decision process, thx. How many hours are you planning yearly?

[@cyrooski4]

Boy did you miss the boat. You want simple but lycs and conts aren't reliable. AOPA: 2019 ...of 194 mechanical accidents, 132 were engine failures. And btw reduction gears and liquid cooling have NOT been failing...at all! 1935 technology sucks. Go Rotax and you'll live.

[@rocroc]

Well, you have a cruiser that you "may" sell. You've indicated that you want to use this back country and STOL flying. If that is really what you are looking for, I would opt for the best combination of horsepower to weight ration that you can get. There are some locations that you want to get into and out of quickly that require horsepower. The less usable horsepower the fewer locations you can get to. You may also be flying at some higher elevations and I would consider performance at those extremes as well. It there are some STOL flight clubs you are interested in they may have best recommendations for participation in their flight club. If it were me, I would really like to participate in some STOL competitions. If that is something that interests you, then you have to determine how effective you want to be in those competitions. Are you comfortable with a tenth place finish looking up at number one? I doubt it. You may have to have two engines!!!!

[@djpcyrus]

I would use the AeroMomentum T-20... 200-300Hp... @ 60% of the cost... Check them out!!!