I'm wondering what is the best engines everyone is installing or running? Also the pros and cons? I am building the Zenith CH 650 and have just started. I like the UL350iS or the Lycoming 233 but I see quite a few Corvair engines out there, so what are the pros and cons about them. I do not like the Rotax. I want something simple. So any input will be greatly appreciate.

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I certainly agree that building engines should be left to those that do it professionally.  I am having someone build my O-200 for me.  I guess I will see for myself with regard to getting the O-200 mounted and running in the 750STOL .  My engine builder is using a C90 CAM and I plan on using a Sensenich carbon fiber ground adjustable prop for good STOL performance.  The C90 CAM generates its power at a lower RPM for optimized take-off power.  But I am an engineer, so once there is real data that will tell.....


I agree that O-200's are old school, but I am funny that way.  I am very comfortable with modern avionics, but like mags, etc when it comes to airplane engines.


Hey, at least I am not including a vacuum pump.....  That's progress for me...







Here is a different perspective: While the O-200 would not win the Zenith Stol competition tile away from Jan and his Viking, it doesn't mean that it will not serve you. If you like old school stuff it is a viable option. The EAA's 750 has one in it, I have seen it in person, and it works. There are merits to what Jan says, and you should factor them in, but if you like it, think of this:


PSRU engines work and are needed on smaller displacement engines, but there are still a lot of direct drive O-320/360 based power plants in the Alaska stol competitions, so it is an overstatement to suggest they don't work in stol planes.


I have a couple of hundred hours in my Wife's Taylorcraft, which has a C-85 set up doing much the same work you are thinking of. We have the plane set up to tow single seat gliders like our 1-26. If you want an alternative prop, look at a McCauley B90 set to 71x42. I did a lot of research to prove that this diameter is better for stol than 74 and less rpm. The static is about 2475, on a cold day solo it will get off the ground in 160'. It tows a glider out of a 2300' grass strip. Sensenich makes good stuff, but this is worth looking at. I bought it at a flymart and had a certified shop overhaul it, total about $1,000.


C-90 cam is the answer to a question you may not be asking. It works well with props at 74" in Cubs, but It may not be the best choice for other props. read up on what works for others in classic planes, but your primary info source should be Bob Barrows, the Bearhawk guy. He builds some wicked 0-200s, I have flown one, they are a very different story than a C-150 engine. He uses more rpm, not less.


Buy a Continental overhaul manual, read all the way through it, and find a rebuilder that will allow you to be there and learn every step of the way as it is overhauled. Take the opportunity to learn more, even if you have to travel to find that guy and pay more money. You got in this to learn, not save money. Learning is a good investment. -ww.


Ps: Nitrous Oxide works great on low tech motors with a lot of piston area like O-200s. It is 20 pounds of equipment, about $800, and it can add 35 hp without stressing the motor. Besides it is old school, used in WWII. One persons insanity is a practical cost effective option for the person who takes the time to learn.

How about a O-200 with C90 cam and higher compression pistons? Anybody seen anything like this?

I like the specs of the UL350iS but haven't come across any pilot reports. Zenith has them fitted to their demonstrators, must have racked up a lot of hours and experience with the type. How about it Sebastion or Roger, would you mind sharing the details of the engines performance to date? :)

It is wonderful that there are so many vendors to choose from!

Most owners are happy with the engines they use.  This means you cannot go wrong if you choose something already out there - up and running in the air.

At HomebuiltHELP (vendor) we have made videos of the installation process for these popular choices in the 650:

Continental O200




(we wont mention Rotax as you have ruled that out)

Engine Videos Click Here

By watching these, you get  a feel for the parts and pieces involved, but not the performance or customer reviews.

Many happy builders flying with all of the above mentioned.


If you havent bought or seen any of Jon (homebuilthelp) videos there well worth it to buy them.Jon does a wonderful job making them.

Im saving to build a 750 stol or cruzer. UL Power is my first choice from all of my home work I have done and all the Zenith builders I have talked to. Viking has come along way from when Jan first started. Viking is really worth looking at if your looking for a auto engine converted to aircraft. The nice thing about Viking is its around 50% savings. 

All of HomebuiltHelp info is a must for anyone wanting to know more.  

I think we all go through the process of deciding with some trepidation regarding engine choice. There are no right or wrong answers. Your engine decision should be based on what your flight mission will be and where you are going to fly your a/c. I live in Northern California where density altitude is a big issue. I also fly with a passenger 90 percent of the time. I fly the CH 601. I typically carry 24 gallons of fuel and I can safely travel any time of the year at any altitude allowed by a Light Sport regs for up to 3 hours with a good reserve. My engine? I fly the Jabiru 3300. The heavier the engine that you choose the less fuel and load capacity you have. Another engine in this category is the UL. A friend has one in a 750 and it runs very well but quite a bit more in dollars and the technology is more sophisticated so maintenance could be more problematic. If you live in what I would call a sea level state, then the Continental or the Corvair would be something to consider if you fly solo most of the time. I'm speaking from experience as I have flown and flown in examples of these engines in the 601 and 650 airframe. I have no experience with the Viking powerplants. There is a fellow named Ken Robbers who lives in Lodi,Ca who could give you some independent insight on this engine. He can be contacted through the Viking website.
Doug Eaton

I haven't yet decided whether or not my IO-240/CH750 combination is optimal. It is heavier, but the fuel injection (not to mention power) has some advantages, and the engine is well-proven. When it comes to an airplane engine, reliability is number one. Initial cost is last. This does not mean that I wouldn't trade out my engine for a lighter one that would out-perform it (in its STOL mission). I, too, wish Zenith would release its test results. Having flown in the Jab 3300's, I have been favorably impressed, especially by the smooth and relatively quiet operation compared to my Continental. Ease of maintenance and repair and parts availability, especially in the field, are big pluses.

This does not mean that I wouldn't trade out my engine for a lighter, cheaper one that would equal or out-perform it (in its STOL mission). But there are a lot of trade-offs I'm willing to make for top STOL performance.

What we really need is more science and less opinion. I know that popular opinion does not follow this, as I have tried it before and gotten nowhere.


I am going with the WW corvair for two reasons, #1 it is affordable, mine is ready to install on my 750 and I have about 9k in it less prop. # 2 I can work on the engine my self very simple design and it looks like a major on the engine will not break the bank, it's a neat feeling to build it yourself and hear it come to life for the first time.the engine has a long track history on light aircraft starting about 1960
I have a Viking 110 hp with a 3 blade IVO prop with spinner. It has about 5 or 6 hours of static run time on it. Starts and runs perfectly. Tom (925)370-6531

asking which engine is like asking which color. :)


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