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 have no problem with APS or you personally and I do treat all people with
dignity and respect. Dan Weseman was very helpful at the Mexico Corvair College but I received very little assistance from you. You ignored me to the point that I though that I had offended you in some manner for which I apologized to you at the college if I had done so in some unknowing manner - you stated that I had not. I have no problem with your Corvair conversion engine or the Weseman 5th bearing. Actually I believe it to be a good design or else I would not have chosen it. However I will restate as I
did to Rachel at APS, "had I known I was going to have this much trouble, I
would have chosen another engine".

Your response to my post about poor customer service is typical
WW - dig in and attack instead of trying to resolve the problem. Lets try working together to resolve the problem. I will see you next month and maybe we can bridge this gap.  Jim Palmer .... bigangel@bellsouth.net.=

Mr. Wynne

I currently have two Corvair cases, cranks and assorted parts in my hangar. Part of my problem is where to start. I have looked at the Corvair off and on, bought the manuals, found some cases and know certain modifications need to be done but getting them done is the problem. I think the issues a lot of people have with their engines, not just Corvairs, is everything is fine until it isn't. No one gets on a forum and reports adequate customer service. No one says I emailed him and they called back in 2 days. For 90% of their customers any organization can have great customer service but it is that pesky 10% where something gets dropped. It is the customer who had to wait and wait for his part from a third party vendor, the one who calls and it doesn't get noted or maybe the number gets written down wrong. The one who has an email that is .net and not .com like he told  you. The customer who goes to the Corvair college but doesn't really understand what is going on with his/her engine. These are the ones who get on these forums and talk about their displeasure, money spent and perhaps give the impression it is harder than it may be ON AVERAGE to get the particular engine on the plane and running.  This are something any small business HAS to deal with daily. In my opinion that is the biggest problem you and Viking engines have is the perception that you might just not be there when the problems arise. Viking has the failed Subaru engine albatross to overcome and Corvair engines have their own set of myths and problems to overcome. Some people just poo-poo anything not certified as okay by the government. Some just don't want to learn about an engine and want something to bolt on and hook up. Some think they want to build or modify their own engine thinking it will be cheap but find the set of skills they have don't match the skills needed or the money involved. Perhaps I will attend the next Corvair college near me to see how it goes. I would like to see a step by step manual for converting the Corvair similar to what is out there for rebuilding a Volkswagen with remove this and replace with X, disassemble Y and check these clearances then reassemble this way etc. I thought that is what your book was but it seems more to the point of what parts are needed and what part numbers they should be. For others reading this. Keep in mind when you see posts about problems someone is having with a vender of any type it may be more about the person posting than the actual service of the vender.

Mr. Hall,

First, let me indicate that I am not sure if it is appropriate for me to submit a "reply" here. But your email is of interest to me. So too is Mr. Palmer's.

Generally, it seems that SPA was, and perhaps still is, having a difficult time getting everything together over the last half year or so. Rachel has indicated that things will start getting smoother in the near future. This has restored somewhat my confidence in the process.

So, rather than cancel my order for the crankshaft, which I ordered shortly after the #34 session in Mexico, I decided to hang onto the project after talking with her.

I am not so sure that was a smart thing for me to do, but we shall see, it will cost me only about $3000 for the shaft, camshaft, bearings and other stuff. Tuition may be high, but who knows?

I appreciate your observations regarding the process. The "manuals" are better than nothing, but I seem to have a difficult time extracting hard information out of the background of non-essential information. And I found that the pricing information is incomplete in critical ways. I was not able to plan a budget or develop a build-process based on the manual(s).

For example, I wanted to use the 2775cc piston, cylinder, rod "kit" that was mentioned last September. I felt stupid not  being able to extract the info from the manual or other literatures. Because it was non-existent.

Rachel finally did get me the information, but I don't know if it will be posted for others to use, and/or made "official".

The idea that you hinted at in providing a build sequence (step by step) has been on my mind for some time now. I don't know if it is best to be done with a spread-sheet and/or with a flowchart sort of thing. Perhaps we the builders need to provide ourselves with such information, since we are the experimenters. I am not confident enough just yet to provide such info, I don't want to add to the confusion.

Anyway, I am trying to keep lab notes, maybe I will submit something in future based on that.

An example: I have the two case halves, cleaned many times. The guts had been given to WW at #34 in Mexico. I would like to make a minimum expenditure at this point by getting the crankshaft, camshaft, front housing, and wait until later to put the  oil housing on, and later still to get the cylinders, pistons, rods kit.

But, can one leave off the oil housing in this segment?  (Apparently yes, according to Rachel). But, using the 5th bearing shaft from SPA entails getting an installation kit from them on loan, drilling new bolt holes for the front housing,  and using  a gage to somehow locate that housing relative to the crankshaft.

Well okay, but I do not recall from the advertisement from either SPA or WW that one had to drill new bolt holes into my lovely case. I need to re-read the literature to see if I missed that, so that will require me to go back into the "manual" to extract the information.

If I had a diagram, a flowchart or spreadsheet, or even a lousy hand-drawn project (pert?) chart, that would have popped right out.

Okay, one of the reasons for commenting thusly was to let you and Palmer and others to know you are not alone in your observations. Knowing these sorts of things is very valuable to me, even though it might incur the wrath of our engine guru, who would of course tell me to do my homework, etc.


P.S. by the way, I am not a complete dolt, having made a living as an engineer. But, I did remove all the studs from my engine, so maybe a little doltish, eh? 

Michael, walk softly or else you will find yourself totally abandoned. I was signed up to attend the CC in San Marco next month but after my post about not being able to get (for going on ten months) ordered parts which are custom built by Mr WW and not getting any response to any email, I have been canceled - I think???? ..... because my deposit was refunded without any explanation what so ever - very unprofessional. If you are considering a Corvair, I do think the WW/Weseman 5th bearing combination is the best available or I would not have chosen it. Also, I have had no problem with Dan Weseman or SPA which has bent over backwards to help when WW failed. Hopefully SPA will be able to pull this together into a well organized and efficient organization. Maybe someday another Corvair conversion company will arise. Competition makes good business.

Mike:  Huh?  You read the manual and you 1) missed that you shouldn't take the studs out except under exceptional cases, no pun intended, or 2) you took them out for other personal reasons?

Re case/5th bearring housing install:  Is it another 'myth' of the manual that you aren't sending your case and crank to SPA to have that taken care of, or did I miss something else?

This is highly questionable statement because SPA told me that they did not handle WW customer service and that they are a separate company. Also said that if I made a purchase from WW then I should deal with him. I can post the email from SPA if anyone would like me to. I have parts that I ordered and paid for over 9 months ago and I have still not gotten them. Neither has WW replied to any email concerning the status of my orders. I STRONGLY RECOMMEND USING ANOTHER ENGINE SIMPLY BECAUSE OF POOR CUSTOMER SERVICE AND INABILITY TO GET PARTS WHEN ODERED FOR MONTHS. Jim Palmer .... bigangel@bellsouth.net if you want more information about whether or not to use a Corvair engine.

Mr, Palmer,


Just so everyone understands, You have met me, the Weseman's, been to their shop, you attended Corvair College #34 in Mexico MO this last September, where both myself and Dan Weseman assisted you in the build of your engine, directly, at no charge to you, and you are currently signed up to come to Corvair College #36 next month in Texas, where I will run your engine and train you in it's use for free in a friendly manner, and your comment above reflects this how?


Yes the Weseman's do handle sales and support, but the change over did include me politely asking existing builders to understand and be courteous of the Weseman's, particularly Rachel as this was getting set up and organized. This was directly said about existing back orders, which predate my agreement with Dan and Rachel That is a simple request that I expect anyone who has directly worked with us to be able to work with, and I don't suspect that any Sothern gentleman should have a problem respectfully communicating, particularly with women. As my friend, Rachel isn't required to offer tech answers to builders who have an issue with this.


Selecting an engine is about homework: Ask any guy who has a flying Corvair, and we have always had long lead times on some items, this isn't a new issue, as 90% of our builders are buying parts as budget allows, and we stay ahead of them. In other case, there are waits. If the parts were no good, or if demand was low, or they were not a good value, they would be siting on the shelf .


As the saying goes, you can have inexpensive engine , free technical training and assembly supervision, and immediate parts availability, please pick two. It has always been this way, and many people can respectful work with it because it meets their goals. If it doesn't meet yours, then more homework was in order before choosing an engine. I will be glad to find you another builder to pick up your engine project, we have many people who understand the strengths of our system better. Send me an email, and I will find another builder who is a better match for the engine project in your shop.


Here is the copy of an email I got from SPA:

On Thursday, December 17, 2015 10:38 AM, "Sales@flywithspa.com" <Sales@flywithspa.com> wrote:

Hi Jim Palmer,
We have not assumed customer service for William/FlyCorvair on parts not ordered through us.  However, as a favor to you, I will let William know that you still need those parts.
Merry Christmas,

OK ... time for a break and message from the Moderator!

This thread is going off the rails - the topic of discussion is pros and cons of engine choices. Let's keep the comments relevant to the topic and I suggest that communication and support problems of individual members and vendors be addressed by direct, private, one-to-one communication  - the private message system on this forum works reasonably well.

Moderating is much more difficult than it might appear. It would be easiest for me to just hit the delete button and make some comments and posts disappear, but I consider that a last resort. I'm appealing to the good nature of all our members to keep discussions on-topic and friendly!

Now we return to our regularly scheduled programming!  ;>)


Zenith.aero Forum Moderator

John, you moderate moderately--just right!

Still, there is sometimes a thin line between malicious gossip and tips about misbehavior.


 I just started building a CH750 STOL, but come from the certified world owning 2 other non-experimental aircraft, so I am going with a Continental O-200 rebuild with lightweight starter and mags.  I would think that the weight issue is more a problem with a STOL, where getting off the ground and over obstacles in a short distance matters most.


A rebuild done right can be very economical and safe.  Being an Electrical Engineer by training and a military avionics guy by trade, I have a healthy mistrust of some of the newer technology based engines.


Also, having talked to Michael Heintz from Zenair in Canada, the O-200 install is probably the most straight forward

of the firewall forward options.


Of course, I am new to building and there are many many very experienced people on here.  I am curious to see where the discussion goes.....

And I will tell you the truth :)  

  • You mention the O-200 as a viable choice for the 750.  It is not at all a good choice.  Lightweight starter, or not, the power to weight is terrible.  A direct drive engine, of any sort, is not conducive for STOL flying.  (For a CruZer or 650, it is a better choice.)
  • Information regarding the O-200 being an easy install in a Zenith:  It is the worst package available.  The engine mount has the wrong angles, the cowling does not clear the spark-plugs, there is no step by step procedure, you need to engineer your own baffles, exhaust, throttle attach bracket, fuel hoses, etc.  Unless you are ultimately familiar with aircraft engine installations, or are ready for a steep learning curve, this is not the engine of choice.  Just because Cessna made it work in a 150 does not make it jump into your airplane.  
  • Continental will tell you straight out that they are engine people only.  Other engine manufacturers invest heavily to provide an easy to install engine package for your Zenith aircraft.    
  • Rebuilding the engine should also be left to qualified personnel with years of aviation experience and will be at least 2 x as expensive as first thought.   The old core will eventually have all new cylinders, camshaft and a mags.  In addition to a bunch of other stuff.  
  • An O-200 powered CruZer fly at 100-110mph.  That is not impressive.  


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