# Engine debate and choices?

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#### snowy_50

##### Active Member
So im still a newbie but i done some fair research
1. Im tempted by the viking for its price/power but im concerned from some bad reviews and the high numbers of engines fails in the auto conv. Category
2. I would go with a lycoming or ul but fuuuuuuuu there 3x times more expensive, and wanted to ask if any one knows companies or a place (other than ebay and this forum) to find air or liguid cooled 130hp engine?

These questions im sure have been asked so many times,so any help would be great and sorry to bother

#### KeithO

##### Well-Known Member
If you can afford it, buy the proven designs that are old. There is nothing to invent. If money is tight, then you may need to look at an "alternative engine". But there are certainly risks involved because that particular type of engine may not be a drop in for your air frame, so that means engine mount development, engine position possibly move for weight and balance ? New radiator/oil cooler setup etc etc. But the advantage is that engines like the Viking or Yamaha have fuel injection, no choke, run like a sewing machine, no carb icing issues to worry about or mixture setting for millenials who have possibly never run anything with a choke.... Usually a substantially lower fuel burn too, compared to the old dinosaurs...

#### wsimpso1

##### Super Moderator
Staff member
Check out Aeromomentum.

#### arj1

##### Well-Known Member
Or AeroVee for the smaller one?
@snowy_50, you could try to check the Kitplanes article:

#### Dan Thomas

##### Well-Known Member
Unless the builder is handy with engines and welding and other stuff, he can easily spend far more time and money on it than if he just bought a used aircraft engine. I installed a Subaru in a Glastar for an owner, no labor charges, and by the time it was done he could have had the Lycoming and been flying sooner and with far less hassle, and the airplane's resale value would have been about double what he ended up selling it for. There is just so much stuff to consider, and it's why we see so few auto engines flying around.

That's not to discourage attempts. It's to make one aware of the complexities. There have been some dandy auto conversions, and for a lot of people, the attempt is the pleasure. Some of us really enjoy creating or modifying. We don't mind if it takes longer, as long as we get something that works and can be called our own creation. If I was young again I'd be tempted to rework a Navion into a taildragger powered by a Chev V-8. It would be so close to looking and sounding like a P-51, my favorite. But at my age I'd be 90 years old and bankrupt before it was done, and I no longer feel like hassling it through the regulatory hurdles.

It comes down to this, the old saying: If you want to build, build. If you want to fly, buy. Building or converting take lots of time and carry considerable frustration at times.

#### Daleandee

##### Well-Known Member
Or AeroVee for the smaller one?

OP mentioned 130 hp so a VW conversion is not an option. I mean asking a VW conversion for 80 hp, in my not so humble opinion is beating on the engine pretty good. Adding a turbo, again in my own not so humble opinion, gets into abuse territory.

I fly a WW Corvair conversion that is rated at 120 hp. Dan Weseman has a Corvair conversion with a bit more stroke on the crank that puts out 125 hp as tested on a dyno. A good auto conversion can work but the advice is to follow a proven path and try to prevent reinventing the wheel, as they say.

As for the Viking engine ... not for me for reasons that are better left alone.

#### Martin W

##### Well-Known Member
.

YES to what Dan said post in # 6 .

But the real problem has never been about engine selection.
It has always been the lack of money
Spend a couple of months doing some extra jobs , bring in some new cash . cut down on frivolous spending , sell stuff you no longer need.

Most people would be surprised how easy it is to find an extra few thousand dollars .
It is often right in front of us at all times.

Our problem is we have all been taught how to earn money
But not how to spend money , we get rid of it as fast as it comes in.

Another advantage is a Lycoming type engine will often be worth more a few years down the road .... whereas the alternative engines are all in the junk pile.

.

#### arj1

##### Well-Known Member
.
Another advantage is a Lycoming type engine will often be worth more a few years down the road .... whereas the alternative engines are all in the junk pile.
.

It is more expensive to run and maintain.
I've missed that it needs to be 130hp, in that case Corvair appears to be OK...

#### TFF

##### Well-Known Member
A Lycoming or Continental is generally abused to run for 30-50 year lifespan for us bottom feeders. That’s hard to quantify. It could be falling apart or a gold mine. Hour per hour, if 500 hour is all you will use, a car engine will be cheaper. 2000 hours, probably not. It’s not so apples to apples.

A car engined plane is cool. If you have to do it over a couple of times before it’s right, which is pretty often, cost equals out. Off the shelf conversions are more like good starting points. If you don’t know what to do with them in the beginning, you will in the end.

#### Dan Thomas

##### Well-Known Member
It [Lycoming] is more expensive to run and maintain.
I've missed that it needs to be 130hp, in that case Corvair appears to be OK...

Well, yes and no. The Lycoming is a stout engine that, if cared for properly and not just ground run (which wrecks any aircraft engine) will reach TBO and beyond. I used to replace the flight school's Lycs at TBO, which varied from 2000 to 2400 hours, and those engines were still running strong, compressions all in the mid- to high-70s (80 is absolutely no leakage at all), no metal in the filters, and they would easily have done another 1000 hours in a homebuilt. The big core charges on them meant that they went back to Lycoming.

The certified engines are built to drive propellers, most of them direct-drive, which means they are designed to produce their max HP at the RPM that suits a propeller. They need no redrive. A direct-drive Subaru needs to run the prop a lot faster, so that prop has to be shorter to keep the tips within Mach .8 or so, and shorter props just aren't as efficient at turning HP into thrust. And even then that Soob will be well under its redline, meaning that it will never deliver its rated power. So now you need a redrive, and that introduces a whole separate set of problems. And more cost and weight. Just ask wsimpso1 (Billski) about that. He's a transmission engineer that specialized in torsional vibration.

The aircraft engines have big cylinders and big bearings to take the pressures at the lower RPMs where they operate. They have heavy valves to stand the heat. They already have magnetos and the places to mount them, though you can get uncertified ignition systems for them if you want. They already have fuel delivery systems optimized for the engine, and you can get uncertified EFI if you want that. They already have engine mounting points that suit an airplane as opposed to a car. That Soob I put in the Glastar required me to design and build a mount that was far more complicated than any Lycoming mount. 17 sections of tubing in it, just to reach around the engine to where I could get the necessary grip on things. The engine mount in my Jodel, for the A-65, has seven sections of tubing in it. Less than half the hassle. The Soob had no place to mount a mechanical fuel pump, meaning that we had to use two electrical pumps for redundancy. They relied on the aircraft's alternator and battery, as did the ignition, and that makes everything less reliable. Electrical failures are a big factor in airplane troubles. It's why the certified airplanes using glass panels have to have a standby battery system to keep the fancy stuff alive if the primary system quits. Extra systems cost more money and add more weight, too.

Details matter. We should ping Ron Wanttaja about the failure rates of auto conversions vs. traditional aircraft engines in homebuilts. I think the numbers are startling.

#### KeithO

##### Well-Known Member
Engines like the Viking have mainly external bolt on parts for integration into the airplane. The engine itself has very little modification, which is good for its reliability. The ECU that was developed is a big part of the success of this application. I believe that even the vehicle lift pump is integrated into the header tank. This is all good, because it is pretty cheap, can be bought from many sources. I have not heard of the Honda engines grenading in this application. They are run less hard in the airplane application than in racing. If the engine did go out on the very popular stol aircraft most of them are fitted to, the pilot should be able to make a safe landing. When putting an automotive engine into a LongEze, you need a much better place to land to avoid damage or injury. The decent weight of the Honda engines makes them more likely to succeed in the LSA category, which by design has a lower stall speed and thus better likelyhood of survival on an engine out landing. A Cozy or a Velocity is not a good test bed for an experimental engine. The Soob engine conversions were very heavy and often resulted in experimentals coming in at higher than gross weight, coupled with poor reliability.

#### Dan Thomas

##### Well-Known Member
The Soob engine conversions were very heavy and often resulted in experimentals coming in at higher than gross weight, coupled with poor reliability.
Maybe some are, but the 2.2 I put in that Glastar weighed within a few pounds of the O-235 it replaced (around 270 pounds), and produced 130 HP. That included the 2.2:1 redrive and cooling system. I didn't have to reposition the engine for CG or use any ballast, and by lowering the engine I was able to use the Glastar cowling for the O-235, with a minor mod to accommodate the redrive's bottom end.

It sure wasn't any lighter than a proper aircraft engine.

The big disadvantage, besides reliability, was the need to operate the engine at very high RPM, where it made a lot of noise and even when leaned it burned plenty of fuel. A Lycoming or Continental, with a redline of, say, 2700, will happily cruise at 2500 all day, all its life. Many of these engines are designed to produce redline HP for the full TBO. When an airplane is designed to use a Lyc or Continental, and with a fixed-pitch prop, that prop is pitched to get redline in level flight at full throttle. I set the ground-adjustable prop on the Glastar to get that 5600 RPM at full throttle in level flight too, but to cruise at 5200 RPM was not pleasant at all. 2500/2700 is roughly equal to 5200/5600, see?

So we ended up cruising it at around 4600, which gave a cruise of about 110 MPH instead of the 130-135 MPH that the 125-HP O-235-F or -G would have produced. It did do about 135 MPH at 5600, though.

#### KeithO

##### Well-Known Member

150-160hp install

#### wsimpso1

##### Super Moderator
Staff member
So im still a newbie but i done some fair research
1. Im tempted by the viking for its price/power but im concerned from some bad reviews and the high numbers of engines fails in the auto conv. Category
2. I would go with a lycoming or ul but fuuuuuuuu there 3x times more expensive, and wanted to ask if any one knows companies or a place (other than ebay and this forum) to find air or liguid cooled 130hp engine?

These questions im sure have been asked so many times,so any help would be great and sorry to bother

Viking? Nope. Just say "NO". The owner's ethics are at issue, we do not want any more sad cases.

Lycoming is actually a pretty good option.

Lots of O-235's and O-320's at Wentworth and Texas Air Salvage. O-320's come in 140, 150, and 160 hp versions, so while it might be a little more power, it is in the right ballpark. Typical engine there has had a prop strike, but if the crank flange dials in straight, the internals usually are not messed up, but the prudent owner will check. IRAN the engine, and the proud owner now has a freshly painted and sealed but run-in engine to do first flight and test program with little to worry over as to break-in or hot running while debugging a new airframe. Find one with out a prop strike? Bonus! Clean it up, pickle it, and hang it on the airplane.

If unfamiliar with engine build up, there are lots of videos and short classes specific to Lycomings you can take to learn the process. Maybe the local EAA chapter (we all belong to at least one for this sort of support, right?) has a friendly A&P or Tech Counselor that is willing to look over our shoulder and make sure we check all the boxes and do it right. If car gas is desired and it is not already a low compression version, low compression pistons can be swapped in while it is apart, or do that after the test program. EFII is also an option.

Billski

#### Dan Thomas

##### Well-Known Member
Viking? Nope. Just say "NO". The owner's ethics are at issue, we do not want any more sad cases.

Lycoming is actually a pretty good option.

Typical engine there has had a prop strike, but if the crank flange dials in straight, the internals usually are not messed up, but the prudent owner will check. IRAN the engine, and the proud owner now has a freshly painted and sealed but run-in engine to do first flight and test program with little to worry over as to break-in or hot running while debugging a new airframe. Find one with out a prop strike? Bonus! Clean it up, pickle it, and hang it on the airplane.
Yes, definitely take apart a propstrike engine. It used to be a standard procedure to dial the flange and call it good if the runout was less than .010" or whatever, but it's not acceptable anymore and hasn't been for a long time. It's risky enough that insurance companies will often pay for the teardown and NDT of the engine. You don't want a crankshaft breaking in flight like I once had. It's not funny. That was a cracked crank from an old propstrike.

Besides the crank, the case can distort or crack. The con rods can distort or crack. Pistons can crack. Magnetos and vacuum pumps can be damaged internally. The shock of a metal prop striking something hard goes all the way through that engine as if someone hit the crank with a 20-pound sledgehammer as hard as they could. Things stop almost instantly, and things that don't want to stop deform and spring back, but cracking could have started.

There is a dowel pin that drives the crankshaft gear in many Lycomings, and an AD was issued to force inspection of that gear, dowel pin and retaining bolt if there was any propstrike whatsoever. That pin could get partially sheared and fail later in flight. And that pin is at the far end of the crank, a long way from the propeller, and turns the camshaft and other gearing that drives accessories. The AD says this about what constitutes a propstrike:

Serious stuff.

Propstrikes in small Continentals regularly crack the crank, particularly in the cheek between the #1 and #2 rod journals, way at the back of the engine. The crank twists and rebounds and can dial just fine, but often isn't.

#### KeithO

I looked at the Corvair option since Im pretty familiar with building engines. The problem is that people know that folks use them for airplane engines and core prices have gone way up. $4500+ several years ago for the "right" serial numbers. Most available engines are the earlier ones with weaker cranks. I think it is easy to put a lot of money into a Corvair conversion and then have the crank break on it. Some people have broken 2 cranks. And one has to know that direct drive at higher RPM is not a good combo to many of the slow flying airframes out there. In that case something with a reduction drive is probably better. #### Daleandee ##### Well-Known Member I looked at the Corvair option since Im pretty familiar with building engines. The problem is that people know that folks use them for airplane engines and core prices have gone way up.$4500+ several years ago for the "right" serial numbers. Most available engines are the earlier ones with weaker cranks. I think it is easy to put a lot of money into a Corvair conversion and then have the crank break on it. Some people have broken 2 cranks. And one has to know that direct drive at higher RPM is not a good combo to many of the slow flying airframes out there. In that case something with a reduction drive is probably better.

If you gave anywhere near $4500 for a Corvair core engine then, as my father would say, "they seen you coming." No one in their right mind gives that kind of money for a Corvair core engine. Also know that there are cores available as GM made about 235,000 Corvairs in 1965 alone. The first year for the "long stroke" engine was during the '64 production run. The last core engine I bought was a few years ago for$150.00. Knowing what you are looking for and where to source cores is a learned skill.

Crank breaks on Corvairs have been nearly eliminated since the addition of a fifth bearing to take prop loads off the crank. Properly prepared original cranks or new billet cranks (stock or stroker) are available and have given great service.

Prices continue to increase on everything so no surprise there. The engine I have in my aircraft is now likely $4,000 more than it was years ago when I bought mine. But I've had such service from mine that I would make the same choice today that I did then. Higher RPM and smaller props? Of course. But direct drive Corvairs are used on some of the slower planes running prop lengths up tp 66" or more. Need to turn a larger prop? Dan Weseman has a 3.3 Corvair conversion that puts out 118 HP (Dyno proven) at 2800 RPM to turn a large prop at slower speeds. A proper Corvair conversion is a great option for many people but I certainly realize that Corvair conversions aren't the answer for everybody. #### raytol ##### Well-Known Member Supporting Member Viking? Nope. Just say "NO". The owner's ethics are at issue, we do not want any more sad cases. Lycoming is actually a pretty good option. Lots of O-235's and O-320's at Wentworth and Texas Air Salvage. O-320's come in 140, 150, and 160 hp versions, so while it might be a little more power, it is in the right ballpark. Typical engine there has had a prop strike, but if the crank flange dials in straight, the internals usually are not messed up, but the prudent owner will check. IRAN the engine, and the proud owner now has a freshly painted and sealed but run-in engine to do first flight and test program with little to worry over as to break-in or hot running while debugging a new airframe. Find one with out a prop strike? Bonus! Clean it up, pickle it, and hang it on the airplane. If unfamiliar with engine build up, there are lots of videos and short classes specific to Lycomings you can take to learn the process. Maybe the local EAA chapter (we all belong to at least one for this sort of support, right?) has a friendly A&P or Tech Counselor that is willing to look over our shoulder and make sure we check all the boxes and do it right. If car gas is desired and it is not already a low compression version, low compression pistons can be swapped in while it is apart, or do that after the test program. EFII is also an option. Billski I know of Viking Aero Engines and Jan Eggenfellners background. I have used their services recently and been pleasantly surprised at the service I got and the quality of their product. They have been supplying heaps of engines and Jan has all you need to know on their website. I would recommend that people give them a go if they are after engines in the power ranges that they offer. I'm a happy case. #### FinnFlyer ##### Well-Known Member Doing an alternative engine install empathizes the "E" in experimental. Only do it if you like to tinker, enjoy the learning experience and challenges and have more time than money or perhaps like building more than flying. I'm working on my 2nd Mazda rotary install and have (had) three RV's powered by them. I only know Mada rotaries and have no clue about Lycomings and other aircraft engines, but understand they may have their challenges too. As for cost, I lucked out (over a decade of inactivity) and got a factory-new Renesis for$1,000, an RWS 2.85:1 PSRU for $3,000. Add another maybe$1,000 for engine controller, oil cooler, radiators, tubing for engine mount, hoses, fittings etc. and was flying for about \$5,000 in engine install. But easily 1,000 hours in research and work on it; probably a lot more. And I'm still working on improving the cooling in extended climbs on a hot day.

So ask yourself: What is my time worth and how patient am I?

Finn