# Why aren't more auto engines being used

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#### aerhed

##### Member
Regardless of all the extra work, it costs a lot of actual money (excepting VW low HP stuff). I can do this easily: 1) 320 core, $3k. 2) Case, crank, cam, tappets, bearings$1500. 3) Cylinders +10 to stud assembly $1000. 4) Valves, keepers, rockers redone, rods redone, gasket set$1250. 5) misc bolts, nuts, etc $100. Total under$7k for 2000 hours of dependable 160HP. Find me a car engine that will even come close.

#### aerhed

Oops, oil pump gears $300? #### mcrae0104 ##### Well-Known Member HBA Supporter Log Member Quite a few Mazdas turning in the 150-300HP range. 200 is average for naturally aspirated. Yes--the only thing is, nobody has made the Mazdas, Subarus, etc. quite as accessible (except for a few turn-key options) as VWs and Corvairs. With either of those, you can pick up a manual, and follow the directions of people who have worked out and tested them--including cooling, oil systems, induction and carburetors, motor mounts, electrical, starters, etc. Nothing wrong with the other auto engines though if they're your cup of tea. We all have decisions to make regarding water cooling, direct-drive vs. PSRU and the like. I wouldn't fault anyone for his own decision. #### mcrae0104 ##### Well-Known Member HBA Supporter Log Member Total under$7k for 2000 hours of dependable 160HP.
Maybe you should go into business if you can deliver an O-320 at that price (or somewhat higher for labor & profit).

#### Vigilant1

##### Well-Known Member
Maybe you should go into business if you can deliver an O-320 at that price (or somewhat higher for labor & profit).
Well, many people will want a few other things that didn't make the $7k list...like a carb, perhaps an ignition system, an alternator, etc. We might be a few dollars higher with those spiffs. But, if the whole thing could be assembled and a 100 hour warranty given, I'd bet folks would pay over$12k for it. Or just put all these easy-to-get bits in a box with a good assembly manual and DVD for $9k. And yet, apparently nobody can make money doing that. Hmmmm.... #### StarJar ##### Well-Known Member Thinking about it, a simple shaft extender/bearing/thrust bearing/hub sure would be nice for the little Suzuki engines. Tap and bolt it to the case. The parts could be less than$150. You could get people in the air for less than $1000, with a smooth light engine... #### ekimneirbo ##### Banned Thinking about it, a simple shaft extender/bearing/thrust bearing/hub sure would be nice for the little Suzuki engines. Tap and bolt it to the case. The parts could be less than$150. You could get people in the air for less than $1000, with a smooth light engine... Exactly what I would like to see happen. The problem has always been concern over the engine bearings not being capable of coping with the the torsional gyrations of the propeller......not the engines reliability. Most people felt you had to employ a reduction drive and spend lots of money. Often the reduction drives fared no better than the crankshaft/bearing assembly. Corvairs have proven the simplicity of a 5th bearing, so it should be a solution for other engines too. #### Dan Thomas ##### Well-Known Member Maybe you should go into business if you can deliver an O-320 at that price (or somewhat higher for labor & profit). Lycoming can build a whole new engine for less than that, probably. But they can't just mark it up 25% and sell it to you. They have huge liability exposure issues to think about, as do the people who provide them with carburetors or FI, magnetos, alternators, spark plugs, and so on, and every one of these outfits has to buy fat insurance policies at fat premiums to protect themselves. That$7K engine can turn into a $40K engine in a big hurry. #### Vigilant1 ##### Well-Known Member Lifetime Supporter Thinking about it, a simple shaft extender/bearing/thrust bearing/hub sure would be nice for the little Suzuki engines. Tap and bolt it to the case. The parts could be less than$150. You could get people in the air for less than $1000, with a smooth light engine... Maybe it will work, but I think it will need to be priced higher unless this is a charity. And if we add just two gears and a damper (what, another$100 in this construct ?) we can double the horsepower and take the TV. Except it really costs about $2k. Last edited: #### ekimneirbo ##### Banned You keep asking that question in every thread you start or answer. Unless you got one turning a prop to prove we are wrong, why keep hitting the same points with no satisfaction? I have already seen you be wrong many times in the past. I'm not sure why you think it's of any importance to me or anyone else to prove you wrong yet again.....or for some unknown reason gain personal satisfaction from your being wrong. I do have to wonder why you continue to read my posts if you find them so redundant. Usually your comments provide nothing in the way of thread related content.....just as this one doesn't. If you decide to be objective instead of objectionable, your posts might actually have some value to add to the thread. #### StarJar ##### Well-Known Member Maybe it will work, but I think it will need to be priced higher unless this is a charity. And if we add much just two gears and a damper (what, another$100 in this construct ?) we can double the horsepower and take the TV. Except it really costs about $2k. These engines are heavier than I thought. Looks like about 160 lbs. without any drive. So maybe not so wonderful without the reduction you suggest. #### Peterson ##### Well-Known Member Yes--the only thing is, nobody has made the Mazdas, Subarus, etc. quite as accessible (except for a few turn-key options) as VWs and Corvairs. With either of those, you can pick up a manual, and follow the directions of people who have worked out and tested them--including cooling, oil systems, induction and carburetors, motor mounts, electrical, starters, etc. Nothing wrong with the other auto engines though if they're your cup of tea. We all have decisions to make regarding water cooling, direct-drive vs. PSRU and the like. I wouldn't fault anyone for his own decision. True, VW and Corvair engines are converted so much you can get step by step instructions plus all the specialty conversion parts quite easily. I'll admit to even being drawn to Corvair conversions myself (even with those evil piston thingies inside), however, these are good for about 100HP. Mazdas get twice that, and are very cost effective for that power range. Lots of headache due to requiring liquid cooling system and one off engine mounts, but that's the price of going cheap: added hassle. #### mcrae0104 ##### Well-Known Member HBA Supporter Log Member Yeah, they're in different power classes. Not that it changes that fact, but you might want to stay tuned to flywithSPA.com, which has recently begun testing a 3.3 liter Corvair stroker. Word is that it has been dyno'd and results may be announced at OSH. It would be great if someone did for the Mazda what has been done for the Corvair (extrensive testing, standardization, documentation, and conversion parts sales). I'd be tempted. #### trifoils ##### Well-Known Member Every RAF2k gyro I've seen has a subaru 2.2l with a very simple belt driven PSRU, sometimes all controlled by the factory ECU injection system. I have a 95 legacy with one of these in it and it's about the smoothest running vehicle I've ever owned (220k on the odometer and still going strong, but leaking oil). #### Vigilant1 ##### Well-Known Member Lifetime Supporter It would be great if someone did for the Mazda what has been done for the Corvair (extrensive testing, standardization, documentation, and conversion parts sales). I'd be tempted. The closest we came was Tracy Crook and his "Real World Solutions." He made a good PSRU for the 13B, he made an ECU, he published a conversion manual and sold specialized parts (apex seals, etc), and he provided handholding to those converting Wankel engines to airplane use. Best of all he flew it all himself, building thousands of flight hours. He had many satisfied customers. Still, it took him a long time to gain all that expertise and design those things and I doubt he made 50 cents per hour for the time he spent building and selling the stuff. Nobody could do it and hope to support themselves financially, it has to be a pseudo hobby. Auto aircraft conversions are a tough business to be in, nearly impossible at the "cheap" end due to the low volume. #### Turd Ferguson ##### Well-Known Member Lycoming can build a whole new engine for less than that, probably. But they can't just mark it up 25% and sell it to you. They have huge liability exposure issues to think about, as do the people who provide them with carburetors or FI, magnetos, alternators, spark plugs, and so on, and every one of these outfits has to buy fat insurance policies at fat premiums to protect themselves. That$7K engine can turn into a \$40K engine in a big hurry.
Some companies have wised up and can play the game too! Tempest, for example bought the rights to the AC line of spark plugs, made a huge improvement in design and now manufacturers those spark plugs with their name on them. The "manufacturing" facility is amazingly simple. Rented building and couple of CNC lathes. The stock is hex bar stock. It's all run under a separate LLC. When I was doing IA training, a rep had a video and said if they get sued they are closing the doors, TU. No insurance. There are almost no assets. Then they will be back in business under a new name/LLC within 3 months.

#### Turd Ferguson

##### Well-Known Member
My grandfathers and my father were all mechanical sorts, and my Dad's Dad ran his own machine shop. I can still do that stuff and many of the guys I grew up with could and can still do it. I made sure my son was able to do it, but my son is a rarity among his peers. Most of them probably couldn't change the oil in their cars, much less build the boats and other things he's made or fix their own cars and motorbikes and those of the people around him that bring him things to fix. He has machines like a lathe and milling machine that many of his friends probably couldn't identify.
I have been teaching my son how to run a lathe and milling machine, the old fashioned way. I just want him to understand when he opens a box from the parts store, where those parts came from. They just don't magically appear on the shelves in an Autozone warehouse. He is proud of the fact that we can build things from raw materials, like you say a concept lost on many today.

#### ekimneirbo

##### Banned
I'm not biased but I am cognizant of reality. It is "easier" to install a certificated engine because the basic process is "purchase a used engine, mount it in an airplane and bolt a prop to it."

While that may be oversimplifying, the actual process is still "easier" than installing a converted auto powerplant (and a minor nit, just because one installs a certified [sic] engine into a homebuilt, does not make it 'formerly' certified [sic] engine)

To further show that I am not biased, I know of converted auto powerplants that have successfully flown ranging from 10 - 1000 hp.

Some people are just not interested in developing a powerplant from a converted auto engine. I'm cool with that. For those that are interested, show me what you got cause I'm interested too!!
Turd, your reply is a perfect example of what this thread was an example of, well meaning

persons who turn people away from the automotive engines by spreading misinformation. First, let me

clarify the fact that many conversions can prove to be time consuming. They can also be simple and they

can also prove to be more efficient, more economical over time, smoother, more powerful, and even more

fun. Anyone with a conversion will probably attest to the satisfaction of having done it themselves. One

thing you must accept is that only certain homebuilt airplanes have established common solutions to the

problems all home builts present
. Most certainly, Vans has such a large following that there is virtually no

component you can't purchase rather than build, and no problem that a solution hasn't been found. When you

step away from Vans though, its pretty much getting back to having problems and finding solutions on most

other homebuilts...especially scratch builds.

Turd quote : I'm not biased but I am cognizant of reality. It is "easier" to install a certificated engine because the basic process is "purchase a used engine, mount it in an airplane and bolt a prop to it."

While that may be oversimplifying, the actual process is still "easier" than installing a converted auto powerplant (and a minor nit, just because one installs a certified [sic] engine into a homebuilt, does not make it 'formerly' certified [sic] engine)

Eki response: Yes, thats a real over simplification, and thats where it becomes misleading. What you left out is that

First a builder has to be able to find a prospective engine thats the size and type he wants. Often there are not

many available in the builders local area...so he is forced to search the internet, tradeaplane,Ebay, Barnstormers, etc.

Then he must either decide on whether the log book is believeable...if there is a logbook. He must either accept on faith

that the seller is honest, or travel to where the engine is located. Most often he will not get to hear the engine run.

"IF" an available engine is well documented and reasonably low time, he should expect to pay a premium price to get it.

If the engine is missing documentation he should still expect to pay dearly for it. Once he has that engine in his posession,

if it does run properly and have no problems (the exception), he should realize that he should check all the ADs for the

engine and insure they were complied with. Often, they haven't been. He may not be legally required to comply with

them in an experimental, but since its his butt is on the line it would be wise to do so. (). He should then hire ()

an AP to physically inspect the engine. Lets say all went perfectly to this point. Now the new builder should

expect to have the engine inspected () yearly if he wants to maintain its reliability. He should also expect to pay a lot

more for aviation oil that has to be added regularly, and aviation fuel. In the likely event that he flies the engine for

several years he should also expect to replace at least one cylinder () before it reaches TBO. "IF" he does reach TBO

he should then expect to lay out somewhere in the neighborhood of the original used engine cost to rebuild it.()

The builder is usually not looking at the big picture, because its so easy to just "plug n play"......or is it.

Lets think about that. Any engine you install is going to have to have similar controls and systems that need to be

built.
Depending on the type of systems you employ, they can often be simple or complex....builders choice.

All engines are going to require an exhaust system. Will it be any more difficult to make an exhaust for an auto engine than an aero engine. Nope. TOSS UP

What about the fuel system ? well if you use a carburetor it should be about the same level of difficulty. If he decides to use fuel injection it will be more complex but will result in greater efficiency and smoothness and no carb icing.

TOSS UP with Carb HARDER With Injection (but better result when finished)

Motor mount...here again, the difference in building one or the other is a moot point. The aero engine can actually

be more difficult because of the special mounting. In all but the most popular kits a builder should expect to build his own.

TOSS UP (Maybe a slight edge to auto engine because of no complex dynafocal alignment)

Cooling System Here again, the builder will be faced with cobbling up something and making it work. It is not a

given that all aircooled engines will automatically cool well. The inference is that water cooling can be more difficult.

Air cooling often does not work and builders spend equal amounts of time trying to cool their engines
...sometimes

damaging their engines before successful airflow is achieved.

TOSS UP (Maybe an edge to the aero engines because some do cool without problems but you will have to
experiment with many air cooled installations to get sufficient cooling. The water cooling will work
better if done properly....no shock cooling probs or cht probs to ferret out later)

Weight Generally the auto will weigh more but it depends on the airplane and engine of choice. The alum V8

really starts to shine when compared to the larger and exceedingly expensive aero engines. As you move to smaller

airplanes the reduction drives might be eliminated and direct drive used to keep weight down. LS engines are cheap,

Rover engines even cheaper and then there are some nice V6s available too.

TOSS UP I say this because the auto engines will always be heavier in smaller airplanes but they are

generally capable of more power .....thru increased rpms.... to help offset the weight. I give a slight edge to

the aero engine strictly on weight.

Ignition System Both types of engines are going to have to have some type of ignition system. Many/most

builders are going to have an electrical system of some kind.
Even if you have magnetos on the aero engine the

builder will also fabricate an electrical system. Is adding a modern multicoil ignition that comes with the auto engine going

to be any more difficult than building the rest of the electrical system ? Many builders add electronic ignition to their aero

engines anyway. TOSS UP

The Bugaboo This is where the aero engine has the advantage. Adapting a prop to the engine. With the aero

engine you certainly can just bolt a prop on to it as long as you have enough money. Just remember that if you install

one which is not the one the factory recommended , you have changed the resonanant frequency and no longer

know where it exists, or to what magnitude it may be. That affects reliability. Yes you can test other props, but thats the

same situation you have with the auto engine. So prop testing and mounting should ensue.

So Turd, this reply is a real world explanation of "just bolt it on and go flying" . There is a big difference between buying

a new discounted Lycoming for a Vans kit and buying a questionable used engine to install in a plans only homebuilt.

The statement that its much more difficult to use an auto engine is sometimes true, but since building an airplane

requires fabrication of mostly the same components, I think its often overstated. To me the only real difference and

difficulty is how to adapt the propellor to the crankshaft. I feel the 5th bearing idea is reasonably easy for someone

to do. It would be great if someone made a universal 5th bearing and only an adapter plate was needed to utilize it

on various engines.

I still believe that technology is not the biggest impediment to auto conversion success, its the negativity

continually espoused by air cooled engine purists and the oft mis-stated "plug n play" scenario.

I would also like to agree with your statement that " many people are not interested in developing a

converted powerplant", but I hate to think that reason is because they have been misled about the

difficulty of one vs the butter smooth ease of the other.

As for a certified engine maintaining its certification after its installed on an experimental airplane, my understanding is

that it loses its certified status. Maybe there is an exception to the rule, but thats how I understand it.

VS

Which will be the most troublefree starting point for a new builder ?

Last edited:

#### davinc

##### Member
I don't post here often, but I thought this was relevant: