# Small block Chevy Ideal Setup

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#### Dan Thomas

##### Well-Known Member
I must be rather ignorant on this subject,,, but...

I thought a "TBO" was just a suggestion from the manufacturer and not a "set" number mandated by the FAA to rebuild a motor

Who does one go to the "apply" for a TBO extension ? and

Who actually grants that extension ?

Ben.
The TBO is a hard number for a Commercial operator. The Private operator can exceed it, and a Commercial operator can apply to the respective government for extensions. In Canada we can get a 10% extension, and Lycoming will allow another 10% if the engine is operated at least 40 hours per month. Or the engine can be operated "On Condition" for periods far longer than that but the maintenance and monitoring requirements go up. I think the FAA in the US will permit similar stuff.

Dan

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#### Toobuilder

##### Well-Known Member
Log Member
...The TBO is a hard number for a Commercial operator...
Right. I read about an air taxi operator who had very standardized procedures over a very standard route. IIRC, they used Lycoming 540's and were able to eventually bump the FAA mandated "hard" TBO up to around 2600 hours, and were working on 3000 based upon the actual condition of their engines on teardown.

#### Toobuilder

##### Well-Known Member
Log Member
Interesting............... I know of several 172's and 182's that are used in training that are WELL past TBO and are flown every day for flight training by commercial operators...... Must a Canada thing you speak of...
If these are US operators and the airplanes are flown for hire, then the TBO is a hard requirement.

#### TFF

##### Well-Known Member
TBO is only required for 135 OPS. One of the flight schools here flew one of their 172 4000 hrs. The mechanic told the owner I gave you a free engine so now it is time to buy one. The engine had minimal wear when torn down. The plane flies every day; one that sits wont make that. 135 operators can ask the FAA for extensions if they have the data to prove it. I think the old radial operators had some of their engines TBOed at 4000.

#### Toobuilder

##### Well-Known Member
Log Member
That's interesting. My only "professional" (as in "hired") experience as an A&P was at the Beale AFB Aero Club - a Part 141 school. We were required to replace at TBO. Google search turns up a Beale document outlining Military Aero Club regulation - and the "replace at TBO" is a military requirement.

So it seems that the Government run 141 schools are held to a different standard than the rest of us. Good to know.

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#### TFF

##### Well-Known Member
There is the insurance question of if I go past TBO will it be covered? Insurance runs the world. Also a gov run anything is not going to contradict any other gov rule, even if they can legally.

##### Well-Known Member
But when they are managed well, aircraft engines generally give exemplary service. There are more than a few Lycoming operators who have applied for TBO extensions far in excess of factory numbers and routinely get them.
I recently read (I think in one of the German magazines) that one of the flight schools in the US got something like an 10K hour MTBF for their injected lycomings or continentals. That's up into turboprop territory. Anybody who knows of some more data on MTBF figures in real operation?

#### Toobuilder

##### Well-Known Member
Log Member
Just as an effort to steer this thread back on course, there are plenty of justifiable reasons to try an auto conversion, but getting "better" reliability is not one of them. There are several components that you can make a reasonable translation from car to airplane in terms of MTBF (alternators, fuel pumps, electronic ignition, etc), but the duty cycles of the powerplants as a whole are vastly different.

E

#### ekimneirbo

Re: Small block Chevy Ideal Setup Overthinking this thing

I guess right from the beginning anyone who wants to build an automotive engine powered airplane should get used to the fact that there are going to be a lot of well meaning critics..........

Instead of overthinking this, lets simplify it.

Even if anyone believes that an airplane engine is reliable, you must admit that it takes far more maintainance and money to purchase and "maintain" them. Virtually everyone who has been fooling with airplanes for a while knows someone who has had to perform an expensive repair on an airplane engine before it reached TBO (cyl replacement, mag ohaul, valve replacement...anything that would cause the engine to quit).
On the other hand, the biggest percentage of pilots would have to think long and hard to remember anyone who in the last ten years has had to have their automobile engine repaired beyond any of the normal wear items. Once started, these engines just don't quit....and each of us knows hundreds of people who own cars compared to only a handful who own airplanes. The percentages
overwhelmingly show that automotive engines are far more reliable.

A Lyc or Continental has a propellor performing all thesame gyrations to them that the prop is going to apply to the automotive engine. The cranks in these engines will routinely last thru 5000 or more hours of the propellor abuse with nothing more than (Lyc) an aluminum surface in the front of the crankcase absorbing thrust, and two bearing surfaces a couple of inches apart, absorbing the twist and side forces.

If someone builds a small case that emulates the end of the case in the Lycoming and allows the propellor to be connected to the rear of the engines crankshaft (via splines like the Cont GO-300),then there is no reason it can't be made to work. Its not magic, its just mechanics.

In order to make it work successfully in an airplane, weight is also going to have to be considered.In a proof of concept, someone might use inexpensive parts combinations but when it comes time to make the final combination, somewhat better parts will be needed.Even though everyone wants to build a cheap airplane engine, the actual parts used are going require some outlay above the basic overhaul of a junkyard dog. I feel a very good 415 cu in LS based engine could be assembled for less than $6K...........certainly not cheap, but not outlandish either. Depending on someones ingenuity and resources, a good direct drive could be built for maybe$2500.

There are probably less expensive ways to make a direct drive, but it does take some figurin.....

To me these are the basic parameters that someone should consider reasonable outlays.

##### Well-Known Member
Re: Small block Chevy Ideal Setup Overthinking this thing

Even if anyone believes that an airplane engine is reliable, you must admit that it takes far more maintainance and money to purchase and "maintain" them. Virtually everyone who has been fooling with airplanes for a while knows someone who has had to perform an expensive repair on an airplane engine before it reached TBO (cyl replacement, mag ohaul, valve replacement...anything that would cause the engine to quit).
On the other hand, the biggest percentage of pilots would have to think long and hard to remember anyone who in the last ten years has had to have their automobile engine repaired beyond any of the normal wear items. Once started, these engines just don't quit....and each of us knows hundreds of people who own cars compared to only a handful who own airplanes. The percentages overwhelmingly show that automotive engines are far more reliable.
Yes, that's true. But cars don't see the frequent abuse of aircraft engines. Standing months at a time in a cold hanger, then being warmed up and run at WOT for a major part of the time. Cars on the other hand are usually driven daily and don't see more than 10-15% average load. I've you've ever seen the disastrous effects on engine oil of this type of abuse in a motorcycle engine for example, the lack of (perceived) aircraft engine reliability really isn't that surprising and you can't "solve" that by using a car engine.

An aircraft engine that's used as a car engine (daily), will do far better as a car engine, possibly even considerably better.

#### WonderousMountain

##### Well-Known Member
So, what you're saying is we have to fly daily, and under 50% power or we'll lose reliability. Well, if we're flying daily, most of us will need to be using minimum power to keep from prohibitive fuel cost.

So we'll be out to fly the airplane every morning as some people walk the dog!

There is a solution, i don't know what it is, but it's around here somewhere trust me!

#### Wagy59

##### Well-Known Member
Re: Small block Chevy Ideal Setup Overthinking this thing

Yes, that's true. But cars don't see the frequent abuse of aircraft engines. Standing months at a time in a cold hanger, then being warmed up and run at WOT for a major part of the time. Cars on the other hand are usually driven daily and don't see more than 10-15% average load. I've you've ever seen the disastrous effects on engine oil of this type of abuse in a motorcycle engine for example, the lack of (perceived) aircraft engine reliability really isn't that surprising and you can't "solve" that by using a car engine.

An aircraft engine that's used as a car engine (daily), will do far better as a car engine, possibly even considerably better.
Personally, I'm not trying to "solve" the airplane engine problem by using an automotive engine...other than maybe cost over time....Also, car engines receive all kinds of constant abuse and neglect and still run well for an amazing length of time, so i think the idea that auto engines typically don't work hard compared to airplane engines is a myth. There are guys that use auto engines for marine use and I knew a guy that ran a chevy v8 in his boat, every weekend for over a decade before he did anything to the engine...I think he went thru several props and a battery and alternator but other than that nothing...change the oil and put gas in it...so when I read all inclusive statements about auto engines dont see the abuse an airplane sees, and that's why car engines last so long, I tend to think that's baloney:ban:..or bananas?

#### billyvray

##### Well-Known Member
Re: Small block Chevy Ideal Setup Overthinking this thing

Why does every thread about someone wanting to use an automobile engine in an aircraft deteriorate into arguments over people's differing opinions as regards to the reliability.

I for one am just interested in the project and would like to see what develops. It is frustrating having to wade through everyone's irrelevant opinions.

~Bill

#### GrizzlyV6

##### Well-Known Member
Re: Small block Chevy Ideal Setup Overthinking this thing

Why does every thread about someone wanting to use an automobile engine in an aircraft deteriorate into arguments over people's differing opinions as regards to the reliability.

I for one am just interested in the project and would like to see what develops. It is frustrating having to wade through everyone's irrelevant opinions.

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~Bill

You sure said a mouthfull there Bill. What I've noticed here is the overwhelming amount of engineers on this forum who need to tell us how much they know about the subject. There is one person on here who had to question how I was getting more than 175hp out of my 4.3 v6. All I could think of to say is "YOU DON'T KNOW DO YOU"? Personally, I have never seen an "aircraft" engine on one of the scale p-51 mustangs, but, the scale mustangs I have seen have all been powered by auto conversions. Obviously, I'm sure someone out there knows of one. I don't care. I do know that the auto conversion movement is so big that it cannot be ignored and those with the proven track records hopefully will continue into the future when the economy recovers. These engineers will continue to argue their point with those of proven success, that will never change. All we can hope is that they will one day just go away.

Jim

#### Himat

##### Well-Known Member
Re: Small block Chevy Ideal Setup Overthinking this thing

Cars on the other hand are usually driven daily and don't see more than 10-15% average load. I've you've ever seen the disastrous effects on engine oil of this type of abuse in a motorcycle engine for example, the lack of (perceived) aircraft engine reliability really isn't that surprising and you can't "solve" that by using a car engine.

An aircraft engine that's used as a car engine (daily), will do far better as a car engine, possibly even considerably better.
The load on a car or aircraft engine is very much depending on how you look at it. The average kW used/cylinder sweept volume is maybe pretty much the same in a car and in an airplane. (A 360 aircraft engine should be god for 300 - 500hp at around 6000rpm as is a car 350 V8. But both are mostly run at 2000 to 2500rpm delevering maybe 75 to 125hp.)

And I am not sure the aircraft engine is that well suited for cold start at -20 celsisus (or lower) twice a day in the winter, run flat out in a pick up truck hauling a trailer upphill, then shock cooled on the downhill side, repeated on one trip, and other "car engine" use.

##### Well-Known Member
Re: Small block Chevy Ideal Setup Overthinking this thing

These engineers will continue to argue their point with those of proven success, that will never change. All we can hope is that they will one day just go away.
A forum is exactly the place to discuss things. With everybody, not just with those who's opinion we agree with

Neither the "car conversions suck and can't possibly work" nor the "car engines are cheaper/more reliable/cheaper/better/more powerful" simplistic views are true. Car conversions certainly can work, as witnessed by many VW's, Subaru's and smaller numbers of other engines. But there are many issues you have to deal with and essential to solving them is understanding the massive difference in operation(al environment) between car engines and aircraft engines, hence my last remark.

Given the large portion of pilots who think "car engines are far better/cheaper", considerable flak is expected, because in reality you're unlikely to do either of those given the historic track-record. That certainly shouldn't prevent people from building them, but a more realistic view, conflicting with the "car engines are better because -analogy" is what causes the often rather intense discussions.

For an on-topic discussion it's usually best to stay absolutely on-topic and ignore the simplistic analogies and limit the discussion to how to build/design/modify your car engine for a suitable aircraft application.

#### GrizzlyV6

##### Well-Known Member
Re: Small block Chevy Ideal Setup Overthinking this thing

Yes, that's true. But cars don't see the frequent abuse of aircraft engines. Standing months at a time in a cold hanger, then being warmed up and run at WOT for a major part of the time. Cars on the other hand are usually driven daily and don't see more than 10-15% average load. I've you've ever seen the disastrous effects on engine oil of this type of abuse in a motorcycle engine for example, the lack of (perceived) aircraft engine reliability really isn't that surprising and you can't "solve" that by using a car engine.

An aircraft engine that's used as a car engine (daily), will do far better as a car engine, possibly even considerably better.

You've got to be kidding me. If you actually knew what you're talking about, you wouldn't have have said it.

Jim

#### stol

##### Well-Known Member
Re: Small block Chevy Ideal Setup Overthinking this thing

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