# Chevrolet engines

Discussion in 'Chevy' started by PTAirco, Jul 9, 2004.

1. Jul 9, 2004

### PTAirco

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Anyone home?????
This topic should be bristling with opinions and questions, so I will try to revive it.

I am designing and building a two seat biplane which will use the small block Chevy in a direct drive mode. I intend to use a crate engine, iron heads, hopefully an Aero Carb, small dia. headers, a towing cam and a basic electronic igntion, with duplicated coils and modules.

The prop drive will be driven through a bellhousing (to be chosen still), a short flanged shaft which bolts to the flywheel (lightened?) and an endplate which will carry a hefty taper roller bearing to take thrust and gyroscopic loads, and a conventional hub. I will probably use an Ivoprop until I can determine the best pitch for the engine, but eventually I want to use a wooden prop in keeping with the rest of the airplane.

Any thoughts on this? (Other than; it will be heavy...). I would like an exact weight for the small block, I cannot believe this, the most popular engine in this country and no one can tell me an exact figure! I am starting with 500 lbs.

Radiator will be up front a la Curtis Jenny and the like .

2. Jul 11, 2004

### orion

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The real issue of engine installations is not so much the engines, as it is the reduction dirve. Too many out there are inadequate, despite company claims. There are however one or two that I would be willing to sit behind so I think this powerplant could be a good one if a good package was developed by a reputable company.

Your initial choices sound reasonable however I think that personally I would tend to spend the extra bucks for an aluminum block and heads - if I recall right, the savings for the block and the heads could be as much as 100 pounds.

Your intention of doing a direct drive is a feasible solution but keep in mind that on an airplane, torque is everything. By going direct drive you sacrifice two things - first, by keeping the rpm low you will not get as much power, and also not as much torque as you could with a redrive and a somewhat higher rpm of operation. The towing cam is the ideal choice but I would also recommend some type of boost, be it turbocharger or supercharger. Both options can be invaluable at generating torque at the low rpms.

Don't forget the forged 4340 crank.

Finally, I would strongly recommend against attaching the output shaft directly to the crank (flywheel). That system is not designed to take the feedback from the prop and most likely what you'll end up with is a split crank, even a forged one. In a car there are many components that attenuate feedback frequencies, pulses or other fatiguing elements, of the drivetrain. In an airplane, you do not have these systems so it is important to, as much as possible, isolate the output shaft and prop from the crank. You'll need to design some form of visco-elastic coupler to protect both, the engine and the outputshaft/prop.

3. Jul 12, 2004

### PTAirco

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Reutput shaft

The method of attaching the propshaft directly to the flywheel was used in some Ford Model A and B conversions if I recall. A short kind of bellhousing held a thrust bearing at the prop hub.

Here in Corona,CA there used to be a scaled down version of a Hawk P6 (subject of several articels in magazines) that used a small block crate engine with something like an extended hub attaching the propeller directly to the flywheel. Now even to my amateur engineer mind this seems a thoroughly bad idea; there was no consideration for the reversed thrust loads on the crank and of course the rear main bearing took all the gyroscopic loads, probably amplified by the long prop hub.
However, it appeared to work just find and had many trouble free hours flying. I know that if something "works" it does not mean it is good engineering.

Back to the output shaft: I considered using a flexible coupling, but that would mean another bearing and a means to hold it. A solidly attached flanged shaft surely would act no different than a one piece crank? Why would it behave any different than say, a Lycoming crank which does not even have the benefit of a flywheel? And would not the prop itself add to the flywheel effect? I understand perfectly the need to isolate output shafts in reduction drives, but a crank extension that is effectively part of the crank? I know it changes the torsional characteristics of the shaft, but how and wether it is in the range I intend to operate is anyone's guess and I doubt if even a FEA analysis would be of more benefit than simply trying it out. (On the ground I hasten to add...)

Vibration engineering is not anything I know much about nor pretend to; my field is more traditional airframe structures.

Regarding the weight issue: the way I look at it is this: my airplane will weigh about 1250 empty with a 250 lb payload. It is a traditional layout biplane which has all the known inherent advantages and disadvantages that brings with it; it will be draggy and slow, but maneuverable and fun to fly. Efficiency is not the key element in the design. If my engine installation weighs in at 600 lbs as opposed to 400 if I used a more lightweight engine, that means an extra 20 square feet of wing area at my design wing loading. Just how much of a performance penalty would that involve? And how much would dragging those extra 20 sq.ft through the sky cost me in the sheer enjoyment of flying an open cokpit biplane? Plus the cost of a crate engine or long block kit in aluminium is several thousands more; certainly more than double. I will never buy a Lycoming or Continental and not only because I cannot afford them; I just like the experimenting. (And they look hideous, in my opinion, on the front of any biplane...)

4. Jul 12, 2004

### orion

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The problem with many of these "experiments" is that from a practical sense it may work but, from an engineering sense, you really don't know how well or more importantly, how long. The reason the Lycs and others work with a directly coupled prop is because the sytem was designed so that it could absorb the loads and not overstress any part within (there the prop is the flywheel). Not so with an automobile derived engine.

Maintaining the flywheel may help however, as you indicated, this is a torsional spring system and as such, would require a good level of familiarity with the problem in order to get a proper analysis. At this point then, the decision you will have to make is how comfortable you feel about the approach you propose. Keep in mind that ground testing can approximate the flight conditions only to a limited degree. My feeling then would be to proceed in the most conservative manner possible, even if the added components would add the few bucks here or there.

As far as the weight is concerned, I'll tend to agree, as your performance goals seem to be such that the extra weight will not significantly affect the overall goals of what you're trying to achieve. I also agree that using a flat engine in biplane configurations that have round noses does detract from the classicly oriented goals. Will the front mounted radiator still keep the aesthetic?

As a possible alternative to automobile engines (or at least auto engines from auto sources) you might also want to take a look at airboat applications. There are several companies that deal in "crate" engines but they seem to be selected specifically for the airboats. I think this could be a possibly good way to go since in normal service, the airboat engines see a significantly higher set of loads and a worse environment than anything your airplane will most likely encounter.

As a side note, these airboat companies also use reduction drives developed specifically for the harsh use of the boats. It may be possible to use these drives directly or at least modify the drives for aircraft use. I'm sure they would be less expensive than some aircraft reductions and the end result would be that you could swing a larger prop, which I think might scale better to your design goals.

5. Jul 12, 2004

### wally

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Our local EAA chapter pres. has his direct drive Chevy 350 flying now. First flight was in April I think. He is using a stock aluminum Camaro LT1 engine with a 4 blade warp drive prop.

He bought the engine used - don't know if he even tore it down to look inside it.

The prop extension looks to be about 6 inches, maybe a little more. The prop is mounted to an aluminum standard transmission flywheel. Engine is mounted backwards from a car.

The radiator is mounted below the engine at an angle with a duct to guide air to it.

It makes for a square and not very aerodynamic airplane front, however he has less that 10K in the whole thing. the short exhaust stacks are cool looking and sounding tho.

It is not very fast, about 125kts. but his whole purpose was to see if he could do it and make it fly. He had to buy a bunch of books about the Camaro electronics in order to wire up the computer and re-do the electrical harness.

He did! Maybe you can too.

Wally

Last edited: Jul 12, 2004
6. Jul 12, 2004

### StRaNgEdAyS

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If I wan't currently running on my server at the moment (I lent the processor from my computer to my mother while a couple of new ones come in on order from Brissy) I'd be able to give you a link to a guy who is making what appears to be a pretty good small block redrive.
The chevy is an awesome power plant, plenty of lazy low down grunt. The only drawback I could see is the weight issue, but then if that really does not bother you, then go for it!

7. Jul 14, 2004

### PTAirco

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Aesthetics and engines and airboat re-drives

Our type of aircraft generally are not built with the aim of extracting the ulimate efficiency from them or the most MPG or pennies per seat mile, so in my mind the aesthetics of an airplane are high on the list. Now that is a subjective thing; to some a Lancair is a beautiful aircraft with its clean,sweeping lines but it leaves me cold wheras something like a Supermarine Walrus looks to most like an ugly duckling, but I love it.
The engine used to me has a big influence and I in trying to emulate a late 1920's look a flat four engine is simply incongrous. I hate to see a Bucker biplane spoiled with one of those or a Lakes, in name of practicality. To me only inline, V, or radial engines belong on the front of a biplane.
Airboat redrives seem to be out there in planty of designs and some look well-proven, most hover around the $2000 mark. Which actually is starting to look reasonable. Belts seem the most common choice, I personally like a fully enclosed gear or chain type. As my airplane is a design exercise in simplicity I will forgo the temptation of a redrive for now. 8. Sep 26, 2004 ### jdhogg ### jdhogg #### Member Joined: Sep 25, 2004 Messages: 13 Likes Received: 0 Location: oregon buick V6 ya might also consider a buick V6 engine,i believe its a 3.1 they are unbalievably tough and fast as hell.they are quite a torque monster,hell they drag race em with alot of sucess.also ya will save on weight and size of the engine 9. Oct 2, 2004 ### Alaskan ### Alaskan #### Member Joined: Sep 26, 2004 Messages: 7 Likes Received: 0 Location: Fairbanks Alaska There are 3 basic problems with using a automobile engine built for a car in your airplane. 1) The bearingd in the engine were not designed to take the thrust of the propeller on them so you need something else to take the thrust.2) an automobile engines cam is designed to produce max torque (thrust) at 3500+ RPM. to combat both of these problems at once you should use a re-drive unit to take the thrust and re gear the unit. Hre is a link to one I have been looking at. http://www.firewall.ca/main.html the third problem you need to address ar the clearences for the pistons and rings. The stock clearances are to tight because they were designed with a lower cont. HP output. Your higher sustained HP output will produce more heat and cause them to expand more so you need more clearances. Look at the clearances for a Sprint car. also I would add a forged crank, pistons and the strongest rods I can afford. Here is a link to a company that builds shevy 350 engines for aircraft http://www.team-38.com/ I hope this information is usefull Almost forgot the chevy 350 weighs about 440lb installed. you can drop about 125lb if you use an aluminum block and heads Last edited: Oct 2, 2004 10. Jan 29, 2005 ### Phil Fowler ### Phil Fowler #### New Member Joined: Jan 28, 2005 Messages: 3 Likes Received: 0 Location: Rangiora ,NewZealand There's a book out by Richard Finch called Converting Auto Engines For Experimental Aircraft. Worth while read for those thinking down this line. I'm presently building World War 1 fighter replica. Planning to use 400cu in Chevy with a "industrial" cam. This will be one that will limit the rev's while giving plenty of torque at low(max 2200) rev's. 11. Jan 29, 2005 ### org ### org #### Well-Known Member Joined: Mar 14, 2004 Messages: 71 Likes Received: 0 Location: Castle Rock, CO Hi Phil, are you saying you'll run it at a max of 2200 or the peak torque will be at a max of 2200? 2200 is where even the mildest of engines is just getting started into it's power band. Either way, you'll be giving up at least 80 to 100 reliable horsepower. Even if you plan to run a direct drive setup, you could run 2800 or so and still use a standard aircraft prop. People that say an automobile engine can't last putting out 200 plus horsepower for hours at a time are ignoring the marine versions of Chevrolet and Ford V8s and V6s. These engines use almost the identical profile that's required in an airplane: Max power initially, then high horsepower at 3500 to 4000 rpm for cruise. org 12. Jan 29, 2005 ### org ### org #### Well-Known Member Joined: Mar 14, 2004 Messages: 71 Likes Received: 0 Location: Castle Rock, CO Phil, excuse me for not reading your post more closely. What you're looking for is a low rpm engine swinging a fairly large prop, right? The only drawback MIGHT be the weight. The engine with iron heads will be close to 550 pounds without whatever drive you use. If you need the weight, so much the better. org 13. Jan 30, 2005 ### Alaskan ### Alaskan #### Member Joined: Sep 26, 2004 Messages: 7 Likes Received: 0 Location: Fairbanks Alaska If you want to look at a route like that you could use all of the dispacement you can get without adding weight. A "Tall" short block can help by adding as much as .600" to the stroke of a 400 block an end up with a 450cuin and an aluminum block and aluminum heads to save a hundred or so lbs. http://www.flatlanderracing.com/dartalumblocks.html 14. Feb 15, 2005 ### cj357 ### cj357 #### Member Joined: Oct 6, 2004 Messages: 15 Likes Received: 0 Location: Wisconsin I have a lot experience with SBC engines among other GM engines. GM makes a stroked high torque version of the 350. The create motor is called the HT383. It has a NEW 4bolt main block, vortec heads, AL intake, forged 4340 steel crank and rods. The motor produces 430 ftlbs. of torque at 3200 rpm and 340hp at 4500 rpm. This create motor goes for around$4,000. As for weight, 550-560lbs. is about right.
Personally I would go with a reduction drive. A direct drive spinning a large prop at 2200-2300rpm will only produce about 150hp. Also I would HIGHY recommend an oil cooler!

jdhogg
As for the Buick V6, it's a 3.8L turbo. Its an OK motor but had problems w/the oil system. It was not uncommon for the non-turbo motors to throw a rod at 60,000mi. I would NOT use this in an aircraft.
Hope this could help,
Chris

15. Feb 26, 2005

### Phil Fowler

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Sorry for my lack of reply. Lost my password and generally stuffed things up.
The plane I'm building is a World War 1 replica. It was originally powered by a Hispano Suzia V8 of about 11.5 litres. It turned a maximum horse power of 220hp at approximately 2000rpm. Propellor diameter of 8ft. Engine weight was about 530lbs dry.My plan is to build a replica aircraft and turn a original sized propellor (dia & pitch).
There is always a second alternate in the form of a Chevy 4.3L Vortec V6 on a reduction drive.If I can by pass the extra work and associated hassles of a reduction drive by going direct I'll definately look at it. I know that the V6 option will probably be lighter, so I plan to build firewall aft do a weight and balance, then choose from there.

16. Feb 28, 2005

### cj357

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4.3L

The 4.3 is a good motor. It basicly is a 350 with out the #3 and #6 cylinders. I know on th non-Vortec pre 92' many of the parts were interchageable. A car magizne did a buid up on one. They went through all the interchangeable parts. They were able to produce 300hp on 9:1comp. Then they supercharged it to 500hp. before the head gasket blew. I have this list if you are intrested.

Chris

17. Jun 15, 2005

### pulse

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Think Aluminum

Chevy LS1 V8 300+ HP LS6 400+ hp
Very light, Very strong.

I have an LS1 in a car with 167,000+ miles that I drive hard. No signs of wear or oil consumption at this milage. Very relilable too

Someone needs to look at these for aircraft use, they are all aluminum with composite intakes.

18. Jun 18, 2005

### Pete

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Re: 4.3L

It was the August 2002 issue of "Hot Rod". This engine, all iron, weighs in at about 425# including induction and exhaust, but you could get that below 400# with aluminum heads and wayyy down there with a nice expensive aluminum block.

300hp at 5600rpm
275hp at 4600rpm
250hp at 4200rpm
200hp at 3600 rpm

They felt that the buildup was easily strong enough to turbocharge to 400hp. Their total cost was \$3000. Sounds like a viable solution to me in the 250hp range, 300hp turbocharged, for a conservative, long-lived power output.

19. Jun 18, 2005

### rampeyboy

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I am thinking aluminum V-8 also, but the traditional Gen 1 engine. 350 al block and heads, low rpm torque type cam, small port heads for low rpm ops. I'd like to make around 250hp, and gobs of torque, way down in the rpm range, with V-8 smoothness. I'd still use a PSRU to help dampen harmonics and protect the crank.

20. Jun 19, 2005

### Midniteoyl

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Re: Think Aluminum

Several peeps are selling these

http://v8seabee.com/