I don’t see the second spark plug per cylinder, but I really like this design. It more closely fits what I envision.

Again, we don’t need cutting edge technology to get antique piston airplane engines into the 21st century. Just solid engineering.

 

4.7L PowerTech has a cast-iron cylinder block with a 4.09 inch (104 mm) bore spacing, a 9.09 inch (231 mm) deck height, and a 90-degree angle between cylinder banks which is optimal for using one crankpin journal for a pair of connecting rods. The engine block was designed from scratch and all dimensions are new. The debuted engine was fitted with a nodular cast-iron crankshaft, which is attached to the block by using a single bedplate instead of five individual main-bearing caps. The bedplate made of compacted graphite iron adds rigidity to the block and reduces noise and vibration. This engine has powder-forged metal, fracture-split connecting rods (the length is 6.12 inches/155.5 mm) and cast aluminum pistons with moly coated skirts. From underneath, the crankcase is sealed by a stamped steel oil pan. While the 3.7L V6 has a balancing shaft, the 4.7L engine doesn't need it.

The engine is equipped with cast aluminum alloy cylinder heads. Between each head and engine block, there is a three-layer laminated stainless steel gasket. Head bolts are 11 mm. Each cylinder head has only two valves per cylinder and one top-mounted, chain-driven hollow camshaft (SOHC design). Intake and exhaust valves are pushed apart, and rocker arms are turned by 180 degrees relative to each other. This configuration allowed to make the shape of the combustion chamber and the arrangement of spark plugs more efficient (almost hemispherical chambers). The diameter of intake valves 1.89 inches (48 mm) and the exhaust valves are 1.46 inches (37 mm). The valvetrain is equipped with hydraulic lash adjusters. Camshaft specifications: the valve lift is 0.443 inches on the intake and 0.429 inches on the exhaust, the duration is 244 degrees intake and 254 degrees on the exhaust. On top of each cylinder head, there is a cast magnesium valve cover.

The engine has an electronic fuel injection system (sequential multi-port injection). The fuel injectors are mounted to the intake port in the head. The new tuned-length runner intake manifold is made of polymer material. The engine speed is controlled by an electronic throttle body (fly-by-wire). The diameter of the throttle valve is 2.56 inches (65 mm). The 4.7 V8 engine also features a modern coil-on-plug ignition system and a hybrid cooling fan system (in-line electric and engine-driven fans).

In 2002, Chrysler introduced a "High-Output" version of the 4.7L PowerTech engine as an option for the Jeep Grand Cherokee Limited and standard for the Overland models. The 4.7L V8 HO features a 9.7:1 compression ratio, high-compression domed pistons, two knock sensors, new camshafts, and tuned intake. This engine has an additional 30 horsepower and 35 lb-ft of torque over a basic engine. In 2005+ Jeep Grand Cherokee, the 4.7L H.O. version was replaced by a 5.7L V8 Hemi, but for some models, it was being offered until 2008. In 2005, the base version also got two knock sensors and other minor changes.

2008+ Model Year

In 2008, the 4.7L PowerTech has undergone significant changes. From the 2008 model year, the 4.7L V8 PowerTech engine has new cylinder heads with two spark plugs per cylinder (by the way, these two spark plugs are not identical). The bottom received new lightweight pistons and forged steel (36MnVS4 material) connecting rods. The compression ratio was increased from 9.0:1 to 9.8:1. Ports in the heads were reworked and now have a better flow. The valvetrain was equipped with a redesigned valve lash adjuster system. The revised 4.7L engine also features a more aggressive camshaft profile, an improved intake manifold with shorter runners, and a 2.91 inches (74 mm) throttle body.

The longest time of using the PowerTech V8 4.7L engine was on the Dodge Ram 1500 - until the 2013 model year.

 

Cut the Crankcase, Tony !
I am sure you can relate to Lee Iacocca. no money.
He asked me to make a V-10 for him, though he could not pay me.
He gave me two "A" engines to use.
I cut one in half and the other one was cut at the last two cylinders.
I welded the two of them twogether.
This was the FIRST Viper Engine.
MANY Aircraft engines have 10-16 cylinders.
You stated that you would make your own head, simple

 

If Lance can’t do it, it can’t be done.
😀😀😀😀😀😀😀😀😀😀😀

 

Boy, you got THAT right!

 

I would like this engine to be without all the pitfalls of other engines, so durability and weight are important, but durability is the most important. Durability, weight, then FUEL EFFICIENCY at 250-325 hp. The target is 0.38 BSFC or better.

Again, stuff that isn’t on the engine does not break, and does not weigh anything. SOHC eliminates pushrods, and probably eliminates lifters. I can use a really large diameter base circle of the camshaft, and quite easily use a roller on the camshaft (without all the parts required to keep the round lifers of an LS from rotating).

I can run the camshafts at 1:4 revolutions to the crankshaft, and have two “bumps” on each camshaft lobe (the camshaft is physically turning slower… always a benefit).

I’ll bet that the two hollow core camshafts required for this engine will not weigh even two times the weight of the typical solid core unit used on an LS.

I like finger followers because they should break BEFORE it breaks the camshaft, should a valve stick. That’s the ONLY reason that I wouldn’t stick the camshafts directly on top of the “buckets”, with all the valves neatly lined up, like they are in the LS. Ok, one more reason… I suspect that I get many advantages with a roller on the camshaft lobe, that isn’t quite as easy with a cam and buckets.

The two spark plug thing is a problem with the LS head, and all wonderfully engineered by Dodge for the 2008-2013 4.7 V-8 engine.

Without pushrods in the way, the intake ports can be ANY-THING. The cavity above the crankshaft can (and will be) used for something else… perhaps the starter / generator goes there? Or the intercooler(s).

Anyhoo, yes, a “stock” LS-3 might do quite well. Good luck to those folks using them in experimental aircraft.

 

Yes, for prototyping, there will be a LOT of cutting, welding, drilling, etc.

 

Tony-
You didn't really address the gear lash issue, except to mention the 4:1 ratio double lobe cams. It was played with in the 60's but never made any headway. The gear lash I mentioned, and am concerned about, would still be a player here.
The other thing is the 2 plugs per cylinder requirement. This is, of course, due to the horrendous lead levels present in most avgas. If unleaded avgas (right around the corner) were used, plug fouling disappears. Modern engines with strong coil on or near plug ignitions see plugs lasting over 100k miles in normal or even abnormal use. Once unleaded avgas is universally accepted, the dual ignition issue becomes moot.
Again, not to torture the dead horse, but nearly every aspect of the LS engine design lends itself quite well to aviation use, especially if turbo-normalized to sane (sub-500HP) levels
Keep posting and keep an open mind. I'll try to... LOL!

 

Will an Air Boat Fly with DD and a Turbo ?

 

There are more than a few LS aircraft conversion companies out there. Many putting out over 450hp N/A

Instead of reinventing the wheel, why not expand on the many hundreds of thousands of hours successful development already done vs going off on a tangent

 

Five pages in, and I still don't see what this has to do with LS engines at all, other than trolling an LS forum.

 

Let's just say it veered off onto a solid unrelated tangent into obsessed engine "designing".

 

Hi Tony, how fast will YOUR LS powered airplane travel in the air ?
I Do KNOW THE SPEED of a Blackbird (SY-17).

 

The plane that this is primarily intended for is the Cessna 421 series. In absolutely perfect conditions, with two 375 hp Continental GTSIO-520 engines, at about 23,000 feet, I suspect that the aircraft can go about 230 knots (mph is a 1.15 multiple of knots).

Here’s a pic of me flying from Salt Lake City (KSLC) to Las Vegas (KVGT), at 22,000 feet altitude, with the engines pushing the plane along at 137 knots, which makes 193 knots “True Air Speed” (TAS), and with a significant tailwind, we are traveling 250 knots Ground Speed (287 mph).

The estimated power to do that is 220 horsepower per engine (65% cruise power of 335 hp for this Cessna 414).

If we had 250-325 cruise hp, I suspect that we only get 10-20 knots faster. But, with 450-500 hp available for takeoff and climb, these aircraft should climb about twice as fast.

So, a typical 750 feet per minute (FPM) climb might be 1500 FPM. That could mean going from sea level to 25,000 feet (Flight Level 250) in half the normal time, which also means more time at the higher TAS associated with the thin air at FL250.

We only can produce maximum power to about FL180, and then the power will decrease at a few percentage per 1000 feet higher.

 

None of those other attempts are FAA certified, and it’s unlikely that they ever will be. Also, I know that I’ve mentioned this a few times, but 450 “NA” horsepower at sea level doesn’t do me much good at 10,000 feet up to 25,000 feet (where the Normally Aspirated air available is only about one third as dense.

We need forced induction, and it must be intercooled. That compressed air is used not only for the engine induction, but also for cabin pressurization (what we refer to as “bleed air”).

We won’t used a mechanically driven compressor, simply because it takes away power from the engine. Exhaust gas driven compressors use what would otherwise be “waste heat” to power the compressor. It’s “free” power.

Hope this helps.

 

Los Angeles to Miami in 35 Minutes, Air to Air.
This was the time stated to me by my customer.
What is that FPM ?

 

Well, we would need to design the gear lash from a frozen solid engine at -40C / -40F temperature, when the metals are all contracted as much as possible. There would be an operational limitation to not attempt to start the engine below -40C (common in FAA certified stuff), and for normal operation, there would likely be another operational limitation to not start below -10C unless engine heating is used.

The other extreme is the engine operating at its hottest temperature, where the aluminum block and cylinder heads have expanded to their maximum. We can measure all this stuff, so it’s not particularly worrisome.

We can also calculate how much change the camshaft timing will change, per 0.001 inch expansion from the crankshaft centerline to the camshaft(s) centerline(s).

I suspect that the camshafts will be set up to be at the ideal timing when the engine is at operating temperature, and everything else is a compromise.


Ya, you’ll have to convince the FAA / EASA on that one!!! Good luck. This engine will be designed to run with leaded 100 octane, and also with unleaded 94 and 100 octane.

There are more requirements than just two spark plugs per cylinder. In addtion, each of the two ignition systems must have independent power (buses). Therefore, the engines will have two alternators, or one alternator and one DC starter/generator. Each will have their own buses.

There may also be an “essential” or “emergency” bus, that is simply a small 28 VDC battery on its own bus.


Ya, I have no idea exactly where we will be with cubic inches to make 500 hp. My thinking at the moment is the shortest stroke, at about 3.25”, but again, we will simply test from about 3 inch to 4 inch strokes. The only “for sure” thing is 4.4 inch bore spacing, and 4.0 to 4.125 inch bore.

 

I saw a picture of a WW2 Panzer tank engine, with a HUGE counter gear to operate the OHC.

 

In a geartrain, how does one adjust backlash where the gear locations are fixed?
I haven't heard of any methodology concerning that, and I believe that will be a stumbling block that can only be solved by overcomplexity, which I KNOW you'd prefer to avoid like the plague.

 

This will not eliminate thermally induced gear lash.