Inline 6

OTOH, you could just let the front wheels pull you out of whatever silly stuff the rear wheels do. I used to do that with my Austin America. I scared the bejesus out of a friend with a 400 Firebird. The 'bird wasn’t stock: it had stiffer suspension, and a 4.56 rear. Probably more, but that’s all I remember.

And I am still insufferably pleased with myself…

Unfortunately, that’s “produced”, the Atlas I6 is no more.

“BMW has (and will continue) to make some of the best in-line sixes for years. My 1998 328i has the best and smoothest engine of any of the 25+ cars I have owned. It also delivers a very respectable 33 MPG on the highway going 85 MPH.”

I disagree. It is not the engine. It is a combination of that engine, the transmission, and the rear end that allow it to get good gas mileage at higher speeds. If it was meant to loaf in overdrive at 55 MPH, it wouldn’t get that great mileage at much higher speeds.

The in-line ship motor presented earlier shows what stout components can do for you. But they aren’t as interested in weight savings as car manufacturers are. In any case, it seems like BMW has it down. The in-line six is a signature accompaniment to their fine cars. They want to do it their way, and others prefer to use the V6. Clever builders continue to exist and get better in the trade space they choose to live in.

They do rule the roost in the inline 6cy department but they are also very involved in V engines with different numbers of cylinders. At one time their flagship 7 series was powered by a inline 6,not any more.

“How many miles would it take to stop?”

That would depend whether you just shut off the propellers or put it into full reverse.

“Do you thing that supertankers use one or two of these behemoths?”

I have no idea.

Sometimes I miss driving a truck. I don’t miss being treated like crap by the company I worked for, but I miss life on the road. Being able to professionally handle a 53 foot trailer is fun when you know what you are doing. Every time I see something that large, or larger, I want to get in and drive. With my health problems, I will have to settle for RVing.

Is it really possible that the pistons accelerate “more abruptly” going up vs going down?? I don’t think so.

One problem with a long crankshaft is that severe torsional vibrations can develop at certain critical rpms. Damping those vibrations is why there is a hamonic damper on front of the crankshaft. Honda made some transverse inline 6 cylinder motorcyles and dealt with the torsional vibration problem by taking the power off of the center of the crank. Many of their four cylinder motorcycles also had a center of the crank power take off.

A horizontally opposed four also cancels both primary and secondary imbalance.

Here’s why an inline four is not perfectly balanced.

When the pistons are at top and bottom center, the collective center of mass of all four pistons is at the center of the stroke. When the crank is in the 90-270 degree position, the collective center of mass of all four pistons is somewhat below the center of the stroke. The shorter the connecting rod is, the worse the second harmonic vibration is. If the connecting rods were infinitely long, the piston motion would be sinusoidal and it would be perfectly balanced.

Hope this explains it.

the ford falcon from Australia http://www.ford.com.au is a good example of a modern I6 engine, the car looks good too

Wouldn’t your theory depend upon the length of the stroke? How much longer would they have to be?

“Wouldn’t your theory depend upon the length of the stroke? How much longer would they have to be?”

It depends on the ratio of connecting rod length to stroke. For example, if the stroke is 4 inches and the connecting rod is 8 inches from center to center, then your rod to stroke ratio is 2 to 1. Rod:stroke ratios typically range from 1.6:1 to 2:1. Shortening the stroke and keeping the connecting rods the same length increases the rod:stroke ratio and makes for a less severe second harmonic.

over the road tractors used to use Detroit diesel engines that were 2 cycle V6s and V8s.

I wonder when they phased out 2 cycle engines in cars and trucks. It must have been before my lifetime.

…and that Verona was not exactly a state-of-the-art vehicle.
Definitely not a prime pick in the automotive market.

"Shortening the stroke and keeping the connecting rods the same length increases the rod:stroke ratio and makes for a less severe second harmonic."
If you shoorten the stroke and keep the rods the same length the piston would not reach the top, thus would have very little compression and probably wouldn’t run.

[B]“I wonder when they phased out 2 cycle engines in cars and trucks. It must have been before my lifetime.”[/B]

Hmmm…How young are you?

Saab finally phased out their 2-cycle engines in 1968. The Saab engine was originally based on a DKW design, but I believe that Auto Union stopped production of their 2-cycle DKWs prior to 1968. The “fabled” 2-cycle Trabant of East Germany was produced up until 1991.

As to trucks, I can’t tell you when the last 2-cycle truck engines were made.

I don’t know when they quit putting 2 cycle engines in tractors but I know they had them in the early 80s, I drove some of them.

Its really impressive to be standing in one of those cylinders using a 10" grinder with a steel brush attachment to remove the soot on the cylinder head and valves. And when you have to pull a turbocharger with a 2 ton crane, you know you’re dealing with proper power. As for driving it a ship with one of these, its impressive, it reacts pretty slowly, reverses even slower, but you can feel it working in the ship all the time. Most supertankers only use one (huge) prop though, so they’ll just add cylinders until the engine is large enough to drive that prop. What really makes you feel the power is putting several of the GE or Rolls Royce gas turbines in, instant power!

I think the idea is that the cylinder bore would be shortened, too, so that adequate compression could take place.

Of course it looks good…

It looks like a 2005 Honda Accord. :wink: