Modern (high-compression) V-8 engines swiftly became the standard power plants, for American cars in the late 1950’s, early 60’s. I can see how that happened, because gasoline was cheap, the V-8 offers high power for a small size, and the large V-8s provided good power and acceleration. My question: before the advent of the modern V-8, most upper end American car makes (Buick, Cadillac, Mercury) used starigh-8 engines. These engines must have been very expensive to make, and needed a lot of under hood space. Were they good engines? I imagine making them run smoothly (with a single carburator) must have been a challenge.
I was told that because the engine block was long and narrow that they would sometimes actually warp slightly. Any degree of misalignment will make for a poor running engine. The V-8 is a superior design for many reasons.
Straight 8s aren’t that difficult to make. I don’t know why they would be more expensive than a V engine. In fact IIRC the Pontiac straight 8 was one of the least expensive 8 cylinder engines of its time.
Overall they ran fairly smoothly. You end up with some vibration problems due to the longer block and shaft and all of that, but that was usually fixed with a harmonic damper on the other end of the crankshaft. Still, you did end up with vibration problems at high power. Straight 8’s, because of the number of cylinders, don’t suffer from the low rpm vibration problems that you get with a straight 6, so the low end vibration wasn’t bad.
Some of the straight 8s used dual carbs, so the long length from the carb to the cylinder wasn’t an issue.
The straight 8s ran well, were generally smooth, and were pretty good engines. As you said, though, they did have some disadvantages when compared to a V8. A V8 is more compact (so you don’t need that 30 foot hood), weighs less for the same horsepower (because the block is more compact), and doesn’t suffer from vibration problems as much at high power, so it is easy to see why the V8 replaced the straight 8 after WWII.
Just go out and read any Clive Cussler novel. It won’t take but a few pages before you are treated to a steamy sex scene involving a Straight-8.
When I was in high school (1968) one of my buddies had a Hudson Hornet with a straight 8.
It was Loooooooooonnnnnngggggg!
I once owned a 1953 Pontiac with a straight eight. IIRC it developed 125 HP, got 13 mpg, and had cruddy acceleration. Passing anything on a hill was problematical. And it had a really bad habit of blowing the #7 piston. Back in those days it took only around $250 to get that fixed, but still…
I am not a bit nostalgic for that car. Nosiree.
Straight 8s. some were nice engines.
I do not remember any vibration problems. But with the blocks being longer they lhad more mass. Also required a larger engine space. When putting the heads on you lhad to tighten the head bolts carefully or the head could warp. Also the straight 8 did not lend itself to overhead cams a well.
That Hudson 8 was a big engine. Most had a main between every two rods. The really big engine had a main between each rod. Now that engine you could reall load and it would take a lot of stress. the Hudson Hornet’s weak point was the rear end. dump the clutch and hit the gas to hard and it was time for a neew rear end. Many a trip to the junk yard.
Dad also had several Packards with the straight 8. Heavy car but that engine could pull it with no problem. That is except when going over 90 you see the gas gage move to empty, and when that 4 barrol kicked in it really moved. But gas was what 0.28 a gallon.
With the big block you had better keep the cooling system in good shape. It was a long way from the water pump back to the radiator.
They kept at it and made a respectable OHC straight 6 in the 60’s. It was smooth and redlined at 6900.
I’ve read that the long crankshaft was a problem, too. I believe that there were some racing straight eights that took the power from the center of the crank rather than from the end.
Straight engines are sturdier than V engines because there is a main bearing between every piston (not shared). They may not rev higher than shorter cranks but that just means you tailor the cam to the appropriate RPM. The straight 6 Turbo Supra was a beast with people making 600 to 1000 hp on the stock crank.
The first car I ever drove was a 50’s era Packard with a straight-8 “Thunderbolt” engine. Open up the hood and you were looking at a solid slab of iron. I swear that car could take on a tank and win.
The Hudson Hornet had a straight six, although it was available with a V8 from 1955 on.
I was also told [by the old master mechanic] that many of the V-8 were cheaper to build than the straight 8’s. The reason had to do with modern manufacturing techniques. The V-8 is lighter, more compact but more sophisticated. The straight 8’s were built in old, inefficient plants while the V-8 was the product of more modern and efficient plants. That didn’t stop the automakers from charging a premium for putting a V-8 in the car.
While not exactly wrong, there is a lot missing from this commonly stated analysis.
Both designs can, and usually do, have a bearing at both ends of every crank throw. The crank and bearings must be sized to handle the stress of the power stroke, so in a straight engine, there is “wasted” weight 75% of the time. The V engine reduces this waste, because the two rods/pistons that share each crank throw have non-overlapping power strokes. Any weakness is not because of the two pistons are doubling the loading on the throw, (they don’t, in fact some of the loading cancels) but because they require a bit more length between mains.
If you have a limited weight budget for the crank and it’s bearings, you can make a much stronger V engine crank than for a straight engine. The fact is, as you state, the crank in a straight engine is usually a bit stronger, but a LOT heavier. The reason is that the extra bearing support does not greatly help it to resist torsion loads. In order to have adequate torsional stiffness, it ends up being over designed with respect to the loads that both designs share.
Which leads to the reason that straight engines are often low rpm designs. Larger diameter bearings increase the crank stiffness, but limit the speed. Limiting the rpm means you need more displacement for a given HP, which tips the power/weight advantage even further to the V engine.
While shorter hood lines are indeed a selling point, the short stiff crank is really what makes V engines dominate in automotive use beyond 6 cylinders. 6 is currently where the trade offs can tip either way. An I-6 lengthens the hood a bit, but leaves extra room for front suspension, so might end up preferred, especially if a torquey engine would be a good fit for the vehicles intended use. If it is a front wheel drive application, then an I-6 would make for an awfully wide car, so the V-6 always wins that one. The popularity of FWD is probably a significant factor in the decline of the I-6 in automotive applications. V6s were rather uncommon when RWD was the norm.
Straight engines are still quite practical when the cylinder count is low, or where low rpm operation is preferable, such as diesels and especially marine diesels. Large ships often need extremely low rpm, and a heavy engine just offsets some of the ballast they’d otherwise carry. Inline engines also allow greatly simplified exhaust and intake plumbing when OTR truck engines are turbocharged and inter cooled, which in modern practice they typically are. The vast majority of tractor-trailer rigs you’ll encounter on US interstates have a turbo-charged, inter cooled I-6 under the hood.
Inline engines are also great for train locomotives, where the extra weight provides added starting traction, yet is still insignificant compared to the total vehicle weight (the whole train).
1952 Straight 8 Packard with three on the column… 140 MPH + using a stop watch and mile markers on the Turner Turnpike near Stroud Oklahoma in the Summer of 1959. Took a while to get up there but ran to the end of the road at that speed no problem. God awful ugly green color it was…
Thanks for the info. In the 1930’s Henty Ford attempted to develop an “X”-4 engine-presumably because it would allow a shorter crankshaft, and be smoother running than a straight 4.
Ford dropped the program, because the engine never worked reliably-presumably this was mostly because of the primative technology of the time. Not much seems to be written about the X4. Of course, the “Boxer” 4 (used by VW and Subaru) were pretty good engines.
That is a truly impressive and dangerous speed for such a car. Now days it is not uncommon to find consumer tires rated for 150mph, but tire blow out at high speed on insufficient tires used to be a significant danger to the lives of teenagers who didn’t know any better.
Yes, I’ve driven that fast. It’s fun, but it was on straight, smooth road with zero traffic on a clear day. And with a car and tires designed to run like that.
VW makes “W” engines or at least did. That is where there are two banks of cylinders on each side of a “V” configuration. There is a documentary on the Bugatti Veyron V-16 that generates 1001 horsepower and has a double clutch tranny so that a gear is always fully engaged except for 15/1000 of a second during shifts. It goes 0 to 60 in 2.5 seconds and tops out at 253 mph.
VW still makes W-configured engines - W12s for its own Phaeton, the Audi A8 and several Bentleys, and the W16 in the Veyron.
I thought the inline 6 (and the V-12) was sort of the gold standard for good harmonic performance/balance, due to its firing angles and number of cylinders. 
It is. A straight six doesn’t require a balancer shaft like a large inline four, V6, etc. because it’s already in mechanical balance. Not sure what e_c_g is saying there.