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Why straight 8's? Why not?

Discussion in 'The Hokey Ass Message Board' started by 50Fraud, Feb 21, 2013.

  1. 50Fraud
    Joined: May 6, 2001
    Posts: 9,318

    50Fraud
    Member

    I'm having a "wonder moment", and I'd like to learn something from those of you that know more about the subject than I do.

    In the years before and after WW2, many engine makers that built exceptionally powerful engines used the straight 8 layout for their race motors and high performance road cars:
    Bugatti, Miller, Duesenberg, Alfa Romeo, and Mercedes all built straight 8's that were highly admired and more than competitive.

    I just read an article on Wikipedia (http://en.wikipedia.org/wiki/Straight-eight_engine) that explains the major advantages and disadvantages of the layout, so my curiosity is pretty satisfied, but I'm curious if any other HAMBers understand this stuff well enough to shine more light on the discussion.

    Inline engines, both 6 and 8 cylinders, apparently have better inherent balance characteristics than V layouts. All other things being equal, 8's deliver smoother power than 6's. The downside of the straight 8's seem to be length, weight, and flexibility of the long crankshaft; Alfa and Mercedes both reduced the problem of shaft flex by putting the cam drives and power takeoffs between cylinders 4 and 5. So, length and weight are the remaining disadvantages, particularly for racing cars.

    I guess that for big luxo cars like Mercedes or Cadillac, those wouldn't be deal breakers, except that nobody wants to tool something as expensive as a new engine if it will only have limited application. A new V8 tooled for Chevrolet, near the low end of the product line, serves perfectly well to power a Cadillac too (if you keep its humble origin a secret from your customers).

    I've deliberately skipped over the several mass-produced American straights like the Buick OHV and several flatheads like Packard and Chrysler, merely because they have only occasionally been competitive in hot rod or racing applications.

    Okay, I've mostly satisfied my own curiosity by doing a little research. Seems a shame, though, that the straight 8 layout is totally history after having been the top of the pile for many years.

    If anyone else finds this interesting and has anything to add, hop on.
     
  2. 50Fraud
    Joined: May 6, 2001
    Posts: 9,318

    50Fraud
    Member

    I did notice that there have been threads on the Buick, Nash, and Pontiac straight 8's here on the HAMB, and a Chrysler or two have been mentioned. Just mentioning that so nobody has to go looking for them.
     
  3. 73RR
    Joined: Jan 29, 2007
    Posts: 6,216

    73RR
    Member

    The biggest drawback for American made inline 8's seems to be the long stroke that was needed to drag the big cars around. Not high rpm friendly but the engines certainly have some appeal whether flathead or OHV.

    .
     
  4. tlaferriere
    Joined: May 14, 2007
    Posts: 151

    tlaferriere
    Member

    Appeal of a Buick OHV Straight Eight
     

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  5. 50Fraud
    Joined: May 6, 2001
    Posts: 9,318

    50Fraud
    Member

    ^ That's pretty neat looking. What does that engine live in?

    Never mind; I found it on your website. That must make a pretty impressive noise!
     
    Last edited: Feb 21, 2013
  6. tlaferriere
    Joined: May 14, 2007
    Posts: 151

    tlaferriere
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  7. M_S
    Joined: Feb 20, 2008
    Posts: 542

    M_S
    Member
    from SoCal

    I'm looking at a 1/8 scale Pocher 8C 2300 Alfa here in my office, and the length of that hood is definitely one of the reasons.
     
  8. Rusty O'Toole
    Joined: Sep 17, 2006
    Posts: 8,974

    Rusty O'Toole
    Member

    I'm fascinated by the twists and turns of engine development, among other things. It's easy to look back and say "why didn't they do this or that". But at the time, they were doing their best with the technology that was available. I suggest that given equal tools, materials etc. today's designers couldn't do much better and might well do worse.

    The V8 actually came to market nearly 10 years before the straight eight. At that time, all V8s had a 4 cylinder type crankshaft and a secondary vibration period to match. Top luxury car makers ignored the V8, which was inferior in terms of smoothness, and stuck to the big 6 cylinder, which has the minimum number of cylinders giving perfect primary and secondary balance, and overlapping power impulses.

    Then, someone invented the 90 degree crankshaft which made the eight cylinder as smooth as a six. About the same time Packard figured out that if you made the cylinders small enough, and the stroke long enough, and squeezed the cylinders together in a single casting, you could build a straight eight with a crankshaft short enough, that it would not snap like a carrot when you revved it up.

    It was really the technology that allowed such a complicated engine block to be made in a single casting that made the straight eight practical. That, plus full pressure lubrication to the bearings. This was in 1923. The straight eight soon swept the market, almost every car maker turned to the straight eight, Marmon went from making a sporty, six cylinder luxury car that cost $3500 to the Marmon "Little Eight" at $995, the lowest priced straight eight on the market.

    In those days all V8 blocks were cast in 3 pieces, 2 - 4 cylinder cylinder blocks bolted to an aluminum crankcase, motorcycle style. The 1 piece V8 block was a very complex casting, harder to make than a straight six or straight eight. The first monoblock V8 was the short lived 1930 Viking, followed by the 32 Ford, Cadillac got a 1 piece engine in 1936 or 37.

    For certain technical reasons, the flathead straight six and straight eight were the best, most practical engines in American cars from 1923 to the early 50s.

    Then, improved fuels, higher road speeds, and better foundry and manufacturing techniques made the short stroke, OHV V8 practical. This was a more efficient layout than the old long stroke flathead engines and they soon came to dominate the market.

    This has led some people to believe that the flathead is a hopeless, inefficient klunker which is far from the truth. Even in the early fifties, the difference was not that marked, and twenty years earlier, the flathead straight six and straight eight had all the advantages.

    Here is an interesting comparison. In 1949, 2 of America's luxury cars got brand new V8 engines. Everyone remembers the OHV Cadillac but who remembers the flathead Lincoln?

    Yet to the technical man, it is an interesting comparison. 2 V8 engines, designed at the same time for the same purpose (to propel a luxury sedan) with the same fuel and technology. The Cadillac was 331 cu in the Lincoln 337 so not much difference. Both had 7.5:1 compression, both burned low octane gas.

    The Cadillac developed 160HP, the Lincoln 154HP. So not much difference in power or efficiency. Makes you wonder why they bothered with the extra cost and complexity of the OHV valve mechanism.

    But as better gas became available, compression ratios went up, engine speeds went up, and the old flathead fell behind.
     
    Last edited: Feb 22, 2013
  9. 50Fraud
    Joined: May 6, 2001
    Posts: 9,318

    50Fraud
    Member

    Useful insight. Thanks!
     
  10. Mr48chev
    Joined: Dec 28, 2007
    Posts: 25,215

    Mr48chev
    ALLIANCE MEMBER

    The big issue with straight 8's for any type of hot rod style car is that you have to build the car around the engine rather than put the engine in an existing car for the most part. The roadster that tlaferriere showed above is a great example.
    Those photos are now in my "inspiration" file for my flathead six powered roadster that hopefully presents it's self as an "old" race car as well as that one does.
     
  11. Rusty O'Toole
    Joined: Sep 17, 2006
    Posts: 8,974

    Rusty O'Toole
    Member

    You got me thinking if there is any car with an engine compartment long enough for a straight eight?

    First car that came to mind was a 1971 - 75 Monte Carlo. The one with the fan a foot behind the rad with a fan shroud that looked like a 5 gallon pail. Likewise, the Grand Prix Pontiac with equally long hood. Or a seventies Tbird or Continental. Or maybe a Cordoba.

    I'm not saying I would want to put a straight eight in one of those cars. But you could, and not have to cut the firewall.
     
  12. 270dodge
    Joined: Feb 11, 2012
    Posts: 623

    270dodge
    Member
    from Ohio

    Oh man, your making me think back to the day. I'm thinkin that my uncle had a Plymouth 6 cyl stock car that had a Chrysler straight 8 installed. If you simply opened the hood and looked you would probably not count the spark plugs! He won many races that way.
     
  13. junk yard kid
    Joined: Nov 11, 2007
    Posts: 2,714

    junk yard kid
    Member

    I heard somewhere that because of the non syncro trans and lots not betting syncro first. People thought it was a pain in the ass to stop the car and go into first when you could power through second gear. Or going around a corner just staying in third. It was luxury to not have to be changing gears and bouncing around your passengers. If you got more torque it makes it easy and nice and smother to drive.
     
  14. Fairlane Mike
    Joined: Sep 21, 2010
    Posts: 389

    Fairlane Mike
    Member

    Ford built, (more as a styling exercise) what they called "T-Drive". One version was a straight 8 with the trans running off the middle! I remember seeing a picture of it at the dealership I worked at in about 1990! Who knows, old ideas sometimes come back! Mike.
     
  15. Normbc9
    Joined: Apr 20, 2011
    Posts: 1,123

    Normbc9
    Member

    Good strong engines that produce huge amounts of torque. But crank lengths do convince builders to keep the RPM's down . Fast out of the hole. Most are hole shot engines that can get a start and get down to the finish line first. There is a turbo straight eight 320 Buick near me and he is a Bonneville contender.
    Normbc9
     

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  16. Buick Guy
    Joined: Jan 29, 2007
    Posts: 27

    Buick Guy
    Member

    One advantage to a straight 8 is that if you want to build a long narrow car the straight 8 lends itself nicely. This car is only 22 inches wide and everything is packaged inside the body. The front axle and the rear end are there in the open out of necessity for stability. If we were to start over we could take at least a foot of height out of the car. Last year the "modernized" old technology enabled the old car to go 242 on the Salt
    Doug
     

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  17. Rusty O'Toole
    Joined: Sep 17, 2006
    Posts: 8,974

    Rusty O'Toole
    Member

    Totally!!! There were basically NO automatic transmissions before the late 40s (well a few starting in 38 or 39 but most people never saw one).

    All through the teens, twenties, thirties and forties if you were a typical driver who didn't like shifting gears, you didn't have to. Much.

    Engines were built with low speed and mid range power. You could idle down to 10MPH in high, step on the gas and pull away without stalling. This was considered the hallmark of a quality car, that smooth turbine like power at low speeds.

    That is one often overlooked reason for the detuned, long stroke, low compression engine. That long stroke makes driving so-o-o-o easy.

    Other reasons were, low octane low lead or no lead gas dictated low compression ratios and developed more power in a long stroke motor.

    When they invented the automatic transmission the engineers started right in to hop up the motors. A typical auto trans car of the forties and early fifties, got a special motor with more compression, possibly a different cam, and 5% or 10% more HP than the standard version. This helped make up the power sopped up by the auto, but it was only possible to do this because they didn't have to worry about Mrs. Peasey Weasey making every driving mistake in the book on her way to the A&P.

    As auto trans caught on with the Peasey Weasies it freed up the designers to develop hot motors coupled to 4 speed trans, specifically for sale to enthusiasts. They didn't have to dumb them down because they knew the Peasey Weasies always bought automatics.
     
  18. Plenty of room in those for almost anything, lengthwise. Once in the 1950's, hood heights started decreasing and those straight-8s were simply too tall. Plus they were heavy cast. The new straight-6 and V8s were lighter.

    Bob
     
  19. Rusty O'Toole
    Joined: Sep 17, 2006
    Posts: 8,974

    Rusty O'Toole
    Member

    The flatheads like Pontiac, Chrysler and Packard aren't that tall. If you equipped them with side draft carbs or fuel injection they wouldn't be any taller than a big block V8, hmmm I wonder.
     
  20. falcongeorge
    Joined: Aug 26, 2010
    Posts: 18,341

    falcongeorge
    Member
    from BC

    Man that looks cool, really something to be said for a straight eight with four SU's with spun velocity stacks. I have often thought something like this would be really cool in a homebuilt with big knock-off 18" wire wheels, brooklands windscreens, cycle fenders, a 4" exhaust pipe down one side, and a lagonda-like body. Oh, and goggles and a leather flyers cap... :p
     
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  21. They are not SU carbs, but Keihin CV carbs, TR
     
  22. Rusty O'Toole
    Joined: Sep 17, 2006
    Posts: 8,974

    Rusty O'Toole
    Member

    In 1995 Chrysler built a straight eight show car called the Atlantic. It had a 4 liter (240 cu in) engine made of 2 Neons joined end to end. It looked pretty good once they dressed it up and put it in the car.

    If you really wanted a modern straight eight that would be an option.
     
  23. falcongeorge
    Joined: Aug 26, 2010
    Posts: 18,341

    falcongeorge
    Member
    from BC

    Ooops, my bad. shoulda put my reading glasses on.
     
  24. Normant93
    Joined: Apr 23, 2009
    Posts: 138

    Normant93
    Member

    I'd like to do a few mild mods to the fladhead 8 in my '53 Catalina, ie aluminum head, duel carb intake, split exhaust or headers (i.e Fenton or similar) as in the picture above, anyone have any ideas where I might find some of that stuff? I suspect it's super rare so it'l have to be fabbed.
     
  25. Rusty O'Toole
    Joined: Sep 17, 2006
    Posts: 8,974

    Rusty O'Toole
    Member

    You are right, Pontiac stuff is super rare, your car was built in the OHV V8 era and was seldom hopped up. Edmunds was the only company that made heads and manifolds, so far as I know. Something might turn up on Ebay or online.
     
  26. Tim Keith
    Joined: Jan 1, 2010
    Posts: 65

    Tim Keith
    Member

    There is a 1950 Buick in Hot Rod this month that is claimed to make 275 HP
     
  27. Buick Guy
    Joined: Jan 29, 2007
    Posts: 27

    Buick Guy
    Member

    And the exhaust pipes make great carb heaters. Help vaporize that good $4.00 a gallon gas we buy today.
    Doug
     
  28. buickvalvenut
    Joined: Oct 29, 2008
    Posts: 659

    buickvalvenut
    Member
    from Rialto

    There's some guys over on the buick site that are doing some interesting things with these straight eights..the main downfall is in the factory trans witch dondt do much other than move heavy steel around.
    There's ways to improve these beast..one is in the heads..a porting job and a valve upgrade to smaller stems makes a dif..I'm currently building one my self..I'm going to trick it out as much as my wallet allows it.
    The 263 wich I'm working on is lighter than most due to it not having the outer reinforcement ribs, not by much but one could feel it when bare block is picked up..another factor to consider is the crank..it weighs close to 100lbs. But they can be altered to make them lighter...with a lil work these beast can give your car some cahones...of course, HP cost money..what you got in your wallet.
     
  29. buickvalvenut
    Joined: Oct 29, 2008
    Posts: 659

    buickvalvenut
    Member
    from Rialto

    This is my current block..its an early 263. Just got it back from H&H..I'm going to send it back tho to have .020 milled of the deck and the same done to the head..wich there going to rebuild/rework as well..I have plans to modify my rocker assembly to change the ratio.
    What ever could be done with out needing boing or nasa to get involved.
    I'm also thinking or upgrading to chevy roller lifters, yes it can be done!..lol.will have to give that more thought for that lifter swap is the cake work..it comes down to the roller cam.
    A transmission upgrade is a must!..that comes second .
     

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  30. spiderdeville
    Joined: Jun 30, 2007
    Posts: 1,136

    spiderdeville
    Member
    from BOGOTA,NJ

    flat earth society
     

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