By on January 31, 2012

Now that I’m scouring eBay Australia for crazy Detroit Down Under cars— maybe even as crazy as a 4-71-blown six-cylinder Torana— I’ve been dragged once again into the Whirlpool Of Arcane Internet Car Knowledge. You know how that goes: you go to look up the Australian Falcon on Wikipedia, a reference to the Valiant Charger leads you to the mother of all Chrysler-related online time-sucks, and then your whole day is used up. This time, Allpar sent me to Valiant.org, and that’s where I found the page on the Chrysler Hemi-Six engine. There you’ll find a description by a Chrysler engineer of how his Australian counterparts tested their new (American-designed) engine:

They couldn’t get an engine to run lab endurance for more than about 20 hours or so without dropping a valve or putting a hole in a piston. Well I suspected right away in the States what it was, and when I got there, sure as hell, they were running wide open throttle lab endurance (their schedule was probably different from ours, but ours consisted of 10 hours each, and I may forget one, but the first 10 hours were 800 wide open – can you believe that? – then 1600 wide open, then 2400, 3200, the fifth 10 hour cycle was 3600, and the last was 9 hours at 4000 and the last hour at 4400, all wide open throttle. And their engines were failing in the second 10 hours due to pre-ignition or valve overheating.

Now, the Aussies were using hot spark plugs, which is the reason they were killing engines, but let’s get back to that standard Chrysler endurance test, circa 1966: ten hours WFO at 800 RPM! That’s like dragging a flat-tired trailer full of dead horses up Grapevine Hill, in top gear, against a 60 MPH headwind (granted, the cooling system on the test stand was probably beefier than the one in a Valiant VC, but still). Just another day on the job for a Chrysler pushrod engine! With that philosophy, it’s no wonder the Slant Six and LA small-block V8 were so tough.

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47 Comments on “Ten Hours, 800 RPM, Full Throttle: How Chrysler Used To Test Engines...”


  • avatar
    PenguinBoy

    My first car was a Canadian spec 1966 Valiant (similar to the US Dart of the same year) with the 225 slant six and torqueflite. It was still running well when I got rid of it in the early ’90s, and the engine and transmission had never been touched. If they return to this sort of testing for their new engines, maybe the new Dart will live up to its namesake.

    The Pentastar has been out for ~18 months, and apparently just hit 1MM units built. So far I haven’t heard anything bad about it, so maybe they are starting to move past the era of blown head gaskets and semi-disposable automatic transmissions. Time will tell…

  • avatar
    greaseyknight

    When Ford was trying to win Le Mans, they had trouble keeping the GT40’s engine together. The solution? They went to Le Man and data logged the entire track. Back in the US they built a dyno cell that would replicate the entire 24 hour race. They weren’t satisfied until they could get engines to last for 2 full races, at full race speed, without stopping.

    • 0 avatar
      Robert Gordon

      “They weren’t satisfied until they could get engines to last for 2 full races, at full race speed, without stopping.”

      Which of course meant that that it was over-engineered for the task at hand and thus likely heavier than it needed to be.

      • 0 avatar
        drvanwyk

        I would disagree with you. Although I completely understand where you’re coming from this, I would simply say that they gave their engines a time-to-failure factor of safety of two.

      • 0 avatar
        greaseyknight

        The weight wasn’t a factor, as they used an existing design, the FE (which is about 700lbs). A motor that was never intended for racing in the caliber of Le Mans. It was a typical American V8, racing against high strung exotics like Ferrari. They are a very reliable street motor, just not intended for racing.

        IIRC I got this info form the book “Go Like Hell: Ford, Ferrari, and Their Battle for Speed and Glory at Le Mans”

  • avatar

    I want to know how they tested the muffler bearings

  • avatar
    highrpm

    This is a good story. Back then, when you bough an engine you knew it could take a lot more punishment than you would ever give it.

    Compare this to my story. In the late 90s, Chrysler had a powertrain test schedule called the PT2. I rode along on one of these test cycles as part of a PCV test that I was working on. This test was ridiculously easy on the car. I told the test driver that I was harder on the car when I drove it over to the proving grounds from the Tech Center.

    He told me that they used to run tougher tests, but they had too many failures. Mostly transmissions. So the test folks decided to make the test easier!

    So upper management saw that the vehicles were passing their tests. Engineers were happy too. Yet the customer wound up buying an under-engineered, unreliable vehicle.

    • 0 avatar
      PenguinBoy

      “He told me that they used to run tougher tests, but they had too many failures. Mostly transmissions. So the test folks decided to make the test easier!”

      Lower the bar until you can prematurely declare victory and move on. That’s a formula for success…

    • 0 avatar
      CJinSD

      So there are institutional reasons for Chrysler’s recent drivetrain issues. Considering Daimler took over in 1998, they probably can’t be blamed for this aspect of Chrysler’s failure to build on their design success of the ’90s.

  • avatar
    Oren Weizman

    800 rpm ? makes perfect sense if your target drivers are the 10AM pool gymnastic club at the Longview Sunset Retirement home in Longbeach Florida

  • avatar
    kitzler

    800 rpm, that is really lugging an engine, it is a wonder you did not blow a valve or head gasket at that speed, not to mention the potential dieseling effect of pre-ignition.

  • avatar
    wstarvingteacher

    Just goes to show that some of the things us oldtimers talk about being in the good old days were actually good.

    Same formula for premature success was tried when dumbing down our schools.

  • avatar
    Lokki

    Is anyone here personally aware of -any- pre-1970 225 slant-6 being successfully destroyed by anyone?

    I know of a couple of good attempts:

    One involved a brick on the gas pedal but it ran out of gas after an hour or so; ran fine after my friend came to his teenaged senses and realized that he didn’t have money for a different car.

    The other was low oil for more than 6 months. In this case I had a friend with a Dart wbich had a perpetual oil light. I finally mentioned it and he told me that months ago he’d put in a quart and the light stayed on; ergo the light was broken. Well, one day I had to borrow his car. Good manners required that I fill the tank, and -what-the-hell- I checked the dipstick. Bone dry. I don’t recall the number of quarts a 225 requires wants but I think I it was at least 5.

    The car was still running fine two years later……

    • 0 avatar

      The BMW E30 with Slant Six swap that we saw at a LeMons race in South Carolina last year had some sort of engine failure, maybe a spun bearing. As I recall, it was an engine that sat for decades before the swap.

      • 0 avatar

        It was not the engine per se… It was as a consequence of a failure on an Exhaust Bearing which clogged the electrovalve and build excess of back pressure. How bout that?
        Ah well yes the old Chrysler engines were good, a friend had a Dart with the slant six, the car body was falling apart but the engine and the manual 3 speed transmission never failed. (When he used to put enough gas on the tank of course).

        Best Regards MM.

    • 0 avatar

      I have newfound respect for the Mercury Racing HP525 engines we used for offshore racing. They basically have two modes (at least for us): OFF or ON. On being 5400rpm, on the rev limiter, all the time. (For a a good hour, then you have used up the 90 gal tank ….)

      Once, I had been fiddling with the setup of the boat for weeks. Suddenly, it went haywire, all lights went on, guardian (=limp) mode. “Overspeed 2200rpm” the monitor said. “BS”, I said, “that’s a good as idle.” Turn off to reset guardian, try again. “Overspeed 1900rpm”. I went home and called my buddy. He said: “Check the oil.”

      Whoa! Dipstick dry! It needed six quarts. It takes 8. Problem gone. Time to turn ON again. Turned out the engine has tons of sensors, except for low oil.

      The engine is based on the 8 cylinder Chevy Big Block, then heavy duty marinized.

    • 0 avatar
      Steve65

      I killed one. 64 Plymouth Belvedere 4 door. I assume it was a 225, but don’t know. It had an oil leak from the valve cover which I never bothered to fix. As a consequence, it was perpetually low on oil. At the time I worked at a gas station which was reached from a downhill cloverleaf ramp. I’d know the oil was getting REALLY low when the g-loading on the ramp would expose the oil pickup, and half way around I’d get serious valve clatter when the pushrods and lifters ran dry. I’d throw in a couple of quarts at work when that happened. After about a year of that treatment, it threw the #6 rod. A couple of days later while I was still driving it around the broken rod end finally punched through the block. Had over 300k on it when I got it, and about 340 when it blew.

    • 0 avatar
      jpcavanaugh

      When I was in college in the early 80s, I worked one summer with a guy who had a 70 Duster with the slant 6. He bought the car at about 100K miles, and followed the theory that you never needed to change oil, just replace the filter and add a quart every 3k. When I knew him, the car had over 200K on it. It was followed everywhere by a pretty good blue cloud, but it started and ran like a champ.

  • avatar
    windswords

    I heard the cranks in these motors were forged not cast. And that the other guys (Ford and GM) were cast. Of course hi-po motors were always forged, I’m talking about the run of the mill units. That might explain why it seems that there are so many old Mopars still running compared with the same era stuff from Ford and GM. I don’t know if it’s true about the forged vs cast cranks or not, but it would explain a lot.

    • 0 avatar
      bikegoesbaa

      I don’t know, but I don’t think that many “run of the mill” cars are taken out of service because they break or wear the crankshaft.

    • 0 avatar
      windswords

      It was just indicative to me of “over engineering”. If they did that to all the crankshafts what about the oil pump, etc.? I hear the same thing said about Japanese cars.

  • avatar
    wmba

    All our schoolbuses back in the early sixties had the 261 six in Chev or GMC chassis’. One driver we had on our run thought that the gears were only for upshifting. On the two really steep hills going home, he would lug the engine in fourth down to just above walking pace, and then encourage forward movement by rocking back and forth in his seat! The bus managed to survive this daily ordeal. Next year, we got a young driver, who could snap off double clutch downshifts with precision. A nice change.

    In fact, back in those old days, the general criticism of small forrin cars was that they couldn’t accelerate from a walking pace in high, like a proper Ford flathead V8, or a 235 Chev six, or the Chrysler L-head six. So there was precedent for lugging the hell out of engines. Probably the reason why they had 800 rpm WOT tests.

    It’s worth checking out that old 261 six via google. Tough as nails also, just like all the engines first run in the 1930s.

  • avatar
    skor

    US car makers produced some bulletproof straight six engines back in the day. The slant 6 Mopar was probably the best durability wise, but the Ford 240/300 6 was probably a close second. The 240/300 were truck engines, different from the 144/170/200/250 sixes installed in passenger cars. I remember the father of a friend had a F150 equipped with the 300, it produced a monstrous amount of torque at an rpm barely above idle.

  • avatar
    gslippy

    While I very much appreciate the romantic sentimentality for the durable old engines (the Slant-6 being tops among them), I’ll argue that today’s engines are far better than that.

    Here in western PA, I’m old enough to remember the days when owning a 100k mile engine was an accomplishment, and the car’s body and engine often failed at the same time. Today, any engine/owner which can’t do that ought to be ashamed, and the engine is almost never the reason a car is junked.

    And the smoothness, economy, power, and cleanliness of today’s engines are far superior to anything from the past.

    • 0 avatar
      golden2husky

      You have a valid point, but the ability to abuse the oldies was legendary. A slant six could be overheated, neglected, overreved, etc and survive. Do that to an aluminum engine – don’t care who makes it – and you end up with a head shaped like a potato chip….

      • 0 avatar
        gslippy

        I think a similar discussion could be had regarding the old cars wearing wagon wheel tires. A Model T could go places that today’s best AWD can only dream of, due to the high chassis and skinny tires.

        But I don’t hear anyone calling for a return to those days, simply because most of us live in more civilized conditions and the compromises of our vehicle’s chassis are biased toward taut handling and direct feedback on smooth roads.

        Similarly, the overdesigned cast iron engines of the past could certainly take a beating in bad conditions, but throughout most of their existence they were just marginally-reliable, polluting gas hogs.

    • 0 avatar
      wstarvingteacher

      I have an unfortunate history with the NapsZ engines in Nissan pickups. Having your engine temp guage start to peak on the interstate when you really cannot get off without killing yourself has been my experience twice. Two ruined engines. Three if you count the POS Saab on the ship channel bridge in Houston. I retch when I think of the SAAB. Ok… I’m past it now.

      I think I would have killed for an old cast iron engine at those times. The Nissan is impervious to wear but do not overheat them. Aluminum head and cast iron block spell disaster and dollars.

      Everything is ok while things are going good. Give me an old one when they are going bad. With the 350 Chev I loaned out, the tstat stuck and ruined the radiator but I changed the oil and kept on running it. I’m working on a 283 now that I hope is just as tough.

      • 0 avatar
        golden2husky

        Chevy 350 can take it. My friend’s sister drove an old Suburban that blew the upper radiator hose. Being incredibly ignorant when it comes to cars, she chose to drive it home with the temp gauge pegged. The truck got slower and slower until it seized. When it cooled, it restarted. She continued home only to repeat the seizing. Again it restarted when cool and she got it home. A new hose, an oil change and back into service it went. It developed an appetite for oil after the overheating – a quart every 1k of less, but it ran for another couple of years before it was traded in. I can’t think of any engine today that could handle that.

  • avatar
    Spike_in_Brisbane

    I have been trying to find the full page ad that Chrysler Australia used to run showing this engine test. It is one of my fond memories of the 70s. It had a beautiful hemi 6 with the triple dual throat Webers and metres of orange glowing exhaust. The closest I could get is this reference from “Street Legal”. I hope you’re allowed to publish the link.
    http://www.streetlegaltv.com/news/video-hey-charger-the-aussies-six-pack-hemi-valiant-charger/

  • avatar
    millmech

    What engine is that in the picture? Details look like some sort of Chrysler, but it’s overhead-valve & straight up&down. I’m only aware of upright flathead Chrysler 6s & leaned-over OHV Chrysler 6s.

  • avatar
    Halftruth

    The 383 in my 65 Newport was bought running on 4 cylinders and though it was underpowered, it still ran. Gumming on the valve stems caused a few to jam and bend the pushrods. I could not believe it ran as well it did. After refurbing the heads, compression is good and uses no oil. This on a bottom end stock 65k miles.. Not bad.

  • avatar
    dvdlgh

    First car was a 1961 Dodge Lancer with 170 cid slant six. Complete lack of maintenance and beating the hell out of it this teenager couldn’t kill it.

  • avatar
    kitzler

    When your goal is to make the best engine, regardless of gas mileage, weight, cubic inch displacement, or environmental concerns, you can engineer a motor that will last and last. my 49 Ford flathead 6 and 63 Chevy 283 V8 were good examples. They would even run on crankase oil.

    However, if you take in account weight, mileage, environment, etc, you will be lucky not to blow the motor without the proper maintenance and oil management. True the plugs will last you a 100K miles, but then so will the engine

    • 0 avatar
      chaparral

      Keep oil and water in most of today’s engines and they’ll reel off 250k+ miles before needing a rebuild. I’m at 152k on a Chevy LS1, got to 212k on a Subaru EJ25 SOHC, got to 190k on a Honda B16, ran another Honda D15 to 275k.

  • avatar
    gslippy

    According to most of the comments here, I guess the measure of a durable engine is how long it lasts without maintenance, because that’s how we treat our cars.

    Come on – maintain an engine properly, and today’s engines are much better.

    But for a nice depiction of this nostalgic durability, watch the movie “Duel”.

  • avatar
    Moparman426W

    I’m short on time right now, but when I return sometime this evening I will explain some of the reasons that chrysler engines, the slant 6, small and big block engines were so rugged. And Gslippy you couldn’t be more wrong, they weren’t worn out by 100k they were just getting started.

  • avatar
    Moparman426W

    The reason the bottom end of the slant 6 was so tough was because it was originally meant to use an aliminum block. Weaker aluminum required extra materil to be rigid, so that was how the tooling was designed. They started out building both cast iron and aluminum versions, because the reynolds aluminum company couldn’t yet meet the supply.
    The aluminum version required a special type of antifreeze, and it was supposed to be changed every year. Most owners neglected to change it and it would cause the deck of the block to erode between cylinders, so chrysler dropped the aluminum version.
    Since it would have been costly to make new tooling for the cast iron version they stuck with the original tooling.
    The result was an extremely beefy bottom end with an excessive amount of cast iron, with a skirt that went about 4 inches below the crank centerline. It used a forged steel 4 main bearing crank. When the bearing size is adequate a 4 main crank is stronger than a 7 main because it has alot less twists and turns, the slant 6 had hemi sized main bearings which gave it plenty of bearing area and a beefy crank. In mid 76 they switched to a cast iron crank. In the chrysler tradition the block also had a very high nickel content.
    The small block chrysler also had a high nickel content in the block, much more than a small block chevy. They also used beefier rods than chevies, in fact the lowly 318 used beefier rods than the mighty LS6 454 chevy. Another important thing is that the rods were longer in the chrysler engines. A longer rod makes for a more stable piston for less side loading of the cylinders reducing wear. A shorter rod pulls the piston inward as it nears the bottom of it’s travel, causing more thrust loading and as it gets ready to travel back up that short rod kicks it out toward the outer side of the cylinder wall.
    That’s why many builders of chevy race engines over the past 20-30 years use aftermarket 6 inch rods in them, the factory rods are 5.7 inches. A few years back Rick Ehrenberg at mopar action was discussing the mopar long rod adavanatge and he said “the next time your chevy buddy starts bragging about his “long” 6 inch custom rods you can proudly point out that the factory rods in your lowly 318 work truck are 6.18 inches long.
    The small block chrysler also has a beefire bottom end than the small block chevy, with thicker webbing, bigger main caps and bigger cap bolts. That is why mopars don’t need a 4 bolt block in the majority of performance applications. They did make 4 bolt block 340’s for the AAR cudas and T/A challengers, but they were considered overkill and unnecessary.
    The big block chrysler has pretty much the same advantages over the big block chevy, much higher nickel in the block, beefier and longer rods and the bottom end is skirted making for an extremely rugged engine.
    All chrysler engines used wider cam lobes with .904 inch diameter lifters compared to .842 diamter gm lifters resulting in a greater wear surface, along with a better hardening process of the cam. That was why you almost never saw a mopar with a bad cam, something that was very common in chevies.
    All mopars back then also used shaft mounted rockers. They were expensive to build and added about 4-5 lbs. of weight. But they kept the rocker arm stable for consistent valve lift.
    The ball stud setup on cheveis let the rocker arm move around altering vale lift, and it progresses with higher valve lifts and rpm’s. That is why most big time chevy racers convert to a mini shaft rocker setup.
    As good as the mopar shaft setup was it was expensive to build, that was why they changed the design on the magnum version of the small block in the early 90’s. They came to a compromise. They came up with a pedestal design, very much like used on the ford cleveland and 429/460 and 73 and later AMC engines. It’s not as good as the old shaft setup, but better than the slip-n-slide ball stud setup used on the chevies, and much cheaper to manufacture than the shaft setup.


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