Mopar Slant Sixes

mminerbimminerbi Member Posts: 88
edited March 2014 in Dodge
Any interesting stories to support the reputation
that this engine had for running almost forever?
My parents owned two, a 1960 Valiant with the 170
c.i. version, and a 1969 Dart with the 225 c.i.
displacement. Both ran over 100,000 miles before
they were sold, but I understand some ran well over
200,000 miles.


  • isellhondasisellhondas Issaquah WashingtonMember Posts: 20,338
    Back in those days, most engines were flat worn out at 80-100,000 miles.

    A slant six was a different story! I knew a guy who had a Dart with over 200,000 miles on it.

    He blew a heater hose on the freeway. The traffic was so bad it took him awhile to pull it over and the engine siezed up!

    He had it towed to a shop, figuring it was the end of the line.

    Not so! The hoses were replaced, the coolant and oil was changed and it ran another few years until it got rear ended and was totalled.

    It died with over 300,000 on the clock!
  • Mr_ShiftrightMr_Shiftright Sonoma, CaliforniaMember Posts: 64,482
    I have never seen a slant six engine blow up, nor have I ever seen one with a thrown rod. I've taken some apart that were so worn and filthy inside that according to all the laws of physics it should not have been running.

    Also a simple engine to rebuild..about as many moving parts as a wood stove.

    Truly great engine, up there with Chevy 283, Studebaker 289, Chrysler 318 & 383, and Volvo B18 and B20. Virtually indestructible.
  • carnut4carnut4 Member Posts: 574
    I bought a "66 Dart GT with the 225 in 1970-for 1100bucks. Had 36,000 miles on it. The thing that we [ex-wife-bothstill in college] noticed about it was how comfortable and quiet the car was. The Darts, with their stretched wheelbase, had great legroom in back-better even than some full-sized cars. Anyway, in 1975, a young gal ran into it while it was parked at the curb-crunchin the left front fender and headlight. The damage came to a little over $600 then-close to a total-but not quite. I told them I wanted the car fixed, and took the check for $600. That night, I thought about it, and decided to just bank the money and drive the car the way it was. I wired in a new headlight, and drove it another 6 years, to a total of 167,000 miles. At this point, it needed a valve job, but was OK other wise. The car didn't owe me a thing, so one night a friend and I decided to see if we could get it to throw a rod. Stomped it continuously, holding it in first, literally beat the hell out of it for 20 minutes or so. Couldnb't break it. So, I finally ended up selling it for $200. My total cost of driving this car 130,000 miles over 11 years was--$400!
    Not bad. That car saved me a bundle when I didn't have it, and hauled us around everywhere in comfort. Now that was a damn good car!
  • Mr_ShiftrightMr_Shiftright Sonoma, CaliforniaMember Posts: 64,482
    I worked in a wrecking yard one summer while in college and one form of amusement was to start up the old cars, put a cinder block on the gas pedal, and run away until the engine seized. We used to keep a record of which engines lasted longest...VWs ran about 3 seconds, but I recall an old Hudson flathead going something like 9 minutes. Slant-6s were also quite rugged.

    I know this sounds cruel and stupid, but these cars were recycled and are now the fenders on your Camry, so their molecules are still circulating.
  • carnut4carnut4 Member Posts: 574
    Mr. Shiftright: That's a funny story. I would have laughed and laughed. Reminds me of a friend who worked in a gas station in high school. If someone he didn't like left their car for an oil change, he'd start it up and immediately race the engine after the change, and then laugh and laugh as he watched the owner drive away. That's one reason I've always changed my own oil......
  • isellhondasisellhondas Issaquah WashingtonMember Posts: 20,338
    Nothing could throw a rod like an old Chevy! I'm talking about the babbitted bearing engines!

    If you didn't heed the short warning...KABOOM!
  • Mr_ShiftrightMr_Shiftright Sonoma, CaliforniaMember Posts: 64,482
    Oh, yes, the 216 engine with (as I remember) little oil scoops attached to the rod caps to fling oil up into the cylinders....not very confidence-inspiring....splash lubrication, they called it.
  • FREDERICKFREDERICK Member Posts: 228
    Your stories are great fun and I thuroughly enjoyed reading them. The Chrysler slant six is on of the few Chrysler products that I've ever really thought of as bullet proof.
  • lockpaullockpaul Member Posts: 1
    For Slant six tricks of the trade, "E" me at [email protected]
  • cooksterdogcooksterdog Member Posts: 9
    i still have my '78' dodge D-100, stick,long bed p.u. and just bought a new Dakota with V-8,auto,
    and just can not say enough about it!I just got back from the sierra's and it performed perfectly!! 18mpg,and comfort up the wazoo! my old p.u. had almost 400M miles and is still hopping.
    in fact i will be using it as a work commuter!all that from a slant 6 that has only been torn down 2 times for repair and valves. still has 95 lbs of compression too! BUUUT the trans is losing its syncros and the rearend is howling like a banshee!
    I located a 1/2 ton van and will probably switch out the components to the p.u.all i can say, is if the Dakota lasts like my old Dodge, i'll be in heaven. {after i pay for 4 years!} SLANTS 4 EVER!
  • FREDERICKFREDERICK Member Posts: 228
    Slant or straight sixes were never real rockets but gosh darn they do last, and last, and last. In the 60's cars weren't so complicated with all the gadgets and it really is easy to keep these very basic cars/trucks on the road forever.
  • esneedesneed Member Posts: 16
    Back in 1979, when Chrysler was out on the street holding out for cash and as 'rich Cornithian leather trimmed' Cordobas were stockpiling on dealer lots, the local Chrysler-Plymouth dealer in my hometown went bankrupt, and sold all their inventory back to the bank - as a result, the bank had a garage full of cars to unload quickly - including 100 (yes, one-hundred) Cordobas - at a time when gas prices were soaring, and large cars were NOT in vogue.

    My parents purchased a 1978 Plymouth Volare 2-door, with a 225 ci Slant Six. In the history books, the Dodge Aspen/Plymouth Volare went down as one of the most trouble-prone cars built - ironically, this car was the opposite. The car was entirely new, and stickered for $6500; my parents purchased it from the bank for $3900. There were MANY exterior flaws with the car when we picked it up - fenders out of alignment, horrible paint job... but we took the car to the local Dodge dealer, insisted on repairs, and all was fixed to our liking - from that day forward - that car NEVER quit! My dad drove the car to Colorado and Nebraska on business very often - through snow storms, heavy rains, heavy winds, etc. - and while other cars would be off the road, my dad would keep chugging in his Plymouth - he put 275,000 miles on that car!!!... and the engine was still running reliably and smoothly when he sold it in 1992 for only $500 - The car had only 1 dent and some minor rust on the lower doors... yea, the Slant 6 engine wasn't quick or sophisticated, but it did its job and then some. it was, by far, the best car my parents ever had.
  • Mr_ShiftrightMr_Shiftright Sonoma, CaliforniaMember Posts: 64,482
    Did I already tell me Slant Six story? Stop me if I did....

    I was helping a friend track down a clicking noise which I thought was coming from a badly adjusted valve I took the valve cover off this greasy, beat-up, neglected, 200K mile pig of a slant six engine and...and...the entire valve train was stuck in a kind of grease-jell...a solid, square-ish, quivering blob of gunk just stuck there, shaped exactly like a glob of jello after you take the tupperware off.

    And I stuck my socket through this mess, tightened down on the valve lifter, without a gauge, until to got quiet, jammed the cover back down as best I could, torqued the bolts to something or other, and it ran great...might still be running, who knows?
  • isellhondasisellhondas Issaquah WashingtonMember Posts: 20,338
    For the youngsters here, it has to be remembered that back in the sixties, cars didn't go 100,000 miles without major work!

    They needed valve jobs, ring jobs, rebores, etc.

    But not the slant six! For some reason, they were indestructable! Even the automatic transmissions (torqueflites) were bulletproof.

    Where did Chrysler lose it?

    Putting new points in, though was a B***H! Remember, Shifty? The distributor was tucked away alongside the engine and it was easy to drop(and lose) the screws!
  • badgerpaulbadgerpaul Member Posts: 219
    I seem to remember, that if you didn't poke a hole in the oil filter you ended up creating quite a mess.
  • Mr_ShiftrightMr_Shiftright Sonoma, CaliforniaMember Posts: 64,482
    I used to just take the distributor out, that was easier in the long run. I remember these engines came with different color valve covers to help identify the CID...there was red, blue and yellow as I recall.
  • isellhondasisellhondas Issaquah WashingtonMember Posts: 20,338
    The early slant sixes were either 170 CID or 225's

    They both had red painted engines. You could tell the differnce by looking at the length of the bypass hoses. The 225 had a hose about 3" long. The 170's were very short.

    There weren't nearly as many 170's as 225's.

    Yeah, pulling the distributor was probably the way to go. Once, I had a distributor pulled out of an old Buick. While it was out, somebody decided to push the car a few feet. It was a stick shift, and it was in gear! I didn't know it had been pushed when I re-installed the distributor.

    Mr. S...You KNOW what happened!
  • Mr_ShiftrightMr_Shiftright Sonoma, CaliforniaMember Posts: 64,482
    Oh, yeah, and on those the distributor could go in about 90 different ways...but it was an easy fix....take out #1 spark plug, stick your finger in the hole, spin the engine with a remote starter until you felt compression, install the distributor with the rotot pointing to #1 wire on the distributor, and bingo! You start it up and a ten foot flame leaps out of the carburator. Then you do it all again, this time correctly.

    Let's see...I distinctly remember yellow valve covers, but that may have been the slant six truck engines, which were beefier in CID.
  • isellhondasisellhondas Issaquah WashingtonMember Posts: 20,338
    Yeah, I think some of the trucks had the yellow valve covers. I also seem to remember a 198 CID slant six in later years.

    Too bad they went away...
  • carnut4carnut4 Member Posts: 574
    The only disappointment I remember was gas mileage. My '66 Dart 225/Torqueflite would get as little as 15 mpg, and usually only 17-18. I expected more. I later had a Dodge Van with the 318. It delivered almost the gas mileage my Dart did, and was also nearly indestructible. I sold that Van with nearly 200,000 miles on the original engine and Trans-the Torqueflite had only been serviced once, and it delivered 18mpg on the road...
  • tdiaz339tdiaz339 Member Posts: 10
    Indeed the 225 I-6 is bulletproof, one of Chrysler's greatest achievements.
  • mminerbimminerbi Member Posts: 88
    Any ideas as to why the slant sixes were so durable compared to other engines of that era? Was it the design, understressed perhaps, or the way they were built?
  • Mr_ShiftrightMr_Shiftright Sonoma, CaliforniaMember Posts: 64,482
    It's all in the engineering...every now and then an automaker gets it just right regarding strength, internal design, oil and cooling properties, etc. Also it probably didn't hurt that the slant six is about as simple as a wood stove inside.
  • carnut4carnut4 Member Posts: 574
    I always wondered how the Slant Six could be so durable, with such a long stroke [4.125] and only 4 main bearings. I guess the massive crank and maybe the design of the crankcase might have helped. Seems like Chrysler made some good engines over the years-solid engineering. Too bad some of their bodies and workmanship weren't up to the same level of quality.
  • mminerbimminerbi Member Posts: 88
    Does anyone have information regarding how the Slant Six compares from a durability standpoint with the Chrysler 2.2 and 2.5 that was introduced in the 1980 K cars (this engine was discontinued with the introduction of the Chrysler Cirrus/Dodge Stratus)?
  • carnut4carnut4 Member Posts: 574
    T can only tell you that I have an 85 2.2 Turbo in a Dodge Daytona that has 210,000 miles on the original Turbo. The thing went 94,000 without a blink-when the timing belt let go. Luckily, Chrysler built in enough clearance in the valve gear [unlike Hondas and some others] I only had to replace the timing belt-for $148.00 including labor. At 167,000, the head gasket sprung a leak,which is fair for any car with an iron block and aluminum head. I figured at that point it was time for more than just a head gasket. Turned out I was wrong. I went for a rebuilt engine that turned out to have a junk head. Meanwhile I looke down the bores of the old block and kicked myself for rplacing it. The old head had been misdiagnosed as cracked-a Chrysler service bulletin showed that too late-to the mechanic who did the work. Anyway, after a year of ironing out problems with the new motor, replacing fuel injectors, etc. I have a beater car that goes like hell and is comforetable and fun to drive. The foreman at the local Chrysler dealer, who builds these things for 300 horsepower, told me I probably could have just replaced the head gasket and gone another 100,000 miles. [I still would have replaced the fuel injectors with fatter ones]. This car's had some bad rap from Chrysler critics and others, but it's a simple, if crude sounding, motor that has given lots of reliable fun [with careful maintenance] for 14 years.
  • bobs5bobs5 Member Posts: 557
    I have an 1986 Plymouth Reliant with a 2.2l, 5spd manual. Just replaced timing belt at 138k, previously at 75k. Bought used with 56k in 1990 for $1000. At the time I needed a "temporary" replacement car after totaling my Ford LTD Stationwagon.

    During my ownership I replaced the following:
    2 exhaust systems, 3 sets of tires, front driveaxles, 2 timing belts, rear springs, rear parking brake cables, front rotors, brakes, one window crank handle, normal tune-up parts, a windshield after a monster branch took it out when traveling 35 mph (ahhh).

    It has a lot of small things that need attention like, headliner is coming down, both windows have a stripped section in the movement, noise in front end while driving, seat is falling apart(duct tape application), small oil leak, left turn directional does not return after making turn, and lots of RUST!!!.

    The engine sounds like a diesel at idle, but keeps on going. I have never been left stranded by a mechanical breakdown. Insurance is cheap $480 a year, no collision.

    I definately got my money's worth out of this car, so am looking for something else.
  • mminerbimminerbi Member Posts: 88
    Interesting stories, Carnut and Bobs5. Is your Daytona equipped with a 5-speed or automatic, Carnut?
  • carnut4carnut4 Member Posts: 574
    5-speed. I must say too that the gear ratios, torque curve, and turbo boost make it lots of fun on a canyon 2 lane. 2nd, 3rd, and 4th are lots of fun wheb the boost comes. The first trans went at 112,000, when I got sucked in to a race with a little [non-permissible content removed] something turbo coupe. Bang scratch through 1st and 2nd, blew him off.. next morning, Trans oil all over my driveway. I'd thrown a spider geatr tooth right through the case-an 800 dollar OUCH! 100,000 miles later, I don't do that anymore.
  • mminerbimminerbi Member Posts: 88
    It could be argued that the "gas crisis" of the '70s and early '80s, which motivated Chrysler, GM and Ford to convert their cars to front wheel drive, was the single biggest factor that led to the demise of the Slant Six. It's too bad that Chrysler didn't save this excellent power plant by using it in its light trucks.

    With the benefit of hindsight, a case could be made that Chrysler lost an opportunity to offer a competitor to the BMW during the gas crisis years and after by introducing a rebadged version of the Plymouth Valiant as a Chrysler, with luxury appointments, such as leather, better suspension and steering, and a fuel injected version of the venerable Slant Six.
    Such a car could have offered more for the money than the BMW in terms of low initial cost and maintenance. The car I envision but never was, call it the Chrylser 200 just to give it a name, could have been marketed to driving enthusiasts, as a luxurious, yet fuel efficient alternative to the gas hungry V8s of the day.
  • carnut4carnut4 Member Posts: 574
    Yeah-Imagine the Slant six with a modern EFI system and other upgrades. The slant of the engine and intake runners could have been worked by Chrysler engineers. Might have been a good, durable base for a line of small SUVs. Or a sedan to compete with the BMWs. The engineering talent was always there for Chrysler-if only the bean counters and assembly quality had followed it through. I'm sure the Slant Six tooling is still there somewhere if someone wanted to play with it. Anyone listening?
  • mminerbimminerbi Member Posts: 88
    Good point, Carnut4. Maybe it's not too late to reintroduce an updated version of the Slant Six. Retro styling seems to be the rage these days? Why not modernized best of breed retro engines?
    It seems to me that the Chevy short block V8 and GM 3800 V6 are excellent examples of what continuous refinement can yield.

    And, as long as we're playing this fantasy game, the pre 1956 GM Hydramatics had four speeds, and very little slippage. They were also rugged.
  • isellhondasisellhondas Issaquah WashingtonMember Posts: 20,338
    And when they changed gears, you knew it!

    One tough, heavy transmission!
  • carnut4carnut4 Member Posts: 574
    I have one of those old Hydramatics in my 55 Pontiac Starchief. The car has 131,000 original miles on it. The fluid coupling acts much different from a torque converter. For example, when lugging at low-speed in 4th, the thing sounds and acts like a stick. And that 2-3 shift! Kick in the 4bb carb and hang on!
  • Mr_ShiftrightMr_Shiftright Sonoma, CaliforniaMember Posts: 64,482
    Oh, do tell us some of the turkey engines!
  • moparmadmoparmad Member Posts: 197
    The top ten worst V8's according to Car Craft,October 99 issue:
    I dont know if there is an order here but here thet are
    1. Pontiac Turbo 301
    2. Chevrolet 262
    3. '75 & '76 Cadillac 500
    4. Oldsmobile Diesel 260
    5. Oldsmobile Diesel 350
    6. Cadillac V-8-6-4
    7. Ford 255
    8. Buick 265
    9. Chevrolet 288
    10. Chevrolet 267
    The most colorful commentary was directed at the Olds 260 Diesel" It could barely outrun the rods falling out of it".
  • isellhondasisellhondas Issaquah WashingtonMember Posts: 20,338
    As bad as that Olds 260 diesel was, I knew a co-worker who drove one 125,000 plus miles without mishap. Even the mechanics at the Olds dealership couldn't believe it!
  • Mr_ShiftrightMr_Shiftright Sonoma, CaliforniaMember Posts: 64,482
    Sure, and there's always one person in a million who falls out of a ten story building onto a mattress.
  • speedshiftspeedshift Member Posts: 1,598
    Has anyone ever seen a Hyper-Pac slant six? Four-barrel, hot cam and high compression, from the factory. It was a regular production option for several years in the early '60s, and the parts were available from the dealer for some time after that. Also, I seem to recall that an aluminum-block slant six was available in the earliest Valiants, before the Hyper-Pac.
  • Mr_ShiftrightMr_Shiftright Sonoma, CaliforniaMember Posts: 64,482
    Yes, that is correct, beginning in mid 1961 you could get the Hyper Pak on the cast iron block or you could order an aluminum block engine with the Hyper Pak...this was a very limited production competition engine and I doubt many, if any, saw the street, either cast iron or aluminum. No real numbers are available, but the engine was rated at 195 HP but most drag racers claim to have verified closer to 275HP on the dyno. You can imagine what they did to Chevy sixes at the races.
  • carnut4carnut4 Member Posts: 574
    project car about 1961 or 62. It was a 32 Roadster with a slant six motor that had been all tweaked up-they called it the XR-6, I believe. Don't remember what the engine had-4 barrel, multi carb, or what. Anyone remember? I do remember it was very fast-for a six.
  • mminerbimminerbi Member Posts: 88
    Anyone know whether the tooling for the Slant Six (SS)is in storage or has been scrapped? I'm thinking that since GM will introduce a line of new inline sixes shortly, taking the venerable SS out of mothballs, equipping it with EFI, plus some other modern updates, could provide Chrysler with a low cost competitor to GM and BMW. Of course, the fact that the SS is an overhead valve design could be a drawback in the marketplace, but, then, Chrysler may reintroduce a modern hemi V8.

    To me, given that the Plymouth Prowler already broke with hot rod tradition by packing a V6 instead of a V8, it would have been even more interesting with a modified SS. Or, since the Plymouth brand will be retired, the '02 Prowler could feature the new Chrysler hemi V8. Personally, I find the notion of a revitalized SS every bit as interesting as a new age hemi.
  • Mr_ShiftrightMr_Shiftright Sonoma, CaliforniaMember Posts: 64,482
    No, I think 60s engines would be too heavy, big and inefficient for modern use. It's a great old engine, but kind of a wood stove, a big hunk of iron for the amount of power it puts out.
  • mminerbimminerbi Member Posts: 88
    Thanks, Shiftright. I respect your opinion, but wouldn't it follow that Chrysler could upgrade the old Slant Six as GM did with the Chevy V8 and the 3800 V6, and , in fact, as Chrysler has done with the pushrod engine that it still produces for its mini-vans and trucks?
  • Mr_ShiftrightMr_Shiftright Sonoma, CaliforniaMember Posts: 64,482
    I suppose they could do that, but I don't see it conforming to a front-wheel drive setup very well...if you get a chance to look at a slant-6, you'll see that it is one big engine...the fact that it lays over kind of hides its substantial size and weight. And besides, it would be hell to get it to conform to current emissions standards. You might as well start from scratch with a new design I think. Newer engines are really much better in terms of power and reliability than old ones.
  • moparmadmoparmad Member Posts: 197
    I agree Mr Shiftright.I think it would cost more to rebirth the bent six,than to make a new engine.I am also pretty sure I read somewhere that Chrysler scraped the tooling long ago.Mopar Action magazine ran an article on the new 300 Hemi C concept car that showcased the prototype of the new hemi.Ironically the new hemi will be 354 cu in,same as when it appeared in the 300B in 1956.It has hemisperical shaped combustion chambers in its aluminum heads,but I dare say that is where the similarity ends.I hope that manufacturers go back to inline sixs for trucks the natural low down torque of the engines would be welcome over the current horsepower war truck engines that give torque to gain less usable horsepower that just looks good on paper.
  • mminerbimminerbi Member Posts: 88
    I'm persuaded. Thanks to Shiftright and Moparmad for your explanations.
  • Mr_ShiftrightMr_Shiftright Sonoma, CaliforniaMember Posts: 64,482
    Actually, while many 6s are good on low end torque, torque itself is not dependent in any way on the number of cylinders. And these days, with all the variable valve time and valve lift technology (pioneeered in the 1980s), small light engines can perform much like larger engines used to.
  • moparmadmoparmad Member Posts: 197
    True,torque is more closely related to the bore/stroke ratio.Small light engines can perform similar to larger engines in horsepower but I think for torque there truly is no replacement for displacement.Many people seem to have forgotten that in a heavy truck intended to pull,and hual high wieghts that low rpm torque is a major plus.I have found many fellow workers in the construction business noticing also that the current V6's just aren't as good at pulling as the older straight sixes.
    Many old staight sixes seemed to have smallish bores and long strokes(torque motors).As the stroke on a V6 increases so does the hieght and width.A long stroke six,only increases in hieght.
  • Mr_ShiftrightMr_Shiftright Sonoma, CaliforniaMember Posts: 64,482
    Yes, that's interesting. I like straight-6s, and espcially DOHC sixes--I think they sound the best of any engine, too.

    Ah, you're talking about the old days when a person drove a truck because they needed to work with it :)
This discussion has been closed.