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If Chrysler Used the 3.9 V6 in the F/J/M Cars?

Discussion in 'F-J-M: Volare, Diplomat, etc, 1977-89' started by PlymouthShelbyCuda86, Feb 27, 2017.

  1. PlymouthShelbyCuda86

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    How would sales of the M-bodies post-1983 have been had Chrysler offered the 3.9 V6 (you know, a 5.2 (318) "LA" V8 minus two cylinders) for the 1984-89 models to replace the 3.7 (225) "Slant Six" (and likewise offering the 5.2 V8 with EFI as well for the trio that was the Chrysler Fifth Avenue, Dodge Diplomat and Plymouth Gran Fury before they all had been dropped)?

    In fact, I believe the 3.9 V6 could've also been marketed for the 1979-81 R-body cars (Chrysler Newport/New Yorker, Dodge St. Regis and Plymouth Gran Fury).

    Another engine that Chrysler could've made a V6 out of during their dark years to replace the now fully-grown-up 3.7 Slant Six was the former 4.5 (273) V8, which was the very first in the "LA" engine series (1964-67), which as a V6 would displace 3.4 liters (205 cubic inches), and which the 3.9 V6 would have also replaced around 1985. The 3.4 V6 (as well as the 3.9) would have competed with the 3.8 V6s made by both Chevrolet and Buick in the early 1980s, as well as Ford's Essex 3.8 V6.

    What would you think?

    ~Ben
     
  2. voiceofstl

    voiceofstl Well-Known Member

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    I think it would have been to little and to late...if they could have used the later v8 magnum engines.....of course thats like saying or use the hemi.
     
  3. valiant67

    valiant67 Rich Corinthian Leather
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    The 3.9 V6, especially in 1987 carb trim was an underpowered slug. It got better in1988 with TBI but yet wasn't overly fuel efficient. Having owned a 3.9 powered Dakota, my opinion is the 3.9 would not have helped the cars.
     
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  4. Lee N. Burns

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    No one buying in those segments was doing so for fuel economy. Not to mention that the 3.9 didn't come around until 86-ish, by which time they had either gone out of production (R) or were already on borrowed time (M). If you really wanted to give those cars a shot in the arm, money would have been much better spent on an overdrive automatic transmission before 1990. That would have allowed axle ratios beyond 2.21:1, yielding better acceleration and quieter operation. Improved city/highway MPG would have been icing on the cake.
     
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  5. valiant67

    valiant67 Rich Corinthian Leather
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    Yep, the "large" Chrysler cars of the 1980s were sized similarly to GM and Ford's intermediate cars and got worse gas mileage than the fullsize GM and Fords.
     
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  6. ImperialCrown

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    The 2.5L OHV, 3.9L and later 3.7L/4.7L were all used as Jeep/Truck engines (JTEC). They were not certified for use in passenger cars, but possibly could have been.
    It was important to get EFI into the domestic 4 cylinder passenger cars first. Chrysler in 1984, then Dodge and Plymouth in 1985. Trucks didn't get EFI until 1987 1/2.
    The Jeep Cherokee 4.0L had the Renix (Renault/Bendix)EFI system when Eagle/Jeep became part Chrysler. Carburetors had had their day.
     
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  7. PlymouthShelbyCuda86

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    But what about if they had turned the former 273 V8 into a 205 V6 by hacking off two cylinders? That may have been the perfect replacement for the 225 Slant Six.

    ~Ben
     
  8. valiant67

    valiant67 Rich Corinthian Leather
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    A V6 engine is usually rougher and has less low end torque than an inline 6 engine. The only reason V6 engines really became popular was because they were shorter (especially when considering the FWD cars with transverse engines).
    There really was no benefit to the M body cars to have the V6 instead of the slant 6.
     
  9. ImperialCrown

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    The first 3.9L engines were uneven-firing V6's. They idled rough. The inherently balanced in-line sixes didn't have this issue. A major customer satisfaction complaint in the carb-emission days was a 'rough idle' anyways.
    Buick was big into V6 engines beginning in the early-'60's. They had an aluminum one and Oldsmobile developed a turbocharged one. Early GM V6's had mechanical problems.
    Ford borrowed V6 engines from their European subsidiaries for small cars, which were more developed and refined than GMs.
    Chrysler was late to the party with V6 engines. The slant-6 did very well for decades.
     
  10. GLHS60

    GLHS60 Well-Known Member

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    V8's converted to V6 with their 90 degree V angle are hard to tame.

    60 degree V6's are inherently smoother.

    Buick tried a 90 deg V6 in 1962 and sold it to Jeep around 1965.

    G.M. bought in back around 1974 and refined it over the years proving you can polish a turd!!.

    All 90 deg V6 Engines are a tough compromise.

    60 deg V6's tend to be very smooth EG: Chrysler 2.7, 3.3. 3.5, 3.8 and now the Pentastar.

    As mentioned Ford borrowed their first V6 from Europe, the Cologne.

    While there were more variations, it was mostly a 2.8, 2.9 and 4.0L & 4.0L SOHC in North America

    Oddly enough the later Ford 3.8 V6 was a copy of the Buick 3.8!!

    Rebuilding The Ford 3.8L Engine - Engine Builder Magazine (at http://www.enginebuildermag.com/2001/09/rebuilding-the-ford-3-8l-engine )

    Thanks
    Randy
     
  11. Dave Z

    Dave Z It's me, Dave
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    I have to agree... injecting the slant six would have been a far better choice... but it was never that easy. (And the execs were cheep. Plenty of cash for image cars, not so much for driveability.)
     
  12. Meester Beeg

    Meester Beeg Active Member

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    If driveability was the priority then tbe /6was the way to go. Proven and tough as nails. The more they made the better their return on investment.
    Money was tight back then and R&D and tooling to produce the LA V6 wasnt there. And the driveability would have sucked. Customers would have screamed seeing the V6 shake like a wet dog at idle.
    Yes, FI would have been the way to go but IMO the engineers may have still had the bad taste from the failed FI from the late 50s that they sold to Bosch which became the Jetronic system.
     
  13. ImperialCrown

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    The '81-'83 Imperial DFI was an expensive mistake as well. Many of them were retrofitted back to a 2-bbl carburetor fuel and intake system.
    They did run nice when they ran. It was a shame that the development and diagnostics weren't better.
    Of course the Lincolns and Cadillacs of this era had problems as well.
     
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  14. valiant67

    valiant67 Rich Corinthian Leather
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    But yet, just a few years later the TBI saved the 2.2 from troublesome carb issues!
     
  15. Dave Z

    Dave Z It's me, Dave
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    Yup - the typical Chrysler mistake of insufficient testing with the Imperial system. It was a unique setup, continuous flow relying on fuel pump pressure changes to alter fuel flow. An interesting idea.

    Even a simple TBI system would have done wonders for the Volare and Aspen.

    I owned a 1979 VW Rabbit which had multiple port electronic injection — very nice to have back in the day. No starting/running problems, though it had a quirk regarding idle maintenance ('twas a stick). Would have loved that on my daily driver cars of the time.
     

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