1985 Eldorado 4100 engine swap
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HT4100 4.1, 4.5, 4.9 Discussion, 1985 Eldorado 4100 engine swap in Cadillac Engine Technical Discussion; I've had it with the original engine and don't have any confidence in a rebuilt. Does any one know of ...
  1. #1
    mrboots54 is offline Cadillac Owners Member
    Automobile(s): 1985 Eldo
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    1985 Eldorado 4100 engine swap

    I've had it with the original engine and don't have any confidence in a rebuilt. Does any one know of a swap that will work or had done one? I had an 84 Buick Riveria front wheel drive with the Pontiac 307, 4 barrel carb that had lots of power yet got very decent gas milage. That would be my swap of choice. Looking for suggestions. Thanks

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  3. #2
    MrDobin is offline Cadillac Owners Fanatic
    Automobile(s): 1985 Cadillac Seville Elegante
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    Re: 1985 Eldorado 4100 engine swap

    I have a similar thread labeled Engine swap need input. I have an 85 seville myself. What I was given by one guy(assuming the instrumentation on your eldo is the same as mine) was as such below-------V

    http://www.cadillacforums.com/forums...eed-input.html

    The best I was told of was these -------

    Bad news: The 4500 is not going to fit in your car. The 4500 was made to fit transversely and for your car, the engine sits longitudinally. However, you do have some other choices including:
    403 Olds
    350 Olds
    6.2 Diesel
    6.5 Diesel
    5.7 Diesel (Not good choice)
    3.8 Buick V6

    The 403 could be made to work with all the electronics. However, it'll be hard on gas but have good power. The 6.2 diesel would get you 35+ mpg and would have even more power than the 403 with a turbocharger
    or some head work but would have that diesel clatter.
    -------------------------------------------------------------------------
    Hope that helps

  4. #3
    ehall's Avatar
    ehall is offline Cadillac Owners Connoisseur
    Automobile(s): 1985 Sedan DeVille
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    Re: 1985 Eldorado 4100 engine swap

    If it's RWD you can use almost any RWD engine available, ranging from generic 350 to LS1

    If it's FWD you are basically stuck with the 4.x series with a replacement longblock under the existing manifold

  5. #4
    MrDobin is offline Cadillac Owners Fanatic
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    Re: 1985 Eldorado 4100 engine swap

    I envy you and your car then sir. Lol.

  6. #5
    carnut is offline Cadillac Owners Master
    Automobile(s): 1988 Allante' (sold), 1984 Eldorado, 84 Sedan DeVille
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    Re: 1985 Eldorado 4100 engine swap

    The 85 Eldo is an E body car, so any E body, Toro, Riviera, or Eldo will provide all the parts to install an engine from a 3.8 Buick to a 403 Olds. Best to buy a diesel donor car to install an Olds gas V/8 engine. The Olds is a 307 a 350 or a 403. All share the same basic block with a diesel and will bolt to the Caddy trans. You need a diesel donor because you need the specific front wheel drive oil pan, oil pump and pick up, engine mounts and belt driven acessories as well as proper exhaust manifolds. Rather an easy swap assuming you have a donor car. One swap not thought about too often is the 4.1 V/6 gas engine in the 84 Cadillac with a 4 bbl carb. Same basic engine as the 3.8 V/6 in a Toronado.

  7. #6
    zac85eldo is offline Cadillac Owners Member
    Automobile(s): 1985 eldorado
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    Re: 1985 Eldorado 4100 engine swap

    Categorize Your QuestionYour Question
    cost to rebuild ht4100?
    I have an 85 eldorado 4100 fwd I got it fairly cheap 1500 good shape will need paint runs fine just slughish and for a car thats suppose to get 20 miles a gallon im getting 11 recently the water pump went out im worried about the over heating it experienced im having the water pump replaced but for such a beautiful car im am realy disapointed with the power I have had 425 caddys 500 and a 501 this has the worst exceleration I have ever experienced out of a v8 I been thinking I could care less about the fi or if the dash warning lights work since I could get after market gauges im worried about the digital spedometer working and other things like fule pump automatic dimmer lights is it posible for me to just get a 350 olds and drop it in without adding to much weight or having to spend to much money on all the electrical work I also heard the 403 would fit I pondered the 307 but heard it only had 20 more ponies If I were to do that I might as well stick with the 4100 plus I have an 85 I heard that their not quite as bad as the earlier 4100"s I also heard if I have mine rebuilt the aluminum would expand like .0001 of an inch beinging after alot of miles the heads are the only thing keeping it from expanding and I would never again have a proper sill I also though about finding a 368-64 and cutting the wire that controls the 8-6-4 application I have 2000 dollars to spend I know thats not that much what whould get the most bang for the buck consider I dont care about fuel economy or I wouldnt have bought an v8 Id be happy with a 500 lol but dont thing the tranny and my wallet could hold up to the 500 please stare me in the most inexspensive route taking in account the 4100 is still running
    Based on your question, we think it belongs in one of these categories:
    Suggested Category

  8. #7
    carnut is offline Cadillac Owners Master
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    Re: 1985 Eldorado 4100 engine swap

    Please!!! from now on use SPELL CHECK and find the period button on your key board.

  9. #8
    83CADMAN's Avatar
    83CADMAN is offline Cadillac Owners Fanatic
    Automobile(s): 83 Eldorado, 90 Seville, 94 Concours
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    Re: 1985 Eldorado 4100 engine swap

    Quote Originally Posted by zac85eldo View Post
    Categorize Your QuestionYour Question
    cost to rebuild ht4100?
    I have an 85 eldorado 4100 fwd I got it fairly cheap 1500 good shape will need paint runs fine just slughish and for a car thats suppose to get 20 miles a gallon im getting 11 recently the water pump went out im worried about the over heating it experienced im having the water pump replaced but for such a beautiful car im am realy disapointed with the power I have had 425 caddys 500 and a 501 this has the worst exceleration I have ever experienced out of a v8 I been thinking I could care less about the fi or if the dash warning lights work since I could get after market gauges im worried about the digital spedometer working and other things like fule pump automatic dimmer lights is it posible for me to just get a 350 olds and drop it in without adding to much weight or having to spend to much money on all the electrical work I also heard the 403 would fit I pondered the 307 but heard it only had 20 more ponies If I were to do that I might as well stick with the 4100 plus I have an 85 I heard that their not quite as bad as the earlier 4100"s I also heard if I have mine rebuilt the aluminum would expand like .0001 of an inch beinging after alot of miles the heads are the only thing keeping it from expanding and I would never again have a proper sill I also though about finding a 368-64 and cutting the wire that controls the 8-6-4 application I have 2000 dollars to spend I know thats not that much what whould get the most bang for the buck consider I dont care about fuel economy or I wouldnt have bought an v8 Id be happy with a 500 lol but dont thing the tranny and my wallet could hold up to the 500 please stare me in the most inexspensive route taking in account the 4100 is still running
    Based on your question, we think it belongs in one of these categories:
    Suggested Category

  10. #9
    steveclv is offline Cadillac Owners Member
    Automobile(s): 84 Eldorado Convertible
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    Re: 1985 Eldorado 4100 engine swap

    I bought my 84 Eldo Convertible with a rebuilt 4100 and it runs beautifully and it gets 27mpg highway and 18mpg town driving on regular gas.

    If you do an engine swap then your fuel consumption is going to go south and at $5 a gallon that might be worth considering.

    Also these cars are on the cusp of becoming collectible in maybe 5-6 years time and so originality might be worth keeping.

  11. #10
    steelybill is offline Cadillac Owners Enthusiast
    Automobile(s): '85 Fleetwood FWD
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    Re: 1985 Eldorado 4100 engine swap

    For a 4100 swap, I was told to just upgrade to the 4.5 and lose some of the 4100 issues. Supposedly, ( I don't know ) the DFI system will work with that swap.

  12. #11
    frankie d is offline Cadillac Owners Member
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    Re: 1985 Eldorado 4100 engine swap

    dose a caddy fleetwood 4100 fit a 1985 caddy eld car

  13. #12
    carnut is offline Cadillac Owners Master
    Automobile(s): 1988 Allante' (sold), 1984 Eldorado, 84 Sedan DeVille
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    Re: 1985 Eldorado 4100 engine swap

    No! unless the Fleetwood is a rear wheel drive car. There were 2 fleetwoods. Front wheel or rear wheel drive.

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