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  1. #1
    Chango1079's Avatar
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    4 cyl to 6 cyl swap

    I have a '93 four banger, 5 speed on 31" all terrains. I don't get any power out of it and have to get a running start to go over bridges or pass someone. I'm thinking I want to swap for a bigger engine but don't know what all I would need to do to even get started. P.S. I'm not very mechanical but I can find someone to help.

  2. #2
    TerryMason's Avatar
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    Re: 4 cyl to 6 cyl swap

    Welcome to Jeepz.com!

    Any idea if your engine is in good shape (good plugs, wires, fuel filter, etc)? If you haven't kept up on maintenance in a while then that may be a good place to start. You could even go as far as doing a compression test on the cylinders, if you think that your engine isn't making the power that it use to.

    Assuming your engine is fine, you could regear the axles. This can be expensive, but may still be less than an engine swap.

  3. #3
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    Re: 4 cyl to 6 cyl swap

    The engine is in pretty good shape as far as I know. It has never had any power. So how expensive are we talking on re gear? Surely it is cheaper than an engine swap. Again I wouldn't even know where to start but I have a mechanic that can help he jus doesn't know jeeps

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    Re: 4 cyl to 6 cyl swap

    From what I see online the parts for 4.88 gear set will run $400 plus labor. 4.88 is the lowest you can go in the Dana 35.

    As far as engine swap your looking at new mounts;engine; transmission;drive shaft. In my opinion not worth the cost to go-to a 6 cylinder may as well above a V8 in it cost would be about the same.

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  5. #5
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    Re: 4 cyl to 6 cyl swap

    Well labor ain't a problem as my father-in-law is a mechanic, but he won't tell me what i need because it only creates more work for him

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  6. #6
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    Re: 4 cyl to 6 cyl swap

    Well start with a pcm. Ecm. Motor mount kit. Headers. And cat and muffler.might want to beef the suspension. Bigger cooling fan. And air intake.


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  7. #7
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    Re: 4 cyl to 6 cyl swap

    I agree with terry post #2 - what shape is this engine in ?

    Swapping an engine for someone not DIY is not a option -

    The 2.5 should make a nice daily driver With a 5sp.

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    xt master's Avatar
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    Re: 4 cyl to 6 cyl swap

    There is some small thing you can do to that 2.5 to gain a little extra power also. I noticed a difference with a better exhaust and CAI. Also you could remove the belt driven fan for some E fans.

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  9. #9
    Bounty__Hunter's Avatar
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    Re: 4 cyl to 6 cyl swap

    Going back to stock size tires will help you get some power and performance back.

  10. #10
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    Re: 4 cyl to 6 cyl swap

    Bounty__Hunter that is not an option. I want my baby to do what i need her to while looking good at the same time

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  11. #11
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    Re: 4 cyl to 6 cyl swap

    Bounty hunters suggestion is NG then we are back to post #2 engine condition then suggested gear change.


    What is differential ratio now?

  12. #12
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    Re: 4 cyl to 6 cyl swap

    I have no idea what the gear ratio is now. All i do know is that it is stock

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    Re: 4 cyl to 6 cyl swap

    Post #2 seems to be my best bet i believe

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    Re: 4 cyl to 6 cyl swap

    Look at each axle, both front and rear. You'll see the differential (the round section), has a cover that is held on by a number of bolts. One of those bolts should have a metal tag attached to it. This tag will tell you the gear ratio of your differential. It will look like this:

    4 cyl to 6 cyl swap-15842d1357679524-terrymason-s-2005-jeep-tj-build-01-axle-id-tag-terrymason-jeep-wrangler-tj-terr.jpg

  15. #15
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    Re: 4 cyl to 6 cyl swap

    Quote Originally Posted by Chango1079 View Post
    I have no idea what the gear ratio is now. All i do know is that it is stock
    4.10/4.11 is the stock ratio. 4.88 is as low as you can go with the stock axles.

    I didn't figure you'd downsize, most don't want to, favoring appearance over performance.

  16. #16
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    Re: 4 cyl to 6 cyl swap

    Will 4.88 be good enough though?

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  17. #17
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    Re: 4 cyl to 6 cyl swap

    It won't pull you back in the seat, that's for sure. It'll have about the same affect on performance as if you were to go back to stock 27" tires. You still have an anemic engine.

  18. #18
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    Re: 4 cyl to 6 cyl swap

    I agree with most if not all that is stated above.
    The gearing will be immediate.
    The comments on health are important. Minimizing losses are as important as adding hp. Look for hp or torque losses. Items as simple as tire pressure, alignment, dragging brake, worn wheel hub, bad u joint or axel joint. Drivetrain angles. The health of the transmission and torque converter all can rob the hp and torque. Items on the engine like an undersized or failing alternator, ax unit and clutch fan rob both ho and torque. Moving to an electric fan was the biggest and easiest improvement.
    The engine health is next as mentioned compression test, fuel pressure, clear exhaust(not blocked CAT) proper plugs and gapping, intake flow and no leaks...
    All are cheaper and primary to output.


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  19. #19
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    Re: 4 cyl to 6 cyl swap

    Thats what I'm saying though, I've had it for twenty years and it has never had any power. I bought it with 31" tires on it and have never financially been in a position to upgrade anything. Now I am but dont know where to start. I was told once putting a straight 6 would do what i want, but it is sounding like all i really need is to regear the front and rear ends.

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  20. #20
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    Re: 4 cyl to 6 cyl swap

    Regearing is the quickest easiest and least expensive direct improvement. You can expect a change in mpg as you will be at a higher rpm to maintain the same speed.


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    JPNinPA

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