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post #1 of (permalink) Old 12-22-2000, 12:03 PM
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4 cyl to 6 cyl Conversion

The other day I was headed home from Maine to New York, a 425 mile trip. To make a long story short I ended up blowing my 4 cylinder engine. Granted that it had 142,000 miles on it so I new that it was not long for this world. Since I really want to up grade the engine to the 4.0 liter High Output engine, what would I have to do to accomplish this? The Jeep is a 1990 Wrangler with the original 4 cylinder still in it. I love this car to death and will do anything to save it. Thank you

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post #2 of (permalink) Old 12-22-2000, 01:13 PM
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Re: 4 cyl to 6 cyl Conversion

You will have to replace the tranny as well. The AX-5/AX-4 verity transmissions wont live long behind a 6 or 8 cyl. engine. Besides I am not sure that there is an adapter for that application(check Advance Adapters to make sure).

To do the I6 swap I would start looking for a Cherokee for swap material. B/c you will have to replace the tranny as well get the whole shooting match from the same vehicle, so you will know for sure that it will all match up. I personally would look for a wrecked Cherokee, they are plentiful. Get everything you need and remember to get one from a 4wd(that way you won't have to purchace the x-fer case adaptor that is already on the 4wd models). You should be able to find the complete engine, computer, and tranny for just a hair over $2,000.

If you have any inclinations to a V8 swap later on down the line, then this is your time. A wrecked TBI 350 chevy 4wd pickup is a great swap, and plentiful too(driving the price down somewhat). Get the engine w/ all assories, computer, tranny(the 700R4 is a good tranny) and you should be set. Should be able to find it all for less than $2,500 if you look enough. Those engines will run forever and there is so much aftermarket for them.

Also, if you dedide to do the swap(either to a 6 or 8 cyl. then you will need a new input gear for your NP231 x-fer case(yours, behind the 4 cyl. is a 21 spline, most 6 and 8 cyl. use a 23 spline input gear.

If you do a swap, either way, you will have engine mounts, large mechanics bill, and misc. other charges that you will incur. Other possibilities include: shifter for auto trans, new radiator, new hoses, new belts, etc.

Good luck, and get that thing back on/off the road.


[]llll[] '90 YJ, NV4500, XD9000i, 35" MT/R, Snorkle, 4.5" RE lift, Tera Revolvers, etc. etc.
post #3 of (permalink) Old 12-22-2000, 04:28 PM
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Re: 4 cyl to 6 cyl Conversion

besides the radiator, belts, hoses, wiring..and whatever.. you will also need new driveshafts.. or your old ones cut/lengthened.. and rebalanced if you do that.. you will also need a new exhaust.. i would go with the cherokee.. like mentioned above.. get the whole engine, tranny, and transfer case.. i would grab the driveshafts also.. you could always use those.. for something.. and take the radiator from it..


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post #4 of (permalink) Old 12-22-2000, 05:09 PM
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Re: 4 cyl to 6 cyl Conversion

have a good used 4 cly ,that whould solve all problems $500 nj jim 609-654-5070

post #5 of (permalink) Old 12-22-2000, 05:10 PM
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Re: 4 cyl to 6 cyl Conversion

have a good used 4 cly ,that would solve all problems $500 nj jim 609-654-5070

post #6 of (permalink) Old 12-31-2000, 12:32 AM
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Re: 4 cyl to 6 cyl Conversion

I do not recommend swapping in a 6 for the 4. I too have a '90 Wrangler and attempted the same swap you are thinking of. Basically to make a long (5 month and counting), sad, story short, go for a V8. The effort of converting to a 4.0L will be greater than that of going to an 8. I seriously caution you. There are big differences between Cherokees and YJs, yes they share the same core block, but differences include: computer/body controllers/wiring harness, engine mounts, and transmissions/mounts issues. Contrary to what you may read, it isn't a simple drop in, plug and play. If you would like to know more about the details of my story, drop me an e-mail.

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