i have an 87 yj with 4.2 and dreaded peugot trans, i can get a 92 wrangler with 4.0 engine and i think it has ax15 trans. what i'm wanting to know is has anyone done this swap and what all is involved. i've built many samurais but this is my first jeep, so welding and fabricating is not a problem, i just need some help from experienced jeepers thanks

i swapped in a 4.0 out of 91 YJ into my 87 YJ. plus i did the 3550 tranny out of 01 TJ so what do you want to know first:flipoff2:

did the 4.0 bolt up to the 4.2 mounts and did you use both wiring harnesses. the factory harness for gauges and lights, and 4.0 harness for engine, or did you just adapt one harness. as far as power how is the 4.0 compared to 4.2. thanks

did the 4.0 bolt up to the 4.2 mounts and did you use both wiring harnesses. the factory harness for gauges and lights, and 4.0 harness for engine, or did you just adapt one harness. as far as power how is the 4.0 compared to 4.2. thanks


yes the 4.0 and 4.2 same motor mounts

i ditched the entire 4.2 wiring and used the 4.0 harness and computer (it's the only way)

you have to splice about 5 wires at the bulkhead plus some misc glitches i had to iron out along the way

i ditched the 4.2 guages and installed some autometers

power? well i just can't get past the FUEL INJECTED advantage to talk about any power gain:flipoff2:

keep the crank and rods from the 4.2 to build a 4.5 stroker in the future.(about 240hp and 290 trq):smokin:

thanks alot sounds like a pretty easy swap when your say bulkhead you mean??????

thanks alot sounds like a pretty easy swap when your say bulkhead you mean??????

wires coming from the dash through the firewall on the drivers side. these wires feed the ignition etc (not sure what all). i had to spile into some 5 or so of these wires with the 91 harness wires to make it work (start).

it's been a couple years so i can't remember all the details but i did the swap on my own with the help of this and other boards info.

i also ditched the stock gas tank and installed a fuel cell at the same time of the swap.

what radiator did you use

also what fuel pump to use, i know it's gonna be electric but what pressure does it need. also the engine i'm using is out of a 90 cherokee, not wrangler i know it dont matter but just thought i'd get that straight.