4.2 to 4.0 motor swap information:

[Jeremy]

I am doing some leg work on a motor swap but I have some questions.    The jeep in question is a 1989 YJ wrangler with a carb 4.2 liter 258cid engine/automatic  it is stock, right down to the itty bity P215R15 tires and D35 rear end.    The motor locked up one week after purchase and it has been at a garage since.  The owners have sourced a 4.0 from a 1993 jeep (might be a wrangler or cherokee I do not know)  I also do not know if it is just the engine, engine with wiring harness, or a whole jeep. 

What do I need to make this swap work?  crank position sensor on the fly wheel or a vibration dampener sensor?

What about O2 sensors?   What are the wiring harness issues?

What about retaining the carb on the 4.0? will the carb intake bolt to the 4.0 head,  Cost is a factor here I am told.

Anyone know of a Running 4.2 available cheap,   I am trying to run down options and costs.   Thanks

[pa2phx]

it would most likely be cheaper to modify the 4.0 to run on the existing vehicle setup. rather than convert the vehicle to match the 4.0. there is a website www.jeepstroker.com, it is all people who do engine swaps in their wranglers and Cherokees. they will be able to give you all the exact info. all you need to do is register (its free) and post your questions. they will most likely ask you for the casting numbers from the block and head and then can tell you the fastest cheapest way to make it work.

[pa2phx]

Not that i am dismissing anyone's knowledge here. Just giving you every available resource.

[BCjeeper]

You could put the intake and carb on the 4.0. Would help cut cost and down time. Will need to slighty modify the intake but it does'nt take very long. If you use the distributor from the 4.2 it will be a bolt in and run. I'm not saying it is the best use of a 4.0, but it is easy and cheap. Jim