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Cummins 4BT YJ Build!

89K views 71 replies 32 participants last post by  Chris.400 
#1 ·
Hey guys, I know there is always talk and controversy over the 4BT YJ engine swap, so I figured I would post my build up here.

The basics:

This was for my senior project to graduate with my BS in Mechanical Engineering Technology from Penn State.

I started with an 89 YJ I bought with no driveline, almost new interior, but ugly faded canary yellow paint.

I drove to Ohio and bought a 4BTA that was in a bread truck, It came with the alternator, power steering pump, turbo, aftercooler and some other junk.

I bought an NV 4500 5 spd, adapter, clutch, flywheel, master/slave, bellhousing, from a dodge ram 2500 that had a 12v cummins.

I got an adapter kit to mate the jeep NP 231 to the NV 4500

Got to work....

These are pics right after I loaded everything up from my house to take down to the school shop. I built this Jeep in the Penn State Harrisburg campus Engineering shop.
 

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#59 ·
A shop near me quoted me $10k to do mine. That supposedly includes everything.
 
#60 ·
That is actually a really good price. There is a shop called Jeff Daniels Jeeps in PA, they do 4BT swaps a lot, and quoted me at around $20K :eek:, including engine, trans and everything, which I thought was absurd.
 
#61 ·
LMAO. That is the shop I am talking about. I was talking about keeping the AX15 though and going with a 4BT that costs about $3k. That was to have all the wiring done, have them do the engine, and fabricate a few things it would take to make it fit. Because of the PITA it is to do that I am going to do a 302 instead. I would preffer the diesel, but its just too expensive.
 
#62 ·
Oh I see you are from the philly area, I grew up in Morgantown PA.

oh yea, 10k is way too much, I am at 7k including the jeep haha, I would never pay someone to do this swap.

A V8 is definietely cheaper
 
#67 ·
Subbed as i just jumped into a 4BT build myself! Found a 4BT all ready to go with trans for what sounds like a great deal and already have a buyer for my 4 banger. I sent you a PM about the brackets and I do have wiring harness questions. Part of me would love to rip out all of my crappy '95 wiring and start from scratch but I think wiring is too much for me to take on and possibly too much for my buddy who redid a bunch of my wiring when i bedlined my YJ inside and out.

Do you have any advice in the wiring department?
 
#68 ·
Wow, it has been a while since I updated, I have been way to busy, that most I have done to my Jeep is mount a Plow on it to push all the snow we had all winter.

I got the intercooler off of ebay, there are tons of cheap "Ricer" aftercoolers on ebay in all sorts of shapes and sizes.

Thanks guys, maybe it will be road legal this summer, but I said that last summer....:atomic:

wiring is a PITA, no way around it haha
 
#71 ·
You can get just as much for a 4 cyl. The only reason people buy stock motors usually is because they are scared to swap in a better motor or they wouldn't be looking at either stock motors. They would go with a v8 or diesel. Usually they have a jeep all ready with a bad motor to drop the motor in so they can make a buck or drive it.
 
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