4.7 or 5.7 Swap

[05KJBaj]

Hello everyone

I have an 05 KJ.
Since I own it I had very bad luck with the 3.7, first blew up 5 years ago after a year of ownership because of water pump failure, replaced the whole engine, lasted until a year ago when the conrods went knock knock. Now a few months ago I installed another 3.7 that seemed to be clean, drove the car less than 5k miles and now surprise it is knocking again...
Now I am seriously considering throwing the 3.7 away and go for a v8. I can get them for a very decent price with the whole harness and ecu (around 800$ which is the same price as a 3.7)

So here is the question, which v8 will be easier to swap with the less modifications possible. 4.7 or 5.7? The 4.7 is just a longer 3.7 and has the same engine mounts and accessories placement. 5.7 looks way more different.

Any answer will be appreciated, and don't tell me it's not worth it I already spent too much on the car to care

 

[tommudd]

An LS

 

[sleazy rider]

Do some measuring in the engine bay and get back with us after measuring the engines you suggest.

 

[JRB]

After owning two ls1's and swapping a ls1/t56 into an fc rx7 after I blew up the dorito's motor with a buddy, I have to go with tom's answer on lsx. If something happened to the 3.7 in mine, that'd be the route I'd take, then I'd be back to a familiar engine to work on lol.

My reason being is the amount of sheer aftermarket options for it for mounts/bellhousings, computer adaptations, plus I've seen two pictures in the archives here of people swapping them in kjs.

Out of the two you listed, the 4.7 'seems' like an easier swap. Always some unforseen trouble with swaps lol.

 

[LibertyTC]

Could also consider another 3.7 from Jasper Engines that drops in.
See this thread. https://www.jeepkj.com/threads/what-engine-to-put-in-my-kj.77748/

 

[05KJBaj]

After owning two ls1's and swapping a ls1/t56 into an fc rx7 after I blew up the dorito's motor with a buddy, I have to go with tom's answer on lsx. If something happened to the 3.7 in mine, that'd be the route I'd take, then I'd be back to a familiar engine to work on lol.

My reason being is the amount of sheer aftermarket options for it for mounts/bellhousings, computer adaptations, plus I've seen two pictures in the archives here of people swapping them in kjs.

Out of the two you listed, the 4.7 'seems' like an easier swap. Always some unforseen trouble with swaps lol.

Thanks. If I was going for a real build with a real budget I would definitely get an ls and 4l80, no question.

But I wanted to do an oem+ kind of swap, I will keep the v8 stock. I am pretty sure it will cost much much less to drop in a Jeep engine in there rather than getting an ls and custom ecu and make custom engine mounts and custom bellhousing. Also I am in the middle east so getting a Jasper engine is not an option, and ls custom parts are not easy to bring.

I will go take measurements tomorrow of both my engine bay and the v8s. I had seen one guy doing the 4.7 swap and it fitted (a little tight), just removed the clutch fan.

 

[beelatch]

There is another 'stock' option. Find a wrecked 05 or 06 2.8 CRD diesel. I get 30 to 33 mpg with mine and it has way more torque than the 3.7 or 4.7. I actually did an 05 CRD swap into an 02 3.7 that was dead, I think I posted a write up but that was 10 years ago. The only things that didn't directly swap were the sun visors, the windshield washer reservoir and the transmission mount on the cross member, but those are all easy fixes. I have seen many 3.7s and 4.7s with blown head gaskets from overheating.

 

[05KJBaj]

There is another 'stock' option. Find a wrecked 05 or 06 2.8 CRD diesel. I get 30 to 33 mpg with mine and it has way more torque than the 3.7 or 4.7. I actually did an 05 CRD swap into an 02 3.7 that was dead, I think I posted a write up but that was 10 years ago. The only things that didn't directly swap were the sun visors, the windshield washer reservoir and the transmission mount on the cross member, but those are all easy fixes. I have seen many 3.7s and 4.7s with blown head gaskets from overheating.

That is an interesting suggestion, also there is one laying in my local junkyard. But sadly the 160hp won't cut it for the type of offroading we do here (big big dunes, 70mph and some ratatata).