99 engine in an 89 xj

[hizroyalty]

hey all i am fairly new to this site, and have found it useful so far, however i am trying to figure something out...i have an 89 xj 4.0 that has a slight rod knock at start up that goes away after warming up, but thats not the concern...i have a 4.0 out of a 99 that i would liek to install....the question is are the long blocks the same??i thought i read somewhere u cant use the newer motor in the older jeep....i can use all the brackets/acessories off of the motor oin the jeep now, as well as intake and exhaust manifolds...is there anything else that will stop me from doing this swap??i dont wanna waste any money on the motor if i cant use it..any input would be great, thanks

 

[ehall]

http://www.terrainstompers.com/forum/viewtopic.php?t=14 has a pretty good write-up and there is also lots of info here if you search

 

[hizroyalty]

ok kool thanks for the info that told me everything i need i believe...i should be able to use the intake manifold off of the 89 on the 99 engine right?if so that will take care of any sensor issues or anything..i was just not sure if the cylinder heads were the same or not...thats my biggest concern...i plan on using all the old parts, just the new long block assembly

 

[1990JEEPXJ]

like you said, you can use the lock block from the newer one. i would do that and use the head, intake, and exhaust from your current engine. that way you can use all your preexisting sensors. i think the newer head might work with the 89 intake and exhaust, but im not 100%. i would verify that.

 

[hizroyalty]

yup thats what i need to know so i can send the right head to my machinist