Calgary Jeep Association

4x4 Related Groups => Tech Talk => Topic started by: Iron James on December 26, 2006, 12:02:21 AM

Title: 5.9L ZJ
Post by: Iron James on December 26, 2006, 12:02:21 AM
I was just wondering if anyone knows if the 5.9L ZJ engines can swap right into the 93-98 ZJ's?? I can't seeing there being any huge issues but just wondering if anyone knows off hand.

 Thanks
 - Joel
Title: 5.9L ZJ
Post by: cLAY on December 26, 2006, 06:46:00 PM
ECM is different but will run with the 5.2L ecm but you won't get the full HP out of the 5.9L The Mopar performance PCM will give better results and a stock 5.2L ECM.

 Somewhere around '95 they changed the tranny to a 42re from the 42rh. re=electronically controlled; rh=hydraulically controlled so the wiring for the tranny is going to change. The 5.9L comes with a 46RE tranny. So you couldn't put the 46RE tranny in place of 42RH(no electronic support) but the 46RE should bolt in place of a 42RE. However I think that you could bolt the 5.9L to a 42RH if you used the correct flexplate/TC. 5.2 and 5.9L are balanced differently so you need to use the correct flexplate/TC for that engine. Also a 42re/rh may not stand up to the 5.9L.

Basically if you take the 5.9L/46RE/ECM from a '98 ZJ and put it into a '98 ZJ that had a 5.2L(not the 4.0L) it should bolt right in and the electronics should hook right up. Step away from that scenario and it would get more complicated but I cann`t see why it couldn`t be done.

Check out www.mallcrawlin.com and NAGCA.com. Both are ZJ specific sites and I have read about guys on there doing 5.9L conversions using Dodge Ram donor engines.
Title: 5.9L ZJ
Post by: Trouble Maker on December 26, 2006, 07:47:17 PM
IIRC 93-95 5.2 ZJs used the 46 RH. 96-96 5.2s used the 42 RE and the 98 5.9 used the 46 RE.
Electronics may not bolt up because 93-95 were OBD I emissions compliant and 96-98 were OBD II.
Tons of info on Jeepforums.com but you have to be a member to use the search.