What year 4.0 engines will be a direct fit into my 2001 TJ?

TJProjectRon

TJProjectRon

Member
Supporting Member
Joined
Dec 27, 2015
Messages
52
Location
Oklahoma
This has probably been posted a million times but i cant find exactly what years of TJ 4.0 engines will directly swap out with my 2001 TJ 4.0. Is there a chart showing the compatibility of all years of TJ 4.0 engines?

Also there seems to be several opinions on how to determine the year of a TJ 4.0. Any knowledge out there on that?
 
Chris said:
https://wranglertjforum.com/threads/4-0-cylinder-block-interchangeability.16801/
Click to expand...
Thanks Chris. I have read this article from Google but can't seem to get a clear picture of what year of complete TJ engines interchange. The article seems to be what TJ blocks interchange with Cherokee blocks. I have 2 complete used TJ 4.0 motors and want to use one in my 2001 Tj. Need to figure out what year TJ they are out of and will they directly swap with my 2001. I saw one article that indicated 97-99 TJ motors would directly swap and 2000-2006 TJ motors would directly swap but not sure if this correct. I think it just me not understanding the article you posted.
 
The engine(s) should be stamped with build information on the side of the block near the spark plugs.

Stole this from a Cherokee forum.
BUILD DATE CODE

The digits of the code identify:
  • 1st Digit—The year (9 = 1999).
  • 2nd & 3rd Digits—The month (01 - 12).
  • 4th & 5th Digits—The engine type/fuel system/ compression ratio (MX = A 4.0 Liter (242 CID) 8.7:1 compression ratio engine with a multi-point fuel injection system).
  • 6th & 7th Digits—The day of engine build (01 - 31).

FOR EXAMPLE: Code * 903MX16 * identifies a 4.0 Liter (242 CID) engine with a multi-point fuel injection system, 8.7:1 compression ratio and built on March 16, 1999.
 
Here is the stamp from my 2001
20200314_102234.jpg
 
Well that sure looks like it lines up with your info. I'll be checking on my stuff in a little while and let you know what i find. Thanks a lot.
 
It appears your information was accurate. The engine in my 2001 TJ has a code stamp beginning with a 1 just as yours does. The two spare engines are marked one with a 5 and one with a 1. So the 2001 spare engine would obviously be a fit but has the 0331 head while the 2005 spare engine has the TUPY head which is said to be more desirable. Everything on the 2005 looks the same as the 2001 except the OPDA. The 2001 has an OPDA with a small head (1.75 in) while the 2005 OPDA has a larger head (3.5 in). Would this 2005 OPDA be compatible with the 2001 electronics? Are the two types of OPDA units interchangeable?
 
Jramos013 said:
You would need to use your 01 opda if you use the 05 motor i belive.
Click to expand...
Believe you are right. I've been searching for an answer and it is looking like 2005 & 2006 are the larger opda. I'm thinking it may be best just to use the 2001 motor and risk the 0331 head. Thank you for your reply.
 
Would anything stop you from swapping the heads?

I have a 0331 head and have no issues. 105k miles. I'm not concerned enough to do anything about it
 
Probably would run it until it gives a problem. I read where many are like you and have had no issues. Think i will hold on to the 2005 motor as another spare or for parts. Thanks for your input.

Good looking Jeep by the way.
 
  • Like
Reactions: Alex01
I mean, you could use the 05 motor with you 01 opda, or replace the head in the 01 with the 05 one
 
I'm not trying to Trump anyones' post , but conventional shop wisdom in my area is get a motor from the exact same year..same with transmissions.

I'm not saying you can't do otherwise , and guys like Mr. Blaine can break the rules , because they know the rules so well. (I'm referring to the old adage "you need to know the rules before you break them".)

Anyway , I know you wouldn't be asking if you weren't exploring options , so all the best on the project .

It amazes me the electronic interface of modern vehicles . It really has changed the game .
 
AndyG said:
I'm not trying to Trump anyones' post , but conventional shop wisdom in my area is get a motor from the exact same year..same with transmissions.

I'm not saying you can't do otherwise , and guys like Mr. Blaine can break the rules , because they know the rules so well. (I'm referring to the old adage "you need to know the rules before you break them".)

Anyway , I know you wouldn't be asking if you weren't exploring options , so all the best on the project .

It amazes me the electronic interface of modern vehicles . It really has changed the game .
Click to expand...
Thank you, AndyG. I appreciate any and all opinions. I have been working on Jeeps for awhile but i don't know a lot about the electronics and don't want to go looking for trouble. The computerization is nothing short of amazing but requires a certain skill set to deal with the issues. Thanks a lot for your input. I have definitely learned some things from this thread.
 
  • Like
Reactions: AndyG
Top Bottom
Back