89 YJ engine swap - JeepForum.com
Search  
Sign Up   Today's Posts
User: Pass: Remember?
Advertise Here
Jeep Home Jeep Forum Jeep Classifieds Jeep Registry JeepSpace Jeep Reviews Jeep Gallery Jeep Clubs Jeep Groups Jeep Videos Jeep Events Jeep Articles
Go Back JeepForum.com > Models > Jeep Wrangler Forums > YJ Wrangler Technical Forum > 89 YJ engine swap

Introducing MONSTALINER™ UV Permanent DIY Roll On Bed LineRuffstuff Axle Simple Swap Kit!ROCK BOTTOM prices on LIFT KITS at Rockridge4wd!! WANT TO

Reply
Unread 11-12-2013, 08:10 PM   #1
kdemoney
Registered User
 
Join Date: Nov 2013
Posts: 5
89 YJ engine swap

I have an 89 YJ with the 4.2. I am new to the Jeep World. The motor I have is making some pretty bad tapping noises. I am trying to find out if it would be better to rebuild or change to an fi 4.0.

kdemoney is offline   Reply With Quote Quick reply to this message
Unread 11-12-2013, 08:17 PM   #2
Chrisnvegas
Web Wheeler
 
Chrisnvegas's Avatar
1992 YJ Wrangler 
 
Join Date: Dec 2012
Location: The Desert, Nv
Posts: 1,579
It is usually customary to diagnose the source of the tapping before replacing the motor. It might not be that bad. I have heard all kind of bad noises come from a bad vibration dampener. A worn timing chain can be quite noisy too. Water pumps can make some bad sounding noises too. A worn valve train does not automatically mean motor replacement. Diagnose it first.
__________________
What happens in my Jeep, stays in my Jeep
Chrisnvegas is online now   Reply With Quote Quick reply to this message
Unread 11-12-2013, 08:44 PM   #3
kdemoney
Registered User
 
Join Date: Nov 2013
Posts: 5
Quote:
Originally Posted by Chrisnvegas View Post
It is usually customary to diagnose the source of the tapping before replacing the motor. It might not be that bad. I have heard all kind of bad noises come from a bad vibration dampener. A worn timing chain can be quite noisy too. Water pumps can make some bad sounding noises too. A worn valve train does not automatically mean motor replacement. Diagnose it first.
My oil pressure is also dropping down next to nothing. Another reason I am considering changing the motor is for more HP. I put a 4" lift kit on with larger tires.
kdemoney is offline   Reply With Quote Quick reply to this message
Unread 11-13-2013, 07:47 AM   #4
owenb95
Registered User
1987 YJ Wrangler 
 
Join Date: Aug 2012
Location: flemington, NJ
Posts: 27
Swap in the 4.0! I did it to my 87. if you are just swapping the motor and mating it to your existing tranny its a very simple swap. It's a bolt in replacement. There are a few modifications that need to be done to the bell housing but that's it. Then you need to make some fuel system improvements (fuel pump and regulator) because the 4.0 runs around 50 psi. Wiring is somewhat simple, depending on the donor motor you put in, I only needed to wire 5 wires to make my 4.0 fire up.
__________________
1987 yj 4.2-4.0 swap AW4 & NP 242, 31inch BFG All Terrains, 2.5 in. rough country lift, Thrush header back exhaust, K&N intake, Subaru World Rally Racing Paint
owenb95 is offline   Reply With Quote Quick reply to this message
Unread 11-13-2013, 08:00 AM   #5
Que89YJ
Web Wheeler
1989 YJ Wrangler 
 
Join Date: Apr 2008
Location: Detroit, Michigan
Posts: 15,678
x2, find a donor XJ or YJ 91 or later and make it a MPFI.
Que89YJ is offline   Reply With Quote Quick reply to this message
Unread 11-13-2013, 09:42 AM   #6
Chrisnvegas
Web Wheeler
 
Chrisnvegas's Avatar
1992 YJ Wrangler 
 
Join Date: Dec 2012
Location: The Desert, Nv
Posts: 1,579
Quote:
Originally Posted by kdemoney View Post
My oil pressure is also dropping down next to nothing. Another reason I am considering changing the motor is for more HP. I put a 4" lift kit on with larger tires.
Gotcha. I had the same problem with my (Previous) CJ7. It was the top end. Had to replace the cam, cam bearings, rockers, pivots, lifters pushrods, ect. Yes oil pressure was low from the worn cam bearings. The bottom end was fine. Ended up with a performance cam, intake, headers ect.
The 4.2 kicked butt after that. I have a 4.0 now and I still think the semi built 4.2 would have given me a run for my money.

The symptoms I had was low oil pressure and a nasty lifter tick after the engine warmed up. It was ok when first started.
__________________
What happens in my Jeep, stays in my Jeep
Chrisnvegas is online now   Reply With Quote Quick reply to this message
Unread 11-13-2013, 06:20 PM   #7
kdemoney
Registered User
 
Join Date: Nov 2013
Posts: 5
Quote:
Originally Posted by Chrisnvegas View Post

Gotcha. I had the same problem with my (Previous) CJ7. It was the top end. Had to replace the cam, cam bearings, rockers, pivots, lifters pushrods, ect. Yes oil pressure was low from the worn cam bearings. The bottom end was fine. Ended up with a performance cam, intake, headers ect.
The 4.2 kicked butt after that. I have a 4.0 now and I still think the semi built 4.2 would have given me a run for my money.

The symptoms I had was low oil pressure and a nasty lifter tick after the engine warmed up. It was ok when first started.
It sounds like you experienced the same thing I am experiencing. I have good oil pressure and no noise when the engine is cold. I may be able to drive for 15 minutes or so before I notice the noise.
Thanks for everyone's input. I will have to way the cost of putting in a donor 4.0 or rebuilding the 4.2.
kdemoney is offline   Reply With Quote Quick reply to this message
Reply

Quick Reply
Message:
Options

Register Now

In order to be able to post messages on the JeepForum.com forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.
User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.
Password:
Confirm Password:
Email Address
Please enter a valid e-mail address for yourself.
Note: All free e-mails have been banned due to mis-use. (Yahoo, Gmail, Hotmail, etc.)
Don't have a non-free e-mail address? Click here for a solution: Manual Account Creation
Email Address:

Log-in

Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.


Thread Tools






Jeep, Wrangler, Cherokee, Grand Cherokee, and other models are copyrighted and trademarked to Jeep/Chrysler Corporation. JeepForum.com is not in any way associated with Jeep or the Chrysler Corp.