4.2 exhaust question - JeepForum.com
 
LinkBack Thread Tools
post #1 of 10 Old 09-16-2011, 03:21 PM Thread Starter
superj
Registered User
1987 YJ Wrangler 
 
Join Date: Mar 2008
Location: corpus christi
Posts: 7,057
4.2 exhaust question

hey guys, i have a 4.2 head and am thinking of using 99 exhaust manifolds. can i do this? i have searched for about 30 minutes now trying different terms and cannot find a thread saying yes or no.

i have a 4.0 head also but need to get it to ndt to check for cracks before i install. i visual'd it and it looked fine but i don't want to install and find something wrong and not have my vehicle to take the kids to practices and such.


also, still no one makes an adapter to put a carb on that 99+ intake manifold? i got that too


I don't feel like working on anything, at this time.
superj is offline  
Sponsored Links
Advertisement
 
post #2 of 10 Old 09-16-2011, 05:42 PM Thread Starter
superj
Registered User
1987 YJ Wrangler 
 
Join Date: Mar 2008
Location: corpus christi
Posts: 7,057
you guys think i should post this in the cj section? i had forgotten about how a lot of people on here don't know too much about the 4.2

i know its only been two hours

I don't feel like working on anything, at this time.
superj is offline  
post #3 of 10 Old 09-16-2011, 06:10 PM
gbeltran
Registered User
1988 YJ Wrangler 
 
Join Date: Nov 2004
Location: Redondo Beach
Posts: 395
No, it won't work. 4.2 stuff is unique to the 4.2 on the exhaust manifold.
gbeltran is offline  
post #4 of 10 Old 09-16-2011, 06:44 PM
mark1305
Member
 
mark1305's Avatar
1989 YJ Wrangler 
 
Join Date: Nov 2010
Location: Merritt Island
Posts: 485
This may or may not help, but in a previous career I spent a lot of time analyzing lots of things. So I tend to look for cause and effect relationships.

I bought my first Jeep about a year ago, an 89 YJ with a 4.2L motor. Had to redo the exhaust system. One of the glitches was a broken manifold stud at the rearmost position. Reading up on here and another forum, the 4.2L motors have a reputation (on the YJs) for either cracking the rear part of the exhaust manifold or shearing that bolt. When I started reassembling with fresh gaskets etc., it became obvious that the manifold hole did not match the stud position closely enough.

I elongated the hole in the exhaust manifold by about .10 inch with a die grinder. I also found one other bolt or stud with questionable alignment near the middle of the head and relieved it slightly. I don't expect to have a repeat of the broken stud problem nor a cracked manifold. New gaskets on both manifolds and all ran well with no leaks.
mark1305 is offline  
post #5 of 10 Old 09-16-2011, 07:00 PM
gbeltran
Registered User
1988 YJ Wrangler 
 
Join Date: Nov 2004
Location: Redondo Beach
Posts: 395
Why are you trying to put a carb on the 99 intake? You would have to make your own adapter. If you want to keep the carb with the 4.0 head you can use your current intake. I think you might have to grind the mounting flange in a couple spots but it will work.
gbeltran is offline  
post #6 of 10 Old 09-16-2011, 08:05 PM Thread Starter
superj
Registered User
1987 YJ Wrangler 
 
Join Date: Mar 2008
Location: corpus christi
Posts: 7,057
Bummer on the exhaust manifolds, I was hoping they fit.

On the intake manifold, I got the whole head (well, engine) but no harness but no ecu so while waiting to collect parts, I figured I would move to a better flowing intake.

I don't feel like working on anything, at this time.
superj is offline  
post #7 of 10 Old 09-16-2011, 10:07 PM
444
Registered User
 
Join Date: Sep 2011
Location: Steinbach
Posts: 146
The 4.0 intake is designed for dry flow with the injectors at the head. It is not suited at all to mounting a carb on. If you want a good flowing carb intake, but one of the aftermarket 4.2 4bbl intakes.
444 is offline  
post #8 of 10 Old 09-17-2011, 04:09 AM Thread Starter
superj
Registered User
1987 YJ Wrangler 
 
Join Date: Mar 2008
Location: corpus christi
Posts: 7,057
I have lOoked at them and if I could find one for a cost I like, I would buy one. I just have a hard time shelling out 2-300 for an intake

I don't feel like working on anything, at this time.
superj is offline  
post #9 of 10 Old 09-17-2011, 06:41 AM
wanabejeeper
Registered User
1987 YJ Wrangler 
 
Join Date: Aug 2009
Location: NJ
Posts: 549
I'm pretty sure the 4.0 HO head will take the 4.0 throttle body intake which can use a carb.

87 YJ The Original!

Quote:
Originally Posted by Anticanman View Post
It goes in that barrel you wheel out to the street once a week.

My build thread http://www.jeepforum.com/forum/f12/n...thread-867043/
wanabejeeper is offline  
post #10 of 10 Old 09-17-2011, 08:36 AM Thread Starter
superj
Registered User
1987 YJ Wrangler 
 
Join Date: Mar 2008
Location: corpus christi
Posts: 7,057
I only know one guy on here with a 99+ intake and running a carb. He made the adapter himself

I don't feel like working on anything, at this time.
superj is offline  
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.



Email Address:
OR

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.




Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page



Similar Threads
Thread Thread Starter Jeep Forums Replies Last Post
97 2.5 Exhaust Manifold Question - Probably a stupid question. F4ion1 TJ Wrangler Technical Forum 7 07-23-2010 08:13 AM
Exhaust question? IH8ROADZ TJ Wrangler Technical Forum 6 03-23-2008 01:07 AM
exhaust question(NO NOT WHICH ONE IS BETTER!!) MZH29 TJ Wrangler Technical Forum 6 11-29-2005 10:08 PM
Exhaust Question ajpthng03 TJ Wrangler Technical Forum 1 04-28-2003 04:56 PM
exhaust question tuggnutt YJ Wrangler Technical Forum 9 09-12-2002 02:39 PM

Posting Rules  
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are On
Refbacks are On

 
For the best viewing experience please update your browser to Google Chrome