4.0L head bolts - Off-Road Forums & Discussion Groups
Jeep-Short Wheelbase All discussion of short wheelbase Jeeps: CJ, TJ, YJ and JK

 
LinkBack Thread Tools Display Modes
post #1 of (permalink) Old 07-02-2001, 11:06 PM Thread Starter
 
Join Date: Nov 2000
Posts: 2,687
Thanks: 0
Thanked 0 Times in 0 Posts
 
4.0L head bolts

Can anyone tell me how long the 4.0L head bolts are and what torque they are to be tightened to? I'm lookng for some 1/2" course thread head bolts that are 3 3/4 long on the spark plug side and 4 1/4 on the intake/exhaust side to fit an 84 4.2 head onto an 80 block (which has 1/2" head bolts). Can't use either's original bolts as they are either the wrong length (the 80 uses 1/2" but all are 4 1/4 and the 84 uses 7/16" but some are short (spark plug side)).

Does the 4.0L use short bolts on the spark plug side?

Closest match I can find are small block chrysler head bolts, some of which are 3 1/2 long.

Help!

Tim

84 CJ7, 258, HEI, M/C 2100 carb, 5 inch lift, RS9000's, 33x12.5 BFG M/T's, Lockright, full cage & belts, Xenon flares, AMC 20 1pc axles, GM dual diaphragm brake booster
TiminMb is offline  
Sponsored Links
Advertisement
 
post #2 of (permalink) Old 07-03-2001, 08:54 AM
 
Join Date: Sep 1999
Posts: 2,137
Thanks: 0
Thanked 0 Times in 0 Posts
 
Re: 4.0L head bolts

Recheck your thread depths in your block, will ya.
I don't recall either syle having staggered head bolt lengths... but my memory could be faulty ...
If you are putting an '84 head on an '80 block, both 4.2s, there is nothing 4.0 to speak about...
For a 4.2L block, both the Hayes and Chilton Manuals recommend 85 ft/lbs or all bolts except #11, which should be torqued at 75 ft/lbs.
The spec for a 4.0L is much higher at 110/100 ft. lbs.
Using the higher torque spec of a 4.0L on a 4.2L block can cause cylinder wall distortion on torque down ... a bad thing so don't fudge it.
The only best way to use the 110/100 spec on a 4.2L block is to have a torque plate (you can rent one from Clifford) bolted to the deck at that spec during cylinder wall boring which negates cyl wall distortion.

JAF
http://www.monsterslayer.com/jeep
Jaffer is offline  
post #3 of (permalink) Old 07-04-2001, 09:38 AM Thread Starter
 
Join Date: Nov 2000
Posts: 2,687
Thanks: 0
Thanked 0 Times in 0 Posts
 
Re: 4.0L head bolts

Found my head bolts. Went to a local jeep restorer, "The Jeep Doctor" and he let me sift thru his boxes of parts from pulled apart sixes. Seems some 4.2's did come with 1/2" head bolts that were shorter on the spark plug side. Manual says 1/2" bolts are to be torqued to 105 ft lbs. Just like a 4.0L. Put her back together last night and it's purrs like a kitten. Replaced the one noisy lifter and that eliminated the tapping noise I have been hearing for the last 3 years!

Can't believe that an 84 CJ used 3 different fasteners for the valve cover! AMC keeps me laughing!

Tim

84 CJ7, 258, HEI, M/C 2100 carb, 5 inch lift, RS9000's, 33x12.5 BFG M/T's, Lockright, full cage & belts, Xenon flares, AMC 20 1pc axles, GM dual diaphragm brake booster
TiminMb is offline  
Sponsored Links
Advertisement
 
Reply

Quick Reply
Message:
Options

Register Now



In order to be able to post messages on the Off-Road Forums & Discussion Groups 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 email address for yourself.

Email Address:
OR

Log-in










Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page
Display Modes
Linear Mode Linear Mode



Posting Rules  
You may not post new threads
You may not 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 On
Pingbacks are On
Refbacks are On

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