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HeadBolt Removal Sequence

7K views 5 replies 5 participants last post by  Alfons 
#1 ·
Hi, Does anyone know if there is a specific headbolt sequence to follow when removing the head? I purchased an 88' with a rebuilt 4.2L, 20k on it. The genius I purchased the jeep from overheated the rebuilt engine. A brand new head & radiator were installed. It runs great except for a wristpin knock in cyl #4. I am looking to rebuild. I ordered a shop manual but am looking at a rainy weekend. So in the meantime I wanted to get started on it. Thanks in advance
 
#4 ·
Hold it!

Cylinder head screws are removed in the reverse order of installation - on the AMC six, this means you're going to start on the outside (driver's side rear, actually) and do an anticlockwise spiral going inwards (pax rear/pax front/driver's front/...)

Suggest you go around and break torque on the screws (turning them about a half-turn should serve,) then unscrew and remove them once you've "broken" them all.

New head screws are a good idea, but not strictly mandatory in most cases (the 242ci head screws are only good for two torque cycles. Diesels in general are only good for one.)

I probably have the torque spec for the 258ci up on my site, but I can't swear to it as of yet. If it's not there, it's an oversight I need to correct.

Installation/torquing sequence starts at the pax side centre, then driver's side centre, and spiral outwards clockwise. I'll typically torque the screws in stages - 25/50/75/... pound-feet (for instance, the 242ci. Head screws are torqued to 110 pound-feet, except the driver's side front at 100. So, 25/50/75/100/110 pound-feet. This gives a more even compression of the cylinder head gasket, and more even downforce on the head (due to the more gradual torquing of the cylinder head screws.) This helps ensure good sealing and helps to prevent warping - yes, I've seen heads get warped from being installed wrong, and not gettting heat-cycled at all (not on an AMC six - not even an iron head in general. But, I'm not about to start, either...)
 
#3 ·
lot of people do the reversal of the installation...

start in the center, loosen a bolt a bit but don't remove it, work your way around till they are all loose. Then remove, them, some say there is less chance of any warping or cracking that way.
 
#6 ·
This should be useful:



Be sure to tighten the bolts to the proper torque and pull them down in stages so that you get an even distribution of the "pull" right across the head.

If you're doing this level of work on your jeep, I'd strongly recommend getting some type of manual - maybe even a cheap Haynes to start with.
 
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