Head Bolt Torque Sequence

[CWeidenkeller]

I've seen it around here somewhere..... anybody know where it is?

 

[LandShark]

Try the service manual. Other wise do this:



Number the head bolts on drivers side starting at rear: 26, 22,18, 14, 10,6, 2, 3, 7, 11, 15, 19, 23. On pass. side starting at rear: 25, 21, 17, 13, 9, 5, 1, 4, 8, 12, 16, 20, 24.



1) Tighten al bolts in sequence to 66 ft lbs. Check the torque. If lower than 66, tighten to 66.



2) Tighten all long 12mm bolts (nos. 4, 5, 12, 13, 20 and 21) in sequence, to 89 ft lbs. Check the torque. If lower than 89, tighten to 89.



3) Tighten all bolts , in sequence, and additional 90 degrees.



The above is from the 1995 service manual.

 

[Strick-9]

Basically, start in the center and work around in a circle getting larger with each revolution. I usually break it up into about 5 separate torque values instead of the 66 ft-lbs, 85 ft-lbs, + 90°.



I end up torquing them to 130 ft-lbs. So far, I've been lucky with that value.



I've also heard that some people recommend torquing the head then loosening all the head bolts and repeating the procedure.



I've never done that myself, but when you get to the point of blowing several headgaskets, many 'ideas' are thrown around to get "that little bit" more clamping force.



-Chris

 

[CWeidenkeller]

Hey, thanks guys. I knew I could count on another Texan steppin' on up.



Is the spec 85 ft-lbs plus 90* or 120 plus 90*?



We're gettin' there. PITA workin on it after I get home from work. Should have the head off tomorrow evening. Hoping to have it plumbed up and ready to go back together by Saturday morning.



Thanks again.

 

[Strick-9]

The service manual says 85 ft-lbs then an additional 90°, but Joe D and Piers told me to not go by that. They recommended torquing them to 120 ft-lbs.



I've noticed that a few of my bolts (3-4) require a lot more turning to get those last 10-15 ft-lbs compared to the rest of the bolts. It seems some of them stretch more so the 90° rule might not deliver equal clamping force.



-Chris

 

[Don M]

Originally posted by CWeidenkeller

Hey, thanks guys. I knew I could count on another Texan steppin' on up.



Is the spec 85 ft-lbs plus 90* or 120 plus 90*?



We're gettin' there. PITA workin on it after I get home from work. Should have the head off tomorrow evening. Hoping to have it plumbed up and ready to go back together by Saturday morning.



Thanks again.

Factroy specs are 89lbs plus 90 degrees. I went about 125lbs on all bolts.



Don~

 

[pwknapp]

Catepillar makes a head bolt grease specifically for aiding in getting correct torque. Big truck mechanic I use won't go without it. JMHO

 

[Speedo]

Head bolts

Don't use thread lube such as international

compound #2 or other thread lubricant unless

specified. The service manual says to "Lightly

lubricate head bolts with engine oil" The use

of thread lubes when not specified can lead to

streched or broken bolts. These thread lubes are

so efficient that you risk pulling the bolt in

two. Also my '99 service manual lists the max.

torque at 105 N-m (77 ft. lbs. ) plus an additional

1/4 turn. It should be noted that the torque/turn

method is considered to be a more accurate method

than a straight torque method by makers of

fasteners.

 

[Don M]

Re: Head bolts

Originally posted by Speedo

Don't use thread lube such as international

compound #2 or other thread lubricant unless

specified. The service manual says to "Lightly

lubricate head bolts with engine oil" The use

of thread lubes when not specified can lead to

streched or broken bolts. These thread lubes are

so efficient that you risk pulling the bolt in

two. Also my '99 service manual lists the max.

torque at 105 N-m (77 ft. lbs. ) plus an additional

1/4 turn. It should be noted that the torque/turn

method is considered to be a more accurate method

than a straight torque method by makers of

fasteners.

A light lubricant will work fine. I agree with that. Your manual shows the 24 valve specs I guess. The 12's all go down to 89ftlbs plus 90 degrees. I go to 125 ft lbs. It works very well with increased cylinder pressures from advanced timing and increased boost numbers.



Don~