Head Bolts & Torque

[KelLogan]

I am replacing the heads on a 2003 Jeep Liberty 3.7L. I used Fel-Pro gasket 26229 PT and new Fel-Pro head bolts ES 71129-1. The FSM calls for the following process:

Step 1: Tighten bolts 1–8, 27 N·m (20 ft. lbs.).
Step 2: Verify that bolts 1–8, all reached 27 N·m (20 ft. lbs.), by repeating step-1 without loosening the bolts. Tighten bolts 9 thru 12 to 14 N·m (10 ft. lbs.).
Step 3: Tighten bolts 1–8, 90 degrees (Fig. 12).
Step 4: Tighten bolts 1–8, 90 degrees, again. Tighten bolts 9–12, 26 N·m (19 ft. lbs.)

Toward the end of the second 90 degrees, on more than one bolt, I felt the resistance to turn the bolt lessen as if the bolts stretched. The FSM states that these are NOT TTY bolts.

Is this normal? Seems like it should not be. Should I reverse the procedure and remove the bolts to inspect them? Can I reuse the gasket if I do not remove the head and leave a small amount of torque on (20 ft lbs) on seven of the bolts to keep the head and gasket from shifting?

I am an old school cast iron head torque it and forget it guy. This torque plus angle and three layered metal gasket thing is new to me.

 

[tjkj2002]

Did you apply a heavy coat of oil on the main head bolt threads(not the 4 small ones,those require RTV on the threads)?

You can't re-use the gasket and never re-use head bolts regardless of what anyone says.

A high end digital torque wrench is almost required to do modern head jobs with angle torque.Snap on digital torque wrench is the only torque wrenches I use doing engine work,yeah they are very expensive but take any guess work out of torque to angle.

 

[KelLogan]

Bolt holes were cleaned out. New bolts were well coated with fresh oil. Initial 20 ft. lbs was spot on. Everything was good until the second +90. That's when things felt a little off. It could have been my imagination but in the words of Han Solo. "I've got a bad feeling about this". Nothing popped or snapped it just felt weird on the last 10 degrees or so.