[Dr. Righteous]

This is a page out of the FSM for my '02 Sebring.

I have to admit this is confusing.
Is it saying the main cap torque spec is 15 ft. lbs. plus an additional 1/4 turn?
For a crankshaft main cap?? That is way too low!
I needed a breaking bar to remove the bolts. I can apply 15 ft lbs tightening with my teeth.
OR is it saying thread the bolt in 15 and 1/4 turns.
This seems more likely but if that is the spec they are providing why does it show a different number of turns for newton meters?? That doesn't make any sense either.
Anyone have a answer??

 

[68RT]

A lot of specs are now starting with a low torque and adding a partial turn which is what I see there. Seems to eliminate the problem of variable friction levels at the head of the bolt affecting the real torque value.

 

[John Wood]

Yeah, it is actually 15 ft-lbs plus the 1/4 turn. It is not unusual for the bolts to become seized over the years to the point where it could take 2 or 3 times the tightening torque to loosen them. Be sure the threads are in good shape and lubricate them with Loctite or an equalvalent product.... or whatever the FSM recommends.

One thing to consider is that when you are tightening or torquing bolts to a spec, do not stop part way through the torquing process. Keep the wrench moving until it clicks. Make sure you have full range of motion of your wrench handle (i.e. not obstructed part way through the turn). This is because static friction (when you stop) is greater than moving friction. This does not apply to the extra 1/4 turn, of course.

 

[rmoore0949]

you would be surprised how tight the bolt would actually be after the 1/4 turn- thats the key here

 

[ImperialCrown]

Plus you are dealing with aluminum parts on the 2.7L, not cast iron like on other engines. All torqued fasteners into aluminum are generally lower.
If the service manual wants the bolts installed with oiled threads as opposed to dry, that will also make a difference in the actual fastener tightness.

 

[Dr. Righteous]

Thanks for the help guys.
I really appreciate the serious and knowledgeable responses on this. All my engine building experience is on old engines that took 100+ Ft lbs of torque on the mains.
Other considerations is this is actually a 4 bolt plus a cross bolted main plus the bolts are much smaller than on old V8s.
This bolt is a 13mm.
My big torque wrench does not go below 20 ft lbs, so I will use my in lbs wrench. This should translate to 180 inch lbs + 1/4 turn.

 

[KOG]

And you really need to be using a turn gauge so that you tighten those things exactly 90 degrees, not 85 degrees or 95 degrees. Using such a gauge is just as important as using a torque wrench.