Hi,

I am rebuilding the 4.2 V6 in my '97 F-150 (build date 3/97) and I need the tightening specifications for the main bearing caps and for the connecting rods.

Can anyone help?

Thanks.

Bill

 

Hi and welcome to the forum

I would really recommend a shop manual for this. It's not simply torquing the bolts like on an older engine.................

Position the main bearing caps and lower bearings.
Install the six main bearing stud bolts and two main bearing bolts in the bearing caps.
Tighten to 50 Nm (37 lb-ft).
Tighten an additional 115-125 degrees.

Install the (A) rear main bearing cap and the (B) lower rear main bearing.
Position the (A) rear main bearing cap and the (B) lower rear main bearing.
Install the two main bearing stud bolts.
Tighten to 50 Nm (37 lb-ft).
Tighten an additional 115-125 degrees.


Tighten the connecting rod bolts to 29 lb-ft and then another 90 degrees.

 

Why would they tell you to tighten to a specific torque, then an 'additional X degrees'?

Isnt that defeating the purpose of the specific torque?

 

Most newer engines are like that now.
They use "torque to yield" bolts that must be replaced any time the engine is apart.
They stretch more than old style bolts and by turning them x degrees they stretch the right amount.

 

Thanks, Dave.

I have the Chilton's 26666, and it has most all the other data but nothing on the crank ? Pretty hard to rebuild without that information.