Can u loosen bolts after engine has been turned on n retorgue? I only did step 3"4"5 n my completion is going out the reservoir tank n it's overheating.plus I used old bolts.
I kinda forget a lot of this but... The first three steps, torque to 72 ft-lbs, loosen, torque to 29 ft-lbs, crushes the head gasket. Once achieved any further tightening of the head bolt will just stretch the head bolt. So, if the bolt is 8 threads per inch, one complete rotation of the head-bolt will stretch the head-bolt 1/8 inches. A half rotation will stretch the bolt 1/16 inch. The procedure calls for two 90 deg rotations, so the first rotation will stretch the bolt 1/32 inch and the seconds rotation another 1/32 inch for a total of 180 deg and 1/16 inch of stretch. This applies a great deal of clamping force to hold the head against the block. Would then have to refer to the "tensile-stress vs strain curve" to determine the tensile stress for 1/16 inch strain. That tensile stress is the force per sq inch clamping the head and block together. It's far more accurate than just torquing to 100 ft-lbs. or something like that...
Thanks for your video my friend
Thank you
Can u loosen bolts after engine has been turned on n retorgue? I only did step 3"4"5 n my completion is going out the reservoir tank n it's overheating.plus I used old bolts.
have to use new bolts every time cause they stretch
Great video sir!!, thank you very much
Great explanation!
I kinda forget a lot of this but...
The first three steps, torque to 72 ft-lbs, loosen, torque to 29 ft-lbs, crushes the head gasket. Once achieved any further tightening of the head bolt will just stretch the head bolt.
So, if the bolt is 8 threads per inch, one complete rotation of the head-bolt will stretch the head-bolt 1/8 inches. A half rotation will stretch the bolt 1/16 inch. The procedure calls for two 90 deg rotations, so the first rotation will stretch the bolt 1/32 inch and the seconds rotation another 1/32 inch for a total of 180 deg and 1/16 inch of stretch. This applies a great deal of clamping force to hold the head against the block.
Would then have to refer to the "tensile-stress vs strain curve" to determine the tensile stress for 1/16 inch strain. That tensile stress is the force per sq inch clamping the head and block together. It's far more accurate than just torquing to 100 ft-lbs.
or something like that...
Makes sense
Hello, why loosen the screws, what's the point
The manual specify that dont know..i guess its to unload the bolts to true torque the maximum strenth
Why do Nissan do all the bs to torque the heads?
Duno....there worses like ford when you have to unbolt then retorque then torque by degrees