So 80 degrees is approx. how many ft lbs.
2.5L Engine
To install:
Negative battery cable
Upper radiator hose and heater hose
Right side fuse/relay box and move aside
Engine undercover
Resonator and air cleaner case
Engine top cover
All electrical and vacuum lines at the head
Fuse hose quick connector at fuel tube side
Engine harness and power steering hose bracket
Timing chain
Drive belt tensioner
Camshafts
Spark plugs
Exhaust manifold
Power steering pump and reservoir and wire aside
Auxiliary drive belts
A/C compressor and wire aside
Upper sway bar links
Front and rear engine mount through bolts
Lower ball joints
2 steering gear housing mounting bolts
Front suspension member bolts and front suspension member
Fig. Removing the front suspension member-Altima
Fig. Cylinder head bolt removal sequence-2.5L engine-Altima and
Sentra
Fig. Cylinder head bolt tightening sequence-2.5L engine-Altima and
Sentra
NOTE
If possible, replacement of the head bolts is suggested.
2 steering gear housing mounting bolts
Lower ball joints
Front and rear engine mount through bolts
Upper sway bar links
A/C compressor
Auxiliary drive belts
Power steering pump and reservoir
Exhaust manifold
Spark plugs
Camshafts
Drive belt tensioner
Timing chain
Engine harness and power steering hose bracket
Fuse hose quick connector at fuel tube side
All electrical and vacuum lines at the head
Engine top cover
Resonator and air cleaner case
Engine undercover
Right side fuse/relay box and move aside
Upper radiator hose and heater hose
Negative battery cable
continue...
continue...
Before servicing the vehicle, refer to the Precautions Section.
Drain cooling system and engine oil.
Relieve the fuel system pressure.
Remove or disconnect the following:
Negative battery cable
Strut tower cross brace
Timing chain
Camshafts
Exhaust manifold
Support the engine from above and below with a suitable jack and
hoist.
Loosen the cylinder head bolts in the sequence shown and remove
the cylinder head.
To install:
Clean the gasket surfaces.
Using new head gaskets, install the cylinder heads.
NOTE
If possible, replacement of the head bolts is suggested.
If replacement of the head bolts is not possible, perform the
following bolt measurement:
Measure the diameter of the head bolt 0.47 in. (12mm) from the
bottom of the bolt.
Measure the diameter of the head bolt 2.17 in. (55mm) from the
bottom of the bolt.
Whenever the size difference between the 2 measurements exceeds
0.0091 in. (0.23mm) the head bolts must be replaced.
Apply clean engine oil to the bolt threads and seating surfaces
and tighten the cylinder head bolts in sequence as follows:
Step 1: 72 ft. lbs. (98 Nm).
Step 2: Loosen all the bolts completely.
Step 2: 29 ft. lbs. (33 Nm).
Step 4: Plus 75-80 degrees clockwise.
Step 5: Plus 75-80 degrees clockwise.
Install or connect the following:
Exhaust manifold
Camshafts
Timing chain
Strut tower cross brace
Negative battery cable
Fill the cooling system and engine oil
Start the vehicle, check for leaks and repair if necessary.
Hope help with this (remember comment and rated this).
Wow... nicely done!
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SOURCE: replacement of a head gasket on 2.5 liter nissan altima 2002
frajogag: First off, be aware that these bolts are "torque to yield" bolts (streach bolts). What this means is that instead of torqueing the head bolts to a specific torque specification, they are torqued down to a set spec and then tightened by rotating the bolts a certain angle, like 90 degrees. and all of them are turned the same amount.
This means that the shanks of the bolts must be checked to make sure they are not too thin (or the bolt has already stretched beyond limits and is prone to snap if used)
Here is how you check the bolts. Measure the bolt using a micrometer, at the base, or within the first 13mm from the end where it threads in. Then go to about 10mm before the threads end heading toward the top of the bolt. There should not be more than a 0.23mm (.0091 inch) or less difference or the bolt should be discarded.
Torque the bolts down to 98.1Nm ( 72.ft lb)
Looking at the head from the side, so you are looking at the full length from side to side, I will number the head bolts in this fashion.
#1 & 2 are directly in front of you and in the center of the cylinder head crossing it width wise.
#3&4 are to the left of #1&2, / #5&6 are to the right of #1&2
#7&8 are to the left of #3&4 / #9$10 are to the right of #5&6
Now, you have the sequence.
After the initial pull, back off all the bolts in the same sequence and then retorque them to 36 Nm ( 28 ft lb)
Using a torque angle wrench or having the ability to accurately judge turning angles. Rotate (clockwise) to a 75 degree angle. do this to all the bolts using the sequence I had provided.
Rotate the bolts (clockwise) 75 degrees again on all bolts in the same sequence. The proceedure is complete!
Fig. Cylinder head bolt loosening sequence - Altima & Maxima 3.5L engine
Install the cylinder head bolts and torque in sequence as follows:
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