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Joe, Technician
Category: Heavy Equipment
Satisfied Customers: 817
Experience:  20-plus Yrs. Master Mechanic , Specializing in Cummins and Cat midrange , RV's and Commercial bus.
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what is the right torque specs of the cylinder head bolts main

Resolved Question:

what is the right torque specs of the cylinder head bolts main bearing , connenting rod bearing ,rocker arm ,jake brake bolts in ft lbs . of a n14 cummins
Submitted: 7 years ago.
Category: Heavy Equipment
Expert:  Joe replied 7 years ago.
Hello , my name is Joe

I have read your question , and will do my best to help.

Would you happen to have your 8 digit engine serial number handy ?

Customer: replied 7 years ago.
Expert:  Joe replied 7 years ago.
Ok , thanks for the reply

Here are the basic torque specs for a N14 STC , or Celect fuel system...

Use clean 15W-40 oil to lubricate the cylinder head capscrews and both sides of the flat washers.

Allow the excess oil to drain from the threads.

Install 12 capscrews and washers in each cylinder head.

Complete the following steps to tighten the capscrews to the specified torque values in the sequence shown:

Torque Value:

Step 1

136 n.m [100 ft-lb]


Step 2

298 n.m [220 ft-lb]


Step 3

Rotate 90 degrees.

Not less than one flat, and not more than two flats.

Repeat the tightening sequence to install each cylinder head.


Main bearings:

Tighten all older block (prior to engine serial number (ESN) 11875596) main bearing capscrews in alternating sequence to the following torque values:

Torque Value:

  1. 122 n.m [90 ft-lb]

  2. 230 n.m [170 ft-lb]

  3. 346 n.m [255 ft-lb]

  4. Loosen completely

  5. 122 n.m [90 ft-lb]

  6. 230 n.m [170 ft-lb]

  7. 346 n.m [255 ft-lb]

All newer blocks (ESN first 11875596) must be tightened in alternating sequence to the following torque values:

Torque Value:

  1. 68 n.m [50 ft-lb]

  2. 136 n.m [100 ft-lb]

  3. 190 n.m [140 ft-lb]

  4. Loosen completely

  5. 68 n.m [50 ft-lb]

  6. 136 n.m [100 ft-lb]

  7. 190 n.m [140 ft-lb]

  8. Rotate 90 degrees

Connecting rod bearing caps:

The tightening procedure is to pre-tighten both of the capscrews to 129 N•m [95 ft-lb].

Torque Value: 278 n.m [205 ft-lb]

Engine brake assembly:

Install the engine brake housing washers and capscrews. Tighten the capscrews in the sequence shown to the torque value listed below.

Torque Value: 102 n.m [75 ft-lb]

Rocker arm shafts:

Alternately tighten the rocker shaft capscrews:

  • Tighten to 54 N•m [40 ft-lb]

  • Tighten to 108 N•m [80 ft-lb]

  • Tighten to 156 N•m [115 ft-lb]

Tighten the capscrews in each rocker lever cover in the sequence shown.

Torque Value: 12 n.m [105 in-lb]

Note: The head bolts , main bearing , and connecting rod bolts require specialized measuring tools , gages , and procedures to determine if the bolts have been stretched or weakened beyond reusable specs.

If you do not have the correct tools and procedures for this , then I would strongly recommend using all new bolts/ capscrews for the cylinder head , main and rod bearings

Please let me know if you still have any concerns on this issue.


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