[Admin]

Fitting of new tie rod 

1. The lower nut of tie rod is screwed on 
2. Clean the seating surface of intermediate ring and upper nut 
3. Screw ring screw on tie rod and lift till the lower tie rod rest against the bearing shield 
4. Tighten the upper tie rod nut with tommy bar until seated firmly, then remove ring screw

 

Tightening Sequence 

1) Measure “L” on all tie rod and record

2) Mount the pre- tension jacks

3) Connect jack to high pressure oil pump and vent 

4) Operate to 350bar(1st stage), tighten using tommy bar 

5) Release pump pressure to zero

6)Tighten all in sequence, describe and measure as L1 

7) Check L1 – L 

8)Repeat for final tightening to 600 bar (stage 2) and measure L2 

9) Compare L2 – L with Maker reference 

10) value must be the same 

Method to check tie rod 

1. immobilization permit 
2. Spares and tools, tool box meeting and risk assessment 
3. Hydraulic jack check, pressure gauge is accurate 
4. refer to manufacture instruction 
5. Take crankshaft deflection
6. Mount pre tension jack and high pressure oil pump
7. Operate slow, purge, raise up to 600 bar and maintain 
8. Check with feeler gauge , check clearance 
9. If clearance exit, tighten with tommy bar, following the sequence
10. Take crankshaft deflection after complete check 

Effect of engine with loose tie bolt 

1) vibration causes fitted bolt holding bed plate, frame, entablature to break

2) machine mating surface will rub and wear 

3) alignment of engine running gear destroyed 

4) transverse girder to bend lead to cracking

5) Main bearing misalignment 

6) tightening tie bolt after fretting pull engine out of alignment 

7) Crosshead guide, cylinder liner, stuffing box will be misaligned and wear 

 

Causes of loose tie bolt 

1) Not tightened properly 

2) Material and threading not properly machined 

3)Ageing of tie rod 

4)Overtightened of tie bolt 

5)Engine Overloaded 

6)Foundation bolt become loose or chocks damage 

7)Scavenge fire loosen the bolts 

• This topic was modified 4 years, 10 months ago by Admin.
• This topic was modified 4 years, 7 months ago by icedcappucino.

[icedcappucino]

Location: Passing through tubes welded into frames. Tie rods extend from lower face of bedplate to the upper face of cylinder block.

Purpose: During firing period, there are downward forces acting on piston. There’s also equal forces acting upwards on cylinder cover that’s transmitted through the cylinder block, engine frame and bedplate transverse girder = tensile stress
Tie rods ensure any tensile stress will be well below fatigue cracking point.

Side note: It’s possible to keep tensile stress low by increasing section thickness -> very heavy and expensive engine

• This reply was modified 4 years, 7 months ago by icedcappucino.

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