Work_Item_88_Main_Diesel_Engines _Alignment_Check.pdf

23300_1112_225B_MDE_ALIGN

Work Item 88:Main Diesel Engines, Alignment Check

1. SCOPE

1.1 Intent. This work item describes the requirements for the Contractor to measure and report on both the Main Diesel Engines to Reduction Gear state of alignment. All the engine mounts (6 per engine) have been recently renewed by Cutters. Contractor shall advise on any required shimming, and if shimming does occur, Contractor shall take a second (final) round of alignment readings to verify satisfactory alignment has been obtained.

1.2 Government-furnished property.

None.

2. REFERENCES

COAST GUARD DRAWINGS

Coast Guard Drawing 225B-WLB 233-1, Rev A, Propulsion Train Installation Drawing

COAST GUARD PUBLICATIONS

Coast Guard Technical Publication (TP) 3518B, 07-MAY-01, Main Diesel Engine (MDE) -

Model 3608/1 Coast Guard Technical Publication (TP) 3523B, May 2001; Coupling, Torsional (Flexible), Manufacturer: American Vulkan, Model NO. RATO-S 3321-2100/1070 (Rev B) Surface Forces Logistics Center Standard Specification (SFLC Std Spec) 3042, Jan 2009, Shipboard Electrical Cable Removal, Relocation, Splice, Repair and Installation

OTHER REFERENCES

The Society for Protective Coatings (SSPC) Surface Preparation Specification No.1 (SSPC-SP 1), 2004, Solvent Cleaning

3. REQUIREMENTS

3.1 General.

3.1.1 CIR.

None.

3.1.2 Technical Representative. The Contractor shall provide the services of qualified Tech Rep, who is familiar with – Large Diesel Engine Alignment to accomplish the following tasks – on site:

• Measure states of alignment.

• Furnish and use laser alignment tools and fixtures in measuring alignment.

• Determine engine movements to obtain satisfactory alignment

• Determine shim thicknesses as required to even load engine mounts.

3.1.2.1 The Contractor shall submit the name of the Tech Rep to the COTR at the Arrival Conference.

3.1.3 Protective measures. The Contractor shall furnish and install suitable covering to seal off and protect all non-affected surfaces/equipment and spaces in the vicinity of the work area against contamination during the performance of work. Upon completion of work, remove protective material and inspect for the presence of contamination. Clean all equipment and spaces, contaminated due to improper protection, to original condition of cleanliness.

3.1.4 Interferences. The Contractor shall handle all interferences in accordance with SFLC Std Spec 0000, paragraph 3.3.5 (Interferences).

3.2 Both Main Diesel Engines Alignment Check.

3.2.1 The engine guards and the Vulkan coupling will have been disconnected from the engine and reduction gear by Cutter personnel in advance of work commencement.

3.2.2 The referenced documents depict the main propulsion system and Reduction gear, Diesel Engine, and coupling utilized on the Cutter.

3.2.3 Measure the engine alignment again in the presence of the COTR. The following tolerances apply for radial(rim) and for angular(face) displacement: +/- 0.020". Total Indicator readings (TIR) would be twice the value. Note the engine is intentionally offset 0.032” to Port per drawing for engine torque effects. In addition additional offsets have been factored in to allow for outboard expansion of Reduction Gear’s input flange due to increased temperatures at normal operating conditions (HOT) vs. ambient conditions found during alignment (COLD). See following Table to re-enforce alignment criteria.

TABLE – PORT MDE ALIGNEMNT CRITERIA

ACCEPTABLE RANGE OF RADIAL

ALIGNMENT (RIM DISPLACEMENT)

ACCEPTABLE ANGULAR ALIGNMENT (FACE

DISPLACEMENT)

Vertical displacement

Horiz displacement

(includes Red Gear expansion outboard due to

60F degree temp delta

HOT-COLD)

Vertical displacement Horiz displacement

0.020” engine high to

0.020” engine low

0.070” engine to port to

0.030” engine to port

0.020” or less

TABLE – STARBOARD MDE ALIGNEMNT CRITERIA

ACCEPTABLE RANGE OF RADIAL

ALIGNMENT (RIM DISPLACEMENT)

ACCEPTABLE ANGULAR ALIGNMENT (FACE

DISPLACEMENT)

Vertical displacement

Horiz displacement

(includes Red Gear expansion outboard due to

60F degree temp delta

HOT-COLD)

Vertical displacement Horiz displacement

0.020” engine high to

0.020” engine low

0.034” engine to port to

0.006” engine to STBD

3.2.4 In the form of a CFR, advise Coast Guard on the existing state of alignment and any required/recommended shimming requirements. Provide calculated shim additions or subtractions for each of the six mounts. Coast Guard will have shim kits on hand.

3.2.5 Since mounts are brand new, any shimming efforts should aim toward the higher end of tolerance band vice the lower end, to combat the known settlement of Christie Grey mounts with time.

NOTE

Earlier when renewing mounts, the engines alignment to reduction gear was attempted to be preserved by use of jacking screws. Engine alignment had just been performed recently on the old mounts and was satisfactory. Basic measurements using micrometers and calculations were utilized to restore shim heights at each mount (top of new mount to bottom of engine base) plus allowances for mount compression were factored in.

3.2.6 After any shimming event re-measure the state of alignment.

3.3 Report. To formalize and document this evolution submit a final report to the Coast Guard, within 48 hours of final alignment readings and job conclusion. Include in report, all alignment reading obtained as well as any other noteworthy findings.

4. NOTES

4.1 Do not scrap unused shims, retain for future use.