ATG 327 - Minor Svc/Repair/GM Engines

1. Perform proper shop safety procedures.
   1. Apply work area safety skills.
   2. Demonstrate personal safety working habits.
   3. Practice tool and equipment safety use.
   4. Follow manufacture’s repair procedures.
   5. Follow manufacture’s warnings and government regulations.
2. Explain the fundamentals of basic engine design and operation.
   1. Describe basic engine operation.
   2. Describe the basic laws of physics involved with engine operation.
   3. Classify engines according to the number of cycles, the number of cylinders, cylinder arrangement, and valve-train type.
   4. Define the four-stroke cycle theory.
   5. Describe the different cylinder arrangements and the advantages of each.
   6. Describe the different valvetrains used in modern engines.
   7. Define engine measurement terms such as bore and stroke, displacement, compression ratio, engine efficiency, horsepower and torque, horsepower losses, mechanical efficiency, and thermal efficiency.
   8. Describe the basic operation of alternative engine designs, including diesel, Miller-cycle, and stratified charge.
   9. Identify engine using vehicle identification number.
   10. Acquire pertinent service information for specific repair procedures.
   11. Identify hybrid vehicle internal combustion engine service precautions.
3. Diagnose and repair cylinder head and valve train.
   1. Remove cylinder head; inspect gasket condition; install cylinder head and gasket; tighten according to manufacturer?s specifications and procedures.
   2. Clean and visually inspect a cylinder head for cracks; check gasket surface areas for warpage and surface finish; check passage condition.
   3. Inspect valve springs for squareness and free height comparison; determine necessary action.
   4. Inspect valve guides for wear; check valve stem-to-guide clearance; determine necessary action.
   5. Inspect valves and valve seats; determine necessary action.
   6. Check valve fact-to-seat contact and valve seat concentricity (runout); determine necessary action.
   7. Check valve spring assembled height and valve stem height; determine necessary action.
   8. Inspect pushrods, rocker arms, rocker arm pivots and shafts for wear, bending, cracks, looseness, and blocked oil passages (orifices); determine necessary action.
   9. Inspect valve lifters; determine necessary action.
   10. Adjust valves (mechanical or hydraulic lifters).
   11. Inspect camshaft drives (including gear wear and backlash, sprocket and chain wear); determine necessary action.
   12. Inspect and replace camshaft and drive belt/chain; includes checking drive gear wear and backlash, end play, sprocket and chain wear, overhead cam drive sprocket(s), drive belt(s), belt tension, tensioners, camshaft reluctor ring/tone-wheel, and valve timing components; verify correct camshaft timing.
   13. Inspect and/or measure camshaft for runout, journal wear and lobe wear.
   14. Inspect camshaft bearing surface for wear, damage, out-of-round, and alignment; determine necessary action.
   15. Establish camshaft(s) timing and cam sensor indexing according to manufacturer’s specifications and procedures.
4. Diagnose and repair engine block assembly.
   1. Disassemble engine block; clean and prepare components for inspection and reassembly.
   2. Inspect engine block for visible cracks, passage condition, core and gallery plug condition, and surface warpage; determine necessary action.
   3. Inspect and measure cylinder walls/sleeves for damage, wear and ridges; determine necessary action.
   4. Deglaze and clean cylinder walls.
   5. Inspect and measure camshaft bearings for wear, damage, out-of-round, and alignment; determine necessary action.
   6. Inspect crankshaft for straightness, journal damage, keyway damage, thrust flange and sealing surface condition, and visual surface cracks; check oil passage condition; measure end play and journal wear; check crankshaft position sensor reluctor ring (where applicable); determine necessary action.
   7. Inspect main and connecting rod bearings for damage and wear; determine necessary action.
   8. Identify piston and bearing wear patterns that indicate connecting rod alignment and main bearing bore problems; determine necessary action.
   9. Inspect and measure piston skirts and ring lands; determine necessary action.
   10. Determine piston-to-bore clearance.
   11. Remove and replace piston pin.
   12. Inspect, measure, and install piston rings.
   13. Inspect auxiliary (balance, intermediate, idler, counterbalance or silencer) shaft(s); inspect shaft(s) and support bearings for damage and wear; determine necessary action; reinstall and time.
   14. Inspect or replace crankshaft vibration damper (harmonic balancer).
   15. Assemble engine block assembly.
   16. Install engine covers using gaskets, seals and sealers as required.