Inspect Connecting Rod and Bearings for Wear Patterns; Measure Pistons, Pins, Retainers

Inspect connecting rod and bearings for wear patterns; measure pistons, pins, retainers, and bushings; perform needed action. Lesson Plan for DIT 110-111 Introduction to Diesel Engines Course HS Title: INTRO TO DIESEL ENGINE Program: KCTCS Courses included in HS Title: (Lesson is prepared for course highlighted.) KCTCS Course No. KCTCS Course Title DIT 110 Introduction To Diesel Engines

Introduction/Context This lesson will instruct students on how to inspect connecting rod and bearings for wear patterns, measure pistons, pins, retainers, and bushings, and perform needed action. Knowledge of these techniques, and the skills required to correct problems associated with this task are necessary for a student to learn if they wish to compete for high paying, high skilled jobs in a Diesel/Medium-Heavy Truck repair facility. Students need to be able to perform this task with 100% accuracy. Incorrectly performing these tasks can lead to engine concerns, safety problems, or create customer satisfaction issues. Prepared By School Date:

Lesson Grade Level No. Students No.IEP's: Length:

Task Inspect connecting rod and bearings for wear patterns; measure pistons, pins, retainers, and bushings; perform needed action.

Objective Given the proper tools and instructions, students will be able to inspect connecting rod and bearings for wear patterns, measure pistons, pins, retainers, and bushings, perform needed action, and pass a written exam on the task with 100% by the end of the course.

Connections: Skills Standards: OH 001 OH 002 OH 003 OD 002 OD 003 OD 005 Common Core Technical Standards: TD-SYS-2 New Common Core Standards: RST 11-12.2 RST 11-12 3 N-Q-1 INSTRUCTIONAL MATERIALS/TECHNOLOGY

Teacher Designed Materials and Other Handouts Instructor may use the content section of this plan to create a handout for the students.

Textbooks and Workbooks Author Title/ISBN No. Edition Publisher Pages Various Diesel Engines Test T2 Fourth Delmar 36-37 Kershaw/Bennett Medium/Heavy Duty Truck Diesel Engines 2001 Delmar 81-82

Equipment Quantity Item Source As Needed Feeler Gauges Various As Needed Inside Micrometer Various As Needed Micrometer Various As Needed Spring Scale Various

Content/Presentation/Demonstration Outline Instruct students that the reasons for piston and engine bearing failures are usually evident in the appearance of the component. Tell students that when all of the main bearings have been removed from the engine, they should line up all of the upper bearing shells in order and all of the lower bearing shells in order. Let them know that the wear patterns should be uniform when compared with each other. Explain that excessive wear in one area is an indication of localized stress of those bearings by something like a misalignment of the bearing bores in the block, or an out-of-balance condition, or out-of- round journal. Inform them that anything that subjects the engine to uneven loads, such as a faulty harmonic balancer, an out-of-balance or out-of-alignment flywheel, clutch, or torque converter, will result in uneven wear. The engine is designed to withstand heavy loads, provided they are steady, even, and not excessive. Tell students to line up the upper and lower rod bearing shells, and make a similar comparison. Instruct students that when misalignment of the main bearing bores is suspected, begin by checking each bearing bore using an inside micrometer for an out-of-round condition. If any are found to be out of round, let them know that the block needs to be line bored. Next, tell students to check for alignment of the all of the main bearing bores using a master alignment bar. Misalignment of any one bore will also require that the block be line bored. Inform them to look for signs that the connecting rods may be bent or twisted. Tell students that the wear pattern on the piston skirt should be slight, with no evidence of scoring, and should be centered on the skirt in a vertical line. Let students know that bent or twisted rods will result in a wear pattern on the skirt that is diagonal, not vertical. Teach students that because of cylinder combustion forces acting on a piston, the slightest misalignment of the connecting rod will create uneven loading on the wrist pin and compromise the lubricant hydrodynamics at the journal or big end of the rod. When this happens, tell them that the big end bearing will show the evidence of the misalignment. Instruct students that each engine manufacturer typically handles piston fitting differently. Tell them they should always consult the OEM service manual for the correct procedure. Explain to students that to measure piston-to cylinder-wall clearance, they should use a micrometer to measure the piston diameter at right angles to the piston pin bore and 1 inch below the bottom edge of the lowest ring groove. Tell them to compare this measurement to the bore diameter of the parent bore or liner. Let them know that the difference between these two valves becomes the piston-to- cylinder-wall clearance. Inform students that the average running clearance is 0.006 in. (0.152 mm), but not less than 0.002 in, (0.050 mm). Let them know that insufficient clearance will cause premature piston or cylinder/liner failure. Instruct students that cam ground pistons are measured at right angles (90 degrees) to the piston pin. Tell students that the running clearance of all pistons can be measured using a spring scale with a feeler gauge attached to its end. Instruct them to insert the 0.5 in. (12.7 mm) feeler gauge in the cylinder (liner), Lubricate the piston with oil and install it (with no rings) bottom up, with the feeler gauge between the cylinder ID and the piston. Have them position the piston about 2 in. (50 mm) below the fire decks with the piston pin bore in line with the crankshaft. Tell them that when the spring scale indicates the specified force in pounds as the feeler gauge is being withdrawn, the running clearance is correct. Let students know that on some DDC (Detroit Diesel) engines you measure piston to liner clearance with a spring-loaded feeler gauge, and that this gauge is sometimes called a fish scale. Inform students that excessive piston-to-bore clearance results in piston knocking against the cylinder wall, which is especially noticeable when engine is cold. Too little piston clearance causes piston scoring and scuffing (localized welding). The film of lube oil on the cylinder wall is scraped off.

Applications/Practice 1 Refer to Content

Evaluation and feedback Prior to Testing or Lab Work Objective 1/ Formative assessment / Instructor will observe students as they practice the procedure to assure correct procedure and safety practices are being followed. A checklist should be utilized to chart 1 student progress on the task. Questioning techniques will be utilized as necessary to demonstrate student comprehension / Adaptations and/or accommodations for special needs students will be added if required.

STUDENT ASSESSMENT: (Assess student progress with performance criteria.) Objective 1/ Summative assessment / written test questions on stated objective / adaptation and / or 1 accommodations for special needs students will be added if required.

IMPACT--Reflection/Analysis of Teaching and Learning: (How did students’ progress in relation to the state objectives? Was the instruction successful? Analyze samples of student work particularly that which is unsatisfactory, for the purpose of planning further instruction.)

REFINEMENT--Lesson Extension and Follow-up: (To be filled in as the lesson is modified during initial planning and/or during the teaching learning process.)