Valve Guide Reaming, and Valve and Seat Grinding
Valve Cleaning Procedure- Use soft bristle wire brush to clean any carbon build-up from the valve head. DO NOT use a wire brush on any part of the valve stem. The valve stem is chrome plated to provide enhanced wear characteristics. Wire brushing the stem could remove the chrome plating.
- Thoroughly clean the valve with solvent and wipe dry.
Valve Visual Inspection Procedure
- Inspect the valve for damage from the head to tip for the following conditions:
| • | Pitting in the valve seat area(1) |
| • | Bending in the valve stem(3) |
| • | Pitting or excessive wear in the stem(4) |
| • | Worn valve key grooves(5) |
- Replace the valve if any of these conditions exist.
Valve Measurement and Reconditioning OverviewNote:| • | Proper valve service is critical to engine performance. Therefore, all detailed measurement procedures must be followed to identify components that are out of specification. |
| • | If the measurement procedures reveal that the valve or valve seat must be reconditioned, it is critical to perform the measurement procedures after reconditioning. |
Valve Seat Width Measurement Procedure
- Measure the valve seat width in the cylinder head using a proper scale.
- Measure the seat width on the valve face(1) using a proper scale.
Note: The seat contact area must be at least 0.5mm (0.020in) from the outer diameter (margin) of the valve. If the contact area is too close to the margins, the seat must be reconditioned to move the contact area away from the margin.
- Compare your measurements with the specifications, refer to Engine Mechanical Specifications .
- If the seat widths are acceptable, check the valve seat roundness using the Valve Seat Roundness Measurement Procedure.
- If the seat width is not acceptable, you must grind the valve seat using the Valve and Seat Reconditioning Procedure to bring the width back into specification. Proper valve seat width is critical to providing the correct amount of valve heat dissipation.
Valve Seat Roundness Measurement Procedure- Measure the valve seat roundness using a dial indicator attached to a tapered pilot installed in the guide. The pilot should have a slight bind when installed in the guide.
Caution:The correct size pilot must be used. Do not use adjustable diameter pilots. Adjustable pilots may damage the valve guides.
- Compare your measurements with the specifications, refer to Engine Mechanical Specifications .
- If the valve seat exceeds the roundness specification, you must grind the valve and valve seat using the Valve and Seat Reconditioning Procedure.
- If new valves are being used, the valve seat roundness must be within 0.05mm (0.002in).
Valve Margin Measurement Procedure
- Measure the valve margin using an appropriate scale.
- Reference the specifications in this section for minimum valve margin and compare them to your measurements.
- If the valve margins are beyond specification, replace the valves.
- If the valve margins are within specification and do not require refacing, test the valve for seat concentricity using the Valve-to-Seat Concentricity Measurement Procedure.
Valve-to-Seat Concentricity Measurement Procedure
Note:| • | Checking the valve-to-seat concentricity determines whether the valve and seat are sealing properly. |
| • | You must measure the valve face and the valve seat to ensure proper valve sealing. |
- Coat the valve face lightly with blue dye(3).
- Install the valve in the cylinder head.
- Turn the valve against the seat with enough pressure to wear off the dye.
- Remove the valve from the cylinder head.
- Inspect the valve face.
| • | If the valve face is concentric, providing a proper seal, with the valve stem, a continuous mark will be made around the entire face(1). |
| Note:The wear mark MUST be at least 0.5mm (0.020in) from the outer diameter, the margin, of the valve. If the wear mark is too close to the margin, the seat must be reconditioned to move the contact area away from the margin. |
| • | If the face is not concentric with the stem, the mark will NOT be continuous around the valve face. The valve should be refaced or replaced and the seat must be reconditioned using the Valve and Seat Reconditioning Procedure. |
Valve and Seat Reconditioning Procedure
Note:| • | If the valve seat width, roundness or concentricity is beyond specifications, you must grind the seats in order to ensure proper heat dissipation and prevent the build up of carbon on the seats. |
| • | It is necessary to reface the valve if seat reconditioning is required unless a new valve is used. |
- Grind the valve seats(2) to the proper angle specification, refer to Engine Mechanical Specifications .
- Using the proper angle specification, refer to Engine Mechanical Specifications , grind, relieve, the valve seats(1) to correctly position the valve seating surface(2) to the valve.
- Using the proper angle specification listed in engine mechanical specifications, refer to Engine Mechanical Specifications , grind, undercut, the valve seats(3) to narrow the valve seat widths to the specifications, refer to Engine Mechanical Specifications .
- If the original valve is being used, grind the valve to the specifications, refer to Engine Mechanical Specifications . Measure the valve margin again after grinding using the Valve Margin Measurement Procedure. Replace the valve if the margin is out of specification. New valves do not require grinding.
- When grinding the valves and seats, grind off as little material as possible. Cutting valve seat results in lowering the valve spring pressure.
- Install the valve in the cylinder head.
| • | If you are using refaced valves, lap the valves into the seats with a fine grinding compound. The refacing and reseating operations should leave the refinished surfaces smooth and true so that minimal lapping is required. Excessive lapping will groove the valve face and prevent a good seat when hot. |
| Note:Be sure to clean any remaining lapping compound from the valve and seat with solvent and compressed air prior to final assembly. |
| • | If you are using new valves, do not lap the valves under any condition. |
- After obtaining the proper valve seat width in the cylinder head, you must re-measure the valve stem height using the Valve Stem Height Measurement Procedure.
- If the valve stem height is acceptable, test the seats for concentricity using the Valve-to-Seat Concentricity Measurement Procedure.
Valve Stem Height Measurement Procedure
Note:To determine the valve stem height measurement, measure from the valve spring seat to the valve spring retainer.
- Install the valve into the valve guide.
- Ensure the valve is seated to the cylinder head valve seat.
- Install the valve stem oil seal.
- Install the valve spring retainer and valve stem locks.
- Measure the distance(1) between the cylinder head to the bottom of the valve spring retainer. Refer to Engine Mechanical Specifications .
- If the maximum height specification is exceeded, a new valve should be installed and the valve stem height re-measured.
Caution:DO NOT grind the valve stem tip. The tip of the valve is hardened and grinding the tip will eliminate the hardened surface causing premature wear and possible engine damage.
Caution:DO NOT use shims in order to adjust valve stem height. The use of shims will cause the valve spring to bottom out before the camshaft lobe is at peak lift and engine damage could result.
- If the valve stem height still exceeds the maximum height specification, the cylinder head must be replaced.
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FAQs
Service Information means any statement, document or other form of communication, whether verbally or in [writing], which contains information that might influence [organization]'s ability to lawfully or safely deliver the services.
What is service information automotive? ›
This information contains diagnosis procedures, specifications, and service procedures. Technicians must know how to locate and use the information that is available. 1. Vehicle manufacturers publish service information for each model year of the vehicles they manufacture.
What is information services in? ›
Information services, a group of services offered by a library or other institution. Information services, a group of services offered by information professionals of various types. Information Services, a unit or department in an enterprise responsible for delivering information systems.
What is an information service example? ›
These include libraries, computing services, archive services, and information support services. Such functions may be managed separately from each other, or in various combinations.
What is a service example? ›
A service is an act or use for which a consumer, firm, or government is willing to pay. Examples include work done by barbers, doctors, lawyers, mechanics, banks, insurance companies, and so on. Public services are those that society (nation state, fiscal union or region) as a whole pays for.
What are in vehicle information systems? ›
In-Vehicle Infotainment (IVI) is a system in cars that combines entertainment and information delivery through audiovisual interfaces. 4 min read.
What are the eight automotive service content areas? ›
ASE Certification Tests
- A1 – Engine Repair.
- A2 – Automatic Transmission/Transaxle.
- A3 – Manual Drive Train and Axles.
- A4 – Suspension and Steering.
- A5 – Brakes.
- A6 – Electrical/Electronic Systems.
- A7 – Heating and Air Conditioning.
- A8 – Engine Performance.
OBD stands for On-Board Diagnostics and is a computer system inside of a vehicle that tracks and regulates a car's performance. This on-board computer system collects information from the network of sensors inside the vehicle, which the system can then use to regulate car systems or alert the user to problems.
What is information service model? ›
The Information Service Reference model (ISRM) is a model built collaboratively by the SESAR SWIM community. It provides each service with a complete description in terms of functionality, behaviour and logical interfaces.
What is the function of information services? ›
The function of the information systems is to allow you to view the information from your operative applications from any perspective you wish. You are free to define the level of detail in which the information is displayed.
as assigned. Incumbents may be responsible for administering, maintaining, troubleshooting, and monitoring applications, programs, devices, computers, or other technical products, processes, or systems. Responsibilities include user support and problem resolution and provision of support to Analysts.
What does service level information mean? ›
(1) A measurement of the performance of a system or service. The service level is usually expressed as a percentage of a goal; for example, the percentage of time a network or system is operative or the percentage of successful transactions processed.
What is the full meaning of service? ›
1. an act of helpful activity; help; aid. to do someone a service. 2. the supplying or supplier of utilities or commodities, as water, electricity, or gas, required or demanded by the public.
When would you use information as a service? ›
Information as a service is appropriate for any organization that has various data sources and diverse eating up applications. In case your organization is small and you have one database and one main application, at that point information as a service may not make sense.
What is the meaning of of service? ›
: to be helpful or useful to someone. I am glad to be of service.
