Department of automobile engineering
Figure 12 CLEANING PROCEDURE
Download 7.64 Mb.
|
- Navigate this page:
- Date: Signature of faculty member EXPERIMENT : - 4 DATE: - AIM
- DESCRIPTION: VALVES SERVICING
- VALVE INSPECTION
- Cupped Heads
- Valve Stem
Figure 12 CLEANING PROCEDURE EVALUATION TABLE:
Date: Signature of faculty member EXPERIMENT: - 4 DATE:- AIM: - RE-CONDITIONING OF VALVES AND VALVE SEAT OBJECTIVE: - After completion of this experiment student will be able to know. Checking and inspection of valve, valve stem and valve seat. Grinding of valve seat Method of grinding valve seat by grinder. EQUIPMENT:- A cylinder head of any type and disassembly valves clean for holding. Valve refacing handling equipments. Valve seat grinder. Dial guage with surface plate & v-block. Hand-tools Rubber suction cap with stick. MATERILES:- precision blue colour tube piece of cloth grinding plate engine oil petrol ,kerosene, etc DESCRIPTION: VALVES SERVICING:- After removing the valve from the engine clean the carbon deposits from it with a wire brush or buffing and wheel valve stem should be cleaned with a fine abrasive cloth .TO do this clamp the valve in the soft jaws of a vise, wrap the abrasive cloth around the stem and pull it back and for this can also be done on a lathe rotate the valve in a lathe hold the abrasive cloth wrap pad partly around the stem while cleaning the valve examine if it is badly filtered ,cracked ,burned ,worm or bend ,replace it after the valve is cleaned ,inspect the specific parts of the valves for correct dimension. Sodium cooled valves should be handled with special core since sodium is highly relive. VALVE INSPECTION:- After removing the valve from the cylinder head and cleaning, it should be inspected for: No margin: The margin of the valve will get pounded away in time. If the margin is to thin the valve will heat up and burn prematurely Pitting, Burning, Cracks: This usually happens to the exhaust valve because they run hotter than the intake. Exhaust valves are usually made out of high quality stainless steel, but don't benefit from the cool air and fuel the intake valve receives on the intake stroke. Valves usually burn when they are left open during combustion and exposed to extreme temperatures. This usually happens because the valve is left open al little longer as the spring weakens. Keep in mind that older engines with more wear are naturally more susceptible to burned valves if not repaired. Cupped Heads: Once the head is cupped or mushroomed the valve must be replaced. Worn Keeper Grooves or Valve Stem Tip: Look for worn keeper grooves, rotators, and retainers and replace if any of these are worn. If a keeper or retainer pops out of place the valve will drop in the cylinder causing engine damage. A worn valve stem tip will cause retainer and rocker arm damage. Valve Stem: The valve stem should be measured with an outside micrometer in several places to uneven or excessive wear. Check for uneven or excessive wear. Valve Springs should be checked for their installed height which is from the base or pocket in the head to the bottom of the retainer. If this height is excessive a shim must be added to bring the spring back to its proper tension. When placed on a flat surface the springs should remain square and any short ones (*1/16 inch) should be replaced. Tension may also be checked with a valve spring tester. 
Directory: automobile -> Practical -> sem6 automobile -> Certificate automobile -> Arslan Khan Durrani automobile -> Address to the Australian Automobile Association automobile -> Advancing integrity automobile -> Automobile Production automobile -> Training plan automobile mechanic automobile -> Delete box, or place text or logo here sem6 -> Laboratory manual experiment sem6 -> Department of automobile engineering Download 7.64 Mb. Share with your friends:
|