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Lapping Valves
Grinding is performed on the removed valve cylinder head. To extract the valve guides from the cylinder head is necessary to remove the valve springs squeezing them with a special tool and removing crumbs from the spring plates (see. "Replacing the valve stem seals"). For lapping valves is most convenient to use a special mechanical device (reversible drill). In addition, commercially available ready handpiece valve.
| Fig. 5.10. Device for grinding in of valves: 1 - a metal rod; 2 - rubber hose; 3 - screw clamp
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In the absence of ready-made tools, you can use a device manufactured according to drawing (Fig. 5.10). Instead of a rubber hose and hose clamps may be welded to the rod tip device in whose side wall a through threaded hole, the bolt is screwed therein for fixation of the valve stem. In addition, you will need: lapping paste, kerosene, weak spring, the outside diameter passing through the hole of the valve seat. 1. Clean the valve of a deposit. |
| | 2. Coat the valve face a continuous thin layer of lapping compound. | 3. Put on the valve stem pre-matched spring and insert the valve into directing plug from the combustion chamber, the valve stem brushing a layer of graphite grease. |
NOTE Graphite grease prevents the guide sleeve from falling into its hole from abrasive lapping compound and facilitates rotation of the valve during lapping. |
4. Put on the valve stem tool for grinding valves (or some interference with a rubber tube to connect the valve with reversible drill). |
5. Turn the drill on the minimum speed (in reverse mode) or rotate the device (in the case of hand-lapping) alternately in both directions on the half-turn, grind valve, periodically pressing it against the seat, easing the effort of pressing. |
HELPFUL ADVICE In the absence of any of these items, you can grind the valve with the eraser, pressing and turning them to the valve. Loosen the valve pressing, pressing the butt of his rod with the other hand. |
| | 6. grind the valve until its facet matt gray monochrome continuous belt with a minimum width of 1.5 mm, while the ... | 7. ... on the valve seat after grinding also should appear shiny belt with a minimum width of 1.5 mm. |
| 8. After grinding thoroughly clean the valve and seat with a clean cloth and rinse to remove remaining lapping compound. Check the tightness of the valve, which set him in the head with springs and crackers. Then put the head to one side and pour kerosene on the channel, which is closed by a valve. If within 3 minutes kerosene does not seep into the combustion chamber, the valve is sealed. |
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