What is the method of reaming the valve seat?

According to the inner diameter of the valve guide tube, select the appropriate reamer guide rod and insert it into the valve guide tube to make the guide rod coincide with the inner hole surface of the valve guide tube.

Step 2 polish the hardened layer

Because there is a hardened layer on the valve seat, the reamer often slips when reaming. In this case, you can use a coarse emery cloth pad to polish under the reamer and then ream the hole.

3. Initial hinge

First, the 45 reamer (coarse and fine knives as appropriate) is sleeved on the guide rod, so that the keyway of the reamer is aligned with the flange of the lower end face of the reamer handle, and then reaming can be carried out. When reaming, the reamer should be upright, and the force of both hands should be even and steady, and the reaming should be rotated clockwise. If you retract the knife counterclockwise, do not use force to prevent the blade from becoming dull until the ablation, spots, depressions and other defects on the valve seat are eliminated.

Generator valve seat reamer

4. Assemble and trim the contact surface

After the initial hinge, the matching valve with smooth grinding should be used for trial fitting. The assembly method is as follows: Apply red lead oil to the conical working surface of the valve seat, put it into the guide tube and turn it for 2 ~ 3 turns (do not beat it), then take out the valve and observe its contact. The normal requirements are: the contact surface should be in the middle and lower part of the working slope of the valve, the width of the intake valve is about 1.0 ~ 2.0 mm, and the exhaust valve is about1.5 ~ 2.5 mm. If the contact surface is too narrow, it will affect the heat dissipation of the seal, and if it is too wide, it will be easy to deposit carbon and it will not be able to fit closely. The correct contact position between the valve and the valve seat is shown below (Figure). In the middle and lower part of the conical working face of the valve, the width is 1.5 ~ 2mm. For the trial assembly after the initial reaming, if the contact surface is on the upper side, use 15 reamer to ream the upper mouth to make the contact surface move down; If the contact surface is on the lower side, use 75 reamer to ream the lower mouth so that the contact surface moves up. When reaming for the first time, try to make the valve contact surface in the middle and lower part, and try to install it while reaming. In order to prolong the service life of the valve seat and the valve, the hinge fit can be stopped when the contact surface is 65438±0mm away from the lower edge of the valve.

5. Fine hinge

Finally, use 45 (or 30) fine-edged reamer or fine abrasive cloth on the reamer to finely repair (grind) the working surface of the valve seat of the diesel generator to improve the smoothness of the contact surface. Finally, check with red lead oil. The contact surface between the valve and the valve seat should be an uninterrupted endless belt.