2. The most likely causes of valve noise are dirt trapped between the valve plunger and tappet, as well as poor oil circulation, low viscosity or insufficient pressure. Therefore, before proceeding with the removal of the valve, check the oil for the presence of fuel in it; find out if its purity and viscosity meet specifications.
Withdrawal
3. Remove the valve cover (see section 4).
4. Remove the rocker arms and valve lifters (see section 5).
5. Remove intake manifold (see section 7).
6. Remove the pusher guide holder and pusher guides (see illustrations).
8.6a. The guide plate is held by two bolts (indicated by arrows) | 8.6b. Guides of pushers are pulled on pushers |
7. There are several ways to extract the pushers from the holes. Many tool factories make a special puller that allows you to grab and remove the pusher, but you can often do without it. On late-model, low-carbon engines, the tappets can often be reached with a small magnet or even with your fingers. You can also use a bench scriber with a bent end: its tip is wound under the retaining ring located above each pusher.
8.7. You can usually remove the pushers by hand
Attention! If you do not intend to replace the pushers, do not use pliers when removing them. Pliers can damage precision-machined and hardened tappets, rendering them unusable.
8. Before removing the valve lifters, prepare a box with marked cells for storage so that when assembling the assembly, do not confuse their installation locations. After removing the pushers, store them in a place inaccessible to dirt (see illustration).
8.8. On engines with high mileage, the pushers are removed using a special tool. Store pushrods so that they can be easily identified and reinstalled
Examination
9. Parts for valve lifters are not sold separately. The effort expended on re-removing them from the engine if cleaning did not give a positive effect is more expensive than repairing them.
10. Wash the tappets with solvent and dry thoroughly, being careful not to mix them up.
11. Check the bearing surfaces of the body of each pusher and the saddle of the pusher rods for signs of abrasion, scoring and uneven wear. If the tappet walls are damaged or worn, also check the tappet holes in the cylinder block. If the pusher rod seats are worn, check the condition of the rod ends. Carefully inspect the rollers for wear and damage and make sure they turn freely and without excessive play (see illustration).
8.11a. At the top of each pusher, check the push rod seat (shown by arrow) for signs of wear | 8.11b. The roller must rotate freely. Also check if it is worn out and if there is excessive play |
Installation
12. Used roller tappets can be reinstalled on a new camshaft (if they are in good condition); you can also use the old camshaft if new tappets are installed (if it's not worn out).
13. In case of reuse of the pushers removed from the engine, install them in the same holes from which they were removed. Dip tappets in oil to eliminate air bubbles. Apply a coat of molybdenum grease or engine build oil to each of the pushrods before installing them.
14. The rest of the steps in this procedure are performed in reverse order.
15. After starting the engine, check for oil leakage.