Daño en Motor Caterpillar 3406C Bulldozer D8N
en su experiencia que creen que pudo ocacionar este daño en la valvula y a su vez al piston.
In reply to Mahmoud Amer:
Jose - I want to thank you for posting this as it gives all in the Club a chance to learn. To solve this problem - let's write down what the photos tell us: 1. The exhaust valve failed or fractured. 2. The intake valves (larger) do not appear to be seated correctly 3. There is debris denting on the head. 4. The piston is deformed, there is oil in the bowl and there are score marks on the clylinder. 5. The cylinder liner score marks suggest the rings may be stuck. OK - what does this tell us: 1. Exhaust valves typically fail due to excessive localized heat in this case, due to bad seating. 2. I suspect that as the valve fractured, the exhaust gases that escaped were drawn back into the cylinder and recompressed. When this occurs those hot exhaust gases get even hotter on recompression. 3. As the exhaust gases get hotter, keep in mind they are in the cylinder, they would melt and deform the piston. 4. As the piston deforms, metal comes free, denting the cylinder head. 5. Debris would also score the liner and get behind the rings causing them to stick. Possible causes: The cause that sticks out the most is improper valve seating. If you look at the picture above three of the valves are not seated properly. This has numerous causes: 1. High hours on the engine. You don't mention the hours. The chrome plating on valve stems is not very thick (7 um) and may be worn out. 2. Poor machining of the valves. Clearance should be 0.0002". 3. Use of wrong valve stem seals or seal failure. Oil in the piston bowl suggests stem seal failure. 4. Wrong type of valve alloy used. Possible way to prevent: 1. Make sure to get valves from Catepillar. After market valves are often less expensive but do cause performance issues. 2. Get a new head from Catepillar. 3. Make sure the stem seal is correct. 4. Make sure valve and seat clearances are correct. Stellite faced valves are often used to handle high exhaust temperatures and should be used in this case. 5. Have your Caterpillar Dealer oversee the rebuild. They will make sure that compatible materials are used and . proper clearance are set. 6. And of course use Mobil Delvac products. I hope this helps.
In reply to JOSE HIGUERA:
In reply to younes:
In reply to Rick Russo: