Search

Email

A     B     C     D     E     F     G     H     I     J     K     L     M     N     O     P     Q     R     S     T     U     V     W     X     Y     Z




  Mobiles  

  F7     F9

 Bookstore

 Tests

 Formulary




Cylinder head 12 - Repair



Assignment

The assessment of the cylinder head actually begins before it's removal. The first indication is ...

- white smoke in the exhaust gas (coolant),
- coolant leakage,
- blue smoke in the exhaust gas (engine oil),
- excessive oil consumption,
- admixtures in the oil or coolant,
- loss of performance,
- somewhat less serious mechanical noises. With excessive black smoke, the fuel injection system is more likely to be the source of the problem.

When leakage is suspected one should carry out the following checks in the correct order:

- Compression test (starter current)
- Compression test (pressure test)
- Loss of pressure test

The dismantling is only necessary, when it is undoubtedly certain, that a leak exists between the combustion chamber, inlet, exhaust, coolant, oil area or into the open air.

Function

According to the results of the previous checks, after dismantling, one can search for a specific error. First of all, it is important to check the cylinder head surface with a straight edge to see if it's plane. The solution, in this case, would be to plane the head. The close examination of the surface and the cylinder head gasket can also help to find cracks and/or possible leakage points. Cracks can be mostly found, where basically, there is too little material, e.g., between the inlet- and exhaust port and the hole for the spark plug. There are specialists for this type of defect, who can, not only do correction-welding, but can also build up new material. One condition for this is - particularly with older cylinder heads made of cast iron - the slow, even warming of the entire cylinder head. This is only worthwhile when the spare parts are either very expensive or no longer available. Apart from possible cracks and unevenness, the appearance of certain parts alone can be an important indication. If e.g., the exhaust valve and it's immediate surroundings are dark and oily, the valve guide should be very closely examined. Thereby, the valves must be held tight onto their seats and at the same time the valve springs must be pressed downwards. In unfavourable situations, the tapping on an accordingly sized socket, placed on the valve-head above the spring, has also been known to help. In all repair work on the cylinder head, it is important that the head is placed on a relatively soft surface. 12/13

Examples of Tightening Torque*
1. step35 Nm
2. step60 Nm
3. step90°
4. step90°
*New Screws


Imprint