Service Information M43 [PDF]

Zitiervorschau

Service Information

No. 07 / 04

Date: 16-SEP-2004

Ring groove wear and piston burn-off

M43

Due to the good experience gained with our other engine types in the field an expected service life of 30,000 operating hours for the period up to the first overhaul was specified at the time of the M43 market launch. In the past, however, on M43 engines with longer operating time increased ring groove wear was noticed, especially in the first ring groove, which due to the existing wear limit did not permit to leave the piston crown in the engine. An evaluation of the inspection reports showed that not all of the engines in the field are affected by this phenomenon. On some engines the actual wear was within the normal expected range. Calculations, trials on a test engine in Kiel, cross comparisons with other engine types and finally the experience gained on the basis of the cylinder units checked so far have allowed us to increase the wear limit of the first ring groove without affecting the operational safety of the engine. The new wear limit is now 10.80 mm, measured on the outside of the ring groove. In order to provide a reference to the operator when carrying out the 15,000 hours piston inspection it has been determined that a value of 10.50 mm must then not be exceeded for further operation. Furthermore, isolated instances of piston burn-off have been identified in the area of transition between the combustion bowl and the outer edge of the piston. This is permissible for further use provided it remains within certain limits. When carrying out the routine piston check after 15,000 hrs. a burn-off value of 3 mm must not be exceeded, otherwise the piston is to be replaced. When a piston burn-off value of 6 mm is exceeded, a piston crown always has to be replaced. In order to be able to assess the condition of the engine, we recommend a check of all pistons after 15,000 operating hours. The reasons for this action are: Most of the time only individual cylinder units of one engine are affected, i.e. the condition of one inspected piston does not permit any definite conclusions regarding the condition of the other pistons of that engine. A comparison of different engines among each other shows that ring groove wear and piston burn-off cannot be attributed to certain cylinder units. For this reason a check of only certain cylinder units cannot be recommended. We are continuing our efforts to provide an increased piston crown service life. If, due to ring groove wear, a piston crown should have to be exchanged prematurely, the price for replacement piston crowns will naturally be calculated on a pro-rata basis. Due to the manifold operational causes of piston burn-off a decision regarding commercial settlement will be taken on a case-by-case basis.

Caterpillar Marine Power Systems, Kiel, Germany • Phone: +49 (0) 431 3995-2825 • Fax: +49 (0) 431 3995-3080 • E-mail: [email protected] •

Service Information

No. 09 / 04

Date: 02.09.2004

New sealing ring for pushrod guide on the cooling collar

M43

On the pushrod guide of the cooling collar there occurred some isolated instances of oil leaks in the area of the cylinder head connection point. In the course of time the sealing ring lost its sealing capability. A new solution has already been implemented in the current series production (VM43, M43, M43C). As a new feature this sealing arrangement will now include a thicker Viton sealing ring. For subsequent mounting of this new sealing ring it is necessary to carry out the following modification on the cooling collar: The edges of the oil drain are to be rounded with radius r = 4 mm (see figure 1). This can be carried out by means of a metal removing tool such as a pneumatic cutter, a grinding tool or a file. If this required rework is not carried out, there is a risk of the new sealing ring getting damaged by the edges of the oil drain (figure 2).

Figure 1

Figure 2

Caterpillar Marine Division, Kiel, Germany • Phone: +49 (0) 431 3995-28 25 • Fax: +49 (0) 431 3995-30 80 • E-mail: [email protected] •