It’s unwise to pay too much, but it’s worse to pay too little!
(John Ruskin, 1819- 1900) Cus 181 : 10/00
Do you still remember your first car? No matter whether a student or
just started on your job, you surely did not have much money at that
time and did search for a long time to find an economic means for
increasing your mobility.
Whenever your wheels got stuck, you probably spent every free
minute trying to get them going again. The required spare parts
could, at that time, still be bought from a wrecked-car parts dealer or
at the scrap-yard around the corner.
But usually, your faithful companion let you down again within a short
time, either because your technical skills as a mechanic were not
quite sufficient or because the spare part which you got at such a
reasonable price suddenly refused to work.
Did you ever deliberate on how much this first car did actually cost
you? Add your “hours as mechanician” and try to assess how much
more a day at the beach or in the mountains, together with friends,
would be worth than the installation of a new carburettor! One way or
the other, you surely made this calculations later on, at the latest
when the cars became bigger and more expensive or when your wife
and children had to be transported in them instead of a tent and a
crate of beer.
Then, you probably decided to have your vehicle overhauled in a
specialised garage. From now on, original spare parts were the only
possible solution as you did not want to stay at the roadside together
with your enervated wife or whining children. Of course, you also
observed the specified maintenance intervals - even if tears came to
your eyes when you received the invoice of the garage ...
Does this description sound familiar to you? Basically, it can be
reduced to two central statements:
1. The appreciation which a means of transport receives increases
proportionally to the value of the transported load!
2. The question, how safe and reliable this means of transport has to
be, is decided based on the risks which arise in case of a failure!
When practising your occupation, you nowadays almost daily have to
make similar decisions as was the case at that time, regarding your
first car. In this connection, you should always bear in mind that in
return for a low purchase price and also for low maintenance costs
you always have to put up with a higher risk.
Are you aware of this risk? How do you evaluate it? Do you take
precautions?
MAN B&W Diesel Aktiengesellschaft : 86224 Augsburg : Germany : Phone +49-821-322-- 0 : Telefax +49-821-322-3382
Diesel Customer Information Cus 181 : 10/00
Based on an actual case, we would like to draw your attention to the
possible consequences which may result from using other than
original spare parts for the operation of your MAN B&W Diesel engine
plant:
It might be sufficiently known that the load changing elements - i.e.
the inlet and exhaust valves - of Diesel engines belong to the most
stressed components of such a thermal engine. For this reason,
these components are, before they are used, subjected to an
ingenious quality control by MAN B&W, as the failure of such a valve
cone may lead to a damage which, with regard to cost, totals up to
more than one hundred times the value of the damaged part.
Within the scope of the mentioned quality control by MAN B&W,
thermoshock testing is also included by means of which the quality of
the seat armouring with regard to the high alternating thermal loads,
which occur during later operation, is ensured.
We recently had the opportunity to subject new valves of a
non-authorised manufacturer to this thermoshock testing. The result
can be gathered from the enclosed figure.
Figure 1. Valves of a non-authorised manufacturer after thermoshock testing
On both the exhaust valve cone (with rotary vanes on the shaft) and
on the inlet valve cone (without rotary vanes), the seat armouring
shows numerous heat cracks. This damage may easily result in the
rupture of the valve plate which will then have the above-mentioned
consequences.
2
Diesel Customer Information Cus 181 : 10/00
Therefore, do not rely on somewhat cheaper parts from the grey
market, but use original parts for whose quality MAN B&W
automatically guarantees within the scope of their warranty.
SM/TKU
