Lower operating costs and increased reliability by simple
modernisation measures
Medium-speed four-stroke engines Cus 166 : 09/98
Stepped cylinder liners enable a With our Diesel Customer Information No. 138, we informed you in
more economic operation January 1996 about the possibility to render the operation of your plant(s)
equipped with older medium-speed four-stroke Diesel engines more
economic. As this possibility of improvement, which can be retrofitted, in
the meantime has proved a success in numerous cases over prolonged
operating times, we today would like to address you again in this regard.
Advantages The measure described in our Diesel Customer Information concerns the
supplementary use of so-called stepped cylinder liners, which derived
from the development of the four-stroke engines of our present
programme and whose advantages are once again briefly summarised in
the following:
- more favourable wear characteristics of the combustion chamber
components, i.e. pistons, piston rings and cylinder liners,
- prolonged service life of the aforementioned combustion chamber
components,
- reduction of the lube oil consumption,
- reduced strain on the lube oil
- resulting in reduced strain on all components of the lube oil system,
and
- altogether lower material and personnel expenditures for maintenance
and overhaul because of longer TBO’s.
245 cylinders have been Several customers have meanwhile made use of this possibility of
converted obtaining good results improvement. So far, 29 engines with a total of 245 cylinders have been
converted to stepped liners. The longest operating times reached by
such engines presently amount to approx. 15,000 hours. The operating
experiences now available from these plants, especially of engines that
were completely converted to stepped liners, are, without exception, very
good.
The lube oil consumption values could be reduced considerably
compared to the consumption values reached before the conversion. For
example, on older 58/64 engines, the lube oil consumption could, as a
rule, be brought down to below 1 g/kWh, and on 52/55 engines to below
1.8 g/kWh.
The special feature of these stepped liners is that these more favourable
consumption values remain stable over the period of the regular TBO in
case of proper lube oil care.
MAN B&W Diesel Aktiengesellschaft : Postfach 10 00 80 : D-- 86135 Augsburg : Phone ++49 821 3 22-- 0 : Fax ++49 821 3 22 33 82
Diesel Customer Information Cus 166 : 09/98
Even though the original guide value for the price of a stepped liner was
fixed too low with a 15-percent increase as against the corresponding
normal cylinder liner -- actually, an increase of approx. 25% must be
considered, depending on the cylinder liner design -- this does, due to the
considerably improved operating conditions, not have a significant
influence on the pay-back time of approx. two years.
Extended possibility of This gratifying development meanwhile has caused us to keep the
conversion stepped cylinder liners for the L, V 40/45, L, V 52/55 and L 58/64 engine
types on stock.
Should you, too, be interested in converting your engine(s) to stepped
cylinder liners, we kindly ask you to confidently contact one of our service
bases or us directly.
S/TKU
