Mercedes — Metz  347

The  crankshaft  and  connecting  rods  are  practically  iden-
tical to  those  of  the  160-h.p.  engine.  The  valve  gear,  although
similar  in  many  respects,  has  been  greatly  improved.  The
rockers  no  longer  work  through  a  slot,  the  design  now  being
a  close  copy  of  Loomis  valve  gear  that  was  used  on  the  Lib-
erty. The  vertical  camshaft  driveshaft  is  of  new  design,  a
water  pump  similar  to  the  260-h.p.  design  now  being  placed
below  the  engine  at  the  end  opposite  the  propeller.
The  valve  timing  is  changed  to  the  following:  the  inlet
opens  on  top  center  and  closes  40  degrees  late;  the  exhaust
opens  40  degrees  early  and  closes  10  degrees  late.  The  lift  of
both  valves  is  11.5  mm.  (.453  in.).  The  oil  pump  has  been
changed  to  one  similar  in  design  to  the  260-h.p.  engine  pump.
The  fuel  consumption  is  said  to  be  .472  lbs.  per  h.p-hr.,  and
the  oil  consumption  .047  lbs.  per  h.p-hr.
A  650-h.p.  model,  patterned  after  the  260-h.p.  Mercedes
design,  had  a  normal  speed  of  1250  r.p.m.  and  weighed  2315
lbs.  The  bore  was  235  mm.  (9i25  in.),  the  stroke  250  mm.
(9.84  in.),  and  the  total  displacement  3967.49  cu.  in.  In  each
cylinder  were  four  valves  of  90  mm.  (3.54  in.)  diameter.  Dur-
ing the  tests,  severe  vibration  resulted  in  the  failure  of  the
crankcase.
Experiments  carried  on  with  an  eighteen-cylinder  W  type
engine  were  also  unsuccessful.
MfiTALLURGIQUE

The  Metallurgique  engines  were  four-cylinder  vertical
water-cooled  types  produced  in  France  during  1910.  The
smaller  engine  was  rated  32  h.p.  at  1850  r.p.m.,  and  reported  to
weigh  300  lbs.,  or  9.4  lbs.  per  rated  h.p.  The  bore  was  100
mm.  (3.94  in.),  the  stroke  150  mm.  (5.91  in.),  and  the  total
displacement  288.24  cu.  in.
