Hudson Terraplane Special 1935, Owner'S Manual

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ENGINE
The unusual power, efficiency and economy of the Terraplane engine are due
to a combination of such advanced designs as the chrome alloy cylinder block,
giving great strength and wearing qualities so as to almost eliminate wear on
cylinder walls and valve seats; silicon aluminum alloy pistons, cam ground and
fitted with a clearance of .001"; silicon chromium steel valves; patented radial
flow intake manifold with down draft carburetion; all built around a fully
compensated crankshaft and lubricated by the Hudson Duoflo Automatic Lubri-
cating System.
The crankshaft is a heavy forging with integral compensating weights. Full
compensation, together with three main bearings and a torsional dampener
mounted on the front, insures free running of the crankshaft under all operating
conditions. The main bearings are removable bronze hacked, virgin babbitt and
are fitted to .001" clearance and provided with shims for adjustment. The working
member of the dampener is rubber, fully enclosed, requiring no adjustment.
The connecting rods are steel forgings carrying spun virgin babbitt bearings
in the lower end fitted with a clearance of .001" and having shims provided for
adjustment. The upper end is fitted with a bronze bushing, to which the piston pin
is fitted with .0003" clearance:
The pistons are of silicon aluminum alloy of new design. This alloy is hard,
lighter than aluminum and dissipates heat rapidly. The piston is "T" slotted to
compensate for expansion; cam ground to give full bearing on the cylinder wall;
and is fitted with two compression rings and one oil control ring above the piston
pin and one oil control ring below. With this arrangement all of the rings are
located somewhat lower down on the piston, with the result that cooler operating
conditions and bitter oil control are obtained. The piston is attached to the
connecting rod by a full floating pin, which is honed to give a perfect bearing in
the diamond-bored piston bosses. The piston pin is a snug fit in the piston bosses
when the piston is heated to 200° F.
This piston design permits fitting to the cylinder with a clearance of .001". The
pistons are removable from the top of the cylinder bore.
The camshaft is Electric Furnace Alloy, with hardened bearing and cam surfaces.
End play is prevented by a spring and plunger pressing against the front end of the
shaft.
The valves, which are silicon chromium steel, are operated by the cams
through adjustable tappets. The tappets should be adjusted while the engine is at
normal operating To adjust the tappets, remove the engine side cover plates (right
side of engine below intake manifold) and insert a feeler gauge between the top
of the tappet screw and bottom of the valve stem while the engine is running. The
valve tappets should be adjusted to a feeler gauge clearance of .006" on the intake
valves and .008" on the exhaust valves. The tappet screw locking nut should be
tightened securely after adjustment. The tappet clearance is important and should
be set accurately to the recommended dimensions.
14 TERRAPLANE SPECIAL SIX