CRANKCASfS
Vilal
Conterns:
•
Are
crankcase halves
precision-made cast-
ings, so unilarm that
they may
be
purchased
separately?
• Have crankcase
mating surlaces been
machined to assure Ilaw-
less contact and a last-
ing airtight seal?
•
Are
the case halves
sealed with a strong ,
pliable, high-tempera-
ture liquid gasket
compound?
•
Are
crankcase halves
made
01
like materials,
lar
best structural integ-
rity and unilorm thermal
expansion/contraction?
•
Are
crankcase bear-
ings a snug , press-lit
installation to assure
they don't slip or spin
in
their bares?
Analysis:
Spedlitalions:
Shindaiwa T230 / T260 / T270 / T350
AII
have aluminum
al
loy crankcase halves with machined
mating surfaces and press-fit bearings.
Halves are ava
il
able separately. Sealed via liquid gasket.
Echo SRM-2400 / SRM-3100S / SRM-3400
AII
have aluminum a
ll
oy
crankcase halves with press-lit
bearings.
Halves
not available separately. Sealed via paper or
synthetic gaskets
Husqvarna 225L / 232L / 235R
AII
have horizonta
ll
y-split crankcase, with aluminum alloy
top hall, and plastic bottom hall. Mating surfaces are
not machined. Bearings clamped by the screws that
hold crankcase/cylinder assembly together.
Top crankcase half (includes cylinder) and bottom hall
(includes fuel tank) may be purchased separately.
Halves sealed via liquid gasket.
Stihl
FS-76/
FS-88 / FS-108
AII
have aluminum alloy crankcase halves with press-fit
bearings.
Halves are available separately. Sealed via liquid gasket.
Shindaiwa and Stihl offer economical, individual replacement of alloy crank-
case halves.
II
an
Echo crankcase half
is
damaged, both halves must be replaced, at
considerably mare expense.
AII but Echo use modern liquid gasket compounds to seal the crankcase
halves. Echo
sti
ll
relies on paper and synthetic gaskets.
Husqvarna's unconventional design involves crankcase halves made of dis-
similar
materials-plastic
and metal. Ellects
01
high temperature may be less predict-
able than all-a
ll
oy designs. This concern, plus as-cast (non-machined) mating
surfaces, suggest greater risk
01
air leaks and allied engine damage.
HUSQVARNA 232L
Bottom
half
is
p/astic,
top
half
is
a/uminum
alloy
ECHO SRM-3100S
Ha/ves
cannot
be
purchased separate/y
Bearings
clamped
Mating
surface
between
ha/ves.
is
not
machined.
/
Sea/ed
~
by/iquid~
•
gasket.
'"
~
Sea/ed
by
synthetic
gasket.
SHINDAIWA T270
Precision-machined
ha/ves
may
be
purchased
separa
t
e/y
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