Toyota 1PZ Repair Manual page 14

The 1 PZ engine is an in-line 5-cylinder engine
with the cylinders numbered 1 - 2 - 3 - 4 - 5 from
the front. This engine's
1 - 2 - 4 - 5 - 3 .
The 1 HZ and 1HD-T engines are an in-line
6-cylinder engine with the cylinders numbered
1 - 2 - 3 - 4 - 5 - 6 from the front. This engine's
injection order is 1 - 4 - 2 - 6 - 3 - 5 .
The crankshaft is supported by 6 (1 PZ) or 7 (1 HZ
and 1HD-T) bearings on the inside of the crank-
case. These bearings are made of aluminum alloy.
The crankshaft is integrated with 10 weights (1 PZ)
or 12 weights (1 HZ and 1HD-T) which are cast
along with it for balancing. Oil holes are built into
the crankshaft for supplying oil to the connecting
rods, bearings and other components.
The crankshaft bearing cap is of ladder frame
construction and is incorporated into the crank
case.
The cylinder head is made of cast iron with a
cross flow type intake and exhaust layout. The
combustion chambers are swirl chamber type for
the 1 PZ and 1 HZ engines and direct injection type
for the 1 H D-T engine. The camshaft journal part of
the cylinder head has camshaft caps made of alu-
minum alloy and is made of cast iron on the cylinder
head side. The camshaft journal has no bearings
(with the exception of the No.1 journal).
The 1 HZ and 1 HD-T engines has dual-type ex-
haust manifolds.
Exhaust and intake valves are equipped with
irregular pitch springs which are capable of follow-
ing the valves even at high engine speeds.
The camshaft is driven by the timing belt. The
camshaft journal is supported at 6 places (1 PZ) or
7 places (1 HZ and 1HD-T). Lubrication of the
camshaft journal and cam is accomplished by oil
being supplied through the oiler port in the No.6
(1 PZ) or No.7 (1 HZ and 1 HD-T) of the camshaft
journal.
ENGINE MECHANICAL
injection order is
Description
Adjustment of the valve clearance is done by
means of an outer shim type system, in which valve
adjusting shims are located above the valve lifters.
This permits replacement of the shims without
removal of the camshaft.
Pistons are made of highly temperature-resistant
aluminum alloy. As the 1 HD-T engine is the direct
injection type, a deep combustion chamber has
been provided. The No.1 piston ring groove has
been strengthened using a fiber reinforced metal.
Piston pins are the full-floating type, with the
pins fastened to neither the connecting rods nor the
piston boss, but with a snap rings fitted to both
ends of the pin to prevent the pin from slipping out.
The No.1 compression ring is made of steel and
the No.2 compression ring is made of cast iron. The
oil ring is made of steel. The outer diameter of each
piston ring is slightly larger than the diameter of the
piston and the flexibility of the rings allows them to
hug the cylinder walls when they are mounted on
the piston. Compression rings No.1 and No.2 work
to prevent the leakage of gas from the cylinder and
the oil ring works to scrape oil off the cylinder walls
to prevent it from entering the combustion cham-
ber.
The cylinder block is made of cast iron. It has 5
cylinders (1 PZ) or 6 cylinders (1HZ and 1HD-T)
which are approximately 1.7 times the length of the
piston stroke. The top of the cylinders is closed off
by the cylinder head and the lower end of the
cylinders becomes the crankcase, in which the
crankshaft is installed. In addition, the cylinder
block contains a water jacket, through which cool-
ant is pumped to cool the cylinders.
Plastic region tightening bolts are used for the
cylinder head bolts, crankshaft bearing cap bolts
and connecting rod cap bolts.
The oil pan is bolted onto the bottom of the
crankshaft bearing cap with bolts and nuts. The oil
pan is an oil reservoir made of pressed steel sheet.
EM-3