ENGINE GENERAL INFORMATION AND DIAGNOSIS (H27 ENGINE) 6-1-3
General Information
Statement of Cleanliness and Care
An automobile engine is a combination of many machined, honed, polished and lapped surfaces with tolerances
that are measured in the thousands of an millimeter (ten thousands of inch). Accordingly, when any internal
engine parts are serviced, care and cleanliness are important. Throughout this section, it should be understood
that proper cleaning and protection of machined surfaces and friction areas is part of the repair procedure. This
is considered standard shop practice even if not specifically stated.
A liberal coating of engine oil should be applied to friction areas during assembly to protect and lubricate the
surface on initial operation.
Whenever valve train components, pistons, piston rings, connecting rods, rod bearings and crankshaft jour-
nal bearings are removed for service, they should be retained in order. At the time of installation, they should
be installed in the same locations and with the same mating surfaces as when removed.
Battery cables should be disconnected before any major work is performed on the engine. Failure to discon-
nect cables may result in damage to wire harness or other electrical parts.
Throughout this manual, the 6 cylinders of the engine are
identified by numbers; No.1, No.2, No.3, No.4, No.5 and No.6
as counted from crankshaft pulley side to flywheel side.
Figure at the left shows engine with intake manifold removed
and viewed from the top.
LH (No.1) bank consists of No.1, No.3 and No.5 cylinders.
RH (No.2) bank consists of No.2, No.4 and No.6 cylinders.
General Information on Engine Service
When raising or supporting engine for any reason, do not use a jack under oil pan. Due to small clearance
between oil pan and oil pump strainer, jacking against oil pan may cause it to be bent against strainer result-
ing in damaged oil pick-up unit.
It should be kept in mind, while working on engine, that 12-volt electrical system is capable of violent and
damaging short circuits.
When performing any work where electrical terminals could possibly be grounded, ground cable of the bat-
tery should be disconnected at battery.
Any time the air cleaner, air cleaner outlet hose, throttle body, surge tank pipe, intake collector or intake man-
ifold is removed, the intake opening should be covered. This will protect against accidental entrance of for-
eign material which could follow intake passage into cylinder and cause extensive damage when engine is
started.
1. No.1 cylinder 6. No.6 cylinder
2. No.2 cylinder 7. LH (No.1) bank
3. No.3 cylinder 8. RH (No.2) bank
4. No.4 cylinder 9. Crank shaft pulley side
5. No.5 cylinder
CAUTION:
The following information on engine service should be noted carefully, as it is important in preventing
damage, and in contributing to reliable engine performance.
6A2-24 ENGINE MECHANICAL (H27 ENGINE)
ASSEMBLY
1) 2 sizes of piston are available as standard size spare part so
as to ensure proper piston-to-cylinder clearance. When
installing a standard size piston, make sure to match piston
with cylinder as follows.
a) Each piston has stamped number (1 or 2) on its piston
head. It represents outer diameter of piston.
b) There are also stamped numbers of 1 and 2 on the cylinder
block as shown in the figure.
c) Stamped number on piston and cylinder block must corre-
spond. That is, install number “2” stamped piston to cylinder
which is stamped also number “2” and a number “1” piston
to cylinder with number “1”.
Also, a letter A, B or C is stamped on piston head but ordi-
narily it is not necessary to distinguish each piston by this
letter.
Piston-to-cylinder clearance
Piston :
Cylinder :
Piston-to-cylinder clearance :
0.02 – 0.04 mm (0.0008 – 0.0015 in.)
2) Install piston pin to piston and connecting rod :
After applying engine oil to piston pin and piston pin holes in
piston and connecting rod, fit connecting rod to piston as
shown in the figure and insert piston pin to piston and con-
necting rod, and install piston pin circlips. Number at the top (mark) Outer diameter
187.98 – 87.99 mm
(3.4638 – 3.4642 in.)
287.97 – 87.98 mm
(3.4634 – 3.4638 in.)
Number on cylinder block (mark) Outer diameter
188.01 – 88.02 mm
(3.4650 – 3.4653 in.)
288.00 – 88.01 mm
(3.4646 – 3.4650 in.)
NOTE:
“86F” mark on connecting rod must face toward crank-
shaft pulley side.
1. Piston
2. Arrow mark
3. Connecting rod
6A2-32 ENGINE MECHANICAL (H27 ENGINE)
Selection of main bearings
•STANDARD BEARING :
If bearing is in malcondition, or bearing clearance is out of
specification, select a new standard bearing according to the
following procedure and install it.
1) First check journal diameter. As shown in the figure, crank
web has stamped numbers and alphabet at the center.
3 kinds of numbers (“1”, “2” and “3”) represent the following
journal diameters.
Journal diameter :
2) Next, check crankcase (bearing cap) bore diameter without
bearing. On lower surface of lower crankcase 4 alphabets
are stamped as shown in the figure.
3 kinds of alphabets (A, B and C) represent the following cap
bore diameters.
Main bearing cap bore diameter :Stamped numbers Journal diameter
165.000 – 65.006 mm
(2.5590 – 2.5593 in.)
264.994 – 65.000 mm
(2.5588 – 2.5590 in.)
364.988 – 64.994 mm
(2.5586 – 2.5588 in.)
1. Crankshaft
2. Crank web
Stamped numbersBearing cap bore diameter
(without bearing)
A70.000 – 70.006 mm
(2.7559 – 2.7561 in.)
B70.006 – 70.012 mm
(2.7561 – 2.7563 in.)
C70.012 – 70.018 mm
(2.7563 – 2.7566 in.)
1. Crankshaft pulley side
2. Stamped alphabets
3. No.1 bearing
4. No.2 bearing
5. No.3 bearing
6. No.4 bearing
