Isuzu D-Max / Isuzu Rodeo (TFR/TFS). Manual — part 559

6A – 74 ENGINE MECHANICAL

Important Operations

1. Connecting Rod Bearing

If the connecting rod bearings are to be reinstalled, mark
their fitting positions by tagging each bearing with the
cylinder number from which it was removed.

2. Piston

Ring

1) Clamp the connecting rod in a vise.

Take care not to damage the connecting rod.

2) Use a piston ring replacer to remove the piston rings.

Piston Ring Replacer
Do not attempt to use some other tool to remove the
piston rings. Piston ring stretching will result in
reduced piston ring tension.

3. Piston Pin Snap Ring

Use a pair of pliers to remove the piston pin snap rings.

4. Piston

Pin

6. Piston

Tap the piston pin out with a hammer and a brass bar.
If the pistons and piston pins are to be reinstalled, mark
their installation positions by tagging each piston and
piston pin with the cylinder number from which it was
removed.

015R100020

015R100015

ENGINE MECHANICAL 6A – 75

INSPECTION AND REPAIR

Make the necessary adjustments, repairs, and part replacements if excessive wear or damage is discovered during
inspection.

FACE WARPAGE

Cylinder Head Lower Face Warpage

1. Use a straight edge and a feeler gauge to measure

the four sides and the two diagonals of the cylinder
head lower face.

If the measured values exceed the limit, the cylinder head
must be replaced.
Cylinder Head Lower Face Warpage

mm (in)

Standard Limit

0.05

(0.002) or less

0.20

(0.008)

Note:
The cylinder head lower face cannot be reground.

Cylinder Head Height

H

(Reference)

mm (in)

Standard

91.95

–

92.05

(3.620 – 3.624)

Manifold Fitting Face Warpage

Use a straight edge and a feeler gauge to measure the
manifold cylinder head fitting face warpage.
Regrind the manifold cylinder head fitting surfaces if the
measured values are greater than the specified limit but
less than the maximum grinding allowance.
If the measured values exceed the maximum grinding
allowance, the cylinder head must be replaced.
Manifold Fitting Face Warpage

mm (in)

Standard Limit

Maximum Grinding

Allowance

0.05

(0.002) or less

0.20

(0.008)

0.40

(0.016)

6A – 76 ENGINE MECHANICAL

Exhaust Manifold Warpage

Use a straight edge and a feeler gauge to measure the
manifold cylinder head fitting face warpage.
If the measured values exceed the specified limit, the
manifold must be replaced.
Exhaust Manifold Warpage

mm (in)

Standard

Limit

0.05 (0.002) or less

0.20 (0.008)

HOT PLUG (4JG2T ENGINE ONLY)

Hot Plug Depression

1. Clean the cylinder head lower face, taking care not to

damage the hot plug surfaces.

2. Use a straight edge and a feeler gauge to measure

hot plug depression in a straight line from the No. 1
hot plug to the No. 4 hot plug.
If the measured value exceeds the specified limit, the
hot plugs must be replaced.

Hot Plug Depression

mm (in)

Limit

0.02 (0.0008)

Combustion Chamber Inspection

1. Remove the carbon adhering to the inside of the

combustion chamber. Take care not to damage the
hot plug fitting positions.

2. Inspect the inside of the combustion chamber, the hot

plug hole, and the hot plug machined faces for
cracking and other damage.
If cracking or damage is present, the cylinder head
must be replaced.

Note:
Be absolutely certain that there are no scratches or
protuberances on the combustion chamber surfaces
which will be in contact with the hot plug after it is
installed. These flaws will prevent the hot plug from
seating correctly.

ENGINE MECHANICAL 6A – 77

Hot Plug Replacement

Hot Plug Removal

1. Insert a 3 – 5 mm (0.12 – 0.20 in) diameter brass bar

into the nozzle holder fitting hole until it makes contact
with the hot plug.

2. Lightly tap the bar with a hammer to drive the hot plug

free.

Hot Plug Inspection

Inspect the hot plugs for excessive wear and other
damage. Replace the hot plugs if either of these
conditions are discovered.
Refer to “Hot Plug Installation”.

Hot Plug Installation

1. Align the hot plug knock ball

Q

with the cylinder head

groove

R

and tap it temporarily into position with a

plastic hammer.

2. Place a metal plate

S

approximately 25 mm (1 in)

thick over the hot plug upper surface

T

.

3. Use a bench press

U

to exert a pressure of 4,500 –

5,500 kg (9,923 – 12,128 lb/44,100 – 53,900 N) on the
metal plate covering the hot plug upper surface.
This will drive the hot plug into position.

4. Lightly tap the hot plug head to make sure that it is

firmly seated.

5. Repeat the procedure (Steps 1 – 4) for the remaining

hot plugs.

Note:
Do not apply pressure greater than that specified.
Damage to the cylinder head will result.
6. Use a surface grinder to grind off any hot plug surface

protuberances.
The hot plug surfaces must be perfectly flush with the
cylinder head lower face.