The Isuzu is a strange animal-when you do the timing belt you set it with #1 TDC "BUT" the distributor is timed with TDC #4 I found this the hard way and finally had to buy a cd with the procedures on it. Send me an e-mail address and I will forward the associated pictures &
info to you.
TIMING BELT & SPROCKETS R & I
NOTE: Some procedures may differ slightly due to engine
1) Remove all necessary air ducts. Position No. 4 piston at
TDC of compression stroke. Align timing marks. See Fig. 2. Remove fan
and fan shroud. Remove belts. If necessary, remove radiator and
2) Prevent engine from rotating and remove crankshaft timing
pulley retaining bolt. Remove upper and lower timing belt covers.
Remove spring from tension pulley. Loosen adjusting bolt and move
pulley toward water pump. Remove timing belt.
CAUTION: Ensure pistons are at TDC when rotating camshaft or damage
1) Handle timing belt carefully. Avoid twisting or kinking
belt. Do not allow belt to become contaminated by water, oil, dirt or
other contaminates. Inspect belt for cracks or damage. If necessary,
2) Measure tension pulley spring length and force. Spring
length should not exceed 2.76" (70.2 mm) and spring force should not
be less than 197-347 lbs. (27-48 kg).
3) Replace tension pulley spring if not within specification.
1) Pull tensioner fully toward water pump side and
temporarily tighten retaining bolt. Ensure No. 4 cylinder is at TDC on
compression stroke by rotating crankshaft until keyway aligns with
mark on front crankshaft seal housing (12 o’clock). Rotate camshaft
until timing mark on cam gear (arrow) aligns with mark on upper
camshaft cover (notch). See Fig. 2.
NOTE: When timing marks are aligned as stated above, No. 4 piston
is at TDC on compression stroke.
2) Position timing belt over crankshaft sprocket, oil pump
sprocket, camshaft sprocket and tensioner in that order. Ensure belt
is positioned in sequence given and without slack between sprockets.
Loosen tension sprocket adjusting bolt allowing spring tension to
tighten belt. Tighten adjusting bolt temporarily.
3) Temporarily install crankshaft pulley bolt and rotate
crankshaft 2 complete revolutions in opposite direction of engine
rotation, until marks on crankshaft and front oil seal retainer are
aligned again. See Fig. 2. Loosen tensioner lock bolt, allowing
tesioner spring to fully adjust tension. Tighten tensioner lock bolt.
4) Install timing belt covers. To complete installation,
reverse removal procedures. Tighten all bolts to specification. See
TORQUE SPECIFICATIONS table at end of this article.
Fig. 2: 2.3L & 2.6L Timing Alignment Marks
Courtesy of Isuzu Motor Co.