Installation manual

90-898305
2-4
Mechanical Changes to the 2.5L & 3.0L Litre
Powerhead
1) Cylinder Head
a) Direct injector located in the top of the cylinder head.
b) 5/8” hex, long reach spark plug - puts the tip in the direct injector spray
pattern.
c) Head Gasket Change
i) 1998/99 2.5L aluminum gasket with o-ring seals
ii) 1998/99 3.0L & all 2000 models use an o-ring gaskets
2) Pistons
a) Cupped piston dome - directs fuel/air mixture, from the injector back up
towards the spark plug.
b) Outside profile changed and inside shape contoured to pass heat to
skirt and cylinder wall (hotter cylinder temperatures).
c) Pistons are marked “P” for port and “S” for starboard.
3) Cylinder block
a) OpitMax block casting has extra mounting points for OpitMax system
components – different from standard 2.5L or 3.0L block.
OptiMax Cylinder Head
The head is modified to support the fuel/air rails and position the spark plug at
the correct location inside the cylinder.
The OptiMax cylinder head utilizes a unique design to help trap the fuel/air
mixture for efficient and reliable combustion.
Notes
_______________________
_______________________
_______________________
_______________________
_______________________
_______________________
_______________________
_______________________
_______________________
_______________________
_______________________
_______________________
_______________________
_______________________
_______________________
_______________________
_______________________
_______________________
_______________________
_______________________
_______________________
_______________________
_______________________
_______________________
_______________________
_______________________
_______________________
_______________________
_______________________