- Engine:
- G3408 (S/N: 6RJ96-UP; 6NB2547-UP)
G3408C (S/N: 6FW315-UP; BAZ207-UP)
Engine News, SEBD9326, October 2003, "A New Cylinder Head Group For G3408 Engines". Disregard this article. Refer to the following article.
Description of Change: A new taller cylinder head group is now in production on G3408 Engines. The new cylinder head is 13 mm (0.51 inch) taller than the former cylinder head. The new cylinder head improves the engines' overall reliability. The new cylinder head improves cooling of the exhaust valve guides. The cooler exhaust valve guides increase the heat dissipation from the exhaust valves. The new cylinder head has longer valve guides. The longer valve guides provide increased support for the valves. The new cylinder head has reduced overhang of the exhaust valve in the exhaust port. The reduced overhang improves the rigidity of the valve. The improved rigidity of the valve improves the ability to guide the valve as the valve is seated. The internal cooling passages of the cylinder head have been modified in order to improve the overall cooling of the components of the cylinder head.
Adaptable To: The increased height of the new cylinder head requires new valve guides and new valves. Refer to Table 1 for the new valve guides and new valves.
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Table 1
| Intake |
Exhaust |
| 213-7536 Valve Guide |
213-7537 Valve Guide |
| 212-0932 Inlet Valve |
212-0933 Exhaust Valve |
New hardware will be required to install the new cylinder head groups. The hardware that is required is based on the ignition system of the individual engine. Conversion kits have been released. The conversion kits contain all of the parts and the conversion kits will include a cylinder head gasket kit in order to facilitate conversion from the original cylinder head to the new taller cylinder head. Refer to Tables 2, and 3. A cylinder head gasket kit is only required if you are changing a tall cylinder head with a tall cylinder head. Refer to Table 4.
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Table 2
| Cylinder Head Group |
| Old Part |
New Part |
| 200-0609 Cylinder Head Gp |
206-7748 Cylinder Head Gp |
| 200-0608 Cylinder Head Gp |
| 0R-9483 Cylinder Head Gp |
10R-1137 Cylinder Head Gp |
| 0R-9484 Cylinder Head Gp |
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Table 3
| Conversion Kit (1) |
| Ignition Type |
Part Number |
| Electronic Ignition System (EIS) |
226-1801 |
Electronic Ignition System (EIS)
Canadian Standard Association (CSA) |
226-1802 |
Magneto or Caterpillar Digital Ignition System (CDIS)
Canadian Standard Association (CSA) |
226-1800 |
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| ( 1 ) | Use this conversion kit in order to convert from a short cylinder head to a tall cylinder head. One conversion kit supplies one cylinder head. |
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Table 4
| Cylinder Head Gasket Kit (1) |
| Old Part |
New Part |
| 8T-3360 Gasket Kit (2) |
231-5226 Gasket Kit (2) |
| 8T-3359 Gasket Kit (3) |
231-5228 Gasket Kit (3) |
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| ( 1 ) | Use this cylinder head gasket kit in order to replace a tall cylinder head with a tall cylinder head. |
| ( 2 ) | One cylinder head |
| ( 3 ) | Complete engine |
A lower torque is used for the cylinder head bolts in order to prevent distortion of the cylinder head bottom deck. The Special Instruction, REHS1432 has been released in order to explain the torque procedure for the new cylinder head group.