2004.5-2005 Duramax Race Heads (PDM-LLYRH)

Fits

The Industrial Injection LLY Duramax Race Heads are designed for the racer/sled puller in mind. Fully CNC ported heads complete ready to bolt on.

Part Number:  PDM-LLYRH

• 5 Axis CNC Cylinder Head Porting Machine with CAD/CAM software specifically designed for cylinder head porting
• Diamond Honed Guides
• Unshrouded Valves
• High Strength Alloy, Heat Treated iron based valve guides
• Premium valve seat inserts made from a true Nickel Based Non-Magnetic material
• multi-angle valve job
• Performance 130LB valve springs

• Sold in a pair
• To receive full core credit cylinder heads need to be a good, re-useable pair of cylinder heads. No cracks, warping, or excessive wear.

Heads are first jet washed in a high-pressure spray cabinet to remove oil and dirt, then glass beaded to remove carbon. Next, they are checked by magnafluxing, (cast iron only) or pressure testing. They are visually inspected for defects that would make them unusable. Valve guides and seats are removed as needed for porting.

Port development is accomplished using a superflow 600 flow bench with a computer recording all flow measurements.

Many things are considered when designing a cylinder head Port; airflow is only one of the things to think about. Another major concern is port wall thickness.

Anyone can get a head to produce high flow numbers, but if doing so leaves the port wall too thin the casting will crack. High-performance Diesel heads are more prone to crack because of the thermal shock experienced by excessive intermittent or long-term exhaust temperatures.

The porting is then performed using a new 5 Axis CNC Cylinder Head Porting Machine with CAD/CAM software specifically designed for cylinder head porting. CNC porting brings unparalleled accuracy to head porting with each port flowing the same. This helps balance the power that each cylinder produces, making tuning easier.

New High Strength Alloy, Heat Treated iron-based valve guides are installed. These guides are heat treated to Rockwell 22 Scale, which produces the ultimate in wear resistance. This is far superior to original guide material, including Bronze. The guide incorporates a spiral grove inside the guide to hold oil and aid the lubrication of the valve during engine operation.

Guides are then honed (not reamed) to exact size using a diamond honing mandrel. Diamond abrasives allow for consistency of size, surface finish, and bore geometry with no variation from guide to guide. The guide size is then verified using a valve guide bore gauge.

As needed the head receives new Premium valve seat inserts made from a true Nickel Based Non-Magnetic material that was developed for extreme operating conditions.

Next, the head is treated with a multi-angle valve job to help maximize the flow of air in and out of the head. This is accomplished using a Serdi 100 guide and seat machine. Serdi uses a solid carbide straight shank pilot. When inserted into the valve guide, it simulates the real valve stem during the centring process. This guarantees the valve seat is finished for a perfect valve-to-seat match.

Using CBN or Diamond tooling the head is given a new surface. With Industrial Injections Berco Milling machine they can control the surface finish to accommodate different head gasket types. For example, MLS head gaskets require a very smooth surface finish.

Finally, the head is jet washed dried and assembled with new valve seals and new performance valve springs.