The Industrial Injection 3.9L 4BT Cummins Premium Stock Plus Heads are designed to be an affordable & reliable upgraded head complete and ready to bolt on.
New Performance Stainless Steel Valves:
We use the highest quality upgraded stainless steel valves with a nitrate coating for ultimate durability to out-perform and outlast any aftermarket or OE valves available.
High Strength Alloy Valve Guides:
New High Strength Alloy, Heat Treated iron based valve guides are installed. These guides are heat treated to Rockwell 22 "C" 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.
We use the highest quality brand new performance 150lb valves springs custom made right here in the USA. We designed these springs to offer more lift than the competition. Each valve spring is tested multiple times in house before assembly to ensure it maintains it proper spring rate.
The Build Process:
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; air flow 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 to 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.
New High Strength Alloy, Heat Treated iron based valve guides are installed. These guides are heat treated to Rockwell 22 â€œCâ€ 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.
Next the head is treated to 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 centering 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 our berco milling machine we 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.