Cummins Heads

D&J Precision Machine Cummins heads are a step up in the diesel performance industry. With years of experience, we designed our ported Cummins heads for the performance enthusiasts with reliability in mind.

Cummins heads start by being completely disassembled, inspected, and crack checked. If the head passes inspection, all sealing soft plugs are removed before the head casting is baked in our oven to ensure all oil, carbon, paint, and gaskets are easily removed.  Then the cylinder head is steel shot blasted in our rotary shot blaster to remove any rust or debris from the previous processes. The head then goes to the CNC department where all the bolt holes are tapped “including the freeze plugs under the valve cover” with a FLEXARM tapping fixture to ensure all holes are straight and are free of debris. Next, we machine the cylinder heads to accept larger seats, valve guide liners, and resurface them as needed. If the cylinder head needs ported, they move on to our CENTROID A560XL 5 axis CNC machine to receive a stage1, stage2, or stage 3 5 axis CNC port job. All of our cylinder heads then receive a high-performance CNC valve job on our NEWEN CONTOUR B-B to mate perfectly with a freshly resurfaced valve to form a complete seal between the seat and valves. When all of the machine work is complete, we run the cylinder heads through our RENAGADE custom state-of-the-art parts washer which uses high pressure spraying nozzles paired with cleaning agents to completely remove any debris from the machining processes.  Each cylinder head gets inspected by 2 technicians after final cleaning to ensure only the best quality for our customers.  They are double checking every bolt hole for good threads, and for any debris left from the previous operations.    The next steps are to install all new freeze plugs throughout the head, install new Cummins oem valve seals, and completely assemble the cylinder head. “EVERY CYLINDER HEAD HAS TO PASS A PRESSURE CHECK OF THE VALVES AND COOLANT TO PROCEED”. The final step is to paint the cylinder head to customer specifications and prepare it for the shipping method of their choosing.

D&J Stage 2 and Stage 3 replacement style billet intake manifolds are designed to keep the factory fuel rail, lines, map sensor, fuel filter housing, air horn and throttle position sensor all close to the stock location. This allows most twin CP3 kits to work with little to no modification to the kit. Please note the front 3 bolts on the intake runner are 0.300” higher than stock cast cylinder head. ” SOME MODIFICATION IS NEEDED WHEN USING AFTERMARKET INTAKE HORNS”

We developed our replacement style billet intake manifolds after we found some of the intakes with side entrances force air into the cylinders across from the inlet pipe. We noted cylinders 2-4 (depending on what side draft) that are directly across from the inlet run 300-400 degrees hotter. This in some cases has melting pistons. Since our intake utilizes the factory air intake mounting this allows the air to disperse equally throughout the entire intake manifold. Our replacement style billet intake manifold also saves the customer time and money by utilizing their current intake horn.

Using our specialized CNC 5-axis Centroid porting machine has not only let increase consistency but also cut our production time down tremendously. Our porting is proven to increase the flow of the 24v cummins cylinder head while keeping enough material in the areas needed to avoid melting through. Standard cylinder heads have a 2 week turnaround time. Please call to confirm before ordering. Rushed options are available on a per-job basis.

*Cracked cylinder heads are NOT acceptable cores. If you have a damaged cylinder head please call the shop or email with pictures to see if it is an acceptable core. Core cylinder heads should include cylinder head, valves, springs, retainers, keepers, plugs. Please do not send cores in with temperature sensors and complain when you don’t get them back. Core Charge required at time of purchase and will be refunded once we receive your core and if it passes our crack check test.