Long Block Break-in instructions

1998-2024 Precision Plus and Essential Long blocks

Engine Break In Procedure

1998-2024 Precision Plus and Essential Long blocks

Thank you for your purchase of your new D&J Precision Machine Engine. We have created this break in procedure to ensure optimum performance of your new engine.

Every engine comes pre-lubed with 12 quarts of VR1 20W-50 race oil and a filter. We have found this oil works very well with break in.Your engine has been pressure-checked for oil and crankcase leaks. It has also been pressure checked for coolant leaks. Your engine is ready to start putting on your accessories, wiring harness, turbo, and fuel system. There are a few steps we recommend for proper break in.

Step 1: Install engine in truck. Only hook up fuel system, transmission, turbo with oil supply and return, all electrical plug-ins to run the engine. Install radiator and intercooler piping. Do not fill the radiator at this time.  Install an external mechanical oil pressure gauge, crank the engine with the injectors unplugged, and fuel supply pump off (this helps not to build rail pressure and add more load to the starter) until you start to get oil pressure.  Be careful not to overheat your starter; it may take a few minutes to get oil pressure.   Plug everything in and clear codes.

Step 2: Start the engine with no coolant in it. After the engine is running and reading good oil pressure you are going to increase engine RPM to 1,800 rpm and hold it steady for five minutes. Try not to let the engine idle more than necessary. We have found it causes piston rings to glaze and hinders camshaft break in. There will be a little oil residue coming from the exhaust side of the turbo or smoke out the tailpipe depending if your downpipe is hooked up. This is normal. The oil that is used in assembly is burning off or working its way out of the combustion chamber.  It is a good idea to have a friend watch for leaks.

Step 3: After the five minutes run time is complete you can shut off the engine and check for any leaks. This is a good time to make sure all fuel lines are tight and look for any issue with turbo oil lines. If everything looks good, let the engine cool, and fill the engine with coolant. We recommend leaving the heater core hose off the top of the cylinder head as you are filling the radiator with coolant. This allows air to escape the engine as you are filling it. This also allows the cylinder head to be completely filled with coolant and not have any air trapped in the coolant passages. As you are filling the radiator, watch the fitting for coolant. When the coolant starts to come out of the fitting, install the hose, tighten the clamp. Finish filling the radiator. 

Step 4: After the engine is filled with coolant, a 20 minute run at 1,800 rpm can be done. Once again do not let the engine idle for an excessive amount of time. This helps in bringing the engine up to temperature. We recommend stopping every five to ten minutes and checking for leaks or other issues if you are working by yourself. The engine can be left running during these checks. After the 20 minute run, shut off the engine. 

Step 5: Drain oil and change the filter. A hot re-torque can be done at this time. Remove valve cover, injector wiring harness and rocker box. Intake rockers will also need to be removed at this time to re-torque head studs. We recommend removing intake rockers on the stud being tightened then replaced after torquing to help with checking valve lash in the next step. D&J head studs are re-torqued to 125 ft. lbs starting in the center of the engine and working out towards the ends alternating from side to side.   After re-torque intake rockers can be torqued to 26ft/lbs.

 

A core charge is a refundable deposit for the value of a re-buildable part. On certain D&J Precision Machine products, we need to charge a core charge at the time of the sale. Upon receipt of the core, D&J Precision Machine will determine the condition of the core and refund all, part, or none of the core based on the condition.

  • Customer is responsible for all return shipping charges. If you want D&J Precision to arrange shipping, you will be responsible for shipping costs. This will be deducted from your core refund. If your core is unusable, you will be charged for return shipping.
  • Ship all cores to the address on the Core Return Form.
  • Cores must be returned with the Core Return Form properly completed.
  • All cores must be the same model as the original item that was purchased.
  • Cores must be returned within 60 days.
  • Cores should be packed carefully, i.e. fixed to a pallet, to protect from shipping damage.
  • D&J Precision Machine is not responsible for shipping damage.
  • Please allow 30 days after core delivery to our facility, for cores to be processed and refunds to be issued.
  • If core is deemed non-useable, the customer will be notified and given 10 days to respond to have their core returned to them at their expense. After 10 days the deemed non-useable core will be scrapped. 

Core Acceptance Policy

MODEL/PART # FULL CREDIT CRITERIA PARTIAL CREDIT CRITERIA NO CREDIT
Cummins 5.9 and 6.7 Cylinder Heads • Like for Like
• No Visible External Damage
• No Fire Damage
• All Components Present including valves
• No Bolt Hole Damage
• Core Paperwork Returned		 • Missing Valvetrain Components (25% deduction)
• Provide a 5.9 Core as a 6.7 core (30% deduction)
• Cracked or Damaged Intake (25% deduction)
• Damaged Bolt Holes ($25 each)
• Missing or Incomplete Paperwork ($50 deduction)		 • Fire Damage
• Any Form of Damage to the Deck
• Excessive Damage to the Guide Area
• Cracks in any area except the Intake
• Shipping Damage
Cummins 5.9 and 6.7 Crankshaft • Like for Like
• No Visible Damage
• No Rust on Journals
• No Bolt Hole Damage
• No Damage to the Front or Rear Face of the Crank
• No Gear Damage
• No Dowel Damage
• Core Paperwork Returned		 • Damage to Dowel that can be Repaired ($125 deduction)
• Damage to Front or Rear Face that can be Repaired ($125 deduction for each face)
• Damage to Gear that can be repaired (12V/ISB $250 deduction, CR no credit)
• Missing or Incomplete Paperwork ($50 deduction)
• Damaged 2019 up timing gear housings will be a $1750 deduction
• Damaged 2019 up front covers will be a $250 deduction		 • Damage or Rust to Journals that cannot be polished
• Damage to Dowel that cannot be repaired
• Damage to Front or Rear Face that cannot be repaired
• Any Damage to CR Crank Gear
• Damage to 12V/ISB Crank Gear that cannot be repaired
• Any Cracks
• Shipping Damage
Cummins 5.9 and 6.7 Camshaft • Like for Like
• No Visible Damage
• No Rust on Journals
• No Gear Damage
• Core Paperwork Returned		 • Damage or Rust to Journals that can be ground (50% deduction)
• Damage to gear ($250 deduction)
• Missing or Incomplete Paperwork ($50 deduction)
• 2019 up cams will not be accepted as a good core (150 core charge)		 • Damage or Rust to Journals that cannot be ground
• Shipping Damage
Cummins 5.9 and 6.7 Block • Like for Like
• No Visible External Damage
• Can be Remachined without Sleeves
• Core Paperwork Returned		 • 6.7 - If it needs sleeves it will receive no core credit
• Provide a 5.9 Core as a 6.7 core (50% deduction)
• Damaged Bolt Holes ($25 each)
• Missing Main Caps ($250 deduction)
• Missing or Incomplete Paperwork ($50 deduction)
• 2019 up blocks will not be accepted as a good core		 • Cracks
• Damage to Deck Surface that exceeds .010
• Damage to Main Bore that is beyond repair
• Damage Cam Bore that is beyond repair
• Damaged Head or Main Bolt Holes
• General Damage that is beyond Repair
• Shipping Damage
Cummins 5.9 and 6.7 Short/Long Block • Refer to Cylinder Head, Crankshaft, Camshaft and Block Policies for each item
• All Bolts and Accessories that are included with the purchase of your short/long block are returned and rebuildable
• Core Paperwork Returned		 • Refer to Cylinder Head, Crankshaft, Camshaft and Block Policies for each item
• Refer to Core Price Sheet for missing or damaged component partial credit pricing
• Missing or Incomplete Paperwork ($50 deduction)		 • Refer to Cylinder Head, Crankshaft, Camshaft and Block Policies for each item
• Shipping Damage
 

CORE RETURN FORM

Please print out the following form, fill it out, and include it when sending in your product.

 Download Form

 

Step 6: We also recommend rechecking valve lash at this time. Valve lash needs to be checked at top dead center on number one or number six cylinder. Bring the top dead center mark on the harmonic balancer to the 12:00 o'clock position. If both number one cylinder rocker levers are loose, continue to the next step. If both number one cylinder rocker levers are not loose, rotate the crankshaft 360 degrees.
With the engine in this position, valve lash can be measured at the following rocker arms: INTAKE 1-2-4 / EXHAUST 1-3-5  . Measure the valve lash by inserting a feeler gauge between the rocker arm socket and crosshead. Valve lash should be .010” on intake and .020” on exhaust. If the measurement falls within  the limits, adjustment/resetting is not necessary. If measurement finds the lash outside  of the limits, adjustment/resetting is required.

 If adjustment/resetting is required, loosen the lock nut on rocker arms and turn the adjusting screw until the desired lash is obtained. Tighten the lock nut to 24 Nm (18 ft. lbs.) and re-check the valve lash. Using the crankshaft barring tool, rotate the crankshaft   one revolution (360°) to align the damper TDC mark to the 12 o'clock position. With the engine in this position, valve lash can be measured at the remaining rocker arms: INTAKE 3-5-6 / EXHAUST 2-4-6  . Use the same method as above for determining whether valve adjustment is necessary, and adjust those that are found to be outside of the limits.

  If everything checks out you can reinstall rocker box, injector harness, and valve cover.

Step 7: Re-fill engine with oil. We recommend using Hot Shot Secret Green or Blue Diamond full synthetic 15w-40. We have seen good results with these oils. We recommend changing your oil based on usage and horsepower. The more horsepower means more frequent oil change intervals. We have seen oil quality can affect the amount of blow-by an engine can have and ring retention.  Always check engine oil level and also for how clean the oil is. If the oil stains your skin black then it is overdue to be changed. This means the oil is full of soot from combustion and is not going to be as effective in lubricating or cleaning.

These seven steps should ensure a proper break in procedure for your new engine. If you have any further questions, don’t hesitate to call. We will be happy to answer any questions you might have. Thank  you for your purchase.

Engine Break In Procedure

2003-2024 Heavy Hauler, Street Performance, Performance Series, Predator, and Enforcer

Thank you for your purchase of your new D&J Precision Machine Engine. We have created this break in procedure to ensure optimum performance of your new engine.

Every engine comes pre-lubed with 12 quarts of VR1 20W-50 race oil and a filter. We have found this oil works very well with break in.Your engine has been pressure checked for oil and crankcase leaks. It has also been pressure checked for coolant leaks. Your engine is ready to start putting on your accessories, wiring harness, turbo, and fuel system. There are a few steps we recommend for proper break in.

Step 1: Install engine in truck. Only hook up fuel system, transmission, turbo with oil supply and return, all electrical plug-ins to run the engine. Install radiator and intercooler piping. Do not fill the radiator at this time.  Install an external mechanical oil pressure gauge, crank the engine with the injectors unplugged, and fuel supply pump off (this helps not to build rail pressure and add more load to the starter) until you start to get oil pressure.  Be careful not to overheat your starter; it may take a few minutes to get oil pressure.   Plug everything in and clear codes.

Step 2: Start the engine with no coolant in it. After the engine is running and reading good oil pressure you are going to increase engine RPM to 1,800 rpm and hold it steady for five minutes. Try not to let the engine idle more than necessary. We have found it causes piston rings to glaze and hinders camshaft break in. There will be a little oil residue coming from the exhaust side of the turbo or smoke out the tailpipe depending if your downpipe is hooked up. This is normal. The oil that is used in assembly is burning off or working its way out of the combustion chamber.  It is a good idea to have a friend watch for leaks.

Step 3: After the five minutes run time is complete you can shut off the engine and check for any leaks. This is a good time to make sure all fuel lines are tight and look for any issue with turbo oil lines. If everything looks good, let the engine cool, and fill the engine with coolant. We recommend leaving the heater core hose off the top of the cylinder head as you are filling the radiator with coolant. This allows air to escape the engine as you are filling it. This also allows the cylinder head to be completely filled with coolant and not have any air trapped in the coolant passages. As you are filling the radiator, watch the fitting for coolant. When the coolant starts to come out of the fitting, install the hose, tighten the clamp. Finish filling the radiator. 

Step 4: After the engine is filled with coolant, a 20 minute run at 1,800 rpm can be done. Once again do not let the engine idle for an excessive amount of time. This helps in bringing the engine up to temperature. We recommend stopping every five to ten minutes and checking for leaks or other issues if you are working by yourself. The engine can be left running during these checks. After the 20 minute run, shut off the engine. 

Step 5: Drain oil and change the filter. A hot re-torque can be done at this time. Remove valve cover, injector wiring harness and rocker box. Intake rockers will also need to be removed at this time to re-torque head studs. We recommend removing intake rockers on the stud being tightened then replaced after torquing to help with checking valve lash in the next step. D&J 9/16” head studs are re-torqued to 175 ft. lbs starting in the center of the engine and working out towards the ends alternating from side to side.  If your engine has been built with a different stud use their torque spec.  After re-torque intake rockers can be torqued to 26ft/lbs.

 

A core charge is a refundable deposit for the value of a re-buildable part. On certain D&J Precision Machine products, we need to charge a core charge at the time of the sale. Upon receipt of the core, D&J Precision Machine will determine the condition of the core and refund all, part, or none of the core based on the condition.

  • Customer is responsible for all return shipping charges. If you want D&J Precision to arrange shipping, you will be responsible for shipping costs. This will be deducted from your core refund. If your core is unusable, you will be charged for return shipping.
  • Ship all cores to the address on the Core Return Form.
  • Cores must be returned with the Core Return Form properly completed.
  • All cores must be the same model as the original item that was purchased.
  • Cores must be returned within 60 days.
  • Cores should be packed carefully, i.e. fixed to a pallet, to protect from shipping damage.
  • D&J Precision Machine is not responsible for shipping damage.
  • Please allow 30 days after core delivery to our facility, for cores to be processed and refunds to be issued.
  • If core is deemed non-useable, the customer will be notified and given 10 days to respond to have their core returned to them at their expense. After 10 days the deemed non-useable core will be scrapped. 

Core Acceptance Policy

MODEL/PART # FULL CREDIT CRITERIA PARTIAL CREDIT CRITERIA NO CREDIT
Cummins 5.9 and 6.7 Cylinder Heads • Like for Like
• No Visible External Damage
• No Fire Damage
• All Components Present including valves
• No Bolt Hole Damage
• Core Paperwork Returned		 • Missing Valvetrain Components (25% deduction)
• Provide a 5.9 Core as a 6.7 core (30% deduction)
• Cracked or Damaged Intake (25% deduction)
• Damaged Bolt Holes ($25 each)
• Missing or Incomplete Paperwork ($50 deduction)		 • Fire Damage
• Any Form of Damage to the Deck
• Excessive Damage to the Guide Area
• Cracks in any area except the Intake
• Shipping Damage
Cummins 5.9 and 6.7 Crankshaft • Like for Like
• No Visible Damage
• No Rust on Journals
• No Bolt Hole Damage
• No Damage to the Front or Rear Face of the Crank
• No Gear Damage
• No Dowel Damage
• Core Paperwork Returned		 • Damage to Dowel that can be Repaired ($125 deduction)
• Damage to Front or Rear Face that can be Repaired ($125 deduction for each face)
• Damage to Gear that can be repaired (12V/ISB $250 deduction, CR no credit)
• Missing or Incomplete Paperwork ($50 deduction)
• Damaged 2019 up timing gear housings will be a $1750 deduction
• Damaged 2019 up front covers will be a $250 deduction		 • Damage or Rust to Journals that cannot be polished
• Damage to Dowel that cannot be repaired
• Damage to Front or Rear Face that cannot be repaired
• Any Damage to CR Crank Gear
• Damage to 12V/ISB Crank Gear that cannot be repaired
• Any Cracks
• Shipping Damage
Cummins 5.9 and 6.7 Camshaft • Like for Like
• No Visible Damage
• No Rust on Journals
• No Gear Damage
• Core Paperwork Returned		 • Damage or Rust to Journals that can be ground (50% deduction)
• Damage to gear ($250 deduction)
• Missing or Incomplete Paperwork ($50 deduction)
• 2019 up cams will not be accepted as a good core (150 core charge)		 • Damage or Rust to Journals that cannot be ground
• Shipping Damage
Cummins 5.9 and 6.7 Block • Like for Like
• No Visible External Damage
• Can be Remachined without Sleeves
• Core Paperwork Returned		 • 6.7 - If it needs sleeves it will receive no core credit
• Provide a 5.9 Core as a 6.7 core (50% deduction)
• Damaged Bolt Holes ($25 each)
• Missing Main Caps ($250 deduction)
• Missing or Incomplete Paperwork ($50 deduction)
• 2019 up blocks will not be accepted as a good core		 • Cracks
• Damage to Deck Surface that exceeds .010
• Damage to Main Bore that is beyond repair
• Damage Cam Bore that is beyond repair
• Damaged Head or Main Bolt Holes
• General Damage that is beyond Repair
• Shipping Damage
Cummins 5.9 and 6.7 Short/Long Block • Refer to Cylinder Head, Crankshaft, Camshaft and Block Policies for each item
• All Bolts and Accessories that are included with the purchase of your short/long block are returned and rebuildable
• Core Paperwork Returned		 • Refer to Cylinder Head, Crankshaft, Camshaft and Block Policies for each item
• Refer to Core Price Sheet for missing or damaged component partial credit pricing
• Missing or Incomplete Paperwork ($50 deduction)		 • Refer to Cylinder Head, Crankshaft, Camshaft and Block Policies for each item
• Shipping Damage
 

CORE RETURN FORM

Please print out the following form, fill it out, and include it when sending in your product.

 Download Form

 

Step 6: We also recommend rechecking valve lash at this time. Valve lash needs to be checked at top dead center on number one or number six cylinder. Bring the top dead center mark on the harmonic balancer to the 12:00 o'clock position. If both number one cylinder rocker levers are loose, continue to the next step. If both number one cylinder rocker levers are not loose, rotate the crankshaft 360 degrees.
With the engine in this position, valve lash can be measured at the following rocker arms: INTAKE 1-2-4 / EXHAUST 1-3-5  . Measure the valve lash by inserting a feeler gauge between the rocker arm socket and crosshead. Valve lash should be .010” on intake and .020” on exhaust. If the measurement falls within  the limits, adjustment/resetting is not necessary. If measurement finds the lash outside  of the limits, adjustment/resetting is required.

 If adjustment/resetting is required, loosen the lock nut on rocker arms and turn the adjusting screw until the desired lash is obtained. Tighten the lock nut to 24 Nm (18 ft. lbs.) and re-check the valve lash. Using the crankshaft barring tool, rotate the crankshaft   one revolution (360°) to align the damper TDC mark to the 12 o'clock position. With the engine in this position, valve lash can be measured at the remaining rocker arms: INTAKE 3-5-6 / EXHAUST 2-4-6  . Use the same method as above for determining whether valve adjustment is necessary, and adjust those that are found to be outside of the limits.

  If everything checks out you can reinstall rocker box, injector harness, and valve cover.

Step 7: Re-fill engine with oil. We recommend using Hot Shot Secret Blue Diamond full synthetic 15w-40, Black Diamond Outlaw Full Synthetic (non emissions trucks), or Hot Shot’s Secret Adrenaline R4 Full Synthetic (race vehicles) . We have seen good results with these oils. We recommend changing your oil based on usage and horsepower. The more horsepower means more frequent oil change intervals. We have seen oil quality can affect the amount of blow-by an engine can have and ring retention.  Always check engine oil level and also for how clean the oil is. If the oil stains your skin black then it is overdue to be changed. This means the oil is full of soot from combustion and is not going to be as effective in lubricating or cleaning.

These seven steps should ensure a proper break in procedure for your new engine. If you have any further questions, don’t hesitate to call. We will be happy to answer any questions you might have. Thank  you for your purchase.

Core Return

A core charge is a refundable deposit for the value of a re-buildable part. On certain D&J Precision Machine products, we need to charge a core charge at the time of the sale. Upon receipt of the core, D&J Precision Machine will determine the condition of the core and refund all, part, or none of the core based on the condition.

  • Customer is responsible for all return shipping charges. If you want D&J Precision to arrange shipping, you will be responsible for shipping costs. This will be deducted from your core refund. If your core is unusable, you will be charged for return shipping.
  • Ship all cores to the address on the Core Return Form.
  • Cores must be returned with the Core Return Form properly completed.
  • All cores must be the same model as the original item that was purchased.
  • Cores must be returned within 60 days.
  • Cores should be packed carefully, i.e. fixed to a pallet, to protect from shipping damage.
  • D&J Precision Machine is not responsible for shipping damage.
  • Please allow 30 days after core delivery to our facility, for cores to be processed and refunds to be issued.
  • If core is deemed non-useable, the customer will be notified and given 10 days to respond to have their core returned to them at their expense. After 10 days the deemed non-useable core will be scrapped. 

Core Acceptance Policy

MODEL/PART # FULL CREDIT CRITERIA PARTIAL CREDIT CRITERIA NO CREDIT
Cummins 5.9 and 6.7 Cylinder Heads • Like for Like
• No Visible External Damage
• No Fire Damage
• All Components Present including valves
• No Bolt Hole Damage
• Core Paperwork Returned		 • Missing Valvetrain Components (25% deduction)
• Provide a 5.9 Core as a 6.7 core (30% deduction)
• Cracked or Damaged Intake (25% deduction)
• Damaged Bolt Holes ($25 each)
• Missing or Incomplete Paperwork ($50 deduction)		 • Fire Damage
• Any Form of Damage to the Deck
• Excessive Damage to the Guide Area
• Cracks in any area except the Intake
• Shipping Damage
Cummins 5.9 and 6.7 Crankshaft • Like for Like
• No Visible Damage
• No Rust on Journals
• No Bolt Hole Damage
• No Damage to the Front or Rear Face of the Crank
• No Gear Damage
• No Dowel Damage
• Core Paperwork Returned		 • Damage to Dowel that can be Repaired ($125 deduction)
• Damage to Front or Rear Face that can be Repaired ($125 deduction for each face)
• Damage to Gear that can be repaired (12V/ISB $250 deduction, CR no credit)
• Missing or Incomplete Paperwork ($50 deduction)
• Damaged 2019 up timing gear housings will be a $1750 deduction
• Damaged 2019 up front covers will be a $250 deduction		 • Damage or Rust to Journals that cannot be polished
• Damage to Dowel that cannot be repaired
• Damage to Front or Rear Face that cannot be repaired
• Any Damage to CR Crank Gear
• Damage to 12V/ISB Crank Gear that cannot be repaired
• Any Cracks
• Shipping Damage
Cummins 5.9 and 6.7 Camshaft • Like for Like
• No Visible Damage
• No Rust on Journals
• No Gear Damage
• Core Paperwork Returned		 • Damage or Rust to Journals that can be ground (50% deduction)
• Damage to gear ($250 deduction)
• Missing or Incomplete Paperwork ($50 deduction)
• 2019 up cams will not be accepted as a good core (150 core charge)		 • Damage or Rust to Journals that cannot be ground
• Shipping Damage
Cummins 5.9 and 6.7 Block • Like for Like
• No Visible External Damage
• Can be Remachined without Sleeves
• Core Paperwork Returned		 • 6.7 - If it needs sleeves it will receive no core credit
• Provide a 5.9 Core as a 6.7 core (50% deduction)
• Damaged Bolt Holes ($25 each)
• Missing Main Caps ($250 deduction)
• Missing or Incomplete Paperwork ($50 deduction)
• 2019 up blocks will not be accepted as a good core		 • Cracks
• Damage to Deck Surface that exceeds .010
• Damage to Main Bore that is beyond repair
• Damage Cam Bore that is beyond repair
• Damaged Head or Main Bolt Holes
• General Damage that is beyond Repair
• Shipping Damage
Cummins 5.9 and 6.7 Short/Long Block • Refer to Cylinder Head, Crankshaft, Camshaft and Block Policies for each item
• All Bolts and Accessories that are included with the purchase of your short/long block are returned and rebuildable
• Core Paperwork Returned		 • Refer to Cylinder Head, Crankshaft, Camshaft and Block Policies for each item
• Refer to Core Price Sheet for missing or damaged component partial credit pricing
• Missing or Incomplete Paperwork ($50 deduction)		 • Refer to Cylinder Head, Crankshaft, Camshaft and Block Policies for each item
• Shipping Damage
 

CORE RETURN FORM

Please print out the following form, fill it out, and include it when sending in your product.

 Download Form

 

Contact us

D&J Precision Machine 706 Woodlawn Ave. Cambridge, Ohio 43725 (740) 297-7223 info@djprecisionmachine.com