FAQs

John Deere Engine Parts

1. Why do some HD Kits part numbers differ from John Deere® part numbers? John Deere® sometimes assigns different part numbers to the same part used across multiple engine plants. We use the most widely recognized part number to make ordering easier. Where we offer a complete kit that John Deere® only sells as individual components — such as our 531 cylinder kit — we assign our own HD Kits part number for your convenience.

2. Can I use the Litre version 3029, 4045 and 6068 overhaul kits in the 2.9, 4.5 and 6.8 Powertech engines? No. The Litre and Powertech engine families use different components and parts do not interchange between them. Please confirm your engine series before ordering.

3. What is the difference between the two oil pump drive gears listed for the early 6-404? If only the gear needs replacing, order the NR-32428 gear. If the shaft is worn or your engine has a one-piece shaft and gear assembly, replace the entire unit with NR-45134. Replacement shafts compatible with the NR-32428 gear are no longer available from John Deere® or HD Kits.

4. I have a 4-219T turbocharged engine. Do your kits work with it? Yes. When no engine suffix is shown in our catalog (such as D, T, A, or H), the listed part or kit is compatible with all configurations of that engine model, including turbocharged versions.

5. Your 300 series camshafts have a threaded tachometer drive, but my old cam has a press-in drive. Will it work? Yes. When installing a 300 series camshaft, replace your press-in tach drive with one of our thread-in versions. We offer two options: NR-81513 (slotted type) and NR-81514 (helical gear type). Press-in drives are not compatible with Reliance 300 series camshafts and must always be replaced.

6. How do I determine which water pump kit I need? The most reliable method is to provide the water pump housing casting number or your equipment application details. John Deere® uses a wide variety of water pumps across different models, so the correct kit depends on your specific application. For 300 series engines, refer to the Application by Water Pump Housing Number table in our catalog.

7. What does “O-ring in the block” versus “O-ring on the liner” mean for 300 series engines? Early John Deere® blocks have a smooth lower bore, meaning the O-ring grooves are machined into the liner itself. Later blocks have the O-ring grooves in the block bore, and the liners for those engines are smooth. Check your block casting number against our catalog to confirm which liner type your engine requires.

8. What is the difference between borable and honable connecting rod bushings? Borable bushings have a smaller inside diameter so a machine shop can bore them on center, restoring the correct centre-to-centre distance of the connecting rod. Honable bushings have a larger inside diameter, do not correct centre-to-centre variations, and must be finish-honed to achieve the correct pin clearance. If your connecting rod is marginal, a borable bushing is the better choice.

9. What is a 400 series replacement block? It is a block designed for 3010, 3020, 4010 and early 4020 tractors that uses late-style main bearings and cylinder liners while still accepting the original early cylinder head. This allows you to reuse your existing head with a new block, reducing rebuild cost.

10. My 400 series engine crankshaft journals have two drilled holes, but the bearings I received only have one oil hole. Is this correct? Yes, this is correct. Oil is delivered through the single hole in the bearing to lubricate the crankshaft. The second hole in the journal is a manufacturing feature used to drill the piston cooling nozzle orifice and does not affect bearing function.

11. My 6-404 engine only has one O-ring groove in the block. Which O-ring should I use? Use the black Duro-Viton O-ring. It offers higher heat resistance than the orange Duro-Silicon version and is the correct choice for single-groove blocks. Be cautious of aftermarket O-rings made from black Buna material — they look similar but are an inferior substitute for genuine Viton.

12. Why do connecting rod bolts and cylinder head bolts need to be replaced every time they are removed? These bolts are designed to stretch under torque to achieve the correct clamping pressure. Re-using stretched bolts means they cannot reach the required clamping force, which risks bolt failure and serious engine damage. Always replace them during any rebuild.

13. Where do thrust washers fit in John Deere® engines? On 300 and 400 series engines, washers fit on both sides of the block web and on the rear (flywheel side) of the cap, with the slotted face towards the crankshaft. On 500 series engines, washers fit on both sides of the cap and on the rear of the block web, again with the slotted face towards the crankshaft.

Cummins Engine Parts

1. What is a CPL number and why do I need it? CPL stands for Critical Parts List. It is a code stamped on the data plate — usually on the left side of the timing cover — that identifies the exact configuration and series of your Cummins engine. You will need this number to order the correct pistons, fuel injectors and other precision-fit components.

2. Why are some C Series cylinder kits listed under the same CPL number? In these cases, the block marking number determines which specific cylinder kit is required. Always cross-reference both the CPL and the block marking before ordering.

3. What is included in a Cummins piston assembly, and how does it differ from a piston kit? B Series piston assemblies include the piston, pin, retainer and piston rings — matching the OEM specification. C Series piston kits include the piston, pin and retainer only; piston rings are not included and must be ordered separately.

4. Why do B Series overhaul kits not include pistons? There are dozens of possible piston combinations across standard and oversize dimensions. Including every variation would make pre-packaged kits impractical to stock. Simply add the correct piston to your inframe or overhaul kit at the time of order.

5. Why do C Series cylinder kits cost more than some competitor products? We use bainitic hardened cylinder liners, the same specification as Cummins OEM. This hardening process delivers the same service life and durability as the original equipment — which is why professional rebuilders specify it.

6. My equipment is Case-branded but runs a Cummins engine. How do I find the right parts? Many Case machines use Cummins engines. Refer to the equipment section of our Case/Cummins catalog, or contact our team with your equipment model and serial number and we will identify the correct parts for you.

Kubota Engine Parts

1. How do I identify my Kubota engine to order the correct parts? Kubota engine identification requires the engine model and engine code. Please refer to our Parts and Service Bulletin for step-by-step identification guidance, or contact our team directly.

2. What is included in a Kubota piston assembly? All HD Kits Kubota piston assemblies include the piston, piston pin, piston pin retainers, ring set and connecting rod bushing — everything needed for a complete piston rebuild in a single order.

3. What is an engine code? A Kubota engine code identifies engines built to specific requirements for a particular application or equipment manufacturer. It is separate from the engine model number and is required to confirm compatibility for certain components.

4. Why are there two different crankshaft journal diameters for Kubota engines? When Kubota transitioned from Tier I to Tier II emissions standards, they increased the crankshaft journal diameter. Check the serial number breaks listed in our catalog against your engine’s serial number to confirm which bearing size you need before ordering.

Ford / New Holland Engine Parts

1. Why do HD Kits part numbers differ from Case/New Holland part numbers? Most Case/New Holland numbers are legacy Ford part numbers — long, complex and difficult to reference in the field. For Ford/New Holland applications, we use our own streamlined numbering system to make ordering faster and more accurate.

2. Why don’t Ford/New Holland inframe and overhaul kits include pistons? Ford/New Holland agricultural and industrial engines are not wet liner designs. They can be rebuilt using dry sleeves or oversized pistons. Because the combination of piston oversizes and bearing undersizes is extensive, we sell pistons separately so you receive exactly what your engine requires — no guesswork, no wasted parts.

3. What is included in a Ford/New Holland piston assembly? Each assembly includes the piston, ring set, piston pin and piston pin retainers — everything needed for a direct piston replacement.

4. Why do Ford/New Holland gasket sets cost more than some alternatives? Our gasket sets are the most complete available for these applications and use the highest quality materials throughout. Every gasket required to finish the job is included. Paying slightly more upfront is far less costly than stopping a rebuild mid-job because of a missing gasket.

5. Why are there different reference numbers for the same Ford engine model? Ford made specification changes within the same engine model over time. Ordering the wrong version can result in incorrect fitment. Our catalog clearly illustrates the differences between versions to help you identify and order the right parts first time.

International Engine Parts

1. Why does HD Kits offer both narrow and wide gap rings for D/DT 414, 436 and 466 engines? Early engines had the crankcase breather on the block and used narrow gap compression rings. Later, International moved the breather to the valve cover and introduced wide gap rings to address excessive crankcase blow-by. Many engines were subsequently retrofitted with wide gap rings. Always check your breather location before ordering to ensure you receive the correct ring set.

2. Why does HD Kits offer only one oil pump for International applications? Market demand for the additional pump variants does not justify the tooling and inventory investment required. The single pump we stock covers the vast majority of aftermarket rebuild requirements.

3. Why are there narrow and wide crankshaft main bearings for International engines? Early 414, 436 and 466 engines used narrow journal crankshafts. International later introduced wide journal crankshafts for those same engine families, requiring a wider bearing. Note that the thrust bearing is the same for both. Many engines originally built with narrow bearings have since been upgraded to wide journal crankshafts — check carefully before ordering.