Loaded Cylinder Head for Cummins ISX QSX15 Dual Cam 24V
Loaded Cylinder Head for Cummins ISX QSX15 Dual Cam 24V
Overview
Brand-new loaded cylinder head for the Cummins ISX and QSX15 dual cam diesel - a complete assembly that seals the combustion chamber and carries the two camshafts, the valves, the unit injectors and the rocker assemblies on these engines. One camshaft drives the high-pressure unit injectors and the other runs the valves and the engine brake, which is the layout used on these engines from 1998 through the 2010 model year. One casting covers all six cylinders, so a complete engine takes just one. It ships fully assembled with the valvetrain installed and the valves lapped, so there is no machine shop time before you bolt it on.
Includes: Valves, valve guides, valve seats, valve springs, retainers, keepers and valve stem seals - all installed, with the valves lapped so they are ready to seal.
Fitment
| Engine | Fits the Cummins ISX and QSX15 inline 6-cylinder 24-valve turbo diesel with dual overhead camshafts - one cam actuates the unit injectors, the second cam runs the valves and the engine brake |
| Engine Years | 1998-2010; the ISX dropped the injector camshaft when it moved to the common rail fuel system, and this head is for the two-cam engines built before that change |
| Vehicle | Fits Class 8 highway tractors built with the dual cam Cummins ISX |
| Vehicle Years | 1998-2010 |
| Casting Number | 3412277 / 4101420 / 4059264 / 4926774 |
| Replaces | 4962732, 5413782, 5413784, 4331387, 3412280, 3682836, 3683986, 3683002, 3682863, 3680872, 3680855, 4101455, 4101420, 4059432, 4059264, 4059246, 4059238, 4059225, 4026793, 4026626, 4026542, 4926774, 3412277, 3104202, 3104292, 5658283, 4962731 |
| Application | Fits Class 8 highway tractors built with the dual cam ISX: fits Kenworth W900, T800, T660, T2000 and T600, fits Peterbilt 379, 385, 386, 387 and 389, fits Freightliner Cascadia, Century Class, Columbia and Coronado, fits International 9200i, 9400i, 9900i and ProStar, fits Western Star 4900 and 5900. Also fits generator sets, mining trucks, large excavators, marine vessels and oilfield equipment powered by the QSX15 |
Why It's Better
- Brand-new casting - a new head with no heat-cycle history, never welded, never re-decked and with no repaired cracks
- Built to the improved casting pattern that supersedes 3683986 - the revised design carries a thicker top deck, a thicker wall above the exhaust ports and gussets between the bolt boss and the guide boss, the three changes that addressed the cracking that let coolant into the oil and into the exhaust port
- Complete new valvetrain - valves, guides, seats, springs, retainers, keepers and valve stem seals installed, with the valves lapped so they are ready to seal
- Pressure tested on both circuits - the fuel passages and the coolant passages are each checked on their own circuit, and the deck surface is machined flat for a clean gasket seal
Specifications
| Material | Alloy cast iron, brand-new casting |
| Valvetrain | Dual overhead camshafts (one for the unit injectors, one for the valves and engine brake), 4 valves per cylinder (24 valves total) |
| Injection System | Cam-actuated high-pressure unit injectors, as used on the dual cam engines |
| Displacement | 14.9L (912 cu in), 137 x 169 mm bore and stroke |
| Condition | New aftermarket replacement |
| Quantity Per Engine | 1 (one-piece head, covers all 6 cylinders) |
| Warranty | 12 months |
Shipping & Warranty
Free shipping within the continental USA. In-stock orders are processed within 1-2 business days.
Buying by the pallet? Quantity discounts are available - send us the part number and the quantity you need and we will come back with tiered pricing and lead time.
Backed by a 12-month warranty against manufacturing defects.
Frequently Asked Questions
Q: Is this the dual cam head or the single cam head?
It is the dual cam head (also sold as twin cam or DOHC) for the Cummins ISX and QSX15 built from 1998 through the 2010 model year. It does not fit the single cam engines that came with the common rail fuel system - the ISX15 CM2250 and CM2350 from 2010 on, or the X15 from 2017 on. Those engines dropped the injector camshaft and use a different head casting, so check the number of camshafts before you order.
Q: How do I tell whether my ISX is a dual cam engine?
Count the camshafts in the head. A dual cam engine has two: the injector cam sits on the fuel pump side and the valve cam sits on the exhaust side, where it also runs the engine brake. A 2010 and later single cam engine has one camshaft and a high-pressure common rail pump feeding a fuel rail, with no injector cam at all. If you are not sure, send us your engine serial number and CPL and we will confirm it against the build data.
Q: What is the difference between 4962732 and 3683986, and why does it matter?
3683986 is the earlier casting. It was replaced by the improved part number 4962732 on engines built from March 23, 2006, adding a thicker top deck, a thicker wall above the exhaust ports and gussets between the bolt boss and the guide boss. The old casting was known for cracking at the center cup plug on the spring deck, which let coolant mix with the oil, and for cracking at the guide boss in the exhaust port, which showed up as coolant disappearing with no visible leak. This head is built to the improved pattern.
Q: How many do I need?
One. The ISX uses a single one-piece head that covers all six cylinders, so a complete engine takes just 1 cylinder head.
Q: What equipment does this cylinder head fit?
It fits Class 8 highway tractors built with the dual cam Cummins ISX from 1998 to 2010: fits Kenworth W900, T800, T660, T2000 and T600, fits Peterbilt 379, 385, 386, 387 and 389, fits Freightliner Cascadia, Century Class, Columbia and Coronado, fits International 9200i, 9400i, 9900i and ProStar, fits Western Star 4900 and 5900. It also fits generator sets, mining trucks, large excavators, marine vessels and oilfield equipment powered by the QSX15.
Q: Can I reuse my original head bolts?
No - they are torque-to-yield and single-use. Fit a new set and a new head gasket. The ISX uses six head bolts per cylinder with some shared between cylinders, so follow the tightening sequence and the multi-step torque procedure in the factory service manual for your engine serial number rather than a single figure.
This is an aftermarket replacement part. We are not affiliated with, authorized by, or endorsed by the original equipment manufacturer. All trademarks and brand names are the property of their respective owners and are used for reference purposes only.