Cylinder Head w/ Valves for Cummins ISL ISL9 8.9L PX-9

Overview

Brand-new cylinder head with valves and springs for the Cummins ISL 8.9L, ISL9, QSL9 and the 8.3L C-series diesel - a one-piece cast iron head that seals the top of the cylinders and carries the valves, springs and injectors on the L-platform engines. The 8.3L C-series and the 8.9L L-series share the same 114 mm bore, so one head is listed for both Cummins families - and one casting covers ISC, QSC, 6C8.3, ISL, ISL9 and QSL9, plus the PX-9 built for Paccar under licence from the same engine.

Includes: intake valves, exhaust valves, valve springs, retainers and collets installed in the head, with the deck faced and the valve seats cut. This is a head with the valve train in place, ready for your rocker assembly and injectors.

Fitment

Does not fit: the L10, M11 and ISM (10L and 11L platforms); the ISB 5.9 and 6.7 (B series); the ISX and X15 (15L). The natural gas units (ISL G, C GAS PLUS) and the 2017 and later L9 sit in the same head family but are built with a different valve and seat specification - send us the engine serial number and we will confirm the build before shipping. For any 8.3L or 8.9L, quote the ESN or CPL and we will match the ECM code.

Why It's Better

Brand-new casting, not a rebuilt original. The casting has no heat-cycle history behind it - never welded, never re-decked, no repaired cracks and no stripped injector hold-down threads. On an 8.9L that has pulled 80,000 lb for a decade, the crack between the valve seats is what ends the original head, and a used core carries that history with it.

Deck and seats machined, then the valve job is done. The deck is faced flat, the valve seats are cut to the factory angle and the valves are lapped in and checked for seal before the head is packed. You are not paying a machine shop to re-cut seats on a head that was supposed to be finished.

Valves and springs already in the head. The intake and exhaust valves, springs, retainers and collets are installed, so the head goes on with the valve train in place and only the rocker assembly and injectors transfer from your old unit. Fewer loose parts on the bench also means fewer chances to drop a collet into the crankcase.

One casting covers 8.3L and 8.9L, and the PX-9 too. ISC, QSC8.3, ISL, ISL9 and QSL9 all take this head group, and so does the PX-9 built for Paccar in Kenworth and Peterbilt medium-duty trucks - a fleet running those next to a wheel loader or a generator can stock one head instead of three.

Specifications

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.

FAQ

Q: How do I confirm this head fits my engine?
Four checks. First, the engine is 8.9L or the 8.3L C-series - not the 10L L10, not the 11L M11 or ISM. Second, report the ESN or CPL and we match the ECM code: CM554, CM850, CM2150, CM2250 or CM2350. Third, count the valves - 24, four per cylinder. Fourth, decide whether you need the head with valves and springs (this one) or a bare casting. If you are unsure, send the ESN and a photo of your old head's deck and we will confirm before you order.

Q: What is the difference between 5529500, 5347974, 5347976 and 5569669?
They are different points on the same head family. 5529500 and 5529502 are the DCEC assembly numbers used on the Chinese-built ISLe; 5347974 supersedes 4989710 and 5347976 supersedes 5256470, and both cover the same 32 engine models; 5569669 is the North American number that crosses to 5282719 and is used on the ISL9 and the Paccar PX-9. All of them take this casting. Send us the number on your old head or your engine serial number and we will confirm.

Q: How is it packed?
The head is bolted to a wooden pallet base and shipped in a wooden crate so the deck face and the valve train are protected in transit. Multiple heads ship on a single pallet.

Q: What do I need to do before installing it?
Transfer the rocker assembly, the injectors and the injector hold-downs from your old head, fit a new head gasket - 4946619 for the ISLe, 4937728 for the QSL9 - and use a complete new set of head bolts. Torque in the sequence in the service manual for your engine serial number, set the valve lash cold as the manual specifies, then refill with the correct coolant.

Q: Will it fit a natural gas ISL G or a 2017 and later L9?
The catalogues group the gas units and the later L9 into the same head family, but the valve and seat build differs from the diesel. Tell us the engine serial number and the fuel type before ordering and we will confirm which build you need.

Q: What does the warranty cover?
12 months against manufacturing defects - cracks, porosity and valve seat problems. Send us photos and the engine serial number and we will handle the claim.

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.