HPD Special Parts
Euro 4 4JJ1 / 4JJ3 Aluminium Rocker Cover - HPD
Euro 4 4JJ1 / 4JJ3 Aluminium Rocker Cover - HPD
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Cast Aluminium | Twin -10 AN Breather Ports | Isuzu D-MAX, MU-X and Mazda BT-50
The HPD cast aluminium rocker cover is the signature engine bay upgrade for the Euro 4 4JJ1 and the 4JJ3. It comes out of Thailand in small production runs, finished in a durable painted coating, and it sets a build apart the moment the bonnet goes up.
Current stock comes with 2 additional breather ports and the fittings to use them, so it is ready for a proper catch can setup straight out of the box. Count the bolts across the front edge before you order: this one is the 4-bolt cover.
What Is Included (Current Stock)
- HPD cast aluminium rocker cover, painted finish, with 2 additional breather ports.
- Screw-in -10 AN fittings for the additional ports.
- Bung for the factory breather port.
- HPD breather cover.
Not included: cover mounting bolts. Grab the HPD 4JJ1 Euro 4 / 4JJ3 Ti Burnt Blue rocker cover bolt set to finish the install and the look.
Key Features
- Cast aluminium construction. Lightweight and rigid.
- Painted finish. Pick your colour on this page.
- Twin additional breather ports with screw-in -10 AN fittings on current stock.
- Factory port bung and HPD breather cover included.
- Direct bolt-on replacement for the factory cover.
Vehicle Fitment
Suits engines with 4 bolts across the front edge of the rocker cover:
- Isuzu D-MAX and MU-X. Euro 4 4JJ1.
- Isuzu D-MAX and MU-X. 4JJ3, 2020 on.
- Mazda BT-50. 4JJ3, 2020 on.
Not for Euro 2 / 3 4JJ1. The earlier 4JJ1 uses a 3-bolt front pattern and needs the HPD 4JJ1 Aluminium Rocker Cover (Euro 2 / 3) instead. Not sure which you have? Send us your VIN or rego and we will confirm before you order.
Stock and Lead Time
These covers are produced in very limited runs and are hard to source in Thailand. Once a colour sells out, restock lead times typically run 1 to 3+ months.
Need one urgently? Message us before ordering to confirm availability and the latest ETA on your colour.
Shipping and Payment
- Free express shipping Australia-wide.
- Buy now, pay later: Afterpay, Humm, Klarna and Zip.
Frequently Asked Questions
Q: Do the covers come with breather fittings?
A: Yes. All current stock has 2 additional breather ports with screw-in -10 AN fittings included, plus a bung for the factory port and an HPD breather cover.
Q: Are bolts included?
A: No. We stock a matching Ti burnt blue 4JJ1 / 4JJ3 rocker cover bolt set to complete the install.
Q: How do I know if this fits my engine?
A: It suits Euro 4 4JJ1 and 4JJ3 engines with 4 bolts across the front edge of the rocker cover. If unsure, send us your VIN or rego and we will confirm.
Q: Will this fit a pre-Euro 4 4JJ1?
A: No. Earlier Euro 2 / 3 4JJ1 models use a 3-bolt front pattern and need the HPD 4JJ1 Aluminium Rocker Cover (Euro 2 / 3) instead.
Q: When will sold-out colours be restocked?
A: Aluminium covers are very hard to source in Thailand. Restock times vary but typically run 1 to 3 months. Contact us for the latest ETA on your colour.
Genuine Product Of
HPD Special Part Racing Shop
The Centrepiece Of A Serious 4JJ Build
HPD cast aluminium rocker cover with twin -10 AN breather ports and an HPD breather cover included. Limited stock, free express shipping Australia-wide.
Disclaimer: Common Rail Cowboys is not affiliated with Isuzu Motors or Mazda Motor Corporation. HPD and the HPD logo are trademarks of HPD Special Part Racing Shop, used to identify the product supplied. Installation should be carried out by a competent person. Confirming fitment to your engine is the buyer's responsibility. Modifications may affect your vehicle's warranty and compliance.
