Billet TD42 Valve Cover

Ultimate TD Performance and Bling. 

TD42 Billet Valve Cover — Integrated Baffle System

Engineered, not just machined.

This isn’t a stock cover with a fresh coat of paint — it’s a ground-up redesign of the TD42’s valve cover, built entirely in-house over two years of R&D and testing alongside a qualified engineer. Every rib, radius, and internal passage was designed, prototyped, and refined in-house before it ever reached production.

Billet Construction

CNC-machined from a solid billet blank, replacing the factory’s pressed sheet metal cover with something in a different league entirely for strength and rigidity. No oil canning, no flexing under heat and vibration, no denting from a stray tool — just a cover that seals true and stays that way.

Integrated Baffle System — Replaces Factory PCV

The factory TD42 PCV vents crankcase gases to atmosphere, and it does its job — but it’s restrictive by design. At high revs, that restriction lets crankcase pressure build, pushing more oil vapour out with it than you’d like. This cover replaces the factory PCV with a fully integrated internal baffle system that flows significantly more gas, keeping crankcase pressure lower and more consistent right through the rev range.

The baffles themselves are sealed in place by a dedicated baffle plate and face towards the front of the motor, so gravity does the work of guiding separated oil straight back down into the engine rather than letting it pool or get carried back out with the next surge of crankcase gas.

For engines that breathe particularly heavy, there’s also room built into the design above the oil pickup for steel wool or E85 foam to be added. It’s not needed for most applications, but it’s there if you want to squeeze out that extra bit of oil/air separation on a harder-running motor.

The result:

• Higher-flowing crankcase ventilation, even under sustained high-rev load
• Lower, more stable crankcase pressure
• Front-facing baffle design lets gravity assist oil drain-back into the engine
• Reduced oil carryover out the vent
• Optional steel wool/E85 foam provision for heavy-breathing engines
• A simpler, more robust setup with one less factory component in the system

Every Detail Thought Through

Two years of R&D means we’ve had the time to sweat the small stuff most covers ignore. A good example: cut-outs positioned specifically to clear the glow plugs, so you’re not fighting the cover every time you need to pull one for service. It’s a small thing on paper, but it’s the kind of detail that only shows up when a product has actually been designed around the engine it sits on, not just modelled off it.

AN Fittings for a Neater Setup

The -12 ORB outlet is designed around AN fittings, so routing your crankcase gases wherever you need them to go is clean and straightforward — no more improvising with hose clamps and rubber tubing. It’s a small change that makes a noticeably tidier engine bay.

Real-World Tested, Not Just Bench Tested

This cover has done its time on the road, not just on a test bench. It’s been running on our own personal 250hp TD42, a vehicle that doesn’t get an easy life by any measure — towing, off-road work, sustained high-rev running, the lot. If it holds up on our own rig under that kind of use, it’ll hold up on yours.

Built for the Long Haul

Designed for TD42 owners running these engines hard — tow rigs, off-road builds, and daily-driven diesels that don’t get an easy life. This cover is built to outlast the vehicle it’s bolted to.

Two Years in the Making

We didn’t rush this. Two years of design iteration, real-world testing, and refinement went into getting the baffle geometry and sealing surfaces right before this ever went up for sale. What you’re buying is the finished result of that process — not a first draft.

Technical Specifications