Atomic Barra Billet Girdle
Engineering Overview
SPEC-DOCAtomic Billet Main Cap Girdle
**PLEASE NOTE: We are updating the girdles to be Silver Zinc coated instead of yellow/gold as it is more consistent, durable and we think it looks damn good!
We will ship yellow zinc/gold girdles until we have run out.
If you would like a silver girdle please let us know with your order**
Why You Need a Main Girdle
As Barra builds push beyond 400kW at the tyres, the stock bottom-end starts to show its limits. Under high RPM and load, the main caps begin to "walk" or chatter on the block surface. This movement throws off crankshaft alignment, accelerates bearing wear, and can lead to catastrophic main bearing failure. Whilst you might see big power Barras with SBEs stock bottom ends putting out big numbers with minimal mods, it isn't a recipe for a long lasting, trouble free car.
Not all girdles are created equal. Many cheap copies lack proper relief cuts, causing interference with conrod bolts that can destroy an engine on the first rotation. The Atomic Girdle is precision CNC machined to provide a minimum 4mm clearance to rod bolts, ensuring safe operation even with long-stroke combinations.
The Atomic Solution
The Atomic Billet Main Cap Girdle acts as a rigid exoskeleton for your bottom end. By tying all 7 main caps together, it dampens harmonic vibrations and prevents individual cap movement. Laser-cut from high-tensile steel and surface-ground for flatness, it is the most effective way to stabilize your rotating assembly without moving to a full billet block.
Choose Your Strength
10mm Street/Strip
The "No-Mod" Solution. Fits under the standard factory sump without welding or cutting. Sufficient for builds up to 1500hp.
- Fitment: Direct Drop-In
- Sump Mods: None Required
- Rating: Up to 1500hp
16mm Race Spec
Maximum rigidity for extreme applications. The extra thickness creates an incredibly stiff bottom-end structure for engines pushing beyond 1500hp (Methanol/Drag).
- Fitment: Race Only
- Sump Mods: Requires modification/spacing
- Rating: 1500hp+
Tech Specs
Material: High-Tensile Billet Steel
Machining: Laser Cut & CNC Finished in Sydney, AUS
Compatibility: Ford Barra DOHC & SOHC (BA-FGX)
Cap Fitment: Available for Standard or Atomic Billet Caps
⚠️ Critical Install Notes
- Cap Type Selection: You must select the correct girdle for your main caps. Factory cast caps and Atomic Billet Caps have different profiles; the girdles are machined specifically to match.
- 16mm Clearance: The 16mm girdle WILL require modifications to the sump pan or spacers to clear the added height. Ideally suited for fabricated sumps or dry sump setups.
- Main Studs: Requires appropriate length main studs (sold separately) to accommodate the girdle thickness.
