Understanding Timing Wheels

These charts provide a circular view of the valve events relative to the crankshaft rotation:

• 0° (Top / 12 o'clock): Top Dead Center (TDC).
• 180° (Bottom / 6 o'clock): Bottom Dead Center (BDC).
• Blue Arc: Intake Valve Duration.
• Red Arc: Exhaust Valve Duration.
• Overlap: Look at the 12 o'clock position.
  • If the Red and Blue bars cross each other, you have Positive Overlap (e.g., Cam 306552).
  • If there is a gap between them, you have Negative Overlap (e.g., Cam 306550).

LSA & Performance

• 112° LSA: The gap at the top closes and eventually overlaps as you move from the mild 306550 to the aggressive 306552.
• 114° LSA: Widening the LSA shifts the Intake (Blue) slightly clockwise (opening later) and the Exhaust (Red) slightly counter-clockwise (opening earlier), reducing the overlap potential.
• 116° LSA: This setting shows the largest gaps at the 12 o'clock position (least overlap), which correlates to the smoothest idle and highest vacuum.

Key Features

• Suits all Ford Barra DOHC 4.0L 6-cylinder engines (BA–FGX)
• Stage 1 to Stage 5+ profiles available for street, strip, and race
• Designed to enhance breathing and reduce required boost
• “Duo Phased” inlet lobes introduce swirl for better cylinder fill & efficiency
• Inverted flank asymmetrical lobes – rapid valve lift without excessive lift height
• Slightly reduced base circle for improved lifter preload control
• Compatible with VCT and standalone ECUs (VCT-delete optional)
• Developed and tested in-house since 2006 — proven track record
• Used in builds producing 570–1133RWKW

Why Choose Atomic Cams?

We engineer our cams to work as part of a complete system.

• Efficiency: Harness residual exhaust gas energy to spool turbos more efficiently.
• Cylinder Fill: Increase cylinder filling efficiency with better valve timing events.
• Idle Control: Maintain idle vacuum with minimal lope (Stage 3 & 4); aggressive idle (4Plus & 5Plus).
• Power: Gain more power at lower boost – up to 50kW at the same boost after tuning.
• Stability: Designed to retain valvetrain stability at high RPM.
• System Match: Pair perfectly with Atomic HD valve springs, retainers & lifters.

🔧 Installation Guide

1. Remove turbo ducting and rocker cover.
2. Align timing marks, remove VCT units, mark and remove cams.
3. Compare camshaft trigger positions and journal diameters.
4. Check lifter preload, roller follower wear, and spring tension.
5. Fit cams with engine oil, reset tensioner, confirm timing mark alignment.
6. Rotate engine manually to verify timing.
7. Start engine and idle at 1000–1400 RPM for 10 minutes.
8. Ford lifters may take up to 45 minutes to fully bleed.

🛠️ Torque & Setup

• Ensure all bolts torqued to OEM specs.
• Tuning for CAMS required after installation for best results.
• Camshafts do not require a run-in period.