The Unstoppable Cummins 6.7L — Exhaust Flow, Durability, Control

6.7L Cummins Exhaust Manifold, In‑Depth: Heat, Cracks, and the BD Fix

A deeper look at why Ram 2500/3500 (2007.5–2018) manifolds crack and leak, how BD’s high‑silicon ductile iron design with a precision slip joint survives DPF heat cycles, and what to know for a clean install, correct torque, and long‑term sealing.

1046070,102479:F9D32C1C191E66A6F00ADF212D5ABEDF
Quick Summary: Thick‑wall high‑silicon ductile iron • Fully divided pulse design • Precision slip joint to absorb expansion • Grade 10.9 hardware/spacers • Pre‑drilled EGT port • EGR‑compatible • Torque: 43 N·m (32 ft‑lb) center‑out pattern • Re‑torque after first heat cycle.

Product page (Pick‑Up 2007.5–2018): BD 6.7L Cummins Exhaust Manifold Kit

SEMA Certification No. SC‑BDD01‑0155 • Warranty: 36‑Months / 75,000 Miles • Install time: ~8h 41m

Note: Not for sale on licensed California vehicles.

Why Stock Manifolds Crack, Warp, and Leak

  • DPF regeneration heat cycles: Exhaust temps repeatedly spike during regen. Uneven wall thickness and rigid one‑piece castings concentrate stress at runners and the turbo flange.
  • Thermal growth without relief: When a manifold can’t expand/contract uniformly, it bows and pulls studs—gaskets lose clamp, leaks start, and hot gas cuts the sealing faces.
  • Drive pressure & vibration: Towing and long grades elevate drive pressure. Combined with vibration, micro‑cracks propagate into visible fractures around junctions and flanges.

Inside the BD Design: Materials, Geometry, Details

High‑Silicon Ductile Iron

The alloy resists thermal warping, creep, and crack growth better than common gray iron. Thick‑wall sections keep temps uniform during regen to hold gasket load.

  • Fully divided pulse manifold for crisp spool
  • Machined sealing faces, flat and true
  • Pre‑drilled EGT/pyrometer ports

Precision Slip Joint

A controlled expansion joint allows the manifold to grow with heat without bending. That reduces cyclic fatigue, keeps studs straight, and preserves gasket crush.

  • Absorbs expansion across long runs
  • Less stress at the turbo flange
  • Fewer re‑torques over time

Hardware & Compatibility

  • Grade 10.9 black‑oxide bolts and spacers included
  • Includes EGR port, exhaust port, and turbo mount gaskets
  • Fully EGR‑compatible; keeps OEM emissions strategies intact
  • Replaces Chrysler #68027070AA/AB, 68210184AB and Cummins #5301441

Symptoms of a Failing Manifold (and What They Mean)

  • Ticking at cold start that fades when hot → gasket leak starting at outer ports.
  • Soot trails or burnt paint near the manifold/turbo flange → active exhaust leak.
  • Lazy spool, higher EGTs under tow → drive pressure loss from leaks or cracks.
  • Broken studs / warped shield → thermal growth is bending the casting.
Building or maintaining a Cab & Chassis (3500/4500/5500)? See the C&C‑specific kit for 2013–2018 fitment (different outlet geometry) on the BD site.

Install Overview: What to Expect

Time estimate ~8h 41m. A lift is helpful but not required. Always start on a cold engine. Below is a condensed guide—refer to BD’s installation manual for diagrams and model‑year nuances.

Tools & Prep

  • Penetrant, torque wrench (in‑lb & ft‑lb), thread chaser
  • Metric sockets 8–15mm, swivels, line wrenches for delta‑P
  • Coolant drain pan; plug caps for EGR cooler lines

High‑Level Steps

  1. Disconnect batteries, drain coolant, raise and secure vehicle.
  2. Remove shields, intake/airbox, and stepper motor/Bracket as required.
  3. Loosen EGR clamps and hardware; remove EGR flow valve and cooler per manual.
  4. Disconnect delta‑P lines, turbo oil/coolant/charge connections, downpipe; lift turbo off manifold.
  5. Remove lock plates and manifold hardware; remove factory manifold.

BD Manifold Install Highlights

  1. Clean head ports; set new manifold gaskets.
  2. Install supplied M10 studs in specified locations (see manual): 25mm studs in EGR port locations; 30mm studs at lower exhaust ports #4 and #5 and turbo mount threaded hole.
  3. Hang the manifold on the studs to support; start a lower bolt at cyl #2—leave loose.
  4. Add remaining bolts/spacers; install nuts on studs (box‑end access).
  5. Torque pattern: center‑out, criss‑cross, to 43 N·m (32 ft‑lb).
  6. Reinstall lock plates and heat shields; torque shield nuts to 24 N·m (18 ft‑lb).
  7. Install turbo; torque flange nuts to 43 N·m (32 ft‑lb) in a criss‑cross; repeat once.
  8. Reconnect delta‑P line brackets (24 N·m / 18 ft‑lb), bracket bolt (10 N·m / 89 in‑lb), flare nuts (10 N·m / 89 in‑lb).
  9. Reassemble EGR components, intake/airbox, lines; refill coolant; reconnect batteries.

Torque & Reference

Manifold bolts 43 N·m (32 ft‑lb), center‑out pattern
Turbo flange nuts 43 N·m (32 ft‑lb), criss‑cross, repeat pass
Heat shield nuts 24 N·m (18 ft‑lb)
Delta‑P line flare nuts 10 N·m (89 in‑lb)
Delta‑P bracket bolt 10 N·m (89 in‑lb)
Delta‑P bracket nut 24 N·m (18 ft‑lb)

After first full heat cycle: Re‑check manifold fasteners and turbo flange torque.

What You’ll Feel: Spool, EGT Control, and Reliability

On a healthy turbo and fuel system, a sealed, divided manifold restores crisp low‑rpm response and lowers EGTs on long grades. The slip joint and thick‑wall casting stabilize clamp load so the repair stays fixed through regen cycles. Pairing with a pre‑drilled pyrometer lets you monitor load and protect pistons when towing heavy.

Care Tips to Keep It Sealed

  • Use new gaskets and the included spacers; torque on a cold engine only.
  • Chase threads in the head for accurate torque; clean flanges till bright metal.
  • After install, complete one drive‑heat‑cool cycle and re‑torque fasteners.
  • Investigate abnormally high EGTs (towing, fueling issues) that can over‑stress any manifold.

Kit Contents (Summary)

  • BD Manifold assembly
  • Studs: M10‑1.5 × 25 (EGR ports), M10‑1.5 × 30 (select lower ports & turbo mount)
  • Nuts: M10‑1.5; Plugs: 1/8" NPT for sensor ports
  • Gaskets: manifold (6), EGR rear/front, turbo outlet (per kit)
  • Bolts, spacers, and washers (Grade 10.9)

Reference: Part #1045965 (Manifold), #1046065 (Complete Kit). Manual ID I‑00325.

FAQ

Is this manifold emissions compliant?
It’s fully EGR‑compatible and retains OEM emissions hardware. Not for sale on licensed California vehicles.

Do I need tuning after install?
No. This replaces the manifold only; no calibration changes are required.

Will it fit my year?
Designed for Ram 2500/3500 Pick‑Up 2007.5–2018 with 6.7L Cummins. Verify your application on the product page before purchase.

Ready to fix leaks and keep EGTs in check? Shop the Pick‑Up kit here: BD 6.7L Cummins Exhaust Manifold Kit. For Cab & Chassis coverage (3500/4500/5500), see the C&C version on the BD site.

Trademarks are property of their respective owners. Specifications and contents subject to change. Always follow the latest BD installation manual for diagrams and torque sequences for your exact year/trim.