Product Description
Interstate-McBee M-3904409 Exhaust Valve Guide – 51.75mm for 89–98 5.9L Cummins (B-Series)
Premium thick-wall exhaust valve guide engineered to OEM dimensions for Cummins B-Series 4B/6B engines, including 1989–1998 Dodge Ram 2500/3500 5.9L Cummins 12-valve (6BT). Interstate-McBee delivers OEM-style fit and long service life at an aftermarket price.
- Direct OEM cross: Replaces Cummins 3904409 for B-Series applications.
- Correct length: 51.75 mm exhaust guide for 12-valve heads (see intake note below).
- Durable thick-wall design: Maintains valve stem alignment and reduces guide wear.
- Aftermarket value: Interstate-McBee quality at significant savings vs. OEM boxed parts.
Specifications
| Brand / Part | Interstate-McBee M-3904409 |
|---|---|
| OEM Reference | Cummins 3904409 |
| Application | Exhaust valve guide, B-Series (4B/6B), 5.9L 6BT 12-valve |
| Length | 51.75 mm (≈ 2.04 in) |
| Typical Dimensions | Approx. 0.316 in I.D. (semi-finished), 0.554 in O.D. |
| Material | Thick-wall steel/iron valve-guide alloy |
| Cross-References | PAI 192040 / 192040-048 / 192040E; Cummins 4090327 |
| Package Contents | (1) Exhaust valve guide |
Vehicle Fitment
Always verify by engine serial number (ESN) for exact compatibility.
- Dodge Ram 2500/3500 5.9L Cummins 12-Valve (6BT)
- Model Years: 1989–1998 (pre-ISB/24V)
- Quantity guidance: 6 exhaust guides per engine (one per exhaust valve)
- Industrial / Agricultural: Cummins 4B/4BT and 6B/6BT variants where 3904409 is specified.
Install Notes
- Press guides using proper drivers; heat cylinder head and chill guides as needed for correct interference fit.
- Semi-finished I.D.: Ream/hone to final valve-stem clearance after installation per Cummins specs.
- Verify installed height/protrusion and chamfer orientation; lubricate during valve installation.
Important Intake vs. Exhaust Note
Intake guides on many 6BT applications use a longer 60.50 mm guide (e.g., Cummins 3904408). This M-3904409 is the 51.75 mm exhaust guide. Order the correct length for each valve position.
Why Buy From CPP Diesel
- Expert ESN-verified fitment support for B-Series engines
- Fast shipping, easy returns, and knowledgeable techs
- One-stop source for valves, seats, springs, seals, and full head kits
FAQ
Will this fit my 1998.5–2002 24-valve (ISB) 5.9L?No. This guide targets 12-valve 6BT (1989–1998) applications. Later 24-valve ISB heads use different guides.
Is 51.75 mm the intake or the exhaust guide?
51.75 mm is commonly the exhaust guide length. Many intake positions use a longer 60.50 mm guide (e.g., Cummins 3904408). Check your head casting and ESN.
Do I need machining after pressing the guide?
Yes. These guides are typically supplied with a semi-finished I.D. and must be reamed/honed to the valve-stem clearance after installation per the Cummins service manual.
How many exhaust guides are needed for a full 6BT head?
A 12-valve 6BT has 6 exhaust valves, so 6 exhaust guides complete the set (order intake guides separately if needed).
What other parts should I replace during a head refresh?
Consider valves, valve stem seals, seats/inserts, springs, and keepers/locks. Inspect rocker bridges and pushrods.
