Product Description
Cummins 3931623 — Genuine Valve Tappet (Lifter) for 5.9L 6BT & 3.9L 4BT
MPN: 3931623 | Also Known As: valve lifter, cam follower, tappet | Supersedes / Cross-Refs (ID): 3901787, 3907240, 3925031
Genuine Cummins flat tappet engineered for the B-Series mechanical-injection era. Direct-fit on 5.9L 6BT (12-valve) and 3.9L 4BT platforms. Sold individually; order the correct quantity for your engine (12 for 6BT, 8 for 4BT).
Features & Benefits
- OE geometry & hardening to protect cam lobes and ensure quiet operation.
- Direct-fit replacement for 1989–1998 5.9L 12-valve (VE & P7100) and common 4BT builds.
- Durable, consistent metallurgy for long service life on stock and work applications.
- Ideal when installing a new cam or refreshing a high-mileage valvetrain.
- Backed by Cummins quality for fit, function, and reliability.
Verified Fitment (Automotive)
| Year Range | Engine | Chassis |
|---|---|---|
| 1989–1993 | 5.9L 12V (VE pump) | Ram 2500/3500 |
| 1994–1998 | 5.9L 12V (P7100) | Ram 2500/3500 |
Industrial/Off-Highway: 3.9L 4BT, 5.9L 6BT, and seen on some 8.3L C-Series/ISC/QSC builds—verify by ESN prior to ordering.
Compatibility Notes:
- Not for 1998.5–2002 24-valve (VP44) or 2003+ common-rail; those typically use different tappets (e.g., 3942565/3947759).
- When installing a new camshaft, replace all tappets as a set to ensure even break-in.
Specifications
- Type: Mechanical flat tappet (valve lifter), cam follower
- OE Part Number: 3931623
- Supersedes / Cross-Refs (ID): 3901787, 3907240, 3925031
- Quantity Required: 12 per 6BT engine; 8 per 4BT engine (sold individually)
Often Paired With
- Camshaft (OE or performance) — replace tappets any time a new cam is installed
- Pushrods & rockers — inspect/replace if bent or worn
- Tappet cover gasket / grommets — replace seals during service
What’s In The Box
- (1) Genuine Cummins Valve Tappet (3931623)
Installation Tips
- Inspect cam lobes for wear; do not reuse worn tappets on a new cam.
- Pre-lube tappet faces and cam lobes; follow Cummins torque & lash procedures.
- Set valve lash to factory spec after assembly and re-check after initial heat cycle.
FAQ
WILL THIS FIT MY 1989–1998 12-VALVE RAM?
Yes—direct-fit for 5.9L 12V (VE ’89–’93 and P7100 ’94–’98) Ram 2500/3500 applications.
HOW MANY DO I NEED?
Order 12 for a complete 6BT engine, or 8 for a 4BT engine. Sold individually.
DOES THIS FIT 24-VALVE OR COMMON-RAIL ENGINES?
No—1998.5–2002 24V (VP44) and 2003+ common-rail engines use different tappets. Check your VIN/ESN for the correct part number.
IS THIS A GENUINE CUMMINS PART?
Yes—OE Cummins 3931623 with factory geometry and surface hardening.
WHAT ARE THE COMMON CROSS-REFERENCES?
Common legacy identifiers include 3901787, 3907240, and 3925031. Use ESN to confirm interchange.
