Product Description
Interstate-McBee M-3800781 Piston Kit (Standard) – 98.5–02 5.9L Cummins Standard Output
OEM-style standard bore piston kit engineered for the 1998.5–2002 5.9L Cummins 24-Valve (Standard Output). Designed for stock rebuilds with precise fit, durable ring pack sealing, and reliable daily-duty performance.
- Direct-fit, standard bore (STD): Matches OE spec for 24V ISB SO applications.
- Complete kit per cylinder: Piston, ring set, wrist pin, and circlips.
- Sold individually: Order six (6) kits for a full engine set.
- Aftermarket value: Interstate-McBee quality at a fraction of OEM pricing.
Specifications
| Manufacturer | Interstate-McBee |
|---|---|
| Interstate-McBee P/N | M-3800781 (Standard Bore) |
| OEM Cross-Reference | Cummins 3800781 |
| Includes | Piston, rings, wrist pin, circlips (per cylinder) |
| Quantity Required | 6 (six) for a complete engine set |
| Oversize Options | M-3800784 (.020" over), M-3800785 (.040" over) |
| Condition | New, aftermarket replacement |
| Fitment Type | Standard Output (SO) 24-Valve only |
Vehicle Fitment
Always verify with your engine serial number (ESN) for exact fit.
- Dodge Ram 2500/3500 – 5.9L Cummins 24-Valve (ISB), Standard Output:
- 1998.5, 1999, 2000, 2001, 2002 (SO applications)
- Not typically for High Output (HO 245HP/NV5600) unless ESN verification confirms the same piston spec.
Installation Notes
- Measure cylinder bore, taper, and out-of-round; hone as required and set ring end gaps to spec.
- Confirm piston-to-wall clearances and orientation (markings toward front).
- Lubricate pins/rings during assembly; follow Cummins torque specs and sequences.
- Break-in with conventional oil per builder guidelines; monitor blow-by and oil consumption.
Warranty
Interstate-McBee new engine components carry manufacturer warranty coverage. For exact terms on piston kits, please contact us with your ESN and order details.
Why Buy From CPP Diesel
- ESN-verified fitment help from real diesel techs.
- Fast shipping, easy returns, and competitive pricing.
- Deep inventory of 5.9L Cummins rebuild components for one-stop checkout.
FAQ
Is this the correct piston for my 1999 5.9L Cummins?If your truck is a Standard Output (SO) 24-Valve (1998.5–2002), this STD kit is the OE-style match. For HO models (e.g., 245HP/NV5600), verify by ESN before ordering.
What exactly is included in each kit?
Each cylinder kit includes piston, ring set, wrist pin, and circlips. For a full engine, purchase six kits.
Are the rings pre-gapped?
No—rings must be checked and filed to specification after honing. Always confirm end gaps per the service manual.
Do you offer oversize pistons?
Yes. Interstate-McBee offers oversizes such as .020" (M-3800784) and .040" (M-3800785). Choose based on your machine shop measurements.
How many do I need?
The 5.9L Cummins is a 6-cylinder; you will need six (6) kits for a full set.
Product Videos
Custom Field
YEAR 1998.5-2002
MAKE DODGE
ENGINE 5.9L
