CUMMINS 3902343 OEM CYLINDER HEAD ALIGNMENT DOWEL (RING DOWEL) – 5.9L/6.7L CUMMINS (1989–2018)

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The CUMMINS 3902343 OEM CYLINDER HEAD ALIGNMENT DOWEL (ring dowel) is the small but critical piece of hardware that locates your cylinder head precisely on the block, protecting head gaskets, timing geometry, and long-term reliability on your 5.9L and 6.7L B-series Cummins engines. This is a genuine Cummins ring dowel, manufactured to OE tolerances for proper press fit in the block and repeatable alignment on every teardown and rebuild. Cataloged for B-series applications and widely used on 1989–2018 5.9L/6.7L Cummins platforms, it’s the right choice when you want factory-level fit and durability instead of guessing with generic hardware.

During head installation, these dowels carry the alignment load so the fasteners can do their job clamping the gasket. Worn, missing, or improvised dowels can allow the head to “walk” on the block, leading to gasket failure, coolant/oil leaks, and accelerated valve-train and timing wear. Replacing damaged or corroded dowels with new Cummins 3902343 units is cheap insurance for any stock refresh or high-output build. Each dowel is sold individually; most B-series head installs use two dowels per cylinder head.

• Genuine Cummins 3902343 ring dowel – not a universal hardware substitute.
• Precisely locates the cylinder head on 5.9L and 6.7L Cummins B-series blocks.
• Critical for clean head-gasket crush and maintaining timing gear alignment.
• Ideal for stock rebuilds, towing workhorses, and high-boost performance applications.

FITMENT

This alignment dowel is used on a wide range of Cummins B-series cylinder head applications. Always verify by engine serial number (ESN) and service manual, especially on industrial, agricultural, and generator sets.

• Engine Family: Cummins B-Series 5.9L & 6.7L (12-valve & 24-valve)
• Typical Automotive Applications: 1989–2018 Dodge/Ram 2500 & 3500 with 5.9L / 6.7L Cummins
• Position: Presses into engine block to locate cylinder head (ring dowel type)
• Typical Quantity: 2 dowels per cylinder head (sold individually)

WHAT’S INCLUDED

• (1) Genuine Cummins 3902343 cylinder head alignment dowel (ring dowel)

RECOMMENDED CUMMINS COMPANION PARTS

Pair this head alignment dowel with other genuine Cummins hardware and sealing components during top-end or full engine refresh work:

• CUMMINS 3900068 OEM RING DOWEL (14MM) – CYLINDER HEAD / MAIN BEARING CAP – 5.9L & 6.7L – main bearing cap / head dowel for bottom-end alignment.
• CUMMINS 3949326 OEM RING DOWEL – FRONT GEAR HOUSING / CYLINDER BLOCK ALIGNMENT – ISB 5.9L/6.7L – keeps your timing gear housing accurately located.
• CUMMINS 3904483 CRANKSHAFT GEAR ALIGNMENT DOWEL PIN – 5.9L – ensures proper crank gear and timing phasing.
• CUMMINS 3804899 OEM FRONT CRANKSHAFT SEAL – RAM 5.9L/6.7L – great to replace when the front cover and head are off together.
• CUMMINS 3920706 OEM EXPANSION PLUG (TURBO DRAIN) – RAM 5.9L/6.7L – commonly serviced alongside top-end and timing-case work.

INSTALLATION NOTES

• Clean the block bores thoroughly and remove corrosion or burrs before installing new dowels.
• Lightly oil or apply a film of assembly lube to the dowel OD to resist corrosion.
• Press or tap the dowel in squarely until fully seated—do not deform the ring edge.
• Lower the cylinder head straight down onto the dowels to avoid scoring the block or dowel.
• Always follow the factory torque sequence and specs for head bolts or studs.

FAQ

Cummins 3902343 is cataloged as a B-series cylinder head alignment dowel and is widely used across 5.9L and 6.7L platforms from 1989–2018. Because Cummins mixes hardware across automotive and industrial engines, always confirm by engine serial number (ESN) and the Cummins QuickServe parts illustration before ordering.

Most B-series cylinder heads are located by two ring dowels pressed into the block. This part is sold individually, so you’ll typically order two per head. If you are unsure, count the dowels during teardown and replace any that are damaged, missing, or corroded.

While reused dowels can sometimes be serviceable, any signs of mushrooming, corrosion, or loose fit in the block bore are red flags. Because alignment is critical for head-gasket sealing and timing geometry, CPP Diesel strongly recommends replacing questionable dowels with new genuine Cummins 3902343 units during head-gasket or top-end work.

Part number 3902343 is engineered as a cylinder head alignment ring dowel. Part 3900068 is commonly used as a 14 mm ring dowel for main bearing caps and some head locations, while 3949326 is used for front gear housing and block alignment. Each part has specific dimensions and locations—always match the Cummins part number to the service manual and your ESN.

This listing is for a genuine Cummins 3902343 OEM cylinder head alignment dowel. CPP Diesel also offers aftermarket alternatives like Interstate-McBee for budget-conscious builds, but this SKU is the true OE dowel sourced from Cummins.

As a metal engine component, this dowel may be included in general Proposition 65 notices associated with diesel engine parts and vehicle service environments. Handle with standard shop practices and consult your local regulations for more information about California Proposition 65.

Specifications for cummins 3902343