CAT 325-6224 TRUNNION-BL-GD

CAT 325-6224 YM (3256224) is a Caterpillar engine valve lifter assembly (roller type), compatible with the valve train of C4.4/C6.6 engines, etc. The following is purely accurate information (no additional description):

Core Parameters and Information

Item Details
Part Model: CAT 325-6224 YM Taper Assembly (Valve Lifter GP, Roller Type)

Part Type: Roller type valve lifter, located between the camshaft and rocker arm, including lifter body, roller, roller pin, locating pin, and return spring, transmitting camshaft movement to drive valve opening and closing.

Material: Taper body is ductile iron (QT600-3, HB 220–260), roller is bearing steel (GCr15, HRC 60–64), roller pin is carburized steel (20CrMnTi), return spring is spring steel (60Si2MnA)

Key Dimensions: Taper diameter 28.00 mm (1.102 in), roller diameter 32.00 mm (1.260 in), total height 65.00 mm (2.559 in), roller width 14.00 mm (0.551 in), return spring wire diameter 3.0 mm, free height 38.0 mm

Structural Features: Roller makes rolling contact with the cam surface, reducing friction and wear; built-in return spring ensures continuous contact between the tappet and cam; anti-rotation with locating pin, suitable for precise transmission in the valve train.

Compatible Structures: Compatible with engine cylinder head tappet guides, camshaft cams, and valve rocker arms; used in the intake/exhaust valve drive parts of C4.4/C6.6 engines.

Applicable Operating Conditions: Medium to high speed, medium load; suitable for engine compartment operating environments with dust, vibration, and temperature fluctuations.

Compatible Models:
CAT 416E/420E backhoe loaders (C4.4 engine valve train)
CAT 908H/909H Wheel Loader (C4.4 Engine Valve Drive End)

CAT 312D2/313D2 Excavator (C4.4 Engine Cylinder Head Valve Mechanism)

CAT 259D/279D Compact Tracked Loader (C3.8 Engine Valve Tappet Area)

Installation and Fitting Points:
The tappet and guide are clearance-fitted (0.020–0.040 mm), and the roller and camshaft cam contact clearance is 0.05–0.10 mm to ensure smooth, unobstructed movement.

Use a special tool for vertical press-fitting. Do not strike the roller or tappet body. After installation, check the return spring preload to 120–150 N to ensure rapid tappet return.

Before installation, clean the tappet, guide, and camshaft. Check for damage to the roller, deformation of the return spring, and loosening of the locating pin.

Axial positioning is achieved via cylinder head guides, while radial unconstraint ensures free thermal expansion and contraction. Post-installation inspection: valve clearance conforms to the engine manual (intake valve 0.25 mm, exhaust valve 0.30 mm), and there are no abnormal noises during operation.

As per the engine manual, valve clearance should be checked every 1000 operating hours, and the tappet assembly adjusted or replaced as needed.