Hydraulic Valve Lifter Assembly

NOTE: Before replacing lifter for noisy operation, ensure noise is not caused by improper collapsed lifter gap, worn rocker arms, push rods or valve tips. If lifter assembly is stuck in bore, use lifter puller or magnet.

Hydraulic lifter assemblies must be installed in original locations. Remove valve cover and intake manifold. Loosen rocker arm and rotate for clearance from push rod. Remove push rod and, using Hydraulic Lifter Puller (BT-6407 or J-3049) or magnet, remove lifters.
Clean and inspect but DO NOT mix components or positions. Parts are select-fitted and not interchangeable. If lifter is sticking, disassemble and clean dirt, metal chips or varnish from components. If lifter check valve is not functional, obstructions may prevent it from closing when cam lobe is moving lifter or check valve spring may be broken. See Fig 1.

Fig 1: Exploded View of Hydraulic Lifter Assembly
Clean or replace components as necessary. If plunger is not free in body of lifter, replace entire assembly. Plunger should drop to bottom of body by its own weight when assembled dry. Assemble lifter and check free operation by pressing down on cap.
NOTE: Camshaft lobes are ground, hardened and tapered with high side of lobe toward rear of engine. This causes lifters to rotate.
Inspect lifter base-to-cam lobe contact area. Surface must have smooth and convex contact face. Replace any lifter with flat or concave surface. Inspect related cam lobe for proper lobe lift. Replace camshaft (and lifters) if any lobe is worn beyond specification.
Check lifter-to-bore clearance. Standard clearance is .0005-.0020" (.013-.051 mm). Standard diameter of lifter is .8422-.8427" (21.392-21.405 mm). Standard lifter bore diameter is .8435-.8445" (21.425-21.450 mm).
NOTE: When performing leak-down test, lifters cannot be checked with engine oil, only test fluid. New lifters already contain test fluid. If new lifter is installed, remove sealer coating from inside and check leak-down rate. If old lifter is disassembled and cleaned, fill with test fluid before installing and testing.
Place lifter upright in Hydraulic Lifter Leak-Down Tester (J-5790). Check leak-down rate. Leak-down rate is 12-90 seconds measured at .0938" (2.38 mm) plunger travel, under 50 lb. (23 kg) load.
Coat lifter base with Molykote. When installing, ensure lifter is on base circle of camshaft. Tighten rocker arm bolt to specification. Coat gasket surfaces with RTV sealer. Install valve covers and intake manifold.