Exhaust valve guide 02/102189 Perkins AB, genuine

Exhaust valve guide 02/102189 is a genuine JCB part for the Perkins 1004 (AB) engine. The card also lists 02/100634, 3343J021, 905-126.

The valve guide is a bush pressed into the cylinder head; it centres the valve stem and makes the valve seat squarely. A worn guide lets the valve wobble and seat at an angle, so compression drops; oil also passes between stem and guide into the combustion chamber and the engine smokes blue. Guides are always measured when valves are replaced. The clearance between guide and stem must not be too small, or the hot valve can stick. If it is too large, the valve does not centre in its seat and starts to burn at the edge. The guide is made of cast iron or a bronze-based alloy, chosen for its wear properties.

Specifications

Compatibility

The part is listed for JCB backhoe loaders with Perkins engines. Inlet side: inlet valve guide 02/201649. Other parts are in Perkins engine.

Fitting

Guides are usually replaced as a set together with valves and stem seals. After assembly, adjust the valves and watch for smoke on first start. Check the guide height against the service manual figure.